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NBME 24 Answers

Block 1/Question#1
A researcher hypothesizes that exposure to more than 50 μg/L ...
Case-control study

Block 1/Question#2
A 43-year-old woman with a 2-year history of labile ...
Unopposed α-adrenergic tone

Block 1/Question#3
A 52-year-old woman comes to the physician because of severe ...
Intercostal

Block 1/Question#4
A 28-year-old man with AIDS has fever, headache, and ...
Lungs

Block 1/Question#5
The 35-year-old woman indicated by the arrow has a family ...
X-linked recessive

Block 1/Question#6
A 57-year-old woman requires intubation in the intensive care ...
Acute lung injury

Block 1/Question#7
A 65-year-old woman comes to the physician because of blood ...
Cigarette smoking

Block 1/Question#8
A 24-year-old woman at 28 weeks' gestation is brought to the ...
Tremor

Block 1/Question#9
The graph shows expiratory pressure-volume curves that ...
Diffuse pulmonary fibrosis

Block 1/Question#10
A 75-year-old man is brought unconscious to the emergency ...
Atherosclerosis

Block 1/Question#11
A 55-year-old man with type 1 diabetes mellitus comes to the ...
Persistent activation of voltage-gated Na+ channels in the nociceptor

Block 1/Question#12
A 26-year-old man comes to the physician for a follow-up ...
Increased number of LDL receptors on hepatocytes

Block 1/Question#13
A 4-year-old boy is brought to the emergency department by ...
Proliferative glomerulonephritis

Block 1/Question#14
A thin 66-year-old man is brought to the emergency department ...
Urine osmolality > plasma osmolality

Block 1/Question#15
Results of a 5-year screening program for HIV infection in a ...
5%

Block 1/Question#16
A 32-year-old man is brought to the emergency department ...
Flexion at the distal interphalangeal joint

Block 1/Question#17
A 3-year-old boy is brought to the emergency department ...
Annular pancreas

Block 1/Question#18
A 34-year-old woman with a long history of rheumatoid ...
Tuberculous osteomyelitis

Block 1/Question#19
A 35-year-old man comes to the physician because of a 1-week ...
Cluster headache

Block 1/Question#20
Immediately after a spontaneous vaginal delivery, a full-term ...
Fusion of the sclerotomes

Block 1/Question#21
A 35-year-old woman comes to the physician because of a ...
Foramen cecum

Block 1/Question#22
A 50-year-old man undergoes surgical transection of the ...
Adductor brevis

Block 1/Question#23
A 50-year-old man comes to the physician because of diarrhea ...
Generalized malabsorption

Block 1/Question#24
A 6-year-old girl is brought to the office by her mother ...
Pediculus humanus capitis

Block 1/Question#25
A 7-year-old boy has metabolic acidosis and persistent ...
Area labeled ‘B’ (Proximal convoluted tubule)

Block 1/Question#26
An 80-year-old woman with poorly controlled type 2 diabetes ...
Hematocrit: decreased;
Serum parathyroid hormone: increased;
Serum calcitriol: decreased


Block 1/Question#27
A 10-year-old girl with a lifelong history of intermittent ...
Palpable right ventricular lift

Block 1/Question#28
A 32-year-old woman comes to the physician because of a 7-day ...
Eosinophils

Block 1/Question#29
An 80-year-old woman comes to the physician because of a ...
Determination of erythrocyte sedimentation rate

Block 1/Question#30
A 55-year-old man is brought to the emergency department ...
Pulmonary capillary wedge pressure: increased;
Cardiac output: decreased;
Systemic vascular resistance: increased


Block 1/Question#31
An experimental study is conducted to examine the function of ...
Post-translational modification

Block 1/Question#32
A 24-year-old man receives an injection of histamine in the ...
Increased lymph flow

Block 1/Question#33
A 3-month-old girl is brought to the emergency department by ...
Human papillomavirus

Block 1/Question#34
A 62-year-old man comes to the physician for a follow-up ...
Sotalol

Block 1/Question#35
A 1616-g (3-lb 9-oz) male newborn is delivered to a ...
Bronchopulmonary dysplasia

Block 1/Question#36
A 4-year-old girl is brought to the physician because of a ...
Villous atrophy

Block 1/Question#37
A 25-year-old woman at 16 weeks' gestation comes to the ...
Increased hepatic production of T4-binding globulin

Block 1/Question#38
A 37-year-old woman comes to the physician because of nausea ...
Borderline

Block 1/Question#39
A 40-year-old man with AIDS develops severe diarrhea that is ...
Somatostatin

Block 1/Question#40
A 26-year-old man and his 25-year-old wife come to the ...
One in four will have 25% β-globin function and may require occasional transfusions

Block 1/Question#41
A 32-year-old woman who is 20 weeks' pregnant has had ...
Misoprostol

Block 1/Question#42
A 68-year-old woman with acute myelogenous leukemia begins ...
Granulocyte-macrophage colony-stimulating factor

Block 1/Question#43
After completing 6 courses of chemotherapy for cancer of the ...
Doxorubicin

Block 1/Question#44
A 24-year-old man is brought to the office because of fever ...
Alteration in DNA gyrase

Block 1/Question#45
A 71-year-old man is brought to the emergency department ...
Area labeled ‘D’ (Posterior inferior cerebellar artery)

Block 1/Question#46
A 10-year-old girl is scheduled to undergo fixation of a ...
Succinylcholine

Block 1/Question#47
A 35-year-old man comes to the physician 1 week after he had ...
Increased serum angiotensin II concentration

Block 1/Question#48
A 70-year-old man is brought to the emergency department ...
Stroke volume: decreased;
Left ventricular end-diastolic volume: increased;
Cardiac output: decreased


Block 1/Question#49
A 58-year-old man is brought to the emergency department 1 ...
Ruptured spleen

Block 1/Question#50
An 11-year-old boy is brought to the emergency department by ...
Intracellular and extracellular dehydration

Block 2/Question#1
A 73-year-old woman has had easy fatigability for 2 years. ...
Failure of conversion of N5-methyltetrahydrofolate to tetrahydrofolate

Block 2/Question#2
A 45-year-old man comes to the physician because of ...
Oxygen saturation

Block 2/Question#3
A 13-year-old boy is brought to the physician by his mother ...
This will typically resolve within the next 12 to 18 months.

Block 2/Question#4
A 57-year-old man has had hoarseness and difficulty ...
Area labeled ‘F’

Block 2/Question#5
A 55-year-old man is diagnosed with coronary artery disease. ...
Decreased adherence

Block 2/Question#6
A 50-year-old woman is admitted to the hospital for ...
Factitious disorder

Block 2/Question#7
A 75-year-old man with a 10-year history of progressive renal ...
Hydrostatic pressure in Bowman space

Block 2/Question#8
A 17-year-old girl is brought to the hospital by ambulance 45 ...
Beneficence

Block 2/Question#9
In which of the following stages of the cell cycle are ...
G2

Block 2/Question#10
A 29-year-old man is brought to the emergency department ...
Lateral pterygoid

Block 2/Question#11
A public health consultant is contacted by a health ...
Regular exercise

Block 2/Question#12
An 80-year-old man is admitted to the hospital because of a ...
20

Block 2/Question#13
An 80-year-old woman, gravida 4, para 4, comes to the office ...
Damage to the rectovaginal septum

Block 2/Question#14
A 25-year-old man comes to the emergency department because ...
Heroin

Block 2/Question#15
An investigator is studying a new drug for the treatment of ...
Free radical formation

Block 2/Question#16
A 28-year-old man with chronic hepatitis C comes to the ...
HIV

Block 2/Question#17
A 68-year-old man comes to the physician because he is ...
Normal aging

Block 2/Question#18
A 68-year-old man has loss of pain and temperature sensations ...
Right dorsolateral medulla

Block 2/Question#19
A 70-year-old man comes to the physician because of a 1-year ...
Alveolar-arterial Po 2 difference

Block 2/Question#20
A 52-year-old man is admitted to the hospital for treatment ...
Granulation tissue

Block 2/Question#21
A 50-year-old woman with HIV infection comes to the physician ...
Zidovudine

Block 2/Question#22
A 3-month-old boy is brought to the physician because of ...
Peroxisomes

Block 2/Question#23
A 9-year-old boy who was adopted from an African country 2 ...
E

Block 2/Question#24
A 59-year-old man has repeated episodes of gouty arthritis ...
Probenecid

Block 2/Question#25
A 35-year-old African American man comes to the physician for ...
Palms

Block 2/Question#26
A 35-year-old man is brought to the emergency department ...
Catecholamine-mediated intracellular shifts of K+

Block 2/Question#27
A 47-year-old man comes to the physician because of recurrent ...
Monosodium urate

Block 2/Question#28
A 3-year-old boy with AIDS develops giant cell pneumonia 3 ...
Negative-stranded RNA

Block 2/Question#29
A 65-year-old woman with well-controlled type 2 diabetes ...
Atherosclerosis

Block 2/Question#30
A 35-year-old man with small cell carcinoma of the lung has ...
ACTH

Block 2/Question#31
A patient with cancer who is being treated with high-dose ...
Granulocyte colony-stimulating factor

Block 2/Question#32
A 35-year-old woman undergoes a left oophorectomy because of ...
Ureter

Block 2/Question#33
A 58-year-old man comes to the physician because of a 3-day ...
Escherichia coli

Block 2/Question#34
A 40-year-old man who goes horseback riding 3 to 4 times ...
Myositis ossificans

Block 2/Question#35
A 55-year-old woman comes to the physician because of a ...
Lower motoneurons

Block 2/Question#36
A 27-year-old woman comes to the physician for a follow-up ...
Transforming growth factor-β

Block 2/Question#37
In a culture of motile spore-forming bacteria, which of the ...
Irradiation with x-rays

Block 2/Question#38
A 65-year-old man comes to the physician because of ...
Paroxetine

Block 2/Question#39
A 3-year-old boy has short stature and extremities and a ...
Endochondral ossification

Block 2/Question#40
A 4-year-old boy has a 1-cm round midline mass just inferior ...
Tongue

Block 2/Question#41
A 56-year-old man who is admitted to the hospital for ...
Determine whether the patient has decision-making capacity

Block 2/Question#42
A 3-week-old female newborn is brought to the physician for a ...
The patient has another mutation that was not included in the previous analysis

Block 2/Question#43
A 35-year-old woman has difficulty urinating 2 days post ...
Parasympathomimetic stimulation

Block 2/Question#44
A 35-year-old man with quadriplegia develops a urinary tract ...
Area labeled ‘B’ (Proximal convoluted tubule)

Block 2/Question#45
A 2-year-old boy is brought to the physician because of ...
Peptide transporter (TAP)

Block 2/Question#46
In a study of drug action on neoplastic cells in culture, ...
Vincristine

Block 2/Question#47
A 73-year-old man has an incurable malignant neoplasm of the ...
Both legal and ethical

Block 2/Question#48
The breakdown of dipeptides and tripeptides to free amino ...
Intestinal mucosa

Block 2/Question#49
A 17-year-old girl comes to the physician because she has ...
Increased serum testosterone concentration

Block 2/Question#50
An obese 57-year-old man comes to the physician for a routine ...
Normal ciliated columnar epithelium replaced by normal squamous epithelium

Block 3/Question#1
A 3-year-old girl has a history of recurrent infections. In ...
NADPH oxidase

Block 3/Question#2
A 28-year-old man has a blood pressure cuff placed around his ...
Adenosine

Block 3/Question#3
A 37-year-old woman with HIV infection is brought to the ...
Nucleoside reverse transcriptase inhibitor

Block 3/Question#4
A 27-year-old man comes to the physician because he and his ...
Injections of gonadotropins

Block 3/Question#5
A 37-year-old man is admitted to the hospital because of ...
Autoimmune adrenalitis

Block 3/Question#6
A 43-year-old woman comes to the physician because of a ...
Alkaline phosphatase

Block 3/Question#7
A 21-year-old woman with asthma comes to the physician ...
Phase 3

Block 3/Question#8
A 37-year-old man who is a farmworker comes to the emergency ...
Synaptobrevin

Block 3/Question#9
A 43-year-old woman comes to the physician because of a ...
Metastatic carcinoma

Block 3/Question#10
Serum cholesterol concentrations are measured as part of a ...
16%

Block 3/Question#11
The pedigrees of patients with schizophrenia most closely ...
Diabetes mellitus, type 1

Block 3/Question#12
A 35-year-old woman with asthma comes to the emergency ...
Thiabendazole

Block 3/Question#13
An 83-year-old woman is brought to the physician by her ...
Discussion of the diagnosis with the patient privately

Block 3/Question#14
A cohort study is done to evaluate the association between ...
0.05 < p < 1.0

Block 3/Question#15
A 17-year-old girl has significant blood loss after being ...
δ-Aminolevulinate

Block 3/Question#16
An 18-year-old woman is brought to the physician because of ...
Respiratory acidosis

Block 3/Question#17
HOX genes play a role in embryogenesis through which of the ...
Regulation of transcription

Block 3/Question#18
A 55-year-old man with alcoholism is brought to the emergency ...
Competitive inhibitor

Block 3/Question#19
A 23-year-old primigravid woman at 22 weeks' gestation is ...
Ask the patient if she would allow the examination if her husband is present at all times

Block 3/Question#20
A 33-year-old woman comes to the physician because of a ...
Defect in a cell membrane anchor protein

Block 3/Question#21
A 7-year-old girl is brought to the emergency department (ED) ...
Factitious disorder imposed on another

Block 3/Question#22
A 32-year-old woman recently diagnosed with AIDS is at ...
Epstein-Barr virus-induced brain lymphoma

Block 3/Question#23
A 32-year-old woman comes to the physician because of pain ...
Buccinator

Block 3/Question#24
A 3-month-old boy is brought to the emergency department ...
Gluconeogenesis

Block 3/Question#25
An investigator is studying a new virus isolated from a ...
Coronavirus

Block 3/Question#26
A 54-year-old man with a myocardial infarction becomes ...
Decrease in intracellular ATP concentrations

Block 3/Question#27
A 27-year-old man who works from home as a software engineer ...
Avoidant

Block 3/Question#28
A 22-year-old man is brought to the emergency department 30 ...
Area labeled ‘E’ (Cerebellum, posterior lobe)

Block 3/Question#29
Drug X is given to a 25-year-old normal subject. This drug ...
Partial agonist at β-adrenergic receptors

Block 3/Question#30
A 38-year-old woman comes to the physician because of ...
Intraductal papilloma

Block 3/Question#31
A 65-year-old man is brought to the emergency department 30 ...
Systemic vascular resistance: increased;
Pulmonary vascular resistance: decreased;
Pulmonary capillary wedge pressure: increased


Block 3/Question#32
A 15-year-old girl is brought to the physician because of a ...
CD8+ T lymphocytes

Block 3/Question#33
A 12-year-old boy is brought to the physician by his mother ...
Nocturnal luteinizing hormone pulses

Block 3/Question#34
An otherwise healthy 35-year-old man sustains a fracture of ...
Decreased blood volume

Block 3/Question#35
A 4-year-old girl has a history of multiple bone fractures ...
Scar formation

Block 3/Question#36
A 1-month-old male newborn is brought to the physician for a ...
Tyrosine

Block 3/Question#37
A man accidentally touches the surface of a hot stove; 20 ...
Interendothelial gaps in venules

Block 3/Question#38
A 55-year-old man comes to the physician because of a 2-week ...
Serum free thyroxine (FT4): increased;
Serum free triiodothyronine (FT3): increased;
Thyroidal iodine uptake: decreased


Block 3/Question#39
A 34-year-old woman is brought to the emergency department 45 ...
Lunate

Block 3/Question#40
A 2-year-old boy is brought to the emergency department ...
Polysaccharide protein conjugate vaccine

Block 3/Question#41
A 30-year-old man develops tingling around the lips and mouth ...
Sodium

Block 3/Question#42
Which of the following terms best describes the fibrous ...
Lamins

Block 3/Question#43
A 35-year-old woman with a long-standing history of asthma ...
Infiltration of lymphocytes and monocytes

Block 3/Question#44
A 62-year-old man comes to the physician for a follow-up ...
Serum gastrin

Block 3/Question#45
A 59-year-old woman has a 10-year history of progressive ...
Neural crest cells

Block 3/Question#46
A 15-year-old girl with cystic fibrosis has a mutation in the ...
Endoplasmic reticulum

Block 3/Question#47
A 22-year-old woman comes to the physician for a follow-up ...
Intrauterine device

Block 3/Question#48
A 62-year-old man comes to the physician because of a 2-month ...
Phantom limb pain

Block 3/Question#49
A 20-year-old woman with asthma comes to the physician ...
Ask the roommate not to smoke in the apartment

Block 3/Question#50
A group of physicians submits a report to a medical journal ...
Case series

Block 4/Question#1
A 30-year-old woman comes to the physician for follow-up ...
Glycine and succinyl CoA

Block 4/Question#2
A full-term male newborn has lethargy, poor feeding, and ...
Enzymatic reaction labeled ‘C’

Block 4/Question#3
A 23-year-old woman is brought to the emergency department ...
Renal tubular acidosis

Block 4/Question#4
A 63-year-old woman develops flank pain, tachycardia, and ...
ABO incompatibility

Block 4/Question#5
A 45-year-old man comes to the physician because of a 3-day ...
Muscle biopsy

Block 4/Question#6
A 68-year-old woman comes to the physician because of a ...
Inferior mesenteric and superior mesenteric

Block 4/Question#7
A 3-year-old girl is brought to the physician for a ...
Spontaneous regression

Block 4/Question#8
A 1-week-old newborn is brought to the physician because of ...
Organic acid metabolism disorder

Block 4/Question#9
A 10-year-old boy who was adopted from the Democratic ...
Black fly

Block 4/Question#10
A 60-year-old woman is receiving cisplatin therapy for ...
Hyporeflexia

Block 4/Question#11
A 53-year-old woman comes to the physician because of a ...
Fixed cardiac output in spite of increased demand

Block 4/Question#12
A 25-year-old woman takes an overdose of barbiturates and is ...
Extubate the patient and discontinue mechanical ventilation; make no attempt to do cardiopulmonary resuscitation in case of cardiac or respiratory failure

Block 4/Question#13
A 90-year-old man has a 1-week history of constipation and ...
Incarcerated inguinal hernia

Block 4/Question#14
A new screening test for colon cancer is done in 86 patients ...
118/124 = 95%

Block 4/Question#15
A 15-month-old boy is brought to the physician by his mother ...
Migration

Block 4/Question#16
A 24-year-old woman who has diffuse toxic goiter (Graves ...
Phosphate: increased;
Parathyroid hormone: decreased;
25-hydroxyvitamin D: normal


Block 4/Question#17
A 63-year-old woman undergoes operative repair of a leaking ...
Decreased movement through the arachnoid villi

Block 4/Question#18
A 64-year-old man undergoes surgical repair of an abdominal ...
Artery of the ductus deferens

Block 4/Question#19
A 38-year-old woman, gravida 4, para 4, comes to the ...
Internal anal sphincter

Block 4/Question#20
Forty of 100 attendees at a company Christmas party develop ...
Vibrio parahaemolyticus

Block 4/Question#21
An otherwise healthy 45-year-old man comes to the office ...
Aphthous ulcers

Block 4/Question#22
A 45-year-old man is brought to the emergency department 2 ...
Renal calculi in the left ureter

Block 4/Question#23
At 2:00 am, after sleeping for 5 hours, a 32-year-old man ...
Phenylethanolamine N-methyltransferase

Block 4/Question#24
A 13-year-old girl who has a 6-year history of type 1 ...
Discuss further the impact of the patient's illness on the family

Block 4/Question#25
A 26-year-old man is brought to the emergency department 40 ...
Pericardial tamponade

Block 4/Question#26
A 10-year-old girl is brought to the physician by her mother ...
Ovarian Sertoli-Leydig cells

Block 4/Question#27
A 19-year-old man has had weakness of the muscles of his neck ...
Polyneuropathy

Block 4/Question#28
A clinical study is designed to evaluate the association of ...
10%

Block 4/Question#29
A 56-year-old man has a 3-year history of progressive memory ...
Presenilin

Block 4/Question#30
An investigator is studying an outbreak of Escherichia coli ...
Only cookies are independently associated with E. coli cases

Block 4/Question#31
In a study of antibiotic resistance, a strain of Escherichia ...
Conjugation

Block 4/Question#32
A 45-year-old man with hypercholesterolemia (LDL 260 mg/dL) ...
Increased synthesis of LDL receptors

Block 4/Question#33
A 12-year-old boy is brought to the physician by his mother ...
Inhalant abuse

Block 4/Question#34
A 55-year-old woman comes to the physician for a routine ...
Neuroendocrine cell

Block 4/Question#35
An investigator is conducting a study of a novel protein in ...
Basal keratinocyte:suprabasal keratinocyte

Block 4/Question#36
A 68-year-old woman comes to the emergency department 2 hours ...
Alendronate

Block 4/Question#37
A male newborn is delivered in the hospital at 40 weeks' ...
Ingestion of undercooked meat

Block 4/Question#38
A 33-year-old woman at 34 weeks' gestation has a grade 2/6 ...
Stroke volume

Block 4/Question#39
A 30-year-old woman comes to the physician because of a ...
Decreased afferent arteriolar resistance

Block 4/Question#40
A 25-year-old woman is brought to the emergency department by ...
Pulmonary capillary leakage

Block 4/Question#41
A 30-year-old man who is a migrant farm worker comes to the ...
Formation of hypnozoites

Block 4/Question#42
A 40-year-old man who recently immigrated to the USA from ...
Adenine

Block 4/Question#43
A 72-year-old woman with coronary artery disease comes to the ...
Neointima formation in the right coronary stent

Block 4/Question#44
A 71-year-old woman with non-Hodgkin lymphoma is diagnosed ...
Leucovorin

Block 4/Question#45
A 40-year-old woman with a 25-year history of type 1 diabetes ...
Secreted by the proximal tubule

Block 4/Question#46
A 22-year-old woman comes to the physician because of nausea ...
Pineal gland

Block 4/Question#47
A 40-year-old man comes to the physician because of a 6-month ...
HNPCC syndrome

Block 4/Question#48
A 55-year-old woman is brought to the physician by her ...
Posterior cerebral

Block 4/Question#49
A 27-year-old man sustains a spinal cord transection at C-8 ...
Penile stimulation

Block 4/Question#50
A 47-year-old man comes to the physician because of abdominal ...
Superior rectal vein

Recent comments ...

... lsmarshall made a comment on nbme24/block1/q#1 (A researcher hypothesizes that exposure to more than...)
 +8  upvote downvote
submitted by lsmarshall(181)

An experimental design or experimental study must have an intervention, by definition. Case-control studies are observational studies, not experimental. This question is technically incorrect. They wanted to amke a point that case-control studies are time and cost efficient since they don't require following patients over time or any resources besides reviewing/gathering information. Case series could not test this hypothesis.

Also, the wording "associated wit an increased risk" somewhat alludes to case-control studies only having the ability to find odds of an associations between exposure and outcome, but not establish causal relationship.

bigjimbo  classic nbme
... catch-22 made a comment on nbme24/block1/q#1 (A researcher hypothesizes that exposure to more than...)
 +2  upvote downvote
submitted by catch-22(14)

I woud do a retrospective cohort here. I don't think this question is correct and provides too little information to get the correct answer. "Time efficient" is the operant word here but they simply didn't consider that retrospective cohort would be a better design here as long as the variables are coded.

sherry  I agree. I was hesitating between the two choices. I still think cohort study is better regarding the "risk". I hope this kind of questions wont pop out on the real thing.
soph  I think key here was they were measuring risk though
yex  I also chose cohort, since it is comparing a given exposure.
... soph made a comment on nbme24/block1/q#1 (A researcher hypothesizes that exposure to more than...)
 +0  upvote downvote
submitted by soph(9)

I think key here is they are investigating the hypothesis of ammount of arsenicin water increases RISK of cancer.... best way to measure risk is case control.

nbmehelp  If they were measuring risk shouldn't it be a cohort study though? By looking at first aid..
... dentist made a comment on nbme24/block1/q#1 (A researcher hypothesizes that exposure to more than...)
 +0  upvote downvote
submitted by dentist(1)

pretty good summary

drdoom  welcome, O great physician of the skull and oral cavity. we revere your intricate understandings of the face, jaw, maxilla and all their tiny and hidden foramina. teach us your ways.
... xxabi made a comment on nbme24/block1/q#2 (A 43-year-old woman with a 2-year history of labile...)
 +1  upvote downvote
submitted by xxabi(82)

Starting beta blockers before alpha blockade in pheochromocytoma is contraindicated. Beta blockers cancel out the vasodilatory effect of peripheral beta-2 adrenoceptors, potentially leading to unopposed alpha-adrenoceptor stimulation → vasoconstriction → hypertensive crisis.

... lsmarshall made a comment on nbme24/block1/q#3 (A 52-year-old woman comes to the physician because...)
 +9  upvote downvote
submitted by lsmarshall(181)

The most direct path, and most likely path, for breast cancer to metastasize to the vertebra are the intercostal veins. This was on an earlier NBME test as well. Breast cancer will cause mixed, lytic and blastic lesions once in bone.

On an unrealated note; I finally came up with a decent way to remember lytic vs. blastic cancers in bone!

kIdneY and thYroId cause lYtIc

prostate > blastate > blastic

Two breasts > two types of lesions > B reast causes B oth

Two lungs > two types of lesions (depending on type of lung cancer)

small-cell lung > "small blasts"

non-small cell > lytic

artist90  VEINS: 1-Intercostal veins drain into Azygous vein which drains into SVC BUT some blood from this Azygous vein is also draining into BATSONS VERTEBRAL VENOUS PLEXUS how the breast cancer metastasizes to vertebral column. 2-Internal thoracic(mammary) vein drains directly into Brachiocephalic vein. 3-Lateral thoracic vein drains into Axillary vein which drains into Subclavian vein which drains into Brachiocephalic vein. ARTERIES ARE DIFFERENT: Subclavian artery----branches into---Internal thoracic(mammary) artery---Intercostal arteries. Internal thoracic artey is used for CABG if there is 1 vessel block.
... zbird made a comment on nbme24/block1/q#3 (A 52-year-old woman comes to the physician because...)
 +1  upvote downvote
submitted by zbird(2)

@lsmarshall Thanks for sharing BCa met via venous routes spreading through the batson plexus which is a network of veins receiving from azygos vein. The azygos receiving from intercostal veins that drains the breast. Which makes intercostal right

... yex made a comment on nbme24/block1/q#3 (A 52-year-old woman comes to the physician because...)
 +0  upvote downvote
submitted by yex(4)

This was on a previous NBME. How I got it? Intercostal (posterior) is how you get to the vertebral bodies; the other vessels are anterior.

... welpdedelp made a comment on nbme24/block1/q#4 (A 28-year-old man with AIDS has fever, headache, and...)
 +3  upvote downvote
submitted by welpdedelp(64)

Cryptococcal meningitis that is transferred through respiratory droplets

https://www.cdc.gov/fungal/global/cryptococcal-meningitis.html

... seagull made a comment on nbme24/block1/q#4 (A 28-year-old man with AIDS has fever, headache, and...)
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submitted by seagull(355)

https://en.wikipedia.org/wiki/Blastomycosis#/media/File:Blastomyces_dermatitidis_GMS.jpeg

I believe this is actually disseminated Blastomyces due to the "Broad Based Budding" as seen in the picture.

seagull  However, given the stain and some of the features I now see that this is most likely Crypto. THey like similar. my bad
mjmejora  oh what a catch! I also thought this was Blasto until you explained otherwise
... trazabone made a comment on nbme24/block1/q#5 (The 35-year-old woman indicated by the arrow has a...)
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submitted by trazabone(4)

My understanding is that if parents are unrelated by blood to those affected, we assume that they are not carriers (in the recessive case). Therefore, if we have a male father affected with x-linked recessive married to a non-carrier, there's no way any of his offspring would be affected.

"If one parent is not a carrier, then a child can only inherit a disease allele from the other parent. In these problems, we can assume that any individual marrying into the family is not a carrier." https://www.cs.cmu.edu/~genetics/units/instructions/instructions-CP.pdf

... stars and more made a comment on nbme24/block1/q#5 (The 35-year-old woman indicated by the arrow has a...)
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submitted by stars and more(5)

X linked recessive there can never be any Male to Male transfer since the male offspring gets Y from father. the pedigree shows Male to Male transmission so this cannot be X linked recessive

... monoclonal made a comment on nbme24/block1/q#5 (The 35-year-old woman indicated by the arrow has a...)
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submitted by monoclonal(3)

The point here is, they are asking us to eliminate the only answer that is not possible. I got it wrong. read well fellas

... brethren_md made a comment on nbme24/block1/q#6 (A 57-year-old woman requires intubation in the...)
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submitted by brethren_md(39)

Transfusion-related acute lung injury (TRALI) is a rare but serious syndrome characterized by sudden acute respiratory distress following transfusion. It is defined as new, acute lung injury (ALI) during or within six hours after blood product administration in the absence of temporally-associated risk factors for ALI.

... mousie made a comment on nbme24/block1/q#6 (A 57-year-old woman requires intubation in the...)
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submitted by mousie(74)

Is 45 minutes too long to be anaphylactic and would the absence of rash (urticaria, pruritus) RO anaphylactic?

hayayah  Yes! Allergic/anaphylactic blood transfusion reaction is within minutes to 2-3 hours. (pg 114 of the 2019 FA has a list of them ordered by time)
hayayah  (also allergy / anaphylactic presents with more skin findings (urticaria, pruritus)
seagull  The time through me off too. I though ABO mismatch since it occured around an hour. I thought TRALI would take a little longer.
charcot_bouchard  Guys anaphylactic reaction to whole blood doesnt occur much except for selective IgA defi. so look out for prev history of mucosal infection. And it can have all feature of type 1 HS inclding bronchospasm.
soph  I saw hypotension and though anaphylaxis........ -.-
... gonyyong made a comment on nbme24/block1/q#7 (A 65-year-old woman comes to the physician because...)
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submitted by gonyyong(19)

This was in NBME 20 as well. Its painless hematuria + papillary growth is showing transitional cell carcinoma This is associated with "Pee SAC": phenacetin, smoking, aniline dyes, and cyclophosphamide.

... duat98 made a comment on nbme24/block1/q#8 (A 24-year-old woman at 28 weeks' gestation is...)
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submitted by duat98(8)

This probably isn't 100% politically correct but:

Beta 2 agonist is still a beta agonist so it can bind nonspeficially and cause B1 activation which will cause tremor aka activates general sympathetics.

Sweating is generally can be categorized as sympathetic activation but the sweat gland has a muscarinic receptor so it won't be affected by a beta agonist.

the remaining choices are parasympathetic responses.

... lsmarshall made a comment on nbme24/block1/q#8 (A 24-year-old woman at 28 weeks' gestation is...)
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submitted by lsmarshall(181)

"The exact mechanism for tremor induction by β(2)-adrenergic agonists is still unknown, but there is some evidence that β(2)-adrenergic agonists act directly on muscle... More recently, tremor has been correlated closely with hypokalaemia." - NIH publication

First Aid mentions hyperthyroidism causing tremor from β-adrenergic stimulation. It also mentions β2-agonists causing tremor as a side effect. First Aid also mentions β2-agonists driving potassium into cells, which may contribute to tremor. That said, more classic symptoms of hypokalemia are wide QRS and peaked T waves on ECG, arrhythmias, and muscle weakness.

Looking around on the internet looks like if therapy is continued the tremor from a β2-agonists resolves overtime.

xxabi  Sketchy mentions tremor and arrhythmia as side effects!
... medpsychosis made a comment on nbme24/block1/q#8 (A 24-year-old woman at 28 weeks' gestation is...)
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submitted by medpsychosis(18)

The way I thought about it was a little more simplistic. We use non selective beta blockers (e.g. Propranolol) for the treatment of essential tremor. Therefore a beta agonist would have the opposite effect, aka cause or enhance tremor.

... coolcatac made a comment on nbme24/block1/q#8 (A 24-year-old woman at 28 weeks' gestation is...)
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submitted by coolcatac(5)

Plus, all the other options are not associated with B2 agonist, so just by process of elimination, tremor is the only one left

... yb_26 made a comment on nbme24/block1/q#8 (A 24-year-old woman at 28 weeks' gestation is...)
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submitted by yb_26(28)

Albuterol - relaxes bronchial smooth muscle (short acting β2-agonist). For acute exacerbations. Can cause tremor, arrhythmia.

... jus2234 made a comment on nbme24/block1/q#9 (The graph shows expiratory pressure-volume curves...)
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submitted by jus2234(9)

The graph shows a decrease in compliance of the lungs. Of the options, diffuse pulmonary fibrosis is the only choice that is an example of a restrictive lung disease which would decrease compliance

nor16  asthma = emphysema = chronic bronchitits, obstructive. leaves 2 out of 5...
... keycompany made a comment on nbme24/block1/q#10 (A 75-year-old man is brought unconscious to the...)
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submitted by keycompany(105)

Image shows Crescent Sign, a common finding in Abdominal Aortic Aneurysms due to mural thrombus occlusion.

... njspix made a comment on nbme24/block1/q#11 (A 55-year-old man with type 1 diabetes mellitus...)
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submitted by njspix(5)

Per UpToDate, the key here is the allodynia. This patient has intact sensation, it's just "turned up" way too much. The simplest way to explain this is that the sensor itself (the nociceptor) is over-activated.

Note that nociceptive pain (as this is termed) is more often due to inflammation/pressure/tissue damage, whereas neuropathic pain (more central) has a wide variety of causes (diabetes is a prominent one).

... seagull made a comment on nbme24/block1/q#11 (A 55-year-old man with type 1 diabetes mellitus...)
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submitted by seagull(355)

Another approach. Diabetes causes non-enzymatic glycosylation which may negatively impact the function of neurons mainly due to altered blood supply among other things. These glycosylate deposits typically occur peripherally at the legs. The only peripheral answer choice was a nociceptor in the legs. all the other answer choices are at least more centrally located with larger blood supplies.

Again, not perfect but a way to reason out this answer but it does work.

sam1  I believe this concept is referring to peripheral sensitization. Peripheral nerves that have sustained damage (such as through non-enzymatic glycosylation in DM) cause sensitization of their neighboring nerves, thus leading to lower thresholds for activation. This sensitization is thought to be accomplished through mediators such as PGE2.
sam1  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3701208/ ^ Section on peripheral sensitization
... charcot_bouchard made a comment on nbme24/block1/q#11 (A 55-year-old man with type 1 diabetes mellitus...)
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submitted by charcot_bouchard(42)

Allodynia is central pain sensitization. Triggering of pain by a non painful stimuli. Also seen in Fibromyalgia. [vs Hyperalgesia : Inc response to painful stimuli]

Its a positive (i.e Actively feeling, not lack of feeling) symptpms. so B & C is not the answer. D isnt answer either. as vanilloid receptor (TRPV1) is also afferent nociceptive transmission (modulated by capsaicin). Activation is soon followed by desensitization.

A - IDK. if problem was in DRG there would be lot more symptoms.

... m-ice made a comment on nbme24/block1/q#12 (A 26-year-old man comes to the physician for a...)
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submitted by m-ice(116)

HMG CoA reductase inhibitors block the ability of the body to produce its own cholesterol. The liver, unable to make its own cholesterol and still needing to do its job of making lipoproteins, needs to get it from somewhere. So, the liver increases expression of LDL receptors to take more LDL out of the blood for repackaging.

... mousie made a comment on nbme24/block1/q#13 (A 4-year-old boy is brought to the emergency...)
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submitted by mousie(74)

is this subacute endocarditis associated Membrano-proliferative GN?

jus2234  The question describes how he had a strep infection 15 days ago, and now this is poststreptococcal glomeruloneprhitis, which can also be described as proliferative glomerulonephritis
seagull  The question would be too fair if it just said PSGN. Instead we need to smell our own farts first.
yotsubato  And they used terminology NOT found in FA
water  who said they were limited to FA?
nbmehelp  FA uses the common nomenclature and the fact most of our other resources use the same nomenclature for this, I think we can agree that is is the accepted terms. If they're gonna decide not to use the nomenclature that most medical students are taught then they should provide their own study materials at that point for us to use. The test shouldn't be this convoluted for no reason.
... nwinkelmann made a comment on nbme24/block1/q#13 (A 4-year-old boy is brought to the emergency...)
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submitted by nwinkelmann(60)

So actually.... Medscape says that PSGN can progressive to a proliferative glomerulonephritis mechanism and so proliferative glomerulonephritis should be considered as a differential diagnosis for PSGN.

https://emedicine.medscape.com/article/980685-overview#a5: "The presence of acute kidney injury may suggest an alternate diagnosis (eg, membranoproliferative glomerulonephritis [MPGN], Henoch-Schönlein purpura [HSP], systemic lupus erythematosus [SLE]) or a severe or worsening APSGN, such as observed in those with crescentic glomerulonephritis or rapidly progressive glomerulonephritis... Differential Diagnosis: This includes most other types of childhood glomerulonephritides. These include IgA nephropathy, membranoproliferative glomerulonephritis, hereditary nephritis, and other forms of postinfectious glomerulonephritis."

Ironically enough, this must be what they were asking, i.e. complications of PSGN, because AMBOSS (another Step resource) directly linked the above article I found before looking farther and coming across the AMBOSS section.

... dontwanttofail made a comment on nbme24/block1/q#13 (A 4-year-old boy is brought to the emergency...)
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submitted by dontwanttofail(-4)

https://en.wikipedia.org/wiki/Acute_proliferative_glomerulonephritis

Directly from wikipedia:

"Acute proliferative glomerulonephritis is a disorder of the glomeruli (glomerulonephritis), or small blood vessels in the kidneys. It is a common complication of bacterial infections, typically skin infection by Streptococcus bacteria types 12, 4 and 1 (impetigo) but also after streptococcal pharyngitis, for which it is also known as postinfectious or poststreptococcal glomerulonephritis."

... nbmehelp made a comment on nbme24/block1/q#13 (A 4-year-old boy is brought to the emergency...)
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submitted by nbmehelp(4)

This is BS bc PSGN is like the only nephrotic/nephritic syndrome I thought I had down cold

... ap88 made a comment on nbme24/block1/q#13 (A 4-year-old boy is brought to the emergency...)
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submitted by ap88(0)

Why can this not be papillary necrosis? Given the gross Hematuria and proteinuria with a history of analgesic use... I thought that was what this was getting at?

... m-ice made a comment on nbme24/block1/q#14 (A thin 66-year-old man is brought to the emergency...)
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submitted by m-ice(116)

In SIADH, the excessive ADH causes the collecting duct of the kidney to reabsorb huge amounts of water that it should normally excrete. That means that the plasma will now have much more water relative to solute (low osmolality) and the urine will have much more salt relative to water (higher osmolality).

... guillo12 made a comment on nbme24/block1/q#15 (Results of a 5-year screening program for HIV...)
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submitted by guillo12(12)

I don't know the equation for this, but I did this: The sum of incidence per year/ the sum of number reamainig in population. So... 1,500/28,800 = .05208 or 5.2%

... karljeon made a comment on nbme24/block1/q#15 (Results of a 5-year screening program for HIV...)
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submitted by karljeon(19)

I don't know if there is an equation for this, but I basically pumped out every division across the table to get ~5% on average.

Here they are: 400 / 6,000 = 0.067 250 / 5,600 = 0.045 300 / 5,350 = 0.056 300 / 5,050 = 0.059 250 / 4,800 = 0.052

The average of these %s for all the years = 5.58%. So that's close enough to 5%.

seagull  good work. I found this question annoying and gave up doing those considering the amount of time we are given.
vshummy  Well just don’t include the intake year... because that messed me up..
_yeetmasterflex  How would we have known not to include the intake year? From average **annual** incidence?
lamhtu  Do not include intake year because the question stem is asking average annual incidence. The 4000 positives at intake could have acquired HIV whenever, not just in the last year.
neels11  literally didn't think there was an actual way to figure this out. but my thought process was: okay incidence means NEW cases. so the annual average at the end of 5 years would be: (# of NEW people that tested positive at the end of year 5) / (# of people at that were at risk at the beginning of year 5) <--- aka at the end of year 4 250/5050 = 4.95% also if you look at year 5: you'll see that the at risk population is 4800 when 300 new cases were found the year before. 5050 at the end of year 4 MINUS the 300 new cases at the end of year 4 should give you 4750 as the new population at risk. but notice that end of year 5 we have 4800. idk if that means 50 people were false positives before or 50 people were added but in incidence births/death/etc don't matter it's kind of like UWORLD ID 1270. assuming average annual incidence is the same as cumulative incidence this was just a bunch of word vomit. sorry if it was unbearable to follow
... jotajota94 made a comment on nbme24/block1/q#15 (Results of a 5-year screening program for HIV...)
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submitted by jotajota94(11)

incidence = number of new cases/ new cases+ population at risk. new cases= 250. People at risk that year 5050 (including new cases. In one point they were a population at risk) 250/ 5050= 4.9%

... youssefa made a comment on nbme24/block1/q#15 (Results of a 5-year screening program for HIV...)
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submitted by youssefa(6)

So number of cases with positive serology during "intake" represents prevalence and should not be accounted for when calculating population at risk. Population at risk = Total population - prevalence. Doing that, sum up the annual incidences left = 400 + 250 + 250 + 300 + 300 = 1500.

Applying incidence formula = 1500/(10,000-4000) = 0.25 over a total of 5 years.

Annual = 0.25/5 = 0.05%

... lsmarshall made a comment on nbme24/block1/q#16 (A 32-year-old man is brought to the emergency...)
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submitted by lsmarshall(181)

Flexor digitorum profundus is responsible for flexion of DIP. Medial aspect of the muscle (which flexes the 4th and 5th digit) is supplied by the ulnar nerve (C8, T1). The lateral aspect (which flexes the 2nd and 3rd digit) is innervated by the median nerve specifically the anterior interosseous branch (C8, T1). So the question is describing a laceration damaging the nerve supply to the DIP flexor of the 2nd digit (index finger). This is saying the medial nerve is being damaged (C8 and T1; lower trunk roots).

Lumbricals (1st/2nd, median; 3rd/4th, ulnar) are a group of muscles that flex at the MCP joint, and extend PIP and DIP joints.

Could remember as 'flexor digitorum profundus is profoundly long' since tendons insert on DIPs. Compared to flexor digitorum superficialis whose tendon wraps around profundus' superficially but inserts on PIPs.

toupvote  This is dumb but I remember FDP is needed for picking while FDS is need for scratching the superficial layer of the skin
... ihavenolife made a comment on nbme24/block1/q#17 (A 3-year-old boy is brought to the emergency...)
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submitted by ihavenolife(12)

Annular pancreas is an abnormal rotation of the ventral pancreatic bud. It encircles the 2nd part of the duodenum like a ring and narrows the lumen of the duodenum. If the pancreatic ring is tight enough to narrow the lumen enough, it leads to vomiting. The bilious vomiting implies the obstruction is distal to the Ampulla of Vater.

Other answers

Pyloric stenosis -> NONbilious projectile vomiting, olive-shaped mass in epigastric region

Esophageal atresia -> would be non bilious as well. usually neonates present with drooling, choke and vomit with FIRST feeding, this boy is 3 yrs old so it is unlikely.

Biliary atresia -> Fibro-obliterative destruction of extrahepatic bile duct, leads to cholestasis. Usually newborn with jaundice, dark urine and acholic stools because bile backed up.

... haliburton made a comment on nbme24/block1/q#18 (A 34-year-old woman with a long history of...)
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submitted by haliburton(74)

Infliximab is a TNF-alpha inhibitor. from pubmed TNF-α has been demonstrated to have a central role in the host response against tuberculosis, including granuloma formation and the containment of disease (14,15). Notably, antibodies against TNF-α induced reactivation of tuberculosis

bigjimbo  TB can spread to psoas L1-2 often, which then goes to the actual L1-L2 vertebrae itself (Potts or osteomyelitis)
... sympathetikey made a comment on nbme24/block1/q#19 (A 35-year-old man comes to the physician because of...)
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submitted by sympathetikey(260)

Buzzword: excessive tearing

Cluster headaches, in questions, always come with autonomic symptoms.

... m-ice made a comment on nbme24/block1/q#19 (A 35-year-old man comes to the physician because of...)
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submitted by m-ice(116)

The patient in this question has cluster headaches. These headaches can be differentiated from migraines and tension headaches, as they tend to come in episodes across several years, with absent periods in between. Cluster headaches are often described as excruciatingly painful (sometimes called "suicide headaches").

... lsmarshall made a comment on nbme24/block1/q#20 (Immediately after a spontaneous vaginal delivery, a...)
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submitted by lsmarshall(181)

Patient has Spina bifida occulta which is a neural tube defect (failure of fusion of the neuropores). Sclerotomes are the part of each somite in a vertebrate embryo giving rise to bone or other skeletal tissue. Since a part of this patient's spina bifida included "abscense of spinous process" then a sclerotome was involved. Knowing that neural tube defects are an issue with fusion should be enough to get to the right answer.

If the notochord failed to develop then the entire CNS would not develop as the notochord induces formation of neural plate.

If the neural tube failed to develop then the whole CNS would not have developed.

Yolk sac is irrelevant to this patient.

When neural crest cell it has different outcomes in different tissues. Failure of neural crest to migrate in heart can cause Transposition of great vessels, Tetralogy of Fallot, or Persistent truncus arteriosus. Failure of neural crests to migrate in GI can cause Hirschsprung disease (congenital megacolon). Treacher Collins Syndrome can occur when neural crest cells fail to migrate into 1st pharyngeal arch. Neural tube defects has nothing to do with failure of neural crest migration though.

sympathetikey  Exactly. I knew it had to due with fusion of the neuropores but had never heard of sclerotomes. Thanks for the explanation.
... ameanolacid made a comment on nbme24/block1/q#21 (A 35-year-old woman comes to the physician because...)
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submitted by ameanolacid(12)

Great image showing the anatomical relationships:

https://embryology.med.unsw.edu.au/embryology/images/0/03/Thyroid-development-cartoon.jpg

... famylife made a comment on nbme24/block1/q#22 (A 50-year-old man undergoes surgical transection of...)
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submitted by famylife(32)

"Innervates the muscles of the medial compartment of the thigh (obturator externus, adductor longus, adductor brevis, adductor magnus and gracilis)."

https://teachmeanatomy.info/lower-limb/nerves/obturator-nerve/

famylife  Pics: https://www.google.com/search?rlz=1C1CHZL_enUS753US753&biw=1368&bih=809&tbm=isch&sa=1&ei=W6P6XJa3NMSQggfa35YY&q=obturator+nerve+adductors&oq=obturator+nerve+adductors&gs_l=img.3...9024.9024..9214...0.0..0.82.82.1......0....1..gws-wiz-img.rjc4GuKQAYo#imgrc=ZqWtUuDxpzeNMM:
... karljeon made a comment on nbme24/block1/q#23 (A 50-year-old man comes to the physician because of...)
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submitted by karljeon(19)

A man with a Hx of EtOH dependence and chronic abd pain as well as X-ray findings of "calcifications in the mid-upper abdomen" is most likely referring to a chronic pancreatitis.

This leads to a lack of lipase secretion hence, pale, foul-smelling stools with oil droplets per pt Hx. This pt's pancreas also doesn't secrete other enzymes, such as amylases, proteases, nor trypsinogen (to activate other enzymes), so the answer is "generalized malabsorption".

karljeon  p. 367 (FA 2018)
... sympathetikey made a comment on nbme24/block1/q#24 (A 6-year-old girl is brought to the office by her...)
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submitted by sympathetikey(260)

Pediculus Humanus

Blood-sucking lice that cause intense pruritus with associated excoriations, commonly on scalp and neck (head lice), waistband and axilla (body lice), or pubic and perianal regions (pubic lice).

Best give away in this question, for me, is the "white, globular protuberances". Looks just like the pic in First Aid 2019 (see below).

https://i.imgur.com/mh5JA2D.png

... seagull made a comment on nbme24/block1/q#25 (A 7-year-old boy has metabolic acidosis and...)
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submitted by seagull(355)

I thought this was a type 1 RTA but I was wrong. Any suggestions?

seagull  It looks like it was a type II RTA. The difference is incredibly subtle from the info given in this question.
gonyyong  He has Fanconi syndrome which is generalized reabsorption defect in PCT which leads to metabolic acidosis and hypophosphatemia → can lead to rickets Also, does lead to type II RTA
duat98  Also the proximal tubule is the place with the highest phosphate absorption rate. That's why PTH works here mostly and a little bit in the distal tubule.
... radshopeful made a comment on nbme24/block1/q#26 (An 80-year-old woman with poorly controlled type 2...)
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submitted by radshopeful(11)

chronic kidney disease --> decreased EPO --> decreased hematocrit chronic kidney disease --> decreased PO4- excretion --> increased PTH chronic kidney disease --> decreased 1,25 dihydrovitD (calcitriol) --> increased PTH

jotajota94  she is also volume overloaded. more fluid leads to a decrease in Hematocrit.
... lsmarshall made a comment on nbme24/block1/q#27 (A 10-year-old girl with a lifelong history of...)
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submitted by lsmarshall(181)

"Parasternal heave (lift) occurs during right ventricular hypertrophy (i.e. enlargement) or very rarely severe left atrial enlargement." RV hypertrophy can be seen so easily because the RV is at the anterior surface of the chest.

In this patient blood from LA to LV decreases in saturation, so it is going somehwere. From the O2 sat. we can deduce there is probably a VSD (increased RV pressure would cause RVH and parasternal heave). Furthermor, the vignette is likely describing tetralogy of fallot (caused by anterosuperior displacement of the infundibular septum). In Tet spells, RV outflow is too obstructed and patient gets cyanosis and R>L shunting Squats increase SVR, decreasing R>L shunting, putting more blood through pulmonary circuit and relieving cyanosis.

seagull  i'm pretty sure your a prof and not a student.
nor16  nevertheless, we are greatful for explanation!
... tea-cats-biscuits made a comment on nbme24/block1/q#28 (A 32-year-old woman comes to the physician because...)
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submitted by tea-cats-biscuits(64)

Mast cells degranulate, producing histamine which attracts eosinophils. The early stage of an allergic reaction is mast cell mediated, but the late stage (including mucus production) is mediated by eosinophils.

atstillisafraud  Thanks for a good answer. This question made me feel like I was taking T21 pills
... m-ice made a comment on nbme24/block1/q#29 (An 80-year-old woman comes to the physician because...)
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submitted by m-ice(116)

The jaw pain and headaches in an older woman are worrisome for Temporal Arteritis. This is a vasculitis, which could be best identified by determining the erythrocyte sedimentation rate.

... tea-cats-biscuits made a comment on nbme24/block1/q#30 (A 55-year-old man is brought to the emergency...)
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submitted by tea-cats-biscuits(64)

Patient has cardiogenic shock, specifically the LV since it’s an anterior wall MI isn’t pumping. Honestly you don’t need to know what happens to PVR to answer correct since the only choice that has increased SVR and decreased PCWP is the one w/decreased PVR. I’m not absolutely sure if you could figure it out given the values in cardiogenic shock. The equation linking the values is:

PVR = (pulmonary arterial pressure - wedge) ÷ CO

... 2zanzibar made a comment on nbme24/block1/q#30 (A 55-year-old man is brought to the emergency...)
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submitted by 2zanzibar(7)

Patient is in cardiogenic shock. Characteristic features of cardiogenic shock: increased cardiac pressures and decreased cardiac output due to impeded forward flow, as well as increased systemic vascular resistance

... pseudorosette made a comment on nbme24/block1/q#30 (A 55-year-old man is brought to the emergency...)
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submitted by pseudorosette(1)

Why is it that the pulmonary capillary wedge preesssuree is increased? on pg. 307 of FA 2019 it says it can be increased or decreased :/

giggidy  Depends on where the infarct is I guess? Crackles in lung base means increased left sided pressure and therefore PCWP. At least that's how I thought of it.
... famylife made a comment on nbme24/block1/q#30 (A 55-year-old man is brought to the emergency...)
davidw  If the Infarct was on the right side they you would have a decrease in PCWP
... medstruggle made a comment on nbme24/block1/q#31 (An experimental study is conducted to examine the...)
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submitted by medstruggle(5)

Why is alternative splicing or post-transcriptional modification incorrect?

tea-cats-biscuits  You just have to know that POMC is a pro-protein that must be cleaved; not sure if there’s anything in the stem that would really have given it away.
mcl  Dunno if this helps, but it says "this protein" (singular) is the precursor of two different protein products. This must mean that the modification occurs after the protein is made, which means after transcription and splicing has already happened.
ngman  Also I believe mRNA refers to after the splicing already occurs. If the protein products are from the same mRNA then it can't be alternate splicing.
medschul  They're cleaved by tissue-specific proteases
duat98  I think: Alternative splicing occurs with hnRNA not mRNA. You get mRNA from alternatively splicing the hnRNA. an mRNA can only make 1 type of protein. Since the question says the 2 proteins comes from the same mRNA it cannot be alternative splice or post transcriptional mod. FA 2018 page 43 has a good illustration.
... nor16 made a comment on nbme24/block1/q#31 (An experimental study is conducted to examine the...)
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submitted by nor16(3)

POMC is a prohormone peptide chain.

It is translated and later enzymes cut this peptide in the subpeptides.

Transcription is wrong (i had this too...) b/c its not the mRNA that makes different peptide hormones. Moreover, what I see now is, that posttranscriptional modification is more or less splicing... so post-translat. modification. next time we make it correct ;-)

... link981 made a comment on nbme24/block1/q#31 (An experimental study is conducted to examine the...)
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submitted by link981(24)

Keywords from Dr. Turco from Kaplan:

  • Replication- DNA
  • Transcription- RNA
  • Translation- Protein
... fahmed14 made a comment on nbme24/block1/q#32 (A 24-year-old man receives an injection of histamine...)
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submitted by fahmed14(9)

Histamine plays a major role in the cardinal signs of inflammation. It helps mediate vasodilation and vascular permeability (via endothelial cell contraction). These two functions are already contrary to A, B, C, and D. By increasing fluid in the interstitial space, you can reason that there will be increased lymph flow.

youssefa  If more transudates are leaking into the interstitium wont this dilute the interstitial proteins and cause a decrease in oncotic pressure and increase in interstitial hydrostatic pressure?
... famylife made a comment on nbme24/block1/q#32 (A 24-year-old man receives an injection of histamine...)
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submitted by famylife(32)

There is "a direct action of histamine on the lymphatic smooth muscle via stimulation of H1 (and in some vessels H2) receptors. H1 receptors enhance and H2 receptors slow down lymphatic pumping, the dominant effect being an increased contractile activity."

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1573448/

... nor16 made a comment on nbme24/block1/q#32 (A 24-year-old man receives an injection of histamine...)
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submitted by nor16(3)

Histamine increases microvascular permeability, i.e. Fluid + Proteins, this increases pressure in the interstitium > lymph flow increases

... cocoxaurus made a comment on nbme24/block1/q#33 (A 3-month-old girl is brought to the emergency...)
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submitted by cocoxaurus(22)

Papilloma virus causes Papillomatosis in infants. Growth in vocal cords= weak cry, hoarseness, stridor.

... neonem made a comment on nbme24/block1/q#34 (A 62-year-old man comes to the physician for a...)
 +2  upvote downvote
submitted by neonem(227)

Sotalol is a type III antiarrhythmic (K+ channel-blocking) that also has beta-blocker activity (Type II antiarrhythmic). This explains the decreased heartrate and blood pressure (beta-1 blocking activity), with the QT prolongation - all type III AADs cause QT prolongation.

... seagull made a comment on nbme24/block1/q#35 (A 1616-g (3-lb 9-oz) male newborn is delivered to a...)
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submitted by seagull(355)

This infant has oxygen toxicity due to free radical generation. Free radicals damage the lung parenchyma leading to fibrosis and dysplasia (abnormal growth).

link981  Per American Lung Association: Bronchopulmonary dysplasia (BPD) is a form of chronic lung disease that affects newborns (mostly premature) and infants. It results from damage to the lungs caused by mechanical ventilation (respirator) and long-term use of oxygen. Most infants recover from BPD, but some may have long-term breathing difficulty. + Prematurely born infants have very few tiny air sacs (alveoli) at birth. The alveoli that are present tend to not be mature enough to function normal, and the infant requires respiratory support to breathe. Although life-saving, these treatments can also cause lung damage.
... link981 made a comment on nbme24/block1/q#35 (A 1616-g (3-lb 9-oz) male newborn is delivered to a...)
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submitted by link981(24)

Per American Lung Association: Bronchopulmonary dysplasia (BPD) is a form of chronic lung disease that affects newborns (mostly premature) and infants. It results from damage to the lungs caused by mechanical ventilation (respirator) and long-term use of oxygen. Most infants recover from BPD, but some may have long-term breathing difficulty. + Prematurely born infants have very few tiny air sacs (alveoli) at birth. The alveoli that are present tend to not be mature enough to function normal, and the infant requires respiratory support to breathe. Although life-saving, these treatments can also cause lung damage

... neonem made a comment on nbme24/block1/q#36 (A 4-year-old girl is brought to the physician...)
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submitted by neonem(227)

Anti-endomysial and anti-tissue glutaminase antibodies are pathognomonic for Celiac disease, a hypersensitivity to the gliadin antigen of wheat. It mainly manifests in the jejunum and ileum. In adults, it presents as chronic steatorrhea and bloating, while in children it does the same but also causes failure to thrive. Histologically, it is identified by crypt hyperplasia and villous flattening. If you damage your villi, you can't absorb fat through the lacteals of the small intestine --> malabsorption.

PAS-positive granules in macrophages in lamina propria = Whipple disease, an infection with Tropheryma whipplei, an intracellular gram-positive organism. This would similarly cause a malabsorptive state but is not associated with particular antibodies, and might also manifest as arthralgias, cardiac, and neurologic symptoms.

... gonyyong made a comment on nbme24/block1/q#37 (A 25-year-old woman at 16 weeks' gestation comes to...)
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submitted by gonyyong(19)

I think what threw me off with this question was "serum T4" - wasn't sure if that meant total T4 or serum T4. Luckily, I don't think any of the other ones fit for either so I assumed it meant total T4 for which the answer makes sense

... famylife made a comment on nbme24/block1/q#37 (A 25-year-old woman at 16 weeks' gestation comes to...)
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submitted by famylife(32)

"Increased blood concentrations of T4-binding globulin: TBG is one of several proteins that transport thyroid hormones in blood, and has the highest affinity for T4 (thyroxine) of the group. Estrogens stimulate expression of TBG in liver, and the normal rise in estrogen during pregnancy induces roughly a doubling in serum TBG concentratrations."

"Increased levels of TBG lead to lowered free T4 concentrations, which results in elevated TSH secretion by the pituitary and, consequently, enhanced production and secretion of thyroid hormones. The net effect of elevated TBG synthesis is to force a new equilibrium between free and bound thyroid hormones and thus a significant increase in total T4 and T3 levels. The increased demand for thyroid hormones is reached by about 20 weeks of gestation and persists until term."

http://www.vivo.colostate.edu/hbooks/pathphys/endocrine/thyroid/thyroid_preg.html

... neonem made a comment on nbme24/block1/q#38 (A 37-year-old woman comes to the physician because...)
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submitted by neonem(227)

This patient has an unstable mood and a crazy relationship. She's also splitting (a defense mechanism wherein one acts like people are all-good or all-bad) as she talks about the physician and her coworkers. This characteristic is most commonly associated with borderline personality disorder. This one is in Group B ("Wild"), along with antisocial, histrionic, and narcissistic.

medskool123  i get why its borderline now (I guess I kind of always thought suicide was the biggest part of that) but can someone tell me why its not paranoid? Is it just a matter of the "better" choice? The "youre the only one i can trust" thing lead me to that.
... neonem made a comment on nbme24/block1/q#39 (A 40-year-old man with AIDS develops severe diarrhea...)
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submitted by neonem(227)

Somatostatin is normally secreted by D cells in the pancreatic islets and GI mucosa. It basically blocks everything GI-related ("encourages somato-stasis"): decreased gastric acid & pepsinogen secretion, decreased pancreatic and small intestine fluid secretion, decreased gallbladder contraction, decreased insulin & glucagon release.

Decreasing gastrin release blocks the increase of GI motility (increased GI motility is the inherent problem of diarrhea).

The drug in the question is probably octreotide.

... medstruggle made a comment on nbme24/block1/q#40 (A 26-year-old man and his 25-year-old wife come to...)
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submitted by medstruggle(5)

Whats the difference between “heterozygous null mutation in B globin gene” and “heterozygous mutation known to cause 50% decrease in B globin gene function of one allele”?

welpdedelp  I interpreted "null" as meaning full deletion while the other heterozygous mutations was only a 50% decrease in the function. One child would inherit 1 null mutation and 1 50% mutation, which would leave them with a 25% functional gene.
... brethren_md made a comment on nbme24/block1/q#40 (A 26-year-old man and his 25-year-old wife come to...)
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submitted by brethren_md(39)

Make a punnett square with a cross of B B+ and B B0; B+ represents 50% function while B0 represents 0% (null) function. So in this case, the husband would have a B B0 genotype while the wife has a B B+ genotype.

Cross of these two will result in the following genotypes; BB, BB0, BB+, B+B0 BB = 100% function, BB+ = 75% function, BB0 = 50% function, B+B0 = 25% function

So the answer will be 1 in 4 have a 25% function given the genotypes.

... m-ice made a comment on nbme24/block1/q#41 (A 32-year-old woman who is 20 weeks' pregnant has...)
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submitted by m-ice(116)

Misoprostol is a prostaglandin analog (PGE2) that acts on the stomach to promote mucus protection of the stomach lining, but also acts in the uterus to encourage contraction, which makes it useful for abortion.

... pseudorosette made a comment on nbme24/block1/q#42 (A 68-year-old woman with acute myelogenous leukemia...)
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submitted by pseudorosette(1)

I could be wrong.. but the normal ANC (absolute neutrophil count) ranges from (1,500 to 8,000/mm3) this patient is way below the normal ANC range, thus a GMCSF could help boost neutrophils which are granulocytes!

mgoyo89  I think there are two questions with this answer!!I was so scared :(
trichotillomaniac  yep ---not IL-2 bc that stimulates Tcells and NK cells- I think I blacked out when I answered this question
... radshopeful made a comment on nbme24/block1/q#43 (After completing 6 courses of chemotherapy for...)
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submitted by radshopeful(11)

The classic side effect of anthracyclines is dilated cardiomyopathy. This question could have gotten tricky if you thought the pulmonary symptoms were due to the drug which could have led you to bleomycin (causes pulmonary fibrosis) but these pulmonary symptoms were most likely a result of dilated cardiomyopathy leading to HF and pulmonary edema.

nwinkelmann  What is the clue that this is not pulmonary fibrosis? How do I decide between Doxorubicin and Bleomycin?
ilikecheese  Also both bleomycin and methotrexate cause pulmonary fibrosis, so that helped me rule both those out and focus on the HF instead of the pulmonary symptoms
adisdiadochokinetic  The S3 gallop and enlarged heart together are very strong evidence for heart failure. It's much more likely for heart failure to cause interstitial edema than for pulmonary fibrosis to directly cause heart failure.
... trichotillomaniac made a comment on nbme24/block1/q#44 (A 24-year-old man is brought to the office because...)
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submitted by trichotillomaniac(13)

cipro is a fluoroquinolone. the MOA of fluoroquinolones is to inhibit prokaryotic topoisomers II (DNA Gyrase) occasionally Gram (-) organisms like e-coli develop resistance by mutating their DNA gyrase so drugs like cipro cannot inhibit

... drdoom made a comment on nbme24/block1/q#45 (A 71-year-old man is brought to the emergency...)
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submitted by drdoom(167)

The stem is describing sequelae of posterior inferior cerebellar artery occlusion, resulting in Wallenberg syndrome. Here’s a nice schematic of the affected nuclei and brain stem regions:

https://i.ytimg.com/vi/A8S3B9p1t_g/maxresdefault.jpg

... and a 6-minute YouTube video that walks you through it:

https://www.youtube.com/watch?v=A8S3B9p1t_g

nbme4unme  Great video! Very, very solid review of brainstem anatomy.
... m-ice made a comment on nbme24/block1/q#46 (A 10-year-old girl is scheduled to undergo fixation...)
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submitted by m-ice(116)

This girl has malignant hyperthermia, a dangerous adverse effect of some anesthestic agents characterized by sudden high fever and rhabdomyolysis. The only drug among this list that can cause malignant hyperthermia is succinylcholine. The other drugs that cause malignant hyperthermia are the halonated gases (flurane, sevoflurane, etc.), but nitrous oxide does not cause it.

... xxabi made a comment on nbme24/block1/q#47 (A 35-year-old man comes to the physician 1 week...)
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submitted by xxabi(82)

ARBs result in the following changes: increased renin, increased Ang I, increased Ang II, decreased aldosterone and unchanged bradykinin

famylife  ...and just to clarify, they directly inhibit the Ang II receptor (AT1) https://www.drugs.com/mmx/losartan-potassium.html
... jotajota94 made a comment on nbme24/block1/q#47 (A 35-year-old man comes to the physician 1 week...)
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submitted by jotajota94(11)

A good way to think about this is that angiotensin II is present at the ANGII receptors. If you give an angiotensin receptor blocker such as losartan. this will displace the angiotensin II present in the receptors. thus increasing the levels of angiotensin II in serum.

... radshopeful made a comment on nbme24/block1/q#48 (A 70-year-old man is brought to the emergency...)
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submitted by radshopeful(11)

This patient has decompensated left heart failure. Decompensation occurs because of the hearts inability to keep up with demand any longer. This leads to a decrease in SV mainly because of a contractile issue which leads to a decrease in CO (CO = SV x HR). Lastly, the LVEDV will be decreased because the SV is decreased leaving more blood in the left ventricle after systole since it cannot be pumped forward. Hope this helps!!

xxabi  Great explanation - I think you have a minor typo, LVEDV will be increased* bc SV is decreased
smoothie  More blood left in the ventricle after systole is LVESV. I thought LVEDV increases because more blood remains after systole and on top of that blood from left atria from diastole is now also added.
... sympathetikey made a comment on nbme24/block1/q#49 (A 58-year-old man is brought to the emergency...)
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submitted by sympathetikey(260)

Pretty straightforward, but a good reminder that myelofibrosis can cause an enlarged spleen.

sympathetikey  Due to extramedullary hematopoesis
zoggybiscuits  I thought it was spleen but the fact that hematocrit was 24% 4 HOURs later made me think otherwise. It was my understanding that the spleen would bleed you out quick!
need_answers  couldn't also be ruptured spleen because they said intraperitoneal fluid and everything else is retroperitoneal ??
... vshummy made a comment on nbme24/block1/q#50 (An 11-year-old boy is brought to the emergency...)
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submitted by vshummy(44)

So the best i could find was in First Aid 2019 pg 346 under Diabetic Ketoacidosis. The hyperglycemia and hyperkalemia cause an osmotic diuresis so the entire body gets depleted of fluids. Hence why part of the treatment for DKA is IV fluids. You might even rely on that piece of information alone to answer this question, that DKA is treated with IV fluids.

fulminant_life  I just dont understand how that is the cause of his altered state of consciousness. Why wouldnt altered affinity of oxygen from HbA1c be correct? A1C has a higher affinity for oxygen so wouldnt that be a better reason for him being unconscious?
toupvote  HbA1c is more of a chronic process. It is a snapshot of three months. Also, people can have elevated A1c without much impact on their mental status. Other organs are affected sooner and to a greater degree than the brain. DKA is an acute issue.
snafull  Can somebody please explain why 'Inability of neurons to perform glycolysis' is wrong?
johnson  Probably because they're sustained on ketones.
doodimoodi  @snafull glucose is very high in the blood, why would neurons not be able to use it?
soph  @snafull maybe u are confusing bc DK tissues are unable to use the high glucose as it is unable to enter cells but I dont think thats the case in the neurons?
... lsmarshall made a comment on nbme24/block2/q#1 (A 73-year-old woman has had easy fatigability for 2...)
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submitted by lsmarshall(181)

Although Crohn's may have ulcers, fistulas, and bleeding; it usually does not cause iron deficiency anemia and has less bleeding than UC. "Structural abnormalities of the terminal ileum, such as Crohn disease and surgical resection, can cause decreased absorption of vitamin B12." - First Aid General Principles

... lispectedwumbologist made a comment on nbme24/block2/q#1 (A 73-year-old woman has had easy fatigability for 2...)
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submitted by lispectedwumbologist(23)

Why would it not be anemia of chronic disease with decreased serum transferrin concentration?

lispectedwumbologist  Nevermind I'm stupid as fuck I see my mistake
drdoom  be kind to yourself, doc! (it's a long road we're on!)
step1forthewin  Hi, can someone explain the blood smear? isn't it supposed to show hypersegmented neutrophils if it was B12 deficiency?
loftybirdman  I think the blood smear is showing a lone lymphocyte, which should be the same size as a normal RBC. You can see the RBCs in this smear are bigger than that ->macrocytic ->B12 deficiency
seagull  maybe i'm new to the game. but isn't the answer folate deficiency and not B12? Also, i though it was anemia of chronic disease as well.
vshummy  Lispectedwumbologist, please explain your mistake? Lol because that seems like a respectible answer to me...
gonyyong  It's a B12 deficiency Ileum is where B12 is reabsorbed, folate is jejunum The blood smear is showing enlarged RBCs Methionine synthase does this conversion, using cofactor B12
uslme123  Anemia of chronic disease is a microcytic anemia -- I believe this is why they put a lymphocyte on the side -- so we could see that it was a macrocytic anemia.
yotsubato  Thanks NBME, that really helped me....
keshvi  the question was relatively easy, but the picture was so misguiding i felt! i thought it looked like microcytic RBCs. I guess the key is, that they clearly mentioned distal ileum. and that is THE site for B12 absorption.
sahusema  I didn't even register that was a lymphocyte. I thought I was seeing target cells so I was confused AF
... brethren_md made a comment on nbme24/block2/q#2 (A 45-year-old man comes to the physician because of...)
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submitted by brethren_md(39)

Classic sleep apnea in the patient. Cessation of breathing causes nocturnal hypoxia and systemic hypertension/arrhythmic/sudden death can persist. PaO2 is normal during day and decreased during episodes and at night. Classically seen in Obese patients such as the patient in the question stem.

tinydoc  Caused a cessation of breathing rather than a ↓ in lung volume although a patient could develop an obesity related restrictive lung disease thats not whats happening with this question.
... gonyyong made a comment on nbme24/block2/q#3 (A 13-year-old boy is brought to the physician by his...)
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submitted by gonyyong(19)

The kid has gynecomastia due to puberty (excess testosterone → estrogen) This goes away naturally (apparently in 12 to 18 months)

I think you don't have to do blood tests because he has normal sexual development for his age and there are no other signs?

... beeip made a comment on nbme24/block2/q#4 (A 57-year-old man has had hoarseness and difficulty...)
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submitted by beeip(56)

Inability to elevate the palate suggests damage of the vagus nerve.

F. (CN X)

atstillisafraud  I guess F is the vagus nerve. Thanks to NBME I am also training to become a mind reader.
seagull  Thanks to the NBME I have crippling depression
... mcl made a comment on nbme24/block2/q#4 (A 57-year-old man has had hoarseness and difficulty...)
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submitted by mcl(169)

Bonus cadaver diagram, idk why this was on pinterest...........?

yotsubato  nurses
... lamhtu made a comment on nbme24/block2/q#5 (A 55-year-old man is diagnosed with coronary artery...)
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submitted by lamhtu(26)

Platelet adherence and platelet aggregation are different things and this diferrence MATTERS A LOT. Fuck you, NBME. These differences supposedly matter on some questions and not on others. Where is the consistency? Hello?

... step1forthewin made a comment on nbme24/block2/q#5 (A 55-year-old man is diagnosed with coronary artery...)
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submitted by step1forthewin(1)

Can someone please clarify the answer. Is decreased adherence same as decreased aggregation? Wouldn;t inhibition of the IIb/IIIa receptor prevent aggregation?

xxabi  I'm not completely sure...but I think its because its aspirin, and aspirin doesn't work on IIb/IIIa receptors. That's why i picked decreased adherence of platelets, figured that was the closest thing to decreased aggregation that still made sense with aspirin's mechanism of action. Hope that helps!
ihavenolife  Aspirin irreversibly inhibits COX which leads to decreased TXA2. TXA2 normally is a vasoconstrictor and induces platelet aggregation, so aspirin inhibits platelet aggregation by downplaying TXA2 not by interacting with IIb/IIIa receptor. (Source FA and UWorld)
fallenistand  In this case, inhibition of COX-1 by aspirin will also reduce the amount of precursors for vascular prostacyclin synthesis, provided, for example, from adhering platelets https://www.ncbi.nlm.nih.gov/pubmed/9263351
... seagull made a comment on nbme24/block2/q#6 (A 50-year-old woman is admitted to the hospital for...)
 +3  upvote downvote
submitted by seagull(355)

This is a nice approach to identifying and treating factitious disorder.

https://www.google.com/search?q=backhand+slap+text&tbm=isch#imgrc=kvpORbo68F6X2M:

cinnapie  Not all heros wear capes
privwill  Mother of mine strongly believes in this method of treatment...
... famylife made a comment on nbme24/block2/q#7 (A 75-year-old man with a 10-year history of...)
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submitted by famylife(32)

Not a full answer but it's a start (in the context of an obstruction): "Obstruction of urine flow results in an increase in hydrostatic pressures proximal to the site of obstruction. It is this buildup of pressure that leads to the accompanying pain, the distention of the collecting system in the kidney, and elevated intratubular pressures that initiate tubular dysfunction. In the first days of obstruction, the dilatation of the poorly compliant collecting system may be minimal. As the increased hydrostatic pressure is expressed in the urinary space of the glomeruli, further filtration decreases or stops completely." (Harrison's, 20e, Chapter 313)

trichotillomaniac  the key here is the term hydronephrotic kidney. anytime there is that, there is a post renal obstruction of some sort. The fact that he has progressive renal failure just contributes to the idea that his kidneys have seen damage before and are not able to withstand the pressure from the back up as well. I got tripped up on this. The important thing to note is that Hydronephrosis and dilation = back up = increased in volume pressure (hydrostatic)
... guillo12 made a comment on nbme24/block2/q#7 (A 75-year-old man with a 10-year history of...)
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submitted by guillo12(12)

Why there's no increase in Hydrostatic pressure in glomerular capillaries?

rihan  Between the glomerulus and Bowman's space there is a hydrostatic pressure gradient. This gradient is normally the result of a LARGE glomerular hydrostatic pressure and a LOW pressure in Bowman's space which normally favors filtration. Diagram here: http://physiologyplus.com/wp-content/uploads/2017/08/Glomerular-Filtration.png In the case of post-renal obstruction, hydrostatic pressure behind the blockade will rise and urine will reflux into the capsular space and renal tubules (while glomerular hydrostatic pressure is unaffected) effectively decreasing the pressure gradient which reduces the filtration rate.
... famylife made a comment on nbme24/block2/q#8 (A 17-year-old girl is brought to the hospital by...)
 +1  upvote downvote
submitted by famylife(32)

"Beneficence involves balancing the benefits of treatment against the risks and costs involved, whereas non-maleficence means avoiding the causation of harm."

https://www.alzheimer-europe.org/Ethics/Definitions-and-approaches/The-four-common-bioethical-principles/Beneficence-and-non-maleficence

... welpdedelp made a comment on nbme24/block2/q#9 (In which of the following stages of the cell cycle...)
mousie  http://www.sparknotes.com/biology/cellreproduction/cellcycle/section3/page/2/
fahmed14  Cyclins help regulate cell cycle phases. They help with checkpoints before progression to the next phase of a cell cycle. Therefore the checkpoint before mitosis would be in G2 and probably where mitotic specific cyclins are synthesized
artist90  https://en.wikipedia.org/wiki/Cyclin . 4 types of Cyclins and when they rise and fall.
... sweetmed made a comment on nbme24/block2/q#9 (In which of the following stages of the cell cycle...)
 +1  upvote downvote
submitted by sweetmed(28)

Cyclin A,D,E and for G1 to S transition [made in G1]. Cyclin B is for G2 to M transition[made in G2].

... neonem made a comment on nbme24/block2/q#10 (A 29-year-old man is brought to the emergency...)
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submitted by neonem(227)

Pg 491 in FA 2018 (Neurology anatomy & physiology section): 3 muscles close the jaw: Masseter, teMporalis, Medial pterygoid 1 muscle opens the jaw: Lateral pterygoid ALL are innervated by trigeminal nerve, V3 Mnemonic: M's munch (close the jaw), L's lower (loosen/relax the jaw)

... gonyyong made a comment on nbme24/block2/q#11 (A public health consultant is contacted by a health...)
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submitted by gonyyong(19)

Wasn't sure about others, but mammography for general population isn't recommended until 40

_yeetmasterflex  Also wouldn't mammography be secondary prevention since you'd look for asymptomatic disease already present?
... sajaqua1 made a comment on nbme24/block2/q#11 (A public health consultant is contacted by a health...)
 +5  upvote downvote
submitted by sajaqua1(171)

Primary prevention is an active step taken to head off or mitigate a disease- think of vaccinations. In this case, it is lifestyle modification (exercise) to help 30-40 year old women (weight bearing exercise can mitigate osteoporosis, benefits of aerobic exercise).

Seconday prevention is early detection of a disease, promoting early intervention. This could inclue things like HIV testing every 6 months, or or annual mammography.

Tertiary intervention is therapy aiming at reducing complications, allowing relapse, or improving function. Abstinence from alcohol may be here because of substance abuse problems, or because some damage previously done by alcohol cannot be prevented. Similarly for a low carbohydrate diet we may be mitigating the effects on metabolism that have already been done.

... skinnynomore made a comment on nbme24/block2/q#12 (An 80-year-old man is admitted to the hospital...)
 +5  upvote downvote
submitted by skinnynomore(6)

They’re giving a lot of confusing extra information here, maybe to trip us up. They just want volume of distribution, simple as that.

Vd = [drug administered] ÷ [plasma drug concentration]

First convert it all to g/L because this is how the answer will be:

administered: 80 mg = 0.08 g plasma concentration: 4 ug/ml = 0.004 g/L

Thus,

Vd = 0.08 grams ÷ 0.004 g/L = 20 L

Clearance of drug is not a huge factor because the half life is so long that the drug is distributing before significant clearance occurs.

gonyyong  I think the distribution half-life and elimination half-life was saying that by the time you checked, it had fully distributed (10 half-lifes) and had not been cleared yet (super long half-life)
soph  1000ug= 1mg and 1g=1000000ug so then 4ug/ml * 1g/ 1000000ug= 0.000004 g/ml 0.000004g/ml * 1000ml/L= 0.004 g/L 80mg*1g/1000mg= 0.08 g vd= 0.08g/ 0.04g/l =20L
... fahmed14 made a comment on nbme24/block2/q#12 (An 80-year-old man is admitted to the hospital...)
 +3  upvote downvote
submitted by fahmed14(9)

Vd = amount of drug in body / plasma drug concentration.

Amount of drug in body = 80mg

Plasma drug concentration = 4 micrograms/mL = 4mg/L

Vd = 80mg/(4mg/L) = 20L

Distribution half-life is 3 minutes so after 30 min we can assume the drug is maximally distributed. Elimination half-life is 24 hours so we can assume a neglible amount of drug lost

... lm4 made a comment on nbme24/block2/q#12 (An 80-year-old man is admitted to the hospital...)
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submitted by lm4(6)

you could also have used the loading dose equation (because they gave you loading dose and told you it was IV) LD= (Vd x Cp)/ F if you freak out at converting units like I do

... beeip made a comment on nbme24/block2/q#13 (An 80-year-old woman, gravida 4, para 4, comes to...)
lsmarshall  Rectal prolapse through posterior vagina ("rectocele"). https://www.drugs.com/cg/images/en2362586.jpg
famylife  "When a rectocele becomes large, stool can become trapped within it, making it difficult to have a bowel movement or creating a sensation of incomplete evacuation. Symptoms are usually due to stool trapping, difficulty passing stool, and protrusion of the back of the vagina through the vaginal opening. During bowel movements, women with large, symptomatic rectoceles may describe the need to put their fingers into their vagina and push back toward the rectum to allow the stool to pass (“splinting”). Rectoceles are more common in women who have delivered children vaginally." https://www.fascrs.org/patients/disease-condition/pelvic-floor-dysfunction-expanded-version
usmleuser007  really like the pubic hair....
... drachenx made a comment on nbme24/block2/q#13 (An 80-year-old woman, gravida 4, para 4, comes to...)
 +1  upvote downvote
submitted by drachenx(5)

These kinds of questions are really hard because I've never seen female reproductive structures irl. :c

nbmehelp  Lmao
... famylife made a comment on nbme24/block2/q#14 (A 25-year-old man comes to the emergency department...)
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submitted by famylife(32)

opioid withdrawal sxs (FA 2019, p. 558) = sweating, dilated pupils, piloerection (“cold turkey”), rhinorrhea, lacrimation, yawning, nausea, stomach cramps, diarrhea (“flu-like” symptoms)”

... kchakhabar made a comment on nbme24/block2/q#15 (An investigator is studying a new drug for the...)
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submitted by kchakhabar(12)

Radiation causes damage by generating hydroxyl free radicals (Pathoma chapter 3 table). Therefore, if something minimizes the damage of radiation, it has to inhibit free radical formation.

... m-ice made a comment on nbme24/block2/q#16 (A 28-year-old man with chronic hepatitis C comes to...)
 +1  upvote downvote
submitted by m-ice(116)

The patient seems to have an infection due to their elevated temperature and abnormal chest X-ray. However, their leukocyte count is low. In addition, the patient has hepatitis C, which is often associated with similar transmission routes to HIV, like intravenous drug use.

sajaqua1  Not only is their WBC count low, it is not uniform. If we assume a minimum normal WBC count of 5000 cells/mL^3, and a regular range of ~60% neutrophils, then normally a person should have ~3,000 neutrophils/mL^3. This patient has a total of 2000 cells/mL^3, with 1,800 neutrophils/mL^3. Their lymphocytes and macrophages have been whiped out. This is best accounted for by HIV.
... m-ice made a comment on nbme24/block2/q#17 (A 68-year-old man comes to the physician because he...)
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submitted by m-ice(116)

All of the features described of this patient would be expected of a 68-year-old man. Shorter, less intense orgasms, as well as increased time needed between sex could be related to a slight drop in testosterone with age. However, he continues to grow hair well (feet and toes), implying that he hasn't dramatically lost testosterone production. His prostate is slightly enlarged, which could imply benign prostatic hyperplasia, but this should not directly impact his sexual function.

... welpdedelp made a comment on nbme24/block2/q#18 (A 68-year-old man has loss of pain and temperature...)
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submitted by welpdedelp(64)

This was lateral medullar syndrome aka dorsolateral infarct of the PICA.

... m-ice made a comment on nbme24/block2/q#18 (A 68-year-old man has loss of pain and temperature...)
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submitted by m-ice(116)

The patient has loss of pain and temperature on the right side of his face. Sensation of the face is ipsilateral, so the issue must be on the patient's right side, which we can confirm by knowing that sensation of the body is contralateral, and he has lost left sided pain and temperature of the body.

Pain and temperature sensation of the body is part of the spinothalamic tract, which always runs laterally through the brainstem. This can be confirmed by remembering that sensation to the face also runs laterally through the brainstem. So, we can confirm this is a right sided lateral brainstem issue.

The loss of gag reflex and paralysis of the vocal cords imply impairment of cranial nerves IX and X, both of which localize to the medulla. Therefore, the answer is right dorsolateral medulla.

duat98  You're a good man.
charcot_bouchard  You must be handsome too
... brethren_md made a comment on nbme24/block2/q#18 (A 68-year-old man has loss of pain and temperature...)
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submitted by brethren_md(39)

Lateral Medullary Syndrome (Wallenberg) - see FA for more details. Symptoms for this syndrome match up with what is being presented.

... charcot_bouchard made a comment on nbme24/block2/q#18 (A 68-year-old man has loss of pain and temperature...)
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submitted by charcot_bouchard(42)

I get why its lateral but dont all cranial nerve except 4 arise Ventrally? WTF they add this Dorso before lateral?

... neonem made a comment on nbme24/block2/q#19 (A 70-year-old man comes to the physician because of...)
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submitted by neonem(227)

This patient has pulmonary fibrosis, which causes a restrictive (not obstructive)-type disease. Since there was no occupational exposure, I'm assuming this is idiopathic pulmonary fibrosis. This causes thickened alveolar membranes, limiting gas diffusion. Therefore, eventually O2 won't be able to diffuse quickly enough into the blood across the alveolar-arterial membrane, resulting in a larger A-a difference. (I think there's normally a small A-a gradient, from 2-14 mm Hg, but when this gets too big, you get hypoxic)

... medstruggle made a comment on nbme24/block2/q#20 (A 52-year-old man is admitted to the hospital for...)
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submitted by medstruggle(5)

Why is the answer “granulation tissue”? I thought after 14 days you have a fully formed scar.

colonelred_  If you go back and look at the image you can see that it was highly vascular which is characteristic of granulation tissue. Scar tissue formation will be closer to 1 month, plus you will see lots of fibrosis on histology.
sympathetikey  It's a bit misleading, for me, since you do see fibrosis intermixed with the granulation tissue, but granulation tissue was a better answer.
haliburton  According to FA 2017: 3-14d: Macrophages, then granulation tissue at margins. 2wk to several months: Contracted scar complete. Dressler syndrome, HF, arrhythmias, true ventricular aneurysm (risk of mural thrombus). i'm getting pretty frustrated with NBME contradictions to FA, and FA omissions of content. this stuff is hard enough to get straight as it is.
yotsubato  Thats cause the NBME exam writers read FA, then make questions not fit in with FA
trichotillomaniac  This fits the timeline laid out in Pathoma! 1-3 wks = granulation tissue with plump fibroblasts, collagen, and blood vessels
... fallenistand made a comment on nbme24/block2/q#20 (A 52-year-old man is admitted to the hospital for...)
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submitted by fallenistand(5)

Since you see vascularity that is why it is granulation tissue. Fibrous scar would be 1 month after and you wouldn't see that much blood.

dentist  The v-fib/death is an attempt to throw you off. The simple way of asking this question would have been: "18 days after an MI, you should see____?"
... neonem made a comment on nbme24/block2/q#21 (A 50-year-old woman with HIV infection comes to the...)
 +5  upvote downvote
submitted by neonem(227)

NRTIs are the main HIV therapy drug that can cause bone marrow suppression (not as common with NNRTIs). This class includes zidovudine, didanosine, emtricitabine, lamivudine, stavudine, abacavir. Zidovudine is most known for this side effect.

Nelfinavir = protease inhibitor azithromycin = aminoglycoside (not really used for HIV) pentamidine = another antimicrobial, mostly used for pneumocystis I think? Lamivudine = another NRTI but less known for bone marrow suppression

adisdiadochokinetic  Azithromycin is a macrolide, not an aminoglycoside FYI, and its use in HIV is primarily as prophylaxis at very low CD4 counts for, among other things, the mycobacterium avium complex.
nbmehelp  How would we have known to choose Zidovudine over Lamivudine tho
mjmejora  @nbmehelp the sketchy with Princess Izolde (Zidovudine) eating bone marrow was my only tip off
... lsmarshall made a comment on nbme24/block2/q#22 (A 3-month-old boy is brought to the physician...)
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submitted by lsmarshall(181)

Zellweger syndrome - autosomal recessive disorder of peroxisome biogenesis due to mutated PEX genes. Hypotonia, seizures, hepatomegaly, early death (within 1 year). β-oxidation of VLCFA happens in peroxisomes so the child seemingly having some sort of congenital metabolic disorder with elevated VLCFAs should have been enough to get the answer without knowing about Zellweger.

... karljeon made a comment on nbme24/block2/q#23 (A 9-year-old boy who was adopted from an African...)
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submitted by karljeon(19)

Vitamin E deficiency causes hemolytic anemia, acanthocytosis, muscle weakness, posterior column and spinocerebellar tract demyelination.

karljeon  Can anyone explain why the serum lactate dehydrogenase (LDH) level was elevated?
asapdoc  Vitamin E is an antioxidant. Thus a deficiency can cause hemolytic anemia.
sympathetikey  @karljeon Intravascular hemolysis = LDH release from RBCs
... brethren_md made a comment on nbme24/block2/q#23 (A 9-year-old boy who was adopted from an African...)
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submitted by brethren_md(39)

Vitamin B12 is the distractor in this question because it also causes a broad-based, ataxic gait and decrease in vibration. But - Vitamin B12 will not have symptoms like Hemolytic Anemia (decreased hemoglobin, increased LDH). Vitamin E = answer, see below for explanation.

gonyyong  Also the MCV was normal, not megaloblastic like you would see in B12 deficiency
... dbg made a comment on nbme24/block2/q#23 (A 9-year-old boy who was adopted from an African...)
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submitted by dbg(18)

WTF is "weakness of plantar dorsiflexion" ????? it's like saying "extension flexion" This is not the only obvious technical mistake in the new NBMEs ...

karthvee  loool
... lsmarshall made a comment on nbme24/block2/q#24 (A 59-year-old man has repeated episodes of gouty...)
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submitted by lsmarshall(181)

"Probenecid and high-dose salicylates inhibit reabsorption of uric acid in proximal convoluted tubule (also inhibits secretion of penicillin)." - First Aid 2019

uslme123  so ...............
adisdiadochokinetic  So probenecid is the best answer here because they only specified acetylsalicylic acid, not the dosage, and low-dose acetylsalicylic acid has the opposite effect.
... lsmarshall made a comment on nbme24/block2/q#25 (A 35-year-old African American man comes to the...)
 +10  upvote downvote
submitted by lsmarshall(181)

Acral lentigious is most common type of melanoma in African Americans and is on the palms or soels. I guess the typical thinking of chest and back (sun exposed) is a little different in this type? Among all demographics; melanomas occur the majority of time on the limbs (~36% lower and ~19% upper); trunk is ~27%... So based on that and him being of African descent we can choose palms.

... famylife made a comment on nbme24/block2/q#25 (A 35-year-old African American man comes to the...)
... medstruggle made a comment on nbme24/block2/q#26 (A 35-year-old man is brought to the emergency...)
 +2  upvote downvote
submitted by medstruggle(5)

Can someone explain why does this patient have hypokalemia?

colonelred_  Catecholamines activate the Na/K pump, which will drive K inside.
trazabone  Read online that catachelamines are released following tonic clonic seizures. Besides that, BP of 180/100 could indicate that catecholamines are circulating.
fulminant_life  This mechanism is why giving albuterol for hyperkalemia works
nbmehelp  Why does this guy have increased catecholamines tho
johnson  His SNS activity is seriously increased --> increased catecholamines.
nbmehelp  Why is his SNS activity increased? Is the BP literally the only hint?
youssefa  Alcohol withdrawal creates a hyper- catecholaminergic state + Seizures do that as well.
water  My best guess is that withdrawal puts the body in a state of stress (same for seizures) and with stress you have release of catecholamine which we'll see in the BP and the hypokalemia.
... neonem made a comment on nbme24/block2/q#27 (A 47-year-old man comes to the physician because of...)
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submitted by neonem(227)

These are gout crystals. I suppose the best way to differentiate this case from pseudogout is that the crystals are sharp & needle-shaped and not rhomboid-shaped.

sympathetikey  Yep. They tried to throw you off with the picture, but the wording in the stem says its a "photomicrograph" -- not exposed to plane polarized light, where you would see the negative birefringence.
... step420 made a comment on nbme24/block2/q#28 (A 3-year-old boy with AIDS develops giant cell...)
 +3  upvote downvote
submitted by step420(17)

Question pretty much is asking what type of virus is Measles, which is a Negative ssRNA virus.

dragon3  is the AIDS to indicate that he can't get live vaccinations?
tinydoc  Yep, also his unimmunized cousin points you to the fact that he got it from someone else who was unimmunized.
... ameanolacid made a comment on nbme24/block2/q#29 (A 65-year-old woman with well-controlled type 2...)
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submitted by ameanolacid(12)

Atherosclerosis is the MOST common cause of renal artery stenosis...with fibromuscular dysplasia being the SECOND most common cause (even though it is tempting to choose this option considering the patient's demographic).

xxabi  Is there a situation where you would pick fibromuscular dysplasia over atherosclerosis if given both options? Thanks for your help!
baconpies  Atherosclerosis affects PROXIMAL 1/3 of renal artery Fibromuscular dysplasia affects DISTAL 2/3 of renal artery
gonyyong  Why is there ↓ size in both kidneys? This threw me off
kateinwonderland  @gonyyong : Maybe because narrowed renal a. d/t atherosclerosis led to renal hypoperfusion and decrease in size?
drdre  Fibromuscular dysplasia occurs in young females according to Sattar Pg 67, 2018.
davidw  Normally you will see Fibromuscular dysplasia in a young female 18-35 with high or resistant hypertension. She is older has a history type II DM predispose you to vascular disease and normal to moderate elevation in BP
... fenestrated made a comment on nbme24/block2/q#29 (A 65-year-old woman with well-controlled type 2...)
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submitted by fenestrated(5)

My reasoning was 135/80 BP relatively normal.. in fibromuscular dysplasia I believe it would be higher due to increase in renin. Her hx of diabetes + low hemoglobin (damage to renal peritubular capillaries) also pushed me towards atherosclerosis.

also per FA2019 p298--> "usually seen in women of child-bearing age" this pt was 65

... neonem made a comment on nbme24/block2/q#30 (A 35-year-old man with small cell carcinoma of the...)
 +7  upvote downvote
submitted by neonem(227)

Small cell carcinoma of the lung may produce paraneoplastic syndromes, of which ACTH and ADH are the more common subtypes. ACTH excess leads to excess stimulation on the adrenal cortex to produce cortisol, resulting Cushing's syndrome. Excess cortisol (normally a stress hormone) causes hypertension via potentiation of sympathetic stimulation on the vasculature. It can also cause hypokalemia by acting as a mineralocorticoid when in excess, saturating the ability of 11-beta-hydroxysteroid dehydrogenase (present in the renal tubules) to convert cortisol to cortisone, which doesn't act as a mineralocorticoid.

... famylife made a comment on nbme24/block2/q#30 (A 35-year-old man with small cell carcinoma of the...)
 +1  upvote downvote
submitted by famylife(32)

To rule out SIADH type: "Serum potassium concentration generally remains unchanged. Movement of potassium from the intracellular space to the extracellular space prevents dilutional hypokalemia. As hydrogen ions move intracellularly, they are exchanged for potassium in order to maintain electroneutrality."

https://www.medscape.com/answers/246650-8383/how-does-syndrome-of-inappropriate-antidiuretic-hormone-secretion-siadh-affect-serum-potassium-levels

... lsmarshall made a comment on nbme24/block2/q#31 (A patient with cancer who is being treated with...)
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submitted by lsmarshall(181)

Filgrastim (G-CSF) is very commonly tested this way; UWorld and elsewhere. Chemo. patient with bone marrow surpression > give G-CSF.

... bigjimbo made a comment on nbme24/block2/q#32 (A 35-year-old woman undergoes a left oophorectomy...)
 +1  upvote downvote
submitted by bigjimbo(6)

The suspensory ligament contains the ovarian vessels. Since that is not an answer choice, it has to be the ureters, as the ureters and the ovarian vessels run posterior to the ovaries (where the ovarian vessels branch off to be contained in the suspensory ligament).

... seagull made a comment on nbme24/block2/q#32 (A 35-year-old woman undergoes a left oophorectomy...)
... xxabi made a comment on nbme24/block2/q#33 (A 58-year-old man comes to the physician because of...)
 +2  upvote downvote
submitted by xxabi(82)

Most common cause of acute prostatitis in older men is E. Coli, and then Pseudomonas.

charcot_bouchard  Grandpa is monogamous. Sexual history was just to throw u off
... bunye made a comment on nbme24/block2/q#34 (A 40-year-old man who goes horseback riding 3 to 4...)
 +4  upvote downvote
submitted by bunye(4)

Mesenchymal tissue can also undergo metaplasia.

A classic example is myositis ossificansmin which connective tissue within muscle changes to bone during healing after trauma - Pathoma Ch 1 pg 2

bunye  ossificans in which*
famylife  Images: https://www.google.com/search?q=myositis+ossificans&rlz=1C1CHZL_enUS753US753&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjytonS0dfiAhWMVN8KHaE2CUUQ_AUIECgB&biw=1368&bih=809#imgrc=tw9b-AqKfJOb7M:
... coolcatac made a comment on nbme24/block2/q#34 (A 40-year-old man who goes horseback riding 3 to 4...)
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submitted by coolcatac(5)

https://www.medicalnewstoday.com/articles/320718.php

"Myositis ossificans usually occurs where a person has experienced a single traumatic injury, such as sustaining a hit while playing football or soccer that causes a deep muscle bruise.

It can also happen when there is a repetitive injury to the same area, such as in the thighs of horseback riders. Very rarely, myositis ossificans can occur after a severe muscle strain."

... sattanki made a comment on nbme24/block2/q#35 (A 55-year-old woman comes to the physician because...)
 +1  upvote downvote
submitted by sattanki(27)

Does anyone have any idea on this question? Thought it was ALS.

ankistruggles  I thought it was ALS too (and I think it still could be?) but my thought process was that a lower motor neuron lesion would be the more specific answer.
sattanki  Yeah makes sense, just threw me off cause ALS is both lower and upper motor neuron problems. Corticospinal tract would have been a better answer if they described more upper motor neuron symptoms, but as you said, they only describe lower motor neuron symptoms. Thanks!
mousie  Agree I thought ALS too but eliminated Peripheral nerves and LMN because I guess I thought they were the same thing ....??? Am I way off here or could someone maybe explain how they are different? Thanks!
baconpies  peripheral nerves would include motor & sensory, whereas LMN would be just motor
seagull  Also, a LMN damage wouldn't include both hand and LE unless it was somehow diffuse as in Guil-barre syndrome. It would likely be specific to part of a body. right???
charcot_bouchard  No. if it was a peri nerve it would be limited to a particular muscle or muscles. but since its lower motor neuron it is affecting more diffusely. Like u need to take down only few Lumbo sacral neuron to get lower extremity weakness. but if it was sciatic or CFN (peri nerve) it would be specific & symptom include Sensory.
... tissue creep made a comment on nbme24/block2/q#35 (A 55-year-old woman comes to the physician because...)
 +0  upvote downvote
submitted by tissue creep(22)

I treated this like Werdning Hoffman/SMA ("tongue fasciculations"), and just kind of accepted it being weird to be in a 55-year-old.

dr.xx  SMA4 (Adult-onset)?
... guillo12 made a comment on nbme24/block2/q#35 (A 55-year-old woman comes to the physician because...)
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submitted by guillo12(12)

"The loss of lower motor neurons leads to weakness, twitching of muscle (fasciculation), and loss of muscle mass (muscle atrophy)".

https://www.medicinenet.com/script/main/art.asp?articlekey=33870

... tinydoc made a comment on nbme24/block2/q#35 (A 55-year-old woman comes to the physician because...)
 +1  upvote downvote
submitted by tinydoc(39)

I don't think it matters whether or not this was ALS ( which I still think it is). But theres fasiculations and Weakness and atrophy those are LMNL signs. Theres sooo many sneaky questions in this exam, this isnt one of them.

... brethren_md made a comment on nbme24/block2/q#36 (A 27-year-old woman comes to the physician for a...)
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submitted by brethren_md(39)

TGF-Beta is an important fibroblast growth factor. Pathoma Ch2, page 20.

... seagull made a comment on nbme24/block2/q#36 (A 27-year-old woman comes to the physician for a...)
 +4  upvote downvote
submitted by seagull(355)

This is either a hypertropic scar or keloid. Both arise due to over-expression of TGF-beta.

charcot_bouchard  i think its a foreign body granuloma
... snafull made a comment on nbme24/block2/q#36 (A 27-year-old woman comes to the physician for a...)
 +0  upvote downvote
submitted by snafull(1)

Can somebody explain why this is not a foreign body granuloma?

yb_26  because they mention scattered fragments of foreign material (pt presents 2 months after c-section, sutures are either removed in 1 week or dissolve in few weeks (depends on type of suture material)
... famylife made a comment on nbme24/block2/q#37 (In a culture of motile spore-forming bacteria, which...)
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submitted by famylife(32)

"double-strand breaks...are caused by ionizing radiation, including gamma rays and X-rays." vs. "UV radiation causes two classes of DNA lesions: cyclobutane pyrimidine dimers (CPDs, Figure 1) and 6-4 photoproducts (6-4 PPs, Figure 2)."

https://www.nature.com/scitable/topicpage/dna-damage-repair-mechanisms-for-maintaining-dna-344

... usmleuser007 made a comment on nbme24/block2/q#37 (In a culture of motile spore-forming bacteria, which...)
 +2  upvote downvote
submitted by usmleuser007(86)

Simply put: more energy in a light wave the more likely it is to cause cellular (DNA) damage.

Ultraviolet has less energy than X-rays (it goes through your flesh to see bones!)

Order of light strength (cell damaging capability)

  • X-Ray > UVA (also able to cause double strand break) > UVB (most likely single strand break - repaired)
... neonem made a comment on nbme24/block2/q#38 (A 65-year-old man comes to the physician because of...)
 +2  upvote downvote
submitted by neonem(227)

This patient has major depressive disorder: loss of interest/anhedonia (need to have this or depressed mood),sleep problems, weight changes, decreased energy, thoughts of death. Meets criteria because > 2 weeks timeframe. SSRIs are first-line; paroxetine is in this category. SSRIs also help with weight gain - might be an added benefit if the patient is underweight.

The cardiac stuff might have just been a distractor, except that you probably wouldn't want to give tricyclics (i.e. amitriptyline) since they have pro-arrhythmic side effects. Patient probably has prolonged PR interval due to beta blockers.

adisdiadochokinetic  Another reason not to use TCAs (or alprazolam or haloperidol for that matter) is that the Beers criteria state to avoid the use of all of those drugs in patients over the age of 65.
... m-ice made a comment on nbme24/block2/q#39 (A 3-year-old boy has short stature and extremities...)
 +1  upvote downvote
submitted by m-ice(116)

This boy has achondroplasia, which is caused by an autosomal dominant mutation in Fibroblast Growth Factor Receptor 3. FGF signaling is needed for proper cartilage function, and without it, the long bones of the body will not grow because the growth plate (made of chondrocytes) does not function. However, bones that undergo membranous ossification, like the bones of the head, will grow normally. This results in the patient having short extremities with a normal size trunk and large head relative to the limbs.

... famylife made a comment on nbme24/block2/q#40 (A 4-year-old boy has a 1-cm round midline mass just...)
 +5  upvote downvote
submitted by famylife(32)

"Thyroglossal duct cysts most often present with a palpable asymptomatic midline neck mass usually below [65% of the time] the level of the hyoid bone."

"The thyroglossal tract arises from the foramen cecum at the junction of the anterior two-thirds and posterior one-third of the tongue."

https://en.wikipedia.org/wiki/Thyroglossal_cyst

dbg  Am I the only one who thought, my whole life, that it actually originates from the thyroid but just physically connected to the tongue
... dbg made a comment on nbme24/block2/q#40 (A 4-year-old boy has a 1-cm round midline mass just...)
 +1  upvote downvote
submitted by dbg(18)

Am I the only one who thought, my whole life, that it actually originates from the thyroid but just physically connected to the tongue

nbmehelp  same
... m-ice made a comment on nbme24/block2/q#41 (A 56-year-old man who is admitted to the hospital...)
 +2  upvote downvote
submitted by m-ice(116)

Autonomy is the most important ethics principle that supersedes all others. However, it is applied only in situations in which a patient demonstrates decision-making capacity. In this situation, a patient with advanced disease unlikely to be cured is refusing treatment, which is his right under the principle of autonomy. However, his comments about "returning in 6 months after curing arthritis" are questionable, and warrant determining if he has decision making capacity. It is possible that he does, which is why any choices of forcing further treatment on him are incorrect.

... colonelred_ made a comment on nbme24/block2/q#42 (A 3-week-old female newborn is brought to the...)
 +6  upvote downvote
submitted by colonelred_(44)

The analysis only showed a mutation in one allele. CF is an autosomal recessive disease: the disease only manifests if there are mutations in both alleles of the CFTR gene.

If you still have 1 functional copy of the CFTR gene, you can still make the CFTR protein (the chloride channel/transporter), hence your body won’t have any issues.

This is analogous to tumor suppressor genes like Rb: so long as one of the alleles you have is functional, you can make enough of the protein to “make up” for the defective allele. If both get knocked out (Rb-/-), you lose the protection provided by the gene because now you make no protein at all.

The only thing that made sense for this question was the fact that the other allele was not included in the analysis.

charcot_bouchard  OR another allele has a diff type of mutation because CF is done by like hundreds of diff type of mutation. SO the 70 types that we screened covered one type from one parent but not another that was inherited from other parent.
soph  I put D thinking there was a mutation in another protein that interacts with CFTR....thus u dont have CF but some disease with similar phenotype. Is this wrong bc its simply not the case ??
nbmehelp  @charcot_bouchard I think that makes more sense if I understand what you're saying- Probably had a mutation only in 1 of 2 of the same alleles in the analysis but had another mutation in 2 of 2 alleles at a different location not included in the analysis, right?
... sweetmed made a comment on nbme24/block2/q#42 (A 3-week-old female newborn is brought to the...)
 +0  upvote downvote
submitted by sweetmed(28)

you need a mutation in 2 alleles to get CF [since it is autosomal recessive]/

... beeip made a comment on nbme24/block2/q#43 (A 35-year-old woman has difficulty urinating 2 days...)
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submitted by beeip(56)

Can anyone explain what they're getting at here? How can bethanechol be indicated and contraindicated?

sniperx3  I think it's because Bethanechol acts on M3 receptors which can treat her urinary problems but it might exacerbate her asthma symptoms since there are M3 receptors on the lungs.
... coolcatac made a comment on nbme24/block2/q#43 (A 35-year-old woman has difficulty urinating 2 days...)
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submitted by coolcatac(5)

They are asking, in a complicated way, the mode of action of Bethanechol. All the other options are not muscarinic receptors except parasympathetic stimulation.

... neonem made a comment on nbme24/block2/q#44 (A 35-year-old man with quadriplegia develops a...)
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submitted by neonem(227)

Aminoglycosides are nephrotoxic; nephrotoxic chemicals/drugs cause acute tubular necrosis (ATN), characterized by damage to the PCT. ATN causes the formation of brown, muddy, granular casts in the urine. The fact that this patient is a quadriplegic might be suggesting that they have a lower volume of distribution for the drug (and therefore higher blood concentrations).

... yotsubato made a comment on nbme24/block2/q#45 (A 2-year-old boy is brought to the physician because...)
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submitted by yotsubato(214)

Cool another question taken from the list of things not in FA

charcot_bouchard  Actually it is in FA. FA 19 Page 100 - Antigen loaded onto MHC1 in RER after delivery via TAP transporter.... Remember FA is that friend who always say I told you so.
yotsubato  But not in this context
... lsmarshall made a comment on nbme24/block2/q#45 (A 2-year-old boy is brought to the physician because...)
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submitted by lsmarshall(181)

MHC class 1 peptide antigen processing > "Antigen peptides loaded onto MHC I in RER after delivery via TAP (transporter associated with antigen processing)" - First Aid 2019.

Bare lymphocyte syndrome type 2 (BLS II; affecting MHC II) is due to mutations in genes that code for transcription factors that normally regulate the expression (gene transcription) of the MHC II genes. Bare lymphocyte syndrome type 1 (BLS I; affecting MHC I), is much more rare, and is associated with TAP deficiencies.

... m-ice made a comment on nbme24/block2/q#46 (In a study of drug action on neoplastic cells in...)
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submitted by m-ice(116)

Vincristine is a chemotherapeutic drug that stabilizes microtubules and prevents them from disassembling. The cell in the picture is stuck in anaphase, with microtubules attached to its chromosomes, unable to pull them apart because it cannot disassemble its microtubules.

vshummy  So I get that by process of elimination cyclophosphamide, cyclosporine, doxorubicin, and 5-fluorouracil are not related to microtubules but vincristine in First Aid 2019 says it prevents microtubule formation, doesn’t stabilize it because the one that stabilizes microtubules is paclitaxel.
vshummy  Okay, I realize now- the picture is stuck in metaphase, not anaphase. Both paclitaxel and vincristine stop the cell in metaphase but by two different mechanisms. Vincristine prevents mitotic *spindle* formation while paclitaxel prevents mitotic spindle *breakdown*. Mitotic spindle is needed to pull the chromosomes apart before anaphase begins.
... daddyyikes made a comment on nbme24/block2/q#46 (In a study of drug action on neoplastic cells in...)
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submitted by daddyyikes(0)

it wasz the the shittiest question that i have ever read in my entire life ever!

... m-ice made a comment on nbme24/block2/q#47 (A 73-year-old man has an incurable malignant...)
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submitted by m-ice(116)

The most important ethical principle that supersedes all others is autonomy. From an ethical standpoint, this patient has the right to refuse further treatment as he is mentally competent, in this case in the form of having the respiratory removed. From a legal standpoint, the physician is allowed to discontinue treatment for a patient if that is what the patient wants. This is different from situations of physician assisted suicide, which is more complicated and has variable ethics and legality.

rhsteps  isnt this considered physician assisted suicide?
johnson  No - treatment is being withdrawn per the mentally competent patient's wishes. m-ice explained it well.
johnson  No - treatment is being withdrawn per the mentally competent patient's wishes. m-ice explained it well.
johnson  No - treatment is being withdrawn per the mentally competent patient's wishes. m-ice explained it well.
... medstruggle made a comment on nbme24/block2/q#48 (The breakdown of dipeptides and tripeptides to free...)
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submitted by medstruggle(5)

Why is duodenal lumen incorrect? I thought pancreatic enzymes (chymotrypsin, carboxypeptidase) would be located here.

colonelred_  Enterokinase actives trypsinogen and is located closer to the intestinal mucosal (“brush border”).
drdoom  Yeah, @colonelred is right. @medstruggle: the duodenal lumen (and the pancreatic /proteases/ you mention) is the site where pancreatic enzymes (“endopeptidases”) cleave large polypeptides into smaller bits. It is at the BRUSH BORDER where the smallest kinds of peptides (dipeptides, tripeptides) are broken down into their amino acids, which finally can be co-transported with Na+ into the intestinal cell. I think about it this way: stomach acid denatures and “opens up” proteins (without any specific cleavage); pancreatic enzymes then cleave denatured polypeptides into smaller bits; brush border enzymes finally break down tiny peptides into absorbable amino acids.
welpdedelp  http://1.bp.blogspot.com/-UDdBiBiEgec/UzM61mV4pTI/AAAAAAAABRA/_qCG05fliGk/s1600/VBN.PNG
drdoom  Nice schematic, @welpdedelp
... drdoom made a comment on nbme24/block2/q#48 (The breakdown of dipeptides and tripeptides to free...)
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submitted by drdoom(167)

The duodenal lumen (and pancreatic proteases like CHYMOTRYPSIN) is the site where pancreatic enzymes (“endopeptidases”) cleave large polypeptides into smaller bits (=dipeptides,tripeptides). It is at the BRUSH BORDER where the smallest kinds of peptides (dipeptides,tripeptides) are broken down into their amino acids, which finally can be co-transported with Na+ into the intestinal cell.

I think about it this way:

  • stomach acid denatures and “opens up” proteins (without specific cleavage);
  • pancreatic enzymes then cleave denatured polypeptides into smaller bits;
  • brush border enzymes finally break down tiniest peptides into absorbable amino acids.
... seagull made a comment on nbme24/block2/q#48 (The breakdown of dipeptides and tripeptides to free...)
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submitted by seagull(355)

The semantics of this question made me vomit blood.

One day a patient will look me in the eyes and ask, "Where are tripetides broken down?" I will smile at them and say, "the intestinal mucosa and not the duodenum." They'll smile back and I'll walk away and think of this moment as I jump from the window.

sympathetikey  Too real.
mcl  how do i upvote multiple times
trichotillomaniac  I made an account solely so I could upvote this.
dragon3  ty for the chuckle
cinnapie  @trichotillomaniac Same
... seagull made a comment on nbme24/block2/q#48 (The breakdown of dipeptides and tripeptides to free...)
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submitted by seagull(355)

The semantics of this question made me vomit blood.

At least one day a patient will look me in the eyes and ask " where are tripetides broken down at". I will smile at them and say "the intestinal mucosa and not the duodenum". They'll smile back and then i'll then i'll walk away and think of this moment as I jump from the window.

... lsmarshall made a comment on nbme24/block2/q#49 (A 17-year-old girl comes to the physician because...)
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submitted by lsmarshall(181)

Androgen Insensitivity Syndrome - Defect in androgen receptor resulting in normal-appearing female (46,XY DSD). Functioning testes causes increased testosterone at puberty, which is converted to estrogen peripherally, giving female secondary sexual characteristics (female external genitalia). Lack of androgen receptor function leads to absent or scant axillary and pubic hair. Patients have rudimentary vagina, but uterus and fallopian tubes absent.

Androgen insensitivity syndrome is the answer but you might have considered Müllerian agenesis (Mayer-Rokitansky- Küster-Hauser syndrome).

Mullerian agenesis will have normal hormone levels and may present as 1° amenorrhea (due to a lack of uterine development) in females with fully developed 2° sexual characteristics (functional ovaries). Hair development is normal as well. Patients also have normal height.

Seems like this question did not give us much to distinguish besides height and tanner stage 1 pubic/axillary hair.

dbg  100% agreed. Mullerian agenesis was on my mind too. The full breast development kept me fixed at this dx. Did not think how high testosterone at this age and insensitivity would push towards peripheral conversion to estrogen and hence breast development. Thanks.
... seagull made a comment on nbme24/block2/q#49 (A 17-year-old girl comes to the physician because...)
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submitted by seagull(355)

at BMI 15 not only has she never had a period but she never had a meal.

sympathetikey  You're on fire man lol
... lsmarshall made a comment on nbme24/block2/q#50 (An obese 57-year-old man comes to the physician for...)
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submitted by lsmarshall(181)

Metaplasia - A reversible adaptive response in which there is "Reprogramming of stem cellsŽreplacement of one cell type by another that can adapt to a new stress." Both are normal cells. Respiratory tree should not have squamous cells until respiratory bronchioles (before that; cuboidal in term. bron. > columnar in bronch. > pseudostratified columnar in large. bronch.).

shayan  if its a metaplasia, then how it be normal ? I mean Metaplasia is not normal?
artist90  i got it confused bc the question stated that there was a mass in one lobe of lung and i didn't knew that squamous metaplasia also presents as a mass in lung. i missed that on biopsy they were clearly stating squamous metaplasia.
... m-ice made a comment on nbme24/block3/q#1 (A 3-year-old girl has a history of recurrent...)
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submitted by m-ice(116)

This girl has chronic granulomatous disease, in which the immune system cannot properly form reactive oxygen species needed to kill phagocytosed organisms. This is especially bad when dealing with catalase positive organisms (like Staph), because these organisms already use catalase to break down reactive oxygen species. The most common cause of this condition is a mutation in NADPH oxidase, responsible for the generation of the superoxide radical.

et-tu-bromocriptine  To add on: If neutrophils don't have access to NADPH oxidase, they can still use the bacteria's own hydrogen peroxidase to create ROS and kill the bacteria; however, catalase + organisms will not have this hydrogen peroxidase available (because catalase converts hydrogen peroxidase to O2 and water). So then the neutrophils are screwed and have no way of creating ROS.
... pmnbp made a comment on nbme24/block3/q#2 (A 28-year-old man has a blood pressure cuff placed...)
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submitted by pmnbp(1)

could someone please explain why adenosine is correct?

drdoom  After the cuff is tied, the cells and tissue distal to the cuff will continue consuming ATP (ATP->ADP), but no fresh blood will be delivered to “clear” what will be an accumulating amount of ADP and other metabolites. ADP (=Adenosine) is itself a proxy of consumption and drives vasodilation of arteries! (Evolution is smart!) Increasing ADP/Adenosine in a “local environment” is a signal to the body that a lot of consumption is occurring there; thus, arteries and arterioles naturally dilate to increase blood flow rates and “sweep away” metabolic byproducts.
... drdoom made a comment on nbme24/block3/q#2 (A 28-year-old man has a blood pressure cuff placed...)
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submitted by drdoom(167)

After the cuff is tied, the cells and tissue distal to the cuff will continue consuming ATP (ATP->ADP), but no fresh blood will be delivered to “clear” what will be an accumulating amount of ADP and other metabolites. ADP (=Adenosine) is itself a proxy of consumption and drives vasodilation of arteries! (Evolution is smart!) Increasing ADP/Adenosine in a “local environment” is a signal to the body that a lot of consumption is occurring there; thus, arteries and arterioles naturally dilate to increase blood flow rates and “sweep away” metabolic byproducts.

lispectedwumbologist  You're a good man. Thank you.
drdoom  So glad it helped!
seagull  very well put, thank you
... neonem made a comment on nbme24/block3/q#3 (A 37-year-old woman with HIV infection is brought to...)
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submitted by neonem(227)

Just had to know that NRTIs (specifically the nucleosides) cause lactic acidosis

brethren_md  Also NRTIs are hepatotoxic, cause the increased liver enzymes seen in the patient.
sherry  Actually, NNRTIs are more well-known for hepatotoxicity. But I guess NRTIs is the next best option for this one.
... neonem made a comment on nbme24/block3/q#4 (A 27-year-old man comes to the physician because he...)
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submitted by neonem(227)

I think the reason you need to inject gonadotropins in this case is because you need FSH and LH to produce sperm. FSH stimulates the sertoli cells, which line the seminiferous tubules and help the spermatogonia produce spermatocytes. Testosterone is a product of Leydig cells when they're stimulated by LH, so injecting testosterone would bypass that step but it wouldn't really help with spermatogenesis. However, injecting GnRH also doesn't doesn't really help because you need that pulsatile GnRH at night to make LH and FSH whereas long-acting GnRH analogs actually decrease LH and FSH production.

m-ice  Adding on to the answer above. I was stuck between the gonadotropin injections and clomiphene. But, clomiphene acts to increase activity of GnRH which then exerts its effects on the pituitary. The man in this question had his pituitary removed because of an adenoma. So, he needs the FSH and LH directly.
mousie  agree! Removal of the pituitary would case a deficit in Gonadotropins (LH, FSH) and therefore nothing to simulate the testes to make sperm... replacing the T with a patch would not stimulate the testes to make sperm and if his axis was intact (although its not) this would further down regulate the production of sperm. I eliminated Clomiphene because if he dosent have T to induce negative influence on the hypothalamus he will have increased GnRH and further increasing it with Clomiphene would not correct the deficit in Gonadotropins.
neonem  Oh duh... that makes much more sense. Thanks! P.s. I thought clomiphene was more of a fertility drug for women, since it blocks negative feedback of estrogen on the hypothalamus/pituitary. But in men the system is under feedback due to testosterone, not estrogen.
... neonem made a comment on nbme24/block3/q#5 (A 37-year-old man is admitted to the hospital...)
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submitted by neonem(227)

The patient has low cortisol, which causes body wasting. The patient is hyperpigmented since low cortisol increases ACTH secretion from the pituitary, but this shares a common precursor protein with melanocyte-stimulating hormone (MSH), so that's often a sign of either adrenal failure or an ACTH-secreting tumor. Put together, the high ACTH but low cortisol happening over a period of 6 months means that the adrenal must be getting hit by something -- only option here was autoimmune adrenalitis. Waterhouse-Friderichsen syndrome also causes adrenal insufficiency but this happens acutely, in the timeframe of hours-days.

sajaqua1  The combination of low blood pressure (from lack of mineralocorticoids) and low glucocorticoids (cortisol) indicate adrenal failure. Hyperpigmented skin is a sign of elevated ACTH, indicating that this is a failure of the adrenal gland and not the pituitary. In the industrialized western world, autoimmune destruction of adrenal glands is the leading cause of primary adrenal failure (disseminated tuberculoid destruction of the adrenal glands is significant outside of industrialized nations). It also fits the time line better than Waterhouse-Friederichsen syndrome, which is sudden in onset and associated with hemorraging. Metastases to the adrenal glands *might* be a possibility, but autoimmune destruction is simply likelier.
... yotsubato made a comment on nbme24/block3/q#6 (A 43-year-old woman comes to the physician because...)
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submitted by yotsubato(214)

ALT and AST are enzymes within hepatocytes. Without hepatocyte damage, you wont have elevations.

Alkaline phosphatase is present in all tissues throughout the entire body, but is particularly concentrated in the liver, bile duct, kidney, bone, intestinal mucosa and placenta.

... m-ice made a comment on nbme24/block3/q#6 (A 43-year-old woman comes to the physician because...)
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submitted by m-ice(116)

This patient has a gallstone lodged in the common bile duct. Therefore, the markers most likely to be elevated is something from the biliary tract, the best of which is alkaline phosphatase. There could potentially be elevations in AST and ALT, but this is not the MOST likely answer. Unconjugated bilirubin is not a good answer, because the liver can still conjugate all bilirubin, it just has issues now excreting that conjugated form. So the woman's CONJUGATED bilirubin is more likely to be elevated.

... lm4 made a comment on nbme24/block3/q#6 (A 43-year-old woman comes to the physician because...)
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submitted by lm4(6)

in the exocrine pancreas, gallbladder, and liver pathology section of pathoma, sattar mentions that the epithelium lining biliary tract has alkaline phosphatase so when they are damaged it releases this, increasing serum alk phos.

... famylife made a comment on nbme24/block3/q#7 (A 21-year-old woman with asthma comes to the...)
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submitted by famylife(32)

Phase III Clinical Trial (per FA 2019, p. 256): Large number of patients randomly assigned either to the treatment under investigation or to the standard of care (or placebo).

... lsmarshall made a comment on nbme24/block3/q#8 (A 37-year-old man who is a farmworker comes to the...)
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submitted by lsmarshall(181)

Synaptobrevin is the target of tetanospasmin (tetanus toxin); muscle spasms are characteristic. Only other answer you might consider is Acetylcholinesterase since he is a farmer and buzzwords often carry us to the promised land... but symptoms of a cholinergic storm are absent.

vshummy  Synaptobrevin is a SNARE protein. Why they couldn’t just give us SNARE I’ll never know.
yotsubato  Cause they're dicks, and they watched sketchy to make sure our buzzwords were removed from the exam
yotsubato  Oh and they read FA and did UW to make sure its not in there either
soph  This toxin binds to the presynaptic membrane of the neuromuscular junction and is internalized and transported retroaxonally to the spinal cord. Enzymatically, tetanus toxin is a zinc metalloprotease that cleaves the protein synaptobrevin, an integral neurovesicle protein involved in membrane fusion. Without membrane fusion, the release of inhibitory neurotransmitters glycine and GABA is blocked. -rx questions!
... neonem made a comment on nbme24/block3/q#9 (A 43-year-old woman comes to the physician because...)
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submitted by neonem(227)

I think metastasis was the best option here because there are multiple malignant neoplasms... primary cancers tend to start as a single mass in the tissue of origin. In the lung, metastases are more common than primary neoplasms.

dbg  I seriously could not figure out whether those white opacities were actual lesions or reflections from the actual picture (flash light) ... mind went all the way maybe this is the shiny pleura so they're going after mesothelioma. smh
dbg  shiny pleura with tiiiiny granulations if you look closely. but obviously was far off
et-tu-bromocriptine  "Multiple cannonball lesions" is indicative of a metastatic cancer. I think if they were leaning towards a mesothelioma, they'd show the border/edge of the lung ensheathed by a malignant neoplasm (see image): https://library.med.utah.edu/WebPath/jpeg1/LUNG081.jpg
... m-ice made a comment on nbme24/block3/q#10 (Serum cholesterol concentrations are measured as...)
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submitted by m-ice(116)

This question only concerns women in the 50-54 age group. The group has a mean of 246 and standard deviation of 50. Therefore, all those with values greater than 296 are all those above one standard deviation. 2/3 of all values on a normal distribution are within one standard deviation in either direction. Therefore, 1/3 are outside of this in either direction, meaning 1/3 of women have a value less than 196 or greater than 296. If we split that in half to only choose those greater than 296, we get 1/6 women, which is about 16%.

guillo12  Sorry, but there is not other way that I can understand this?
fulminant_life  @guillo12 basically 67% fall within 1 sd. That means that 33% are +/- >1sd. So taking only those with above 296, you only look at those >1sd above the mean which is 16.5% . The other 16.5% are those >1sd below the mean.
guillo12  Thank you!!! @fulminant_life
... monoloco made a comment on nbme24/block3/q#11 (The pedigrees of patients with schizophrenia most...)
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submitted by monoloco(49)

If anyone wouldn’t mind: How am I supposed to know that T1DM has a similar pedigree to schizophrenia? Teach me how to think, ples.

ankistruggles  I think they were getting at how developing T1DM and schizophrenia are both multifactorial. I don’t remember what the other choices were off the top of my head, but they had clear inheritance patterns.
... kchakhabar made a comment on nbme24/block3/q#11 (The pedigrees of patients with schizophrenia most...)
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submitted by kchakhabar(12)

The way I approached this problem was, schizophrenia doesn't have a clear pattern of inheritance. Among the option choices, only Type 1 DM doesn't have a clear inheritance pattern (eg: CF is auto recessive, Fragile X is XD, and so on).

karthvee  lol same here
... lsmarshall made a comment on nbme24/block3/q#11 (The pedigrees of patients with schizophrenia most...)
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submitted by lsmarshall(181)

Monozygotic ("identical") twins have 50% of getting schizophrenia if their twin has it. Dizygotic twins have ~ 20% chance though. This is often mentioned when Schizophrenia etiology is discussed (i.e., we don't know but concordance studies suggest a genetic link). T1DM has less of a genetic link than T2DM but it also has 50% concordance between monozygotic twins. This fact is mentioned in First Aid 2019, page 346... I got this NBME question wrong but it's content is in board sources.

... m-ice made a comment on nbme24/block3/q#12 (A 35-year-old woman with asthma comes to the...)
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submitted by m-ice(116)

This woman has a lot of signs that point toward an intestinal parasitic infection: recent travel to Papua New Guinea, cough and alveolar infiltrates, high eosinophil count, and a stool sample that has a worm in it. Most likely the patient has a Strongyloides infection, as this is the intestinal parasite that shows larva on stool sample. Basically all intestinal parasites can be treated with Bendazole drugs, such as Thiabendazole. Praziquantel would be more appropriate for a worm or liver fluke infection.

fulminant_life  just to add to the explanation above," cutaneous larva currens" is a specific finding for strongyloides. Also the picture they used is the exact same one on wikipedia lol
yb_26  they really should add Wikipedia in the list of top-rated review resources with A+ level of recommendation in FA2020)))
... lispectedwumbologist made a comment on nbme24/block3/q#13 (An 83-year-old woman is brought to the physician by...)
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submitted by lispectedwumbologist(23)

Can anybody explain this one? I put repeated tests because I assumed an 83-year-old woman is an unusual demographic for syphilis.

m-ice  83 might seem an uncommon age, but we don't know for sure her sexual history. She only recently (8 months ago) started showing some signs of mild cognitive impairment. She has all these results implying that she has syphilis, so the most likely answer is that she has syphilis, so we should speak to her privately about her sexual history. The tests don't necessarily means she got syphilis very recently, it's possible she's had syphilis for a while and never got treated.
mousie  I understand that she could possibly have syphilis but I also put repeat tests because I know there are a few things that can cause false positive VRDLs but if she also has a + RPR does this make a FP less likely? And also if she has mild cognitive impairment you still discuss with her not her daughter correct ...?
m-ice  This definitely could be a false positive, but before we want to consider it to be a false positive, we should talk to the patient about it privately. Assuming that it's a false positive before asking the patient about it could delay treatment of her syphilis. There's a chance she didn't want to disclose her sexual history in front of her daughter or maybe she was embarrassed or didn't think it was important to mention. And you're absolutely right, she only has mild cognitive impairment, so we most definitely should talk to the patient alone without her daughter first.
seagull  She has dementia. She doesn't have the capacity to determine her own care (23/20 MME). I feel the daughter should have the word on the care since Grandma likely doesn't have the capacity to understand her actions.
sajaqua1  From what I remember, dementia is typically a combination of impaired memory *and* impaired thought processes. There is nothing to indicate that the patient has impaired thought processes, and the memory impairment is only mild. The patient can still reasonably said to be competent, and so her private information should be discussed with her alone.
yotsubato  Elder care homes or elderly communities actually have a high rate of STDs. Turns out, when you put a bunch of divorced/widowed adults together in a community they have sex.
yotsubato  Additionally, you should respect the privacy of a competent adult with "Mild memory" impairment. I know I could have mild memory impairment considering the crap I forget studying for step 1
drdoom  @seagull dementia ≠ absence of competence -- the two are separate concepts and have to be evaluated independently. see https://meshb.nlm.nih.gov/record/ui?ui=D003704 and https://meshb.nlm.nih.gov/record/ui?ui=D016743
wowo  also important to note, d) repeated tests is also incorrect as the microhemagglutination assay is a confirmatory treponemal test (along the same lines as FTA-ABS) https://www.uofmhealth.org/health-library/hw5839
... stapes2big made a comment on nbme24/block3/q#14 (A cohort study is done to evaluate the association...)
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submitted by stapes2big(3)

I’m not sure about this one but the way I thought about it was that since the confidence interval included 1, it was not significant. And thus p value must be above 0.05

tea-cats-biscuits  That makes sense!
asapdoc  Had the same reasoning
jkan  I get that it's not significant, but why is it 0.05<p<1 and not p>1.0
jkan  nvm, it's can't be greater than 1 because then it would have a negative% confidence interval which cannot happen (Think if p>0.05 means at least 95% within confidence interval)
charcot_bouchard  p=0.05 means theres 5% chance null hypothesis is true. p=1 means theres 100% chance null hypothesis is true. >1 means >100% chance which isnt possible.
wowo  p is a probability, so can't be greater than 1
... neonem made a comment on nbme24/block3/q#15 (A 17-year-old girl has significant blood loss after...)
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submitted by neonem(227)

the body responds to blood loss by hematopoiesis. This occurs by upregulating transferrin (an iron transporter in the blood), erythropoietin production (a hormone made exclusively in the renal peritubular interstitial cells), and heme synthesis. First step of heme synthesis was actually alluded to in another question on this test: condensation of glycine and succinyl CoA into delta-aminolevulinate. This is rate-limiting step of heme synthesis.

wowo  FA2019 p417
... keycompany made a comment on nbme24/block3/q#16 (An 18-year-old woman is brought to the physician...)
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submitted by keycompany(105)

This patient has a pneumothorax. Hyperventillation is not enough to compensate for the overall decrease in lung surface area.

_yeetmasterflex  Could the pneumothorax also cause less ventilation due to decreased lung surface, retaining more CO2 causing respiratory acidosis? That's how I got to the answer at least.
duat98  I think pneumothorax would increase RR because you're probably hypoxic. Also I'm sure when you have a lung collapse on you you'd be scared and that would trigger your sympathetic so your RR will go up either way.
kateinwonderland  Arterial blood gas studies may show respiratory alkalosis caused by a decrease in CO2 as a result of tachypnea but later hypoxemia, hypercapnia, and acidosis. The patient's SaO2 levels may decrease at first, but typically return to normal within 24 hours. (https://journals.lww.com/nursing/Fulltext/2002/11000/Understanding_pneumothorax.52.aspx)
... m-ice made a comment on nbme24/block3/q#17 (HOX genes play a role in embryogenesis through which...)
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submitted by m-ice(116)

All HOX genes are transcription factors that help regulate body layout and different expression of genes for each body segment.

... mcl made a comment on nbme24/block3/q#18 (A 55-year-old man with alcoholism is brought to the...)
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submitted by mcl(169)

lolol so instead of using fomepizole they just gonna get him real drunk

johnson  yep - supposedly, ethanol is used when a hospital/facility doesn't have fomepizole.
... m-ice made a comment on nbme24/block3/q#18 (A 55-year-old man with alcoholism is brought to the...)
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submitted by m-ice(116)

Competitive inhibitors increase the Km of the substrate. The Km represents how easily a substrate can bind the active site, with a lower Km representing easy binding, and a higher Km meaning more difficult. If you add a competitive inhibitor, like ethanol in this case, it makes it more difficult for the methanol to bind the active site, because it must compete with the ethanol.

... m-ice made a comment on nbme24/block3/q#19 (A 23-year-old primigravid woman at 22 weeks'...)
 +3  upvote downvote
submitted by m-ice(116)

The patient needs medical attention immediately, which eliminates obtaining a court order, or transferring her. A nurse does not have the same training and qualifications as a physician, so it would be inappropriate to ask them to examine the patient. Asking the hospital chaplain again could be inappropriate, and would take more time. Therefore, the best option among those given is to ask the patient if she will allow with her husband present.

sympathetikey  Garbage question.
masonkingcobra  So two men is better than one apparently
zoggybiscuits  GarBAGE! ?
bigjimbo  gárbágé
fulminant_life  this question is garbage. She doesnt want to be examined by a male how would the presence of her husband make any difference in that respect?
dr.xx  I guess this is a garbage question because what hospital, even small and rural, does not have a female physician on staff. NBME take notice -- this is the 2010s not 1970s. https://images.app.goo.gl/xBL4cK31ta7nG4L39
medpsychosis  The question here focuses on a specific issue which is the patient's religious conservative beliefs vs. urgency of the situation. A physician is required to respect the patient's autonomy while also balancing between beneficence and non-maleficence. The answer choice where the physician asks the patient if it would be ok to perform the exam with the husband present is an attempt to respect the conservative religious belief of the patient (not being exposed or alone with another man in the absence of her husband) while also allowing the physician to provide necessary medical treatment that could be life saving for her and or the child. Again, this allows for the patient to practice autonomy as she has the right to say no.
sahusema  I showed this question to my parents and they said "this is the kind of stuff you study all day?" smh
sherry  I totally agree this is a garbage question. I personally think there is more garbage question on new NBME forms than the previous ones...they can argue in any way. I feel like they were just trying to make people struggle on bad options when everybody knows what they were trying to ask.
... m-ice made a comment on nbme24/block3/q#20 (A 33-year-old woman comes to the physician because...)
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submitted by m-ice(116)

This woman has Paroxysmal Nocturnal Hemoglobinuria. This most often presents in a young adult who has episodes of dark urine in the middle of the night or when waking up in the morning. It's caused by complement activity directly against the patient's own RBCs. Certain glycolipids are needed on the RBC surface to prevent attack from complement, the most notable of which are CD55 and CD59. Patients with PNH have a somatic mutation in which they lost function of a PIGA enzyme needed for proper presentation and attachment of CD55/CD59 on the RBC surface. Therefore the answer is a defect in a cell membrane anchor protein. Without this, complement attacks RBCs.

usmleuser007  I knew the disorder and its pathophysiology. But sometimes the answer choices are so wordy or colorful that you still get it wrong....
... sweetmed made a comment on nbme24/block3/q#20 (A 33-year-old woman comes to the physician because...)
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submitted by sweetmed(28)

The Ham test is a test used in the diagnosis of paroxysmal nocturnal hemoglobinuria (PNH). The test involves placing red blood cells in mild acid; a positive result (increased RBC fragility) indicates PNH

... hyoid made a comment on nbme24/block3/q#21 (A 7-year-old girl is brought to the emergency...)
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submitted by hyoid(7)

Can someone explain this one––I didn't really know what to make of the lab values. Clearly she was taking too much insulin, but how can you differentiate factitious disorder from a type 1 diabetic who takes too much of their insulin dose?

m-ice  I think the trick here is that they don't mention that the daughter has a history of Type 1 DM, so she has no reason to be taking insulin at all. She's definitely receiving insulin, but we don't have any history implying she's a type 1 diabetic. That, combined with the fact that there have been multiple episodes like this one, favors that the mother is giving the daughter insulin when she doesn't need it.
sajaqua1  C-peptide is produce by endogenous insulin, but is not part of exogenous insulin. She has elevated insulin, with low C-peptide, so she is receiving too much exogenous insulin. A history of recurrent episodes this year implies a behavioral issue; Factitious disorder imposed on another (also called Munchausen syndrome by proxy).
... jkan made a comment on nbme24/block3/q#21 (A 7-year-old girl is brought to the emergency...)
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submitted by jkan(9)

c-peptide is low with exogenous insulin. (c-peptide made as a byproduct of insulin production in the body) repeated visits+ high insulin+low c-peptide= exogenous insulin abuse. In a child-> factitious by proxy

... lsmarshall made a comment on nbme24/block3/q#22 (A 32-year-old woman recently diagnosed with AIDS is...)
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submitted by lsmarshall(181)

I thought this was a trick question since skin cancers are the most common type of cancers overall. But actually among HIV patients, HIV-related cancers are much more common than non-HIV-related cancers (even skin cancers). EBV-induced primary CNS lymphoma is the only option that is AIDs-defining illness/cancer.

medskool123  why not hep B? i guess another whats the better answer ones... Just rem reading that it was more common with aids pts.. anyone have an idea about this?
haliburton  Yes, I think CNS lymphoma as an AIDS defining illness wins the day. My thought was since SHE has AIDS it is most likely from IVDA, which has a high risk of HBV that could go undiagnosed for a long time. at 32, that might not be long enough to have HBV and get HCC (but with no immune system...?)
yotsubato  God damn this is such BULLSHIT...
trichotillomaniac  Why you gotta do me dirty like this NBME
... sympathetikey made a comment on nbme24/block3/q#23 (A 32-year-old woman comes to the physician because...)
yb_26  @at0xibolic, I think you won this competition on finding better picture lol thanks
... neonem made a comment on nbme24/block3/q#23 (A 32-year-old woman comes to the physician because...)
haliburton  ^^^ THIS ONE SHOWS DUCT ^^^
... ben2024 made a comment on nbme24/block3/q#23 (A 32-year-old woman comes to the physician because...)
 +1  upvote downvote
submitted by ben2024(1)

The secretions of the parotid gland are transported to the oral cavity by the Stensen duct. It arises from the anterior surface of the gland, traversing the masseter muscle. The duct then pierces the buccinator, moving medially. It opens out into the oral cavity near the second upper molar.https://teachmeanatomy.info/head/organs/salivary-glands/parotid/

... dentist made a comment on nbme24/block3/q#23 (A 32-year-old woman comes to the physician because...)
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submitted by dentist(1)

duct through the bucc. (you can feel it with your tongue)

... tea-cats-biscuits made a comment on nbme24/block3/q#24 (A 3-month-old boy is brought to the emergency...)
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submitted by tea-cats-biscuits(64)

The disease here is fructose bisphosphatase deficiency. In it, IV glycerol or fructose doesn’t help because both enter the gluconeogenesis pathway below fructose bisphophatase. Galactose on the other hand enters above it. I don’t think you really need to know this to choose the correct answer since the clinical picture of fasting hypoglycemia that is corrected w/ some sort of sugar that can enter the gluconeogenesis pathway should clue you into the right answer.

neonem  I don't think you could have *totally* ruled out the other answers - I picked glycogen breakdown because it sounded kind of like Von Gierke disease (glucose-6-phosphatase) to me: characterized by fasting hypoglycemia, lactic acidosis, and hepatomegaly since you're not able to get that final step of exporting glucose into the blood. However, I guess in this case you wouldn't see that problem of glycerol/fructose infusion not increasing blood glucose. Nice catch.
vshummy  I think you were super smart to catch Von Gierke! Just to refine your answer b/c I had to look this up after reading your explanation, von gierke has a problem with gluconeogenesis as well as glycogenolysis. So they’d have a problem with glycerol and fructose but also galactose since they all feed into gluconeogenesis before glucose-6-phosphatase. Great thought process!
... usmle11a made a comment on nbme24/block3/q#24 (A 3-month-old boy is brought to the emergency...)
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submitted by usmle11a(2)

guys VG would worsen with galactose infusion, remebmber they dont have G6Pase which means they cant convert anything to glucose

... tea-cats-biscuits made a comment on nbme24/block3/q#25 (An investigator is studying a new virus isolated...)
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submitted by tea-cats-biscuits(64)

You know it’s an enveloped virus since it doesn’t hold up to acid or being dried. You know it causes a fever and a cough, while affecting the larynx. Only virus category that fits all that info is the coronavirus (causes SARS) from that list.

zelderonmorningstar  EBV doesn’t cause fever and cough?
zelderonmorningstar  Wow, just checked First Aid and it doesn’t list “cough” as a symptom of EBV.
drdoom  EBV is not a “respiratory virus”; it’s a *B cell virus*. Even though you might associate it with the “upper respiratory tract” (=kissing disease), it doesn’t cause respiratory inflammation since that’s not its trope. B cells are its trope! That’s why EBV is implicated in Burkitt Lymphoma, hairy leukoplakia and other blood cancers. (EBV is also known as “lymphocryptovirus” -- it was originally discovered “hiding” in *lymphocytes* of monkeys.) So, EBV = think B cells.
fulminant_life  EBV does cause pharyngeal and laryngeal inflammation along with fever, malaise, and cough and LAD. The only thing that pointed me away from mono and towards coronavirus was the patients age.
nbmehelp  Can someone explain what not holding up to acid or being dried has to do with being enveloped?
yb_26  @nbmehelp, the envelope consists of phospholipids and glycoproteins => heat, acid, detergents, drying - all of that can dissolve the lipid bilayer membranes => viruses will loss their infectivity (because they need an envelope for two reasons - to protect them against host immune system, and to attach to host cells surface in order to infect them)
... drdoom made a comment on nbme24/block3/q#25 (An investigator is studying a new virus isolated...)
 +2  upvote downvote
submitted by drdoom(167)

EBV is not a “respiratory virus” -- it’s a B cell virus. It infects B cells; not laryngeal cells.

Even though you might associate it with the “upper respiratory tract” (=kissing disease), it doesn’t cause respiratory inflammation since that’s not its trope. B cells are its trope! That’s why EBV is implicated in Burkitt Lymphoma, hairy leukoplakia and other blood cancers. (EBV is also known as “lymphocryptovirus” -- it was originally discovered “hiding” in lymphocytes of monkeys.) So, EBV = think B cells. From the MeSH library:

The type species of LYMPHOCRYPTOVIRUS, subfamily GAMMAHERPESVIRINAE, infecting B-cells in humans. It is thought to be the causative agent of INFECTIOUS MONONUCLEOSIS and is strongly associated with oral hairy leukoplakia (LEUKOPLAKIA, HAIRY;), BURKITT LYMPHOMA; and other malignancies.

https://meshb-prev.nlm.nih.gov/record/ui?name=HERPESVIRUS%204,%20HUMAN

... neonem made a comment on nbme24/block3/q#26 (A 54-year-old man with a myocardial infarction...)
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submitted by neonem(227)

General theme of pathology: hypoxia impairs oxidative phosphorylation --> less ATP --> less Na-K pump activity so sodium builds up in the cell, causing swelling. This is the first step. Then you'd get the calcium buildup in the cell and eventual anaerobic glycolysis, causing lactic acid production and lowered pH... but this happens later and isn't the direct cause of cellular swelling, which is what the question is after.

... m-ice made a comment on nbme24/block3/q#27 (A 27-year-old man who works from home as a software...)
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submitted by m-ice(116)

Avoidant personality disorder is characterized by a desire for social relationships, but a fear of being rejected or feeling inadequate for others. This is different from Schizoid, because Schizoid individuals do not desire relationships with others, and want to remain alone. The trickiest differentiation might be between Avoidant and Schizotypal, but Schizotypal individuals tend to remain isolated because of odd thinking, or "magical beliefs".

... m-ice made a comment on nbme24/block3/q#28 (A 22-year-old man is brought to the emergency...)
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submitted by m-ice(116)

Dysmetria is the lack of coordination of intended movements. Normally these movements are coordinated by the cerebellum. This is located specifically on the man's right side, not both sides, so only one lobe will be injured.

... atstillisafraud made a comment on nbme24/block3/q#28 (A 22-year-old man is brought to the emergency...)
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submitted by atstillisafraud(39)

Dysmetria ( also, dysdiadokinesia and intention tremor) is lateral cerebellum. (E).

Ataxia is a problem with the central cerebellum (D) or at least thats the best I could come up with.

ronald-dumsfeld  I actually think D is pointing at the Flocculonodular lobe. See here: https://en.wikipedia.org/wiki/Flocculus_(cerebellar)#/media/File:Human_brain_midsagittal_view_description.JPG So a lesion at D would present with Nystagmus
... seagull made a comment on nbme24/block3/q#28 (A 22-year-old man is brought to the emergency...)
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submitted by seagull(355)

A- primary motor cortex = wrong side of body (deficit of UMN on left side body)

B - Thalamus = sensory information conduit - motor deficits unlikely to originate from here

C - Pons - CNs 8,7,6,5, likely result in "locked in syndrome" or complete loss of motor function on right side + facial features.

D. Vermis - central body coordination. Damage results in ataxia

Not complete but maybe helpful..

yotsubato  C - Pons - CNs 8,7,6,5, likely result in "locked in syndrome" or complete loss of motor function on LEFT side + RIGHT sided facial features. Decussation occurs in medulla
... nwinkelmann made a comment on nbme24/block3/q#28 (A 22-year-old man is brought to the emergency...)
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submitted by nwinkelmann(60)

Dysmetria = discoordination of planned, voluntary movements (my own words for the different findings and used specifically to help me remember location) controlled by the posterior lobe of the hemisphere which does planned voluntary movement. Also, the hemisphere is the periphery of the cerebellum, and it deals with planned, voluntary movements of the periphery (i.e. limbs). I got this from this image with memory tips: https://www.medicowesome.com/2013/04/cerebellum-mnemonics.html.

Other helpful links:

  1. Pretty detailed anatomy: http://www.fmritools.com/kdb/_Media/image002-3_med_hr.png

  2. Interactive site all about the cerebellum (https://nba.uth.tmc.edu/neuroscience/m/s3/chapter05.html), but the most helpful picture for me was this one (https://nba.uth.tmc.edu/neuroscience/m/s3/images/copyright_marked_images/5-3_NEW.jpg)

... tea-cats-biscuits made a comment on nbme24/block3/q#29 (Drug X is given to a 25-year-old normal subject....)
 +8  upvote downvote
submitted by tea-cats-biscuits(64)

Partial agonists have weak agonist activity on their own (thus in this case it causes HR to increase, b-adrenergic effect) but when an actual agonist is present (aka when you are exercising, you are producing NE and E that have full b-agonist effects), partial agonist actually have a mild antagonist effect (thus the heart rate decreases).

... neonem made a comment on nbme24/block3/q#30 (A 38-year-old woman comes to the physician because...)
 +5  upvote downvote
submitted by neonem(227)

This is the most common cause of painless bloody discharge from the nipple in a woman of reproductive age. It is a benign tumor and there are no characteristic radiologic/mammographic changes.

... louisville made a comment on nbme24/block3/q#31 (A 65-year-old man is brought to the emergency...)
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submitted by louisville(6)

Answer: SVR increased; PVR decreased; PCWP increased.

... keycompany made a comment on nbme24/block3/q#31 (A 65-year-old man is brought to the emergency...)
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submitted by keycompany(105)

Can somebody who understand why PVR decreases with a Left-Sided infarct please enlighten me. I would also appreciate it if you could relate it to right sided heart failure too (i.e. how would it change).

sajaqua1  I believe that keycompany's answer comes the closest. In an MI, consider it as cardiogenic shock. The heart is a pump, and it is failing to move blood out of the heart and into vasculature. This is why PCWP increases. Because of insufficient output, the body has a sympathetic response. The catecholamines then cause vasoconstriction in peripheral vasculature to keep blood pressure up and continue flow, leading to increased SVR. Meanwhile, the sympathetic response causes vasodilation in the lungs; this would be an appropriate autoregulatory response, because the body is trying to keep up the flow of oxygen throughout the system. This decreases PVR. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5715548/ Is a pretty good article on this. Of course the binding of catetcholamines changes depending on saturation and the response is not perfectly understood.
usmleuser007  My understanding is that the pulmonary circulation changes very little in terms of an acute MI. It is b/c pulmonary circulation has a lot more room to fill with blood much like the spleen in terms of blood accumulation. With higher volume of blood in pulmonary circulation, more blood vessels are able to be recruited specially the apex. With more recruited blood vessels = reduced pressure d/t circulation in parallel.
... keycompany made a comment on nbme24/block3/q#31 (A 65-year-old man is brought to the emergency...)
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submitted by keycompany(105)

Answered my own question. Increased stress from a STEMI will activate the sympathetic nervous system -- Pulmonary vasodilation.

... mousie made a comment on nbme24/block3/q#31 (A 65-year-old man is brought to the emergency...)
 +0  upvote downvote
submitted by mousie(74)

if your CO falls ... wouldn't that cause vasoconstriction in the lung vasculature? hypoxia induced vasoconstriction?

ug123  My take on this----His respirations are high-22/min--that will cause c02 washout---so actually lung has high oxygen---pulmonary vasodilation. Dont know if its right.
usmleuser007  My understanding is that the pulmonary circulation changes very little in terms of an acute MI. It is b/c pulmonary circulation has a lot more room to fill with blood much like the spleen in terms of blood accumulation. With higher volume of blood in pulmonary circulation, more blood vessels are able to be recruited specially the apex. With more recruited blood vessels = reduced pressure d/t circulation in parallel
... usmleuser007 made a comment on nbme24/block3/q#31 (A 65-year-old man is brought to the emergency...)
 +0  upvote downvote
submitted by usmleuser007(86)

My understanding is that the pulmonary circulation changes very little in terms of an acute MI.

It is b/c pulmonary circulation has a lot more room to fill with blood much like the spleen in terms of blood accumulation.

With higher volume of blood in pulmonary circulation, more blood vessels are able to be recruited specially the apex.

With more recruited blood vessels = reduced pressure d/t circulation in parallel

... yb_26 made a comment on nbme24/block3/q#31 (A 65-year-old man is brought to the emergency...)
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submitted by yb_26(28)

My simple understanding is that pt's heart contractility is decreased due to MI => heart can't pump a lot of blood => increased backup flow into pulmonary vasculature => increased PCWP.

More blood in pulmonary vasculature => they will dilate in order to just keep all these blood => decreased pulmonary vascular resistance

Decreased cardiac output => peripheral vasoconstriction => increased systemic vascular resistance

... m-ice made a comment on nbme24/block3/q#32 (A 15-year-old girl is brought to the physician...)
 +4  upvote downvote
submitted by m-ice(116)

This girl has Mono caused by Epstein-Barr Virus. The symptoms are relatively vague, but lymphadenopathy like this would be common for Mono. The CBC shows elevated lymphocytes, implying this is not a bacterial illness, so viral is likely. Combined with the lymphadenopathy, this makes us worry about Mono. The Mono-Spot test for EBV is what the question is referring to when describing the sheep erythrocytes agglutinating. From there, this question requires that you know that in EBV infection, EBV infects B cells, but does not cause them to become abnormal. Instead, CD8 cells, which are actively trying to kill the B cells, become abnormal.

medskool123  NBME does trick now and then.. when they zig you zag. then when you think they are going to zag, they zig just to destroy yourself confidence.
kylemax  The abnormal T-cells are known as Downey type II cells (Sketchy)
haliburton  I was recognized EBV, then knew EBV infects Bc, and the atypical lymphocytes are Tc. Then I said CD8 are MHC1 for virii, and bingo bango, boom.
trichotillomaniac  congrats you played yourself
... lsmarshall made a comment on nbme24/block3/q#33 (A 12-year-old boy is brought to the physician by his...)
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submitted by lsmarshall(181)

"In the years preceding physical puberty, Robert M. Boyar discovered that the gonadotropin pulses occur only during sleep, but as puberty progresses they can be detected during the day. By the end of puberty, there is little day-night difference in the amplitude and frequency of gonadotropin pulses.

Some investigators have attributed the onset of puberty to a resonance of oscillators in the brain.[89][90][91] By this mechanism, the gonadotropin pulses that occur primarily at night just before puberty represent beats." - Wiki

... davidw made a comment on nbme24/block3/q#33 (A 12-year-old boy is brought to the physician by his...)
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submitted by davidw(9)

Is this found in other resources other then Pub med articles?

... nwinkelmann made a comment on nbme24/block3/q#33 (A 12-year-old boy is brought to the physician by his...)
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submitted by nwinkelmann(60)

Does anyone have a good explanation for why decreased levels of inhibin is wrong? From my understanding, inhibin and activin work together, in that inhibin binds and blocks activin leading to decreased feedback on hypothalamus and activin increases FSH and GnRH production.. thus, if you decrease inhibin then you would have increased activin which would lead to increased GnRH and FSH, right? I found one article talking about it in regards to puberty, but it seems to be a hypothesis/not confirmed at this point... is that why? But still... how do I rule it out on a test?

yb_26  I also picked decreased inhibin. may be it was one of the "experimental questions", which are not even counted on the real exam
artist90  Inceased FSH will lead to spermatogenesis and spermiogenesis NOT Increase in Testosterone which is causing increased Height of this pt
artist90  Inhibin B only has negative feeback on FSH not GnRH. see the diagram on the topic of semineferous tubules in FA. Testosterone has a negative feedback on BOTH LH and GnRH
... tea-cats-biscuits made a comment on nbme24/block3/q#34 (An otherwise healthy 35-year-old man sustains a...)
 +7  upvote downvote
submitted by tea-cats-biscuits(64)

Because you are supine, there’s increased preload going back to your heart (no need to work against gravity, your blood isn’t pooling in your legs as much either). As a result, ANP is secreted due to RA stretch, leading to diuresis and a reduction of blood volume.

... colonelred_ made a comment on nbme24/block3/q#34 (An otherwise healthy 35-year-old man sustains a...)
 +7  upvote downvote
submitted by colonelred_(44)

Looked it up and found that because you’re in a supine position for a long time you’re going to have increased venous return which leads to increased CO. This negatively feedsback on RAAS, leading to decreased aldosterone. As a result, you’re going to have increased diuresis which leads to decreased blood and plasma volume.

medstruggle  Doesn’t supine position compress IVC leading to decreased venous return? (This is the pathophys of supine hypotension syndrome.) There was a UWorld questions about this ...
tea-cats-biscuits  @medstruggle *Supine position* decreases blood pooling in the legs and decreases the effect of gravity. *Supine hypotension syndrome*, on the other hand, seems specific to a pregnant female, since the gravid uterus will compress the IVC; in an average pt, there wouldn’t be the same postural compression.
welpdedelp  this was the exact same reasoning I used, but I thought the RAAS would inactivate which would lead to less aldosterone and less sodium retention
yotsubato  You gotta be preggers to compress your IVC
nwinkelmann  Could you also think of it in a purely "rest/digest" vs "fight/fright/flight" response, i.e. you're PNS is active, so your HR and subsequently your CO is less? But the explanation given above does make sense. Also because I think just saying someone is one bed rest leaves a lot up for interpretation, maybe not with this patient because his pelvis is broken, but lots of people on bed rest aren't lying flat.... ?
... zelderonmorningstar made a comment on nbme24/block3/q#34 (An otherwise healthy 35-year-old man sustains a...)
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submitted by zelderonmorningstar(9)

Why is the answer decreased blood volume as opposed to decreased plasma sodium concentration?

tea-cats-biscuits  I think it might just be what NBME feels “decreased plasma sodium concentration” means, since through the mechanism that BV is lowered in bedrest, you would definitely have a decreased plasma sodium concentration compared to not-bedrest. However you won’t be presenting with any pathologic signs of hyponatremia because the Na+ would still be maintained in normal limits. Low blood volume is the cause of one of the main pathologic states associated w/bedrest -- cardiac deconditioning and postural hypotension once out of bedrest. Seems like poor wording though.
mnemonia  Remember that changes in sodium concentration over a long period time need to be due to a water dysregulation problem (like SIADH, polydipsia, HF, etc.). Here we just have physiologically increased effective circulating volume, and the body will compensate by diuresing, and since Na+ (and K+) are regulated ions, their plasma levels will not fluctuate.
... cocoxaurus made a comment on nbme24/block3/q#34 (An otherwise healthy 35-year-old man sustains a...)
... itsdrgoodwood made a comment on nbme24/block3/q#35 (A 4-year-old girl has a history of multiple bone...)
 +7  upvote downvote
submitted by itsdrgoodwood(7)

The diagnosis is Osteogenesis Imperfecta. Disease causes a defect in Type 1 Collagen that leads to “brittle bones”, meaning the patients have frequent fractures with little trauma. Type 1 collagen is also a major component of the sclera -> this is what the picture was hinting at (i think?) and it causes “blue sclera”. The sclera are thin/translucent so they look blue due to underlying choroidal veins.

Finally, patients have poor wound healing. Wound repair with granulation tissue involves type 3 collage which is then converted to type 1 collagen during scar formation. Defects in type 1 collagen obviously don’t allow this process to take place.

... gainsgutsglory made a comment on nbme24/block3/q#35 (A 4-year-old girl has a history of multiple bone...)
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submitted by gainsgutsglory(4)

She has Osteogenesis Imperfecta. Aka “Brittle Bone Dz” aka Collagen Type I deficiency. U need collagen type I to make scars (granulation tissue is type III and then metalloproteases and zinc cofactors help digest into the firm type I collagen).

wowo  FA 2019 p51
... atstillisafraud made a comment on nbme24/block3/q#35 (A 4-year-old girl has a history of multiple bone...)
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submitted by atstillisafraud(39)

Thank you NBME for the high quality pictures. It makes these exams stress free and enjoyable.

sympathetikey  Feels bad man.
zoggybiscuits  Those Sclera sure look blue. wow.
yotsubato  the same girl shows up on so many NBME exams its not even funny. Its just like that poor kidney that's cut in half that shows up in all kidney questions.
... adisdiadochokinetic made a comment on nbme24/block3/q#35 (A 4-year-old girl has a history of multiple bone...)
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submitted by adisdiadochokinetic(7)

It really looks to me like her sclera have been photoshopped, anyone else notice that? xD

... sweetmed made a comment on nbme24/block3/q#35 (A 4-year-old girl has a history of multiple bone...)
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submitted by sweetmed(28)

I legit thought her oversized pupils were the problem. What genius decided to use this photo.

... zelderonmorningstar made a comment on nbme24/block3/q#36 (A 1-month-old male newborn is brought to the...)
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submitted by zelderonmorningstar(9)

Can someone explain why the answer couldn’t be phenylalanine?

donutsnduodenums  The kid has albinism, which is due to decreased tyrosinase activity. If he has a problem metabolizing Phenylalanine, he would be presenting with the PKU sx like intellectual disability, musty body odor, etc., in addition to his fair complexion.
zelderonmorningstar  I see, so if it was PKU he wouldn’t just be presenting for a routine examination. It would be one of those “oh crap what’s wrong with my baby” ones.
wowo  FA2019 p83
nbme4unme  Just a note that UWorld says phenylketonuria patients ALSO have albinism, it's just that the neuro sx and musty order are giveaways.
... guillo12 made a comment on nbme24/block3/q#37 (A man accidentally touches the surface of a hot...)
 +2  upvote downvote
submitted by guillo12(12)

In situation of an inflammatory response such as in burns, anaphylaxis or sepsis, intercellular contacts disintegrate in post-capillary venules leading to intercellular gap formation.

https://www.ncbi.nlm.nih.gov/pubmed/28231640

... sympathetikey made a comment on nbme24/block3/q#37 (A man accidentally touches the surface of a hot...)
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submitted by sympathetikey(260)

As per Pathoma,

"Vascular permeability occurs at the post-capillary venule"

This is why, when you have edema, you would have gaps in the venules.

... seagull made a comment on nbme24/block3/q#37 (A man accidentally touches the surface of a hot...)
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submitted by seagull(355)

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paanvaannd  lollll this doesn't exactly come through on desktop but it sure is funny on a mobile browser.
... cr made a comment on nbme24/block3/q#37 (A man accidentally touches the surface of a hot...)
 +0  upvote downvote
submitted by cr(1)

Which type of cell we r going to find in blisters?, neutrophils?

... m-ice made a comment on nbme24/block3/q#38 (A 55-year-old man comes to the physician because of...)
 +9  upvote downvote
submitted by m-ice(116)

They explicitly state that the patient has been taking excess of his levothyroxine medication. Levothyroxine is the exogenous form of T4. Therefore, free T4 must be elevated. T4 is converted to T3 at most peripheral tissues, so T3 will also be elevated. Because the body has more thyroid hormone than needed, less TSH will be made, and the thyroid will be less active, taking up LESS iodine.

... sweetmed made a comment on nbme24/block3/q#38 (A 55-year-old man comes to the physician because of...)
 +1  upvote downvote
submitted by sweetmed(28)

Taking excess Levothyroxine will cause, Incr fT4, Incr fT3, decr TSH, decr Thyroidal iodine uptake. Excess liothyronine intake will cause incr T3, Decr T4, decr rT3, Decr TSH, because T4 gets converted to T3 and rT3 in periphery.

... neonem made a comment on nbme24/block3/q#39 (A 34-year-old woman is brought to the emergency...)
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submitted by neonem(227)

Falling on outstretched hand: scaphoid is most common one to be fractured, lunate is most common to be dislocated. Lunate dislocation can cause acute carpal tunnel syndrome.

Think of the mnemonic "Straight Line To Pinky, Here Comes The Thumb" for the bones of the palm, drawing a football shape starting below the thumb MCP joint adjacent to the radius, then moving to your medial wrist, and then back to the thumb.

Scaphoid, lunate, triquetrum, pisiform, hamate, capitate, trapezoid, trapezium. The lunate looks like it's posteriorly dislocated here.

sympathetikey  Yep. I didn't even look at the X-ray.
dr.xx  loonies love lunate
wes79  she landed on her "right hand", but the X-ray is showing a left hand??
wes79  i legit have no idea whats going on in that xray lol
nbme4unme  X-ray confused the hell out of me, I was going to put lunate based on Q stem but ended up putting Pisiform because it looks like that's what's messed up in the photo? Should have ignored the picture haha.
nwinkelmann  for @dr.xx, love your mnemonic. I added to it, or at least found an explanation on why it works. "loonies love lunate" and "loonies" are "dislocated" from reality.
doctorevil  She Looks Too Pretty, Try To Catch Her is a mnemonic that works for me.
... m-ice made a comment on nbme24/block3/q#40 (A 2-year-old boy is brought to the emergency...)
 +1  upvote downvote
submitted by m-ice(116)

This boy has meningitis caused by Strep pneumoniae, the most common cause of infectious meningitis in general. The vaccine for Strep pneumo is a polysaccharide protein conjugate vaccine. The other major bacteria with a vaccine like this is H. influenzae.

... m-ice made a comment on nbme24/block3/q#41 (A 30-year-old man develops tingling around the lips...)
 +3  upvote downvote
submitted by m-ice(116)

Tetrodotoxin, found in puffer fish, inhibits sodium channels. This prevents depolarization of cardiac muscle and neurons, which leads to death if consumed in high enough quantity. The symptoms are vague (nausea, diarrhea, paresthesia), so questions will need to give some form of history about eating at a Japanese restaurant or eating pufferfish to give you a big hint. There is unfortunately not treatment.

... tea-cats-biscuits made a comment on nbme24/block3/q#42 (Which of the following terms best describes the...)
 +5  upvote downvote
submitted by tea-cats-biscuits(64)

Fibronectin is an extracellular matrix glycoprotein, while lamin is an intermediate filament that specifically provides support to the cell nucleus. Don’t confuse lamin with laminin (science hates us clearly); laminin is like fibronectin, an ECM glycoprotein and a major component of the basal lamina of basement membranes.

masonkingcobra  Lamin looks like a "cross" and held up Jesus and the basal lamina is super important just like jesus (you bet there are people who believe this) https://answersingenesis.org/biology/microbiology/laminin-and-the-cross/
dr.xx  blasphemy @masonkingcobra
... atstillisafraud made a comment on nbme24/block3/q#42 (Which of the following terms best describes the...)
 +8  upvote downvote
submitted by atstillisafraud(39)

I like this question because it reminds me that examiners think objects can exist in 2 dimensions.

... nwinkelmann made a comment on nbme24/block3/q#42 (Which of the following terms best describes the...)
 +0  upvote downvote
submitted by nwinkelmann(60)

So... I didn't know what it was so I looked it up... and legit, granum is part of plants.......... really?! lol

cinnapie  We out here treating plants!!
... soph made a comment on nbme24/block3/q#42 (Which of the following terms best describes the...)
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submitted by soph(9)

"Nuclear laminin dissasembles + reform nuclear envelope during mitosis. They are helpfull for structure and transcriptional regulation in cell nucleus." -OSMOSIS

... soph made a comment on nbme24/block3/q#42 (Which of the following terms best describes the...)
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submitted by soph(9)

"Nuclear laminin dissasembles + reform nuclear envelope during mitosis. They are helpfull for structure and transcriptional regulation in cell nucleus." -OSMOSIS

... sweetmed made a comment on nbme24/block3/q#42 (Which of the following terms best describes the...)
 +0  upvote downvote
submitted by sweetmed(28)

Lamins form a nuclear membrane surrounding DNA. imp for structural support, organizing genome, regulating gene transcription. Defective in Progeria and muscular dystrophy.

... neonem made a comment on nbme24/block3/q#43 (A 35-year-old woman with a long-standing history of...)
 +3  upvote downvote
submitted by neonem(227)

Histoplasma can act like TB and cause cavitary lesions and calcified nodules with fibrotic scarring. In general, fungi are combatted by lymphocytes and macrophages, not eosinophils or neutrophils.

... dragon3 made a comment on nbme24/block3/q#43 (A 35-year-old woman with a long-standing history of...)
 +0  upvote downvote
submitted by dragon3(3)

Can anyone explain why bacteria is neutrophils, viral/fungi are lymphocytes? I know this is a fundamental concept...

lolmedlol  i think neutrophils (in addition to lacking granzymes and perforins which are used to kill viruses and fungi) dont recognize intracellular things; viral antigens needs to be processed and presented on an MHC for the lymphocytes to recognize
... welpdedelp made a comment on nbme24/block3/q#44 (A 62-year-old man comes to the physician for a...)
 +1  upvote downvote
submitted by welpdedelp(64)

I thought this was just referencing zollinger ellison, which would have elevated gastrin

... neonem made a comment on nbme24/block3/q#44 (A 62-year-old man comes to the physician for a...)
 +6  upvote downvote
submitted by neonem(227)

I think the idea here is that if you take someone off a PPI, if there's no neoplasm or any problem with gastrin production then you should see it go down from baseline due to more negative feedback of gastric acidity. If not, you probably have a neoplasm that's just making tons of gastrin, such as in the case of Zollinger-Ellison syndrome.

gonyyong  I thought it was that if you are taking a PPI, you will see elevated gastrin regardless of it you have a gastrinoma. Thus to confirm diagnosis, you make them stop taking it, then re-measure gastrin → if it's still high, you have confirmed. If it's normal, it's something else
... dentist made a comment on nbme24/block3/q#44 (A 62-year-old man comes to the physician for a...)
 +0  upvote downvote
submitted by dentist(1)

To me: this seemed more straightforward. You'd want to follow up and check Gastrin levels on a patient who previously had 4x normal.

... neonem made a comment on nbme24/block3/q#45 (A 59-year-old woman has a 10-year history of...)
 +4  upvote downvote
submitted by neonem(227)

Cerebellopontine angle mass = Vestibular schwannoma (AKA acoustic neuroma). Derived from Schwann cells, which are of neural crest origin.

yotsubato  Ugh. Of course they dont put schwann cells as a choice. So I pick oligodendrocytes like a dumbass
... welpdedelp made a comment on nbme24/block3/q#46 (A 15-year-old girl with cystic fibrosis has a...)
... seagull made a comment on nbme24/block3/q#46 (A 15-year-old girl with cystic fibrosis has a...)
 +0  upvote downvote
submitted by seagull(355)

I have an issue with this question which also conflicts with UWorld. In order to be degraded by proteosomes the misfolded protein would need to be present in the cytosol for ubuination. It it accumulated in the RER then how does it get tagged? Honestly, so conflicted...

sajaqua1  So ordinarily a misfolded protein does undergo ubiquitination and proteolysis. It is noteable that CFTR misfolding doesn't even allow it escape the ER, so it accumulates in the ER
... vshummy made a comment on nbme24/block3/q#46 (A 15-year-old girl with cystic fibrosis has a...)
 +3  upvote downvote
submitted by vshummy(44)

I think more generally, protein folding happens at the RER and the stem says the protein doesn’t fold properly. Specifically, the most common CF mutation is a misfolded protein and the protein is retained in the RER and not transported to the cell membrane - FA 2019 pg 60.

... m-ice made a comment on nbme24/block3/q#47 (A 22-year-old woman comes to the physician for a...)
 +6  upvote downvote
submitted by m-ice(116)

The patient states that she does not want a hormonal form of birth control. So, the question is really asking which of the non-hormonal options is most effective. The tricky part here, I think, is that the question makes you want to not pick IUD, because many IUDs are hormonally based. However, a non-hormonal IUD, like a copper IUD, is still more effective than the other options listed.

... yotsubato made a comment on nbme24/block3/q#49 (A 20-year-old woman with asthma comes to the...)
 +2  upvote downvote
submitted by yotsubato(214)

Cold air induces asthma attacks.

Decreasing course load wont help

Taking steroids is too much for now

Moving back to the dorms is not viable

Air cleaners dont work enough

Dont get rid of the Good Boye

Smoking indoors is disgusting

sherry  Stress can actually be a trigger for asthma. I think the problem here is that she has alwasys carried a heavy course, while the disease just started recently.
... tissue creep made a comment on nbme24/block3/q#49 (A 20-year-old woman with asthma comes to the...)
 +10  upvote downvote
submitted by tissue creep(22)

The poodle is hypoallergenic, and a 10/10 good boy.

... dragon3 made a comment on nbme24/block3/q#49 (A 20-year-old woman with asthma comes to the...)
 +0  upvote downvote
submitted by dragon3(3)

I almost picked asking the roommate not to smoke in the apartment, but then I figured that's beyond the scope of the doctor... another person said taking steroids would be too much for now, and I suppose that's because the asthma is well-controlled with her inhaler rn? (that's what I had picked)

sherry  I would say the patient's asthma only got worse after her moving out. So its more allergen-related. Getting rid of the allergen is always better than upgrading medications.
et-tu-bromocriptine  Rippp the "don't be a dick" strategy definitely failed me on this one. For some reason, I thought requesting the patient to ask someone else to change their smoking habits would be a tad too much. I can just picture UWorld smacking me with a "Although it is likely that the roommate's cessation of smoking could alleviate the patient's asthma exacerbations, this request would be out of the physician's scope....etc."
... m-ice made a comment on nbme24/block3/q#50 (A group of physicians submits a report to a medical...)
 +0  upvote downvote
submitted by m-ice(116)

Case series is a study in which the researchers present the history and treatment of a small group of similar patients, without describing any sorting into groups or randomization.

... m-ice made a comment on nbme24/block4/q#1 (A 30-year-old woman comes to the physician for...)
 +1  upvote downvote
submitted by m-ice(116)

Question is basically asking what are the substrates used the first step in heme synthesis. In that step, glycine and succinyl CoA are combined to make aminolevulinic acid.

... trazabone made a comment on nbme24/block4/q#2 (A full-term male newborn has lethargy, poor feeding,...)
 +2  upvote downvote
submitted by trazabone(4)

Ornithine transcarbamolase deficiency. Carbomoyl phosphate (CP) is shunted to pyrimidine synthesis --> increased orotic acid production (CPS you would not see orotic acidemia). Urea cycle also inhibited --> increased ammonia levels.

... cocoxaurus made a comment on nbme24/block4/q#3 (A 23-year-old woman is brought to the emergency...)
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submitted by cocoxaurus(22)

BUT why is the serum potassium normal?

I was able to narrow it down to RTA, because none of the other answer choices made much sense, but the potassium had me second guessing myself. Can someone explain that lab finding? Thanks!

subclaviansteele  My take is that hes not super acidotic and the K is at the low end.
nwinkelmann  see the comment by @zbird, which explains that the urine anion gap is important (which I took to interpret as more important than the serum K+ level, lol, because the normal K threw me off too).
... brethren_md made a comment on nbme24/block4/q#3 (A 23-year-old woman is brought to the emergency...)
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submitted by brethren_md(39)

Requires knowing how to calculate an anion gap - look it up. In this case, it is a normal anion gap metabolic acidosis. Know the mneumonics MUDPILES and HARDASS. Renal Tubular acidosis is the only answer choice that is an example of a normal anion metabolic acidosis.

mousie  Anion Gap: Na - (Cl + HCO3) = normally around 10-12
seagull  good to know. I keep looking up the urine values but all it said was "varies", then I threw my computer and yelled "does that vary Mother F****ers. I do feel better now.
_yeetmasterflex  glad I wasn't the only one who got very pissed off at the urine values
fulminant_life  Usually the first thing I look at is whether or not the Cl- is high. Generally if the Cl- is high its going to be a normal gap
henoch schonlein  i think they gave you the urine values bc you can calculate the URINE anion gap which is (Na + K - Cl). In this case the Urine Anion Gap is positive (5). Boards and Beyond mentions that a positive UAG is due to Renal Tubular Acidosis Type 1 (inability of alpha intercalated cells to secrete hydrogen ions). just another approach to answer this q
... sherry made a comment on nbme24/block4/q#3 (A 23-year-old woman is brought to the emergency...)
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submitted by sherry(3)

Diarrhea in HARDASS can lead to metabolic acidosis as well. On second thought I decided to take crohn disease cuz I figured the clinical picture is more intermittent with potassium disturbances. I guess I just overthink due to the lack of other physical abnormalities.

daddyyikes  other than the patient not haveing any sxs of crohn's i dont see any reason why its not crohn's. we differ crohn's and rta by urine anion gap. in chronic diarrhoea it is negative while in rta its +ve but in question the anion gap was normal
... zbird made a comment on nbme24/block4/q#3 (A 23-year-old woman is brought to the emergency...)
 +1  upvote downvote
submitted by zbird(2)

This patient has Distal-Type I RTA which is explained by Normal Serum Anion gap (8) Metabolic acidosis with her positive urinary anion gap(+5).

... medstruggle made a comment on nbme24/block4/q#4 (A 63-year-old woman develops flank pain,...)
 +0  upvote downvote
submitted by medstruggle(5)

Why was the acute hemolytic transfusion reaction due to ABO incompatibility, but not Rh incompatibility?

colonelred_  Rh incompatibility comes more into play with Rh- mother and Rh+ babies.
... roygbiv made a comment on nbme24/block4/q#4 (A 63-year-old woman develops flank pain,...)
 +0  upvote downvote
submitted by roygbiv(5)

Why could this not be extravascular hemolysis? In FA it says acute hemolytic transfusion reaction can be due to ABO incompatibility or extravascular hemolysis.

... haliburton made a comment on nbme24/block4/q#4 (A 63-year-old woman develops flank pain,...)
 +0  upvote downvote
submitted by haliburton(74)

FA 2017 states that extravascular hemolysis has jaundice where ABO incompatibility would not.

... neonem made a comment on nbme24/block4/q#4 (A 63-year-old woman develops flank pain,...)
 +7  upvote downvote
submitted by neonem(227)

This is acute hemolytic transfusion reaction, a type II hypersensitivity where pre-formed IgM antibodies bind to incompatible ABO antigens on donor RBCs, which causes intravascular hemolysis. Rh incompatibility, like colonelred_ said, comes more into play with Rh-compatibility of pregnancy and it is due to IgG antibodies, which more often cause extravascular hemolysis since splenic macrophages have those Fc-gamma-R receptors to bind whatever IgG has caught. Extravascular doesn't cause that hypotension, fever, flank pain associated with hemoglobinuria since the macrophages hold on to the degraded RBCs and convert it to biliverdin, which can safely be excreted by the liver.

mousie  Could you help me with understanding why this isn't a Type I HSR? I understand that ABO incompatibility is Type II HSR but I don't know how to tell the difference between a patient who is IgA deficient and having a Type I Reaction to an infusion vs ABO incompatibility ....
sympathetikey  @mousie - https://imgur.com/QH5rCEX Basically, think of Type 1 HS like a normal allergic reaction (itchy, wheezing, etc.). Whereas, with ABO incompatibility you get the question's presentation.
medpsychosis  When it comes to Acute hemolytic transfusion reactions, they are Type II hypersensitivity and divided into Intravascular (ABO) and Extravascular (host Ab against foreign antigen on donor RBC). The differentiating factor between them is simple. Intravascular (ABO) will present with hemoglobinuria alongside all the other common symptoms (fever,hypotension, tachypnea etc.) Extravascular hemolysis will stand out with Jaundice as one of the presenting symptoms. Hope this helps!
... sattanki made a comment on nbme24/block4/q#5 (A 45-year-old man comes to the physician because of...)
 +7  upvote downvote
submitted by sattanki(27)

Muscle pain + periorbital edema is a classic presentation for trichonella spiralis. Best diagnosis for this is a muscle biopsy, as the wormy likes to hangout within the muscles.

sympathetikey  That's what you get for killing polar bears.
dr.xx  That's what you get for not cooking them well.
charcot_bouchard  Theres nothing called "well cooked polar bear meat"
... neonem made a comment on nbme24/block4/q#5 (A 45-year-old man comes to the physician because of...)
 +4  upvote downvote
submitted by neonem(227)

Apparently trichinella lies around in muscle of all of the random exotic animals that most people wouldn't normally eat... things like bear, wild boars/pork (like in Sketchy Micro), big cats, foxes, dogs, horses, seals, walruses. In case you needed another reason to not hunt and consume these animals?

... fahmed14 made a comment on nbme24/block4/q#6 (A 68-year-old woman comes to the physician because...)
 +1  upvote downvote
submitted by fahmed14(9)

The 3-cm ectatic aorta means she has an abdominal aortic aneurysm. Generally, they tend to occur below the renal branches so I went with the two closest branches- SMA (slightly above renal) and IMA (below renal). Also, splenic flexure is a common watershed area supplied by SMA and IMA so involvement of both can cause her symptoms

... ankistruggles made a comment on nbme24/block4/q#6 (A 68-year-old woman comes to the physician because...)
 +0  upvote downvote
submitted by ankistruggles(6)

Why are the IMA and SMA most likely to be affected in her condition?

sattanki  Again, not too sure, but I think they were describing a patient with chronic intestinal angina, which is classically from atherosclerosis of the IMA/SMA.
mcl  I was also thinking about which areas have crappy blood supply (watershed areas), which I assume would be worse off in the case of chronic mesenteric ischemia. If you look on page 357 of FA 2019, SMA & IMA at the splenic flexure is a watershed area; the other is rectosigmoid junction (sigmoid branch from IMA and superior rectal).
... cocoxaurus made a comment on nbme24/block4/q#6 (A 68-year-old woman comes to the physician because...)
 +3  upvote downvote
submitted by cocoxaurus(22)

The presentation here seems to fit that of mesenteric vascular occlusion- postprandial pain that lasts 1 hour, food aversion, weight loss. The patient also has risk factors associated with mesenteric vascular occlusion- older than 60 years old, Hyperlipidemia, Hypertension, PMHx.

"The mesenteric circulation consists of three primary vessels that supply blood to the small and large bowel: the celiac artery, superior mesenteric artery (SMA), and inferior mesenteric artery (IMA). Blood flow through these arteries increases within an hour after eating due to an increase in metabolic demand of the intestinal mucosa.Chronic occlusion of a single vessel allows collateral blood flow to compensate, thus symptoms do not typically present until at least two primary vessels are occluded." https://www.ncbi.nlm.nih.gov/books/NBK430748/

Collaterals between SMA and IMA near the splenic flexure (Meandering Mesenteric artery). There is also collateral between Celiac Artery and SMA (Pancreaticoduodenal arcade).

Lastly, I know that there is a 3-cm ectatic aorta found on CT, but an aortic aneurysm would not produce these symptoms. Even if you thought that the symptoms were due to the AAA, you could still get to the correct answer if you use fahmed14's reasoning.

honey-crusted lesion  Great explanation! There's also a slide about this in the 100 Anatomy Concepts pdf but doesn't go into as much detail as this explanation. Thanks!
... brethren_md made a comment on nbme24/block4/q#6 (A 68-year-old woman comes to the physician because...)
 +0  upvote downvote
submitted by brethren_md(39)

Chronic Mesenteric Ischemia aka intestinal angina. Main clues are postprangial epigastric pain, weight loss. Usually due to Celiac (a), SMA, or IMA atherosclerosis.

neonem  What's tough about these answer choices though is that you have 2 different viable combos.
codyluvr95  The ectatic aorta might also mean AAA below the renals, affecting the IMA,
sherry  Also since there is this ectatic aorta, the arteries involved need to be adjacent to one another. If there is a choice as in celiac and SMA, it could also be correct.
... mousie made a comment on nbme24/block4/q#6 (A 68-year-old woman comes to the physician because...)
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submitted by mousie(74)

looking back at this Q I notice that the patient also has hypertension ...could that have been a clue to include the SMA bc its so close to the renal arteries (Renal a stenosis)?

nwinkelmann  I didn't know how to approach this either, but now this is my thought process: Patient has pain after eating. If it's not due to an ulcer (which is the only thing I could come up with because I didn't know what else it was talking about), why would eating cause pain? Well... eating causes increased GIT activity which means increased blood flow. As you pointed out, the patient has HTN and CAD, indicating likely extensive atherosclerosis. This is important because why would eating leading to increased blood flow cause pain, when usually it doesn't? Well... atherosclerosis in the heart leads to stable angina. This presentation sounds like a "stable angina" of the abdomen.
... colonelred_ made a comment on nbme24/block4/q#7 (A 3-year-old girl is brought to the physician for a...)
 -1  upvote downvote
submitted by colonelred_(44)

The diagnosis is strawberry hemangioma, commonly happens in kids, often resolves on its own as they get older.

shaeking  A strawberry hemangioma is normally pink or red (which is why it is named strawberry). The description has a flat purplish lesion which makes me think of a port wine stain on the face. How do you know to think of strawberry hemangioma over port wine based on this question stem?
sheesher  This sounds more like a nevus simplex, which is very similar to a port wine stain, though it regresses over time.
seagull  the age is key here. Newborns have strawberry hemangiomas typically on their face. Sturge-Weber could also be the case but none of the answer choices matched to that description.
vshummy  I would agree with Sturg Webber nevus flammeus but I also noticed First Aid says it's a non-neoplastic birth mark so I should have known not to pick malignant degeneration or local invasion. Also because capillary hemangiomas don't have to be flat but the nevus flammeus is consistently flat. But I'm also reading on Wiki that the nevus flammeus doesn't regress so they must be trying to describe strawberry hemangioma even though I don't agree with their color choice...
nala_ula  Maybe (and I can only hope I'm right and the test makers are not -that much of- sadists) they would have made sure to write "in a cranial nerve 5 (either ophthalmic or maxillary) distribution" if it were Sturge-Weber.
... medskool123 made a comment on nbme24/block4/q#7 (A 3-year-old girl is brought to the physician for a...)
 +0  upvote downvote
submitted by medskool123(7)

how did you know it was a strawberry hemangioma and not a port wine stain?I thought I had this one in the bank

kateinwonderland  Me too! TABLE 1 Classification of Vascular Lesions Vascular malformations (flat lesions) -Salmon patch (also known as nevus simplex or nevus telangiectaticus) -Port-wine stain (also known as nevus flammeus) Hemangiomas (raised lesions) -Superficial hemangioma (also known as capillary nevus hemangioma) -Deep hemangioma (also known as cavernous hemangioma) https://www.aafp.org/afp/1998/0215/p765.html
... fenestrated made a comment on nbme24/block4/q#7 (A 3-year-old girl is brought to the physician for a...)
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submitted by fenestrated(5)

I don't know what's going on here because in name 23 I picked "cavernous vascular spaces" for strawberry hemangioma and it was incorrect, then they go and describe it here as "cavernous vascular channels" and they expect me to know it's a strawberry hemangioma also????????????!!!!!!!!!!

fenestrated  nbme23*
... sattanki made a comment on nbme24/block4/q#8 (A 1-week-old newborn is brought to the physician...)
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submitted by sattanki(27)

Can’t help much on the exact reasoning why, but there are a few UWorld questions on this where if a neonate has hypoglycemia, ketosis and hyperammonemia, a organic acid disorder should be suspected (propionic acid or methylmalonic acid). Less suspicious of an RTA cause hypoglycemia is not characteristic of that.

sweetmed  Im assuming because N-acetylglutatmate is an allosteric activator of CPS I needed in urea cycle. and N-AG is made of glutamate and acetyl coA. So in organic acidemias, all the acetyl CoA is being used to make ketones for energy since gluconeogenesis is messed up. So Urea cycle doesnt work as well and NH3 accumulates
... lsmarshall made a comment on nbme24/block4/q#8 (A 1-week-old newborn is brought to the physician...)
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submitted by lsmarshall(181)

Urea Cycle Disorders > Isolated severe hyperammonemia (> 1000; i.e., no other severe metabolic disturbances

Ornithine transcarbamylase deficiency > (most common urea cycle dis.) orotic acidemia/aciduria, hyperammonemia

Organic Acidemias > Hyperammonemia, anion-gap acidosis, ketosis (from hypoglycemia)

Medium-chain acyl-CoA dehydrogenase deficiency > Hyperammonemia, hypoketotic hypoglycemia (seen in β-oxidation disorders, EXCEPT adrenoleukodystrophy)

Liver dysfunction > Hyperammonemia, LFTs messed up, older pt.

lsmarshall  Summary of metabolic issues relating to hyperammonemia
seagull  i'm leaning towards Ornithine transcarbamylase deficiency.
notadoctor  Not sure why this isn't considered a mitochondrial disorder since the issue is Ornithine transcarbamylase deficiency in the mitochondria?
charcot_bouchard  if it was mitochondrial disorder no one would escape
wowo  figure in OTC deficiency, they might have to explicitly mention the orotic aciduria AND typically presents earlier, around 24-48hrs of life after they've fed (at least per BB) + also per BB, propionic acidemia and MM acidemia have an onset of weeks to months and lead to build up of organic acids --> acidemia in addition to hyperammonemia (not sure why, but several aa enter the TCA cycle via propionyl CoA --> methylmalonyl CoA --> succinyl CoA, but now this is defunct d/t enzyme deficiencies...?). Anywho, propionic acidemia described on FA2019 p85, but doesn't list hyperammonemia
artist90  i think it cannot be Ornithine transcarbamylase deficiency bc it is XR disease. this pt has a healthy 2yr old brother which rules out X-linked recessive disease correct me if i m wrong
artist90  it is 100% Propionic acidemia Uworld Q-id: 1340. it is an exact copy question of uworld. i got it wrong bc i forgot these are organic acids. But i am still confused on 2 things 1-how does acidosis cause Hypoglycemia and Ketosis. 2-why is Ammonia elevated in these pts bc urea cycle will be fine?
yb_26  1) hyperammonemia is seen in all urea cycle disorders except arginase deficiency 2) organic acids directly inhibit urea cycle => hyperammonemia (from UWorld)
... brethren_md made a comment on nbme24/block4/q#9 (A 10-year-old boy who was adopted from the...)
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submitted by brethren_md(39)

Onchocerca Volvulus via female blackfly. Black flies, black skin nodules, "black sight" (aka Blindness). Question stem here describes the black nodules seen in Onchocerca.

... famylife made a comment on nbme24/block4/q#9 (A 10-year-old boy who was adopted from the...)
... consistentwrongdoer3 made a comment on nbme24/block4/q#10 (A 60-year-old woman is receiving cisplatin therapy...)
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submitted by consistentwrongdoer3(4)

The answer is hyporeflexia because the afferent arc of the muscle stretch reflex has to go through the dorsal rami and dorsal root ganglia. Dumb question, I know, but it’s the only answer that made sense. If you hurt the DRG, you not only lose afferent somatic sensory fibers, you also lose the sensory bodies involved in the various reflexes.

You can also get hyporeflexia from damaging the efferent neurons that innervate the muscle (like a LMN), but as you know these are in the anterior horn and ventral rami.

ankistruggles  Thanks! I agree with you.
brethren_md  Great explanation.
gonyyong  Agreed - I think I got this by thinking about tabes dorsalis (syphillis) and why it has hyporeflexia is due to dorsal root damage
duat98  I'm confused about why it wouldn't cause muscle atrophy. Isn't that a fever of LMN damage?
charcot_bouchard  Muscle atrophy wont occur because alpha motor neuron is intact. Motor control of Corticospinal tract on this is intact. so no atrophy. u can move shiti/ But remeber muscle spindle that is responsible for INITIATING stretach reflex send Ia fibre to DRG from where it synapse with Alpha motor neuron. if DRG is damage ur muscle is fine but u cant initiate strech reflex. areflexia
... enbeemee made a comment on nbme24/block4/q#10 (A 60-year-old woman is receiving cisplatin therapy...)
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submitted by enbeemee(3)

i get why it's hyporeflexia, but why not fibrillations? it's also an LMN sign

et-tu-bromocriptine  Imagine a simple reflex arc: you have an afferent neuron, some interneuron shenanigans, and an efferent neuron (aka LMN neuron). If you damage the LMN, you will get hyporeflexia (due to damaged reflex arc) and fibrillations (because your LMN won't be able to effectively contract muscle on command). However, if you damage the afferent part of the arc, you will still get a damaged reflex arc (hyporeflexia), but your motor neuron will still be able to do its stimulating effectively, so your muscles won't show weak contractions when stimulated by a higher pathway. Kinda confusing but I hope I made it a tad simpler!
... neonem made a comment on nbme24/block4/q#11 (A 53-year-old woman comes to the physician because...)
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submitted by neonem(227)

this patient has symptomatic aortic stenosis. This can be identified by the ventricular hypertrophy (to compensate for increased functional afterload from non-compliant aortic valve), midsystolic murmur and the location at the normal aortic area.

Per UpToDate on Clinical manifestations of Aortic Stenosis:

"Dizziness and syncope — Syncope occurs as a presenting symptom in approximately 10 percent of patients with symptomatic severe AS (or approximately 3 percent of all patients with severe AS) [3]. There are several proposed explanations for exertional dizziness (presyncope) or syncope in patients with AS, both of which reflect decreased cerebral perfusion. Exercise-induced vasodilation in the presence of an obstruction with fixed cardiac output can result in hypotension."

guillo12  What does "fixed cardiac output" signify?
usmleuser007  "fixed cardiac output" might mean that with the stenosis (ie. narrowed aortic valve) there is a limited or rather reduced cardiac output. Exercise would not increase cardiac output because the stenosis is caused by a mechanical (physical) rather than a biochemical process. Therefore, At any given moment the heart can not increase its output no matter how forcefully it contracts.
... m-ice made a comment on nbme24/block4/q#12 (A 25-year-old woman takes an overdose of...)
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submitted by m-ice(116)

The patient shows no sign of cortical activity, but has some brainstem function intact, which implies she is in a form of persistent vegetative state. She has a living will that designates mechanical ventilation should be discontinued if that situation arises, so we must follow it and make not attempt to resuscitate.

lfsuarez  Why would the second part of that be correct when there is not mention of a DNR?
ug123  DNI and DNR are different right? This patient had a DNI. Why would we assume it to be DNR too?
sherry  DNI and DNR are indeed different. But it is not the case here. The patient needs to be extubated means she did not sign a DNI or DNR in the first place. I assume her living will is more like terminate supporting treatment in a vegetative state. So there is no need to do resuscitation anyways. But I agree this is not a good question.
shayan  "The patient has signed the living will and is consistent with her directives" but the stem doesnt tell has what is in her living will about the extubation? we are extubating on the request of her husband? this is confusing !
criovoly  I believe this question was not well constructed... it's one of those!
... yotsubato made a comment on nbme24/block4/q#13 (A 90-year-old man has a 1-week history of...)
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submitted by yotsubato(214)

Why is the patient not in pain. I wouldnt expect Incarcerated hernia to present with zero pain, but 1 week of constipation and swelling.

yotsubato  Incarcerated hernia. If the contents of the hernia become trapped in the weak point in the abdominal wall, it can obstruct the bowel, leading to severe pain, nausea, vomiting, and the inability to have a bowel movement or pass gas. Like really? Why is he not in pain?
medschul  I thought that inguinal hernias were reducible?
fahmed14  could be a femoral hernia as they are more likely to cause incarceration. They do, however, present more often in females. (FA 2019- 364)
wowo  incarcerated, not strangulated, thus no pain as there's no serious tissue damage/ischemia. Incarcerated hernias may progress to strangulated in which case he would have pain Under section, "complications" https://www.amboss.com/us/knowledge/Inguinal_hernia
... ankistruggles made a comment on nbme24/block4/q#13 (A 90-year-old man has a 1-week history of...)
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submitted by ankistruggles(6)

How do you know he has an incarcerated inguinal hernia and not fecal impaction?

sattanki  So as far as I understand, you don’t really get a bulging, defined abdominal mass with fecal impaction. Much more likely to see this with a hernia.
xxabi  Fecal impaction can be palpated in the abdomen, since it'd be accumulating in the rectum and colon, not the groin. Hope that helps!
pseudorosette  a little late but they also mention that the mass had bowel sounds hence it was an incarcerated bowel! :)
... m-ice made a comment on nbme24/block4/q#14 (A new screening test for colon cancer is done in 86...)
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submitted by m-ice(116)

Specificity is equal to the number of true negative tests over the number of true negatives plus false positives:

Spec = TN /(TN + FP)

... neonem made a comment on nbme24/block4/q#15 (A 15-month-old boy is brought to the physician by...)
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submitted by neonem(227)

Lack of CD18 (LFA-1 integrin) on phagocytes is the cause of leukocyte adhesion deficiency type 1 (LAD1). Since phagocytes like neutrophils and macrophages can't get out of the bloodstream, they are stuck in the blood, hence the leukocytosis with WBC count > 10,000. Since the leukocytes are stuck in the blood, they can't mount an effective immune response against bacteria.

... trazabone made a comment on nbme24/block4/q#16 (A 24-year-old woman who has diffuse toxic goiter...)
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submitted by trazabone(4)

Kidney makes 1-25, hydroxy vitamin D. (calcitriol) 25-hydroxy vit D (calcidiol) is made in the liver, and hypoparathyroidism would not decrease its levels as it acts to increase 1-alpha hydroxylase in the kidney to increase calcitriol concentrations --> Ca/phosphate reabsorption from the bone and small intestine.

queezyfish  I'm confused about the phosphate level in questions like these. Decreased calcitriol would decrease phosphate absorption while PTH decrease lowers phosphate excretion. I'm assuming that the PTH decrease has the greater effect with serum phosphate levels?
mousie  PTH = "Phosphate trashing hormone" if PTH is high Phosphate must be low - they are always opposite (unless d/t renal failure then Phosphate will be high - kidneys will be unable to get rid of phosphate) So low Ca d/t low PTH does not effect 25 H. Vit D ... only 1,25 H Vit D (active Calcitriol)?
haliburton  Clarification because I was confused: PTH stimulates kidney to produce 1,25-(OH)2 D3 (calcitriol) via 1α-hydroxylase in proximal convoluted tubule. Therefore, without parathyroid glands, low PTH, 25,D is not converted and therefore not down (normal or up). phosphate "trashed" by PTH as eloquently stated above.
zbird  Here the primary defect is high up from the parathyroid gland, there is decresed or no PTH which normally trashes phosphate but not in this case so serum PHOSPHATE INCREASES and the serum calcium is low because PTH should have prevented the urine calcium so there is calciuria and no resorption from bone-LOW CALCIUM, Vitamin-D is independent of PTH so stays NORMAL
... tinydoc made a comment on nbme24/block4/q#16 (A 24-year-old woman who has diffuse toxic goiter...)
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submitted by tinydoc(39)

This question is very sneaky, but in essence this is whats happening.

The accidental removal of the PTH glands during thyroidectomy ⇒ ↓ PTH

PTH normally: --in bone: ↑ removal of Ca²⁺ and Phophate from bone --in kidneys: ↑ Ca²⁺ reabsorption and ↓ PO₄³⁻ reabsorption --↑ conversion of 25, Hydroxyvitamin D to 1,25 Hydroxyvitamin D (Calcitriol - active form) via ↑ activity of 1-a Hydroxylase deficiency

Therefore a ↓ PTH would lead to:

⇒ ↑ PO₄³⁻ ⇒ ↓ Ca²⁺ ⇒ ↓ 1,25 Hydroxyvitamin D

The question is sneaky (much like the rest of this exam) because someone who isnt focusing really hard or in a rush might pick the option C where phophate is ↑ and PTH is ↓ BUT ↓ 25 hydroxyvitamin D

This is wrong as only 1,25 hydroxyvitamin D would be decreased, the conversions before this are done by the skin (sunlight) and liver.

I really wish they would stop making the questions confusing PURELY for the sake of making them confusing. Isnt it enough that we have to know this ridiculous amount of information, without having them intentionally making it harder by pointing you to 1 answer choice but changing a minute detail to make you answer wrong. Or using a random ass nomenclature for a disease to avoid making it too simple (PSGN = "proliferative GN")

tinydoc  I literally got this wrong because I had the font zoomed in and assumed the 1 was on the line above like on uworld when it tries to squish the whole title in the same space x_X
... dentist made a comment on nbme24/block4/q#16 (A 24-year-old woman who has diffuse toxic goiter...)
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submitted by dentist(1)

Follow the Calcium and work backwards. ↓Ca means ↓ Phosphate resorption in the PCT (which pulls Ca with it)

25-hydrovitD normal b/c its unrelated to PTH.

... colonelred_ made a comment on nbme24/block4/q#17 (A 63-year-old woman undergoes operative repair of a...)
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submitted by colonelred_(44)

Normally the arachnoid villi drains the CSF from the subarachnoid space to the venous system; if this part becomes defective then you can imagine all that CSF now building up in the subarachnoid space.

keycompany  Also take into account this patient had surgery that requires penetration into the subarachnoid space (hence through the arachnoid mater). This can lead to scarring of the arachnoid granulations and subsequent communicating hydrocephalus.
... roygbiv made a comment on nbme24/block4/q#17 (A 63-year-old woman undergoes operative repair of a...)
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submitted by roygbiv(5)

The patient has a leaking berry aneurysm --> this leads to a subarachnoid hemorrhage (or leakage into subarachnoid space) --> acute SAH can lead to decreased absorption and movement via arachnoid villi

zbird  So this patient has a leaking berry aneurysm which undergone to surgery and repaired but in two days she developed widening of the SA space which could be explained by increased CSF production but a decreased in absorption, which is due to blockage of the arachinoid granulations by the leaked red and white cells therefore there is a decreased movement of the CSF via the arachinoid villi
... roygbiv made a comment on nbme24/block4/q#18 (A 64-year-old man undergoes surgical repair of an...)
... xxabi made a comment on nbme24/block4/q#18 (A 64-year-old man undergoes surgical repair of an...)
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submitted by xxabi(82)

Arteries of the spermatic cord - testicular a., ductus deferens a., cremasteric a.

roygbiv  https://i2.wp.com/obgynkey.com/wp-content/uploads/2017/06/A302767_1_En_1_Fig2_HTML.jpg?w=960
roygbiv  Omg I keep adding comments instead of a post LOL
... lm4 made a comment on nbme24/block4/q#18 (A 64-year-old man undergoes surgical repair of an...)
roygbiv  https://i2.wp.com/obgynkey.com/wp-content/uploads/2017/06/A302767_1_En_1_Fig2_HTML.jpg?w=960
... nwinkelmann made a comment on nbme24/block4/q#18 (A 64-year-old man undergoes surgical repair of an...)
... neonem made a comment on nbme24/block4/q#19 (A 38-year-old woman, gravida 4, para 4, comes to the...)
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submitted by neonem(227)

Internal anal sphincter is composed more of smooth muscle and is under parasympathetic/sympathetic control, while external anal sphincter is skeletal muscle and controlled by pudendal nerve. All of the other muscles listed are skeletal muscle of the pelvic floor and are more likely to be involved in Kegel exercises.

... masonkingcobra made a comment on nbme24/block4/q#19 (A 38-year-old woman, gravida 4, para 4, comes to the...)
charcot_bouchard  When i faced this ques i did some Kegel. Felt something in my pee pee but not in my b*e. I exclude all option because they are bigger muscle of pelvic floor except EUS & IAS. And also remeber Kegel can be used as a treatment of prem. ejaculation not premature defication.
... sajaqua1 made a comment on nbme24/block4/q#20 (Forty of 100 attendees at a company Christmas party...)
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submitted by sajaqua1(171)

Vibrio cholera and V. parahaemolyticus are frequently associated with consumption of undercooked seafood like shellfish. V. vulnificus is associated with brackish water or saltwater.

A) B. cereus- vignettes tend to associate this with reheated rice at a buffet, vomiting is more common than diarrhea. B) C. jejuni- associated with undercooked food, especially chicken, or can be contracted by contact with animals. It causes inflammatory, bloody diarrhea, and may also lead to Guillan-Barre syndrome. C) C. perfringens- as a sporulator, this is associated with good that is reheated then left to germinate at room temperature for a long time before consumption. Symptoms include vomiting and diarrhea. D) S. aureus- a heat stable toxin produced by S. aureus is associated with rapid onset of vomiting, may be accompanied by diarrhea. Most often associated with dairy products and meat.

... medstruggle made a comment on nbme24/block4/q#21 (An otherwise healthy 45-year-old man comes to the...)
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submitted by medstruggle(5)

Why is it aphthous ulcers if there are no GI symptoms? Why can’t it be herpes zoster?

colonelred_  It’s just canker sores, they come and go. I think in herpes the gingivostomatitis really only happens when you first get infected. After that you just get recurrent cold sores.
hyoid  Herpes zoster is not the same as herpes simplex virus.
bigjimbo  you would see dermatome rash in zoster
kateinwonderland  cf) Just in case someone wanted to know the causative organism of aphthous ulcers :The precise cause of canker sores remains unclear, though researchers suspect that a combination of factors contributes to outbreaks, even in the same person. Unlike cold sores, canker sores are not associated with herpes virus infections.
charcot_bouchard  Herpes Zoster doesnt cause gingivostomatitis. Herpengina can cause vesicular lesion in mouth but happens to children in summer season by entero virus
drdeeznuts1  I'm wondering if this could be a mild case of Behcet syndrome without genital involvement
sherry  It sure can be Behcet or Pemphigus if the q provides us with more info. Canker sores just come and go for years with unclear mechanism. Also herpes zoster is shingles by VZV, not HSV1.
... sajaqua1 made a comment on nbme24/block4/q#22 (A 45-year-old man is brought to the emergency...)
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submitted by sajaqua1(171)

The keys to this answer are that it is fairly sudden in onset, and migrates. None of the other answers could explain the movement of pain from flank to LLQ to scrotum. While the kidney stone does not actually enter the scrotum, the pain can be referred to the testicles.

... lispectedwumbologist made a comment on nbme24/block4/q#22 (A 45-year-old man is brought to the emergency...)
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submitted by lispectedwumbologist(23)

How do you distinguish this from testicular torsion? Is it just because it started in the left flank?

neels11  and there's no mass in the scrotum, whereas testicular torsion will have that "bag of worms" feel (along with a lack of cremaster reflex) testicular torsion usually happens in a younger age group
medpsychosis  @neels11 I would like to clarify a piece of information. I believe you are confusing Varicocele with Testicular Torsion. Varicocele will present with "bag of worms" feeling. While the absence of cremasteric reflex is a sign of testicular torsion.
johnson  This is the classic "loin to groin pain" of nephrolithiasis.
... youssefa made a comment on nbme24/block4/q#22 (A 45-year-old man is brought to the emergency...)
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submitted by youssefa(6)

I mean why would a testicle turn around itself when someone's sleeping. This typically occurs after sports/ bicycle riding etc..

... sweetmed made a comment on nbme24/block4/q#22 (A 45-year-old man is brought to the emergency...)
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submitted by sweetmed(28)

Testicular torsion mostly happens in young boys, rarely in adults. Also the pain started at the flanks, which is not how torsion pain starts.

... sympathetikey made a comment on nbme24/block4/q#23 (At 2:00 am, after sleeping for 5 hours, a...)
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submitted by sympathetikey(260)

I just tried to think of what's released by the Adrenal Medulla (Epinephrine). PNMT is the only choice that made sense.

... xxabi made a comment on nbme24/block4/q#23 (At 2:00 am, after sleeping for 5 hours, a...)
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submitted by xxabi(82)

NE is converted to EPI via PNMT, which is induced by cortisol.

wowo  FA2019 p83
... subclaviansteele made a comment on nbme24/block4/q#24 (A 13-year-old girl who has a 6-year history of type...)
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submitted by subclaviansteele(2)

Ugh... got tripped up with "Refer both patient and her parents to a dietician"

Over thinking...I thought the source of their arguments were at meal times especially...so maybe they can find a good solution with a dietician.

OCCAMs RAZOR THIS SHIT. keep it simple stupid. The answer fits the best after re reading it.

nwinkelmann  SAME.... ugh!
johnson  Also - you're almost NEVER referring/passing on a patient with the USMLE.
... nwinkelmann made a comment on nbme24/block4/q#24 (A 13-year-old girl who has a 6-year history of type...)
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submitted by nwinkelmann(60)

I just thought of a way to (hopefully) avoid getting these types of answers wrong. First, when I read them I always look for the least "asshole" answer. Then, if you're still stuck, try to put the statement into a quote that you would say to a patient as a physician, remembering that open-ended, non-judgmental questions are ideal.

The answer for this could be phrased as a question/statement by the doctor, to the family, as "Tell me more about how this impacting your family and daily life." Had it been phrased like that, I DEFINITELY wouldn't have gotten it wrong. I would have never even had the opportunity to make an assumption about the family's fighting being due to diet concerns and thus needing a nutritionist referal (which is what I chose).

... m-ice made a comment on nbme24/block4/q#25 (A 26-year-old man is brought to the emergency...)
 +4  upvote downvote
submitted by m-ice(116)

This man has pulsus paradoxus, a sign in which blood pressure decreases drastically during inspiration. Pulsus paradoxus is a classic sign of pericardial tamponade.

When fluid (often blood) has pooled around the heart, the heart struggles to expand and fill with blood. This becomes a bigger problem for the right ventricle during inspiration, because the right side of the heart receives increased venous return during inspiration. Because there is fluid preventing the right ventricle from expanding outward, the only other place it can expand to accommodate is by pushing on the septum, shrinking the size of the left ventricle. This causes decreased BP when the left ventricle contracts during that cardiac cycle.

sajaqua1  In addition to causing pulsus paradoxus, we see jugular venous distension, and muffled/distant heart sounds (hard to hear through the cardiac tamponade). https://radiopaedia.org/articles/beck-triad?lang=us
... medstruggle made a comment on nbme24/block4/q#26 (A 10-year-old girl is brought to the physician by...)
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submitted by medstruggle(5)

Why is it not ovarian follicle cells? I thought the female analog of Sertoli and Leydig is theca/granulosa cells.

colonelred_  Females can get sertoli-leydig cell tumors, which are notorious for producing lots of androgen.
brethren_md  Females can get sertoli-leydig cell tumors, which are notorious for producing lots of androgen
sympathetikey  Females can get sertoli-leydig cell tumors, which are notorious for producing lots of androgen
s1q3t3  Females can get sertoli-leydig cell tumors, which are notorious for producing lots of androgen
masonkingcobra  Females can get sertoli-leydig cell tumors, which are notorious for producing lots of androgen
mcl  Wait, but did anyone mention that females can get sertoli-leydig cell tumors, which are notorious for producing lots of androgen???
mcl  But seriously though, pathology outlines says sertoli-leydig tumor "may be suspected clinically in a young patient presenting with a combination of virilization, elevated testosterone levels and ovarian / pelvic mass on imaging studies." As for follicle cell tumors, granulosa cell tumors usually occur in adults and would cause elevated levels of estrogens. Theca cell tumor would also primarily produce estrogens. Putting the links at the end since idk if they're gonna turn out right lol Link pathology outlines for sertoli leydig granulosa cell tumor theca cell tumor
bigjimbo  LOL
fallenistand  Females can get sertoli-leydig cell tumors, which are notorious for producing lots of androgen.
medpsychosis  So after doing some intense research, UPtoDate, PubMed, an intense literature review on the topic I have come to the final conclusion that...... ...... ...... ...... Wait for it.... ..... ..... Females can get sertoli-leydig cell tumors, which are notorious for producing lots of androgen.
charcot_bouchard  Hello, i just want to add that Females can get sertoli-leydig cell tumors, which are notorious for producing lots of androgen
giggidy  Hold up, so I'm confused - I read all the posts above but I still am unsure - are sertoli-leydig cells notorious for producing androgen?
subclaviansteele  Hold the phone.....Females can get sertoli leydig cell tumors which are notorious for producing androgen? TIL TL;DR - Females can get sertoli leydig cell tumors = high androgens
cinnapie  I just found a recent study on PubMed saying "Females can get sertoli-leydig cell tumors, which are notorious for producing lots of androgen"
youssefa  Hahahahaha ya'll just bored
water  Bored? you wouldn't think so if you knew that females can get sertoli-leydig cell tumors, which are notorious for producing lots of androgen
nbmehelp  I dont get it
redvelvet  how don't you get it that females can get Sertoli Leydig cell tumors, which are notorious for producing lots of androgen?
... medstruggle made a comment on nbme24/block4/q#27 (A 19-year-old man has had weakness of the muscles of...)
 +1  upvote downvote
submitted by medstruggle(5)

Can someone please explain this? What is the diagnosis here?

welpdedelp  I thought it just as it was, polyneuropathy is supposed to be a burning pain affecting the extremities, he might have acute intermittent porphyria. He was too young and didn't fit ALS due to the rapid onset. No loss of pain in the arms so it couldn't be syringomelia. Wasn't asymmetric so couldn't be polio. Didn't have anything resembling Parkinson.
... lsmarshall made a comment on nbme24/block4/q#27 (A 19-year-old man has had weakness of the muscles of...)
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submitted by lsmarshall(181)

Polyneuropathy - A condition involves damage to multiple peripheral nerve fibers. Patients typically present with symmetric distal sensory loss or a burning sensation associated with motor weakness. Classic polyneuropathy is burning so this question was more process of elimination. Others did not fit well.

... majic made a comment on nbme24/block4/q#27 (A 19-year-old man has had weakness of the muscles of...)
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submitted by majic(0)

"Poly- meaning many/multiple + nueropathy. Nueropathies in multiple locations that results in weakness, impaired position or burning pain. The most common cause of polyneuropathy is a Vitamin B6 deficiency. The most common genetic cause is Charcot-Marie-Tooth The most common infectious cause is Guillain-Barré

... ameanolacid made a comment on nbme24/block4/q#27 (A 19-year-old man has had weakness of the muscles of...)
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submitted by ameanolacid(12)

Couldn't be ALS b/c he had sensory involvement...ALS is distinctly only motor. Not Syringomyelia (which is upper extremities sensory then motor later on) bc I assumed by the wording that all 4 extremities were involved. Obv not Parkinsons, and not polio bc again, he has motor + sensory.

sympathetikey  Probably in part due to early age presentation, but I hear you
wowo  FA2019 p518 - process of elim for other spinal cord lesions
... m-ice made a comment on nbme24/block4/q#28 (A clinical study is designed to evaluate the...)
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submitted by m-ice(116)

The "likelihood of missing an association" refers to Type II error. The risk of Type II error is represented by beta. This could be confused with power, which is 1 - beta.

usmleuser007  Just rereading this question without the stress, i got it quickly! Could't believe i missed something as simple as this.
... yotsubato made a comment on nbme24/block4/q#29 (A 56-year-old man has a 3-year history of...)
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submitted by yotsubato(214)

Amyloid A : seen in chronic inflammatory conditions, deposition of amyloid in tissues

B2 microglobulin: associated with ESRD and long term dialysis

Neurofilament protein: Form the cytoskeleton of neurons (in healthy individuals)

Presenilin: associated with familial alzheimers disease

... neonem made a comment on nbme24/block4/q#29 (A 56-year-old man has a 3-year history of...)
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submitted by neonem(227)

Per Pathoma: early inherited cases of Alzheimer's dementia are associated with mutations in presenilin-1/presenilin-2, as well as Down's syndrome. Down's would be due to an extra chromosome 21, which carries the gene for amyloid precursor protein (APP). Extra APP is converted to A-beta amyloid and this forms extracellular neuritic plaques, a prominent feature of Alzehimer's.

Important to not confuse Amyloid A protein (one of the answer choices) with Amyloid precursor protein. Deposition of AA amyloid is more associated with chronic inflammatory states, malignancy, and Familial Mediterranean Fever. Beta-2 microglobulin is another amyloid association: dialysis-associated (deposits in joints)

... sattanki made a comment on nbme24/block4/q#30 (An investigator is studying an outbreak of...)
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submitted by sattanki(27)

This one there were four odds ratios, one provided under each table. The only one that had an odds ratio greater than 1.0 was the table in the top right (Odds Ratio = 6, I believe), which when you looked at the labels, led to the right answer.

... sne made a comment on nbme24/block4/q#30 (An investigator is studying an outbreak of...)
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submitted by sne(10)

OR >1 indicates increased occurrence of event. The only OR greater than 1 was in the table that indicated that the subject ate cookies but didn't drink milk. Thus, that is the only one with a significant occurrence

... famylife made a comment on nbme24/block4/q#30 (An investigator is studying an outbreak of...)
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submitted by famylife(32)

"An odds ratio of 1 indicates that the condition or event under study is equally likely to occur in both groups. An odds ratio greater than 1 indicates that the condition or event is more likely to occur in the first group." (https://en.wikipedia.org/wiki/Odds_ratio)

... youssefa made a comment on nbme24/block4/q#30 (An investigator is studying an outbreak of...)
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submitted by youssefa(6)

Initially milk drinking was associated with E.coli outbreak with OR=3.9 and P<0.001 (Significant)... After stratification into ate cookies and did not eat cookies OR became 1 instead of 3.9 meaning the association disappeared. Therefore, eating cookies was a confounder and there is no real association between drinking milk and E.coli....instead, milk's (the confounder) contribution was responsible for the OR of 3.9 in the first place. This was furthered demonstrated with OR of 6 in the cookies alone group.

... doodimoodi made a comment on nbme24/block4/q#30 (An investigator is studying an outbreak of...)
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submitted by doodimoodi(2)

Did no one notice that the Odds ratio on the top left is wrong? Am I missing something? If you calculate it, it's 6 just like the top right one....

mjmejora  thats actually really funny
yex  Because I said so, applies here... :-/
... medstudied made a comment on nbme24/block4/q#31 (In a study of antibiotic resistance, a strain of...)
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submitted by medstudied(2)

Can someone explain why the correct answer for the question here is conjugation but can’t be transposition?

catacholamine16  Transposition is when a segment of DNA (in this case, coding for resistance) jumps onto a plasmid within the same bacterial cell. That plasmid might then transfer to another nearby bacterial cell via conjugation. Transposition is happening WITHIN the bacterium. Conjugation is how that resistance gene gets transferred.
lsmarshall  Also, E. coli is the classic example of a bug tat uses conjugation. ^but explanation above is correct^
seagull  I think he might have did what I did. I got Transformation mixed up with transposition. FML
... medskool123 made a comment on nbme24/block4/q#31 (In a study of antibiotic resistance, a strain of...)
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submitted by medskool123(7)

can someone explain why this is not transduction? Last nbme I said conjugation and got it wrong for transduction.. this one I say transduction and its conjugation.

pseudorosette  I would say because this happened between two bacteria, but in transduction what causes the acquisition of bacterial resistance is coming from a bacteriophage, which is a virus that infects bacteria, but that is never hinted at the question!
medpsychosis  Quick Overview of the involved topics and answer choices that are relevant in this question: Transduction: Involves phage, cleaves DNA and takes a part with it as it is packaged. Generalized is when is happens by accident. Specialized is an excision event. Transformation: bacteria takes up naked DNA around it and incorporates it therefore becoming "transformed" e.g. (SHiN) S. Pneuma, H. Influenza type B, and Neisseria. Transposition: Jumping from one location to another within same bacterial organism (e.g. from chromosome to plasmid) Conjugation: Above mentioned plasmid gets transferred from conjugal bridge from one bacteria to another.
wowo  FA2019 p130
zbird  Easy here...first both are G-ves which likely have a sex pilus and if cultured together as in this case transfer their plasmid. Transduction need phage. Transposition is exchange of genetic material inside the bacteria b/n the dna and the plasmid or vv (FA2019)
... m-ice made a comment on nbme24/block4/q#32 (A 45-year-old man with hypercholesterolemia (LDL 260...)
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submitted by m-ice(116)

HMG CoA Reductase inhibitors prevent the liver from synthesizing its own cholesterol. In order to maintain its need for cholesterol, the liver has no choice by to increase its LDL receptor expression in order to take cholesterol from the blood.

... lsmarshall made a comment on nbme24/block4/q#33 (A 12-year-old boy is brought to the physician by his...)
 +4  upvote downvote
submitted by lsmarshall(181)

Inhalant abuse could be done with glue, paint thinners, fuel, nitrous oxide, or alkyl nitrites. Usually in high-school aged kids. Inhalants are 'downers' so whatever intoxication effects there are should be depressant and fully resolve within 30 min. to a couple hours. Patients may look drunk when intoxicated with inhalants, but usually quickly resolve. A characteristic "glue sniffer's rash" around the nose and mouth is sometimes seen after prolonged use.

... sympathetikey made a comment on nbme24/block4/q#33 (A 12-year-old boy is brought to the physician by his...)
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submitted by sympathetikey(260)

Everyone who got this question right is a cop. ༼⌐■ل͟■༽

... mousie made a comment on nbme24/block4/q#33 (A 12-year-old boy is brought to the physician by his...)
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submitted by mousie(74)

A Teen with injection of both conjunctiva = weed could also be abusing other drugs Is 12 years old and four months just too old and too long of a time for it to be impetigo? I narrowed it down to these two and guessed but... I wasn't sure I could eliminate it.

medskool123  I picked impetigo because of the gold stippling... I guess I took that as honey crusted lesions. F*ck NBME.
yotsubato  Huffing gold spray paint. A la the chrome huffers in Mad Max
subclaviansteele  LOL I think that might be what they were going for here. Gold spray paint.
et-tu-bromocriptine  Anyone know what may be causing his weight loss and unwillingness to eat? I thought too much into it and put "mercury poisoning", since I thought the heavy metal's abdominal symptoms may have caused him to not want to eat. ¯_(ツ)_/¯
... neonem made a comment on nbme24/block4/q#34 (A 55-year-old woman comes to the physician for a...)
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submitted by neonem(227)

Since this patient is a non-smoker, it is less to be small cell carcinoma, squamous cell carcinoma, or large cell carcinoma of the lung. Besides small cell carcinoma being from neuroendocrine origin, the one major lung cancer described by nests of well-differentiated, "regular" cells is a carcinoid tumor. Additionally, rosettes are histological features of carcinoid tumors (fun fact: rosettes also in neuroblastomas/ependymomas (in CNS), retinoblastomas, granulosa cell tumors (ovarian cancer))

mousie  When ever I hear Rosettes I always think NE tumors .... and I agree non smoking kind of RO small cell, squamous cell, or lg cell
charcot_bouchard  I thought it was Hamartoma & pick chondrocyte! Can lung even have hamartoma? Pardon me it was the laast ques of whole nbme
... usmleuser007 made a comment on nbme24/block4/q#34 (A 55-year-old woman comes to the physician for a...)
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submitted by usmleuser007(86)

Some other endocrine like cells and disorders for reference:

  1. Salt-and-pepper chromatin (fine granular cytoplasm) in Endocrine tumors:

  2. Medullary thyroid carcinoma

  3. neuroendocrine tumors and pheochromocytoma
  4. Carcinoid Tumor (serotonin) --- (also has sheets of uniform cells)
  5. Small Cell Carcinoma of lungs = Small, blue cells with scant cytoplasm and granular chromatin) = flat, oval-shaped cells with scant cytoplasm and hyperchromatic nuclei

  6. Small Blue Cells

  7. Ewing sarcoma (anaplastic malignant tumor)
  8. SCC of lungs
  9. flat, oval-shaped cells with scant cytoplasm and hyperchromatic nuclei
... yex made a comment on nbme24/block4/q#34 (A 55-year-old woman comes to the physician for a...)
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submitted by yex(4)

I think they are referring to Kulchitsky cells = pulmonary neuroendocrine cells (PNEC). According to Wikipedia: Specialized airway epithelial cells that occur as solitary cells or as clusters called neuroepithelial bodies (NEB) in the lung. They are located in the nasal respiratory epithelium, laryngeal mucosa and throughout the entire respiratory tract from the trachea to the terminal airways. They can be the source of several types of lung cancer- most notably, small cell carcinoma of the lung, and bronchial carcinoid tumor.

... ankistruggles made a comment on nbme24/block4/q#35 (An investigator is conducting a study of a novel...)
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submitted by ankistruggles(6)

Why is basal keratinocyte : suprabasal keratinocyte the cell junction that’s most likely to be affected? Is it because it’s the only answer that lists a junction between two keratinocytes?

sattanki  Not too sure on this one, but I interpreted the basal keartinocyte:suprabasal keratinocyte as the stratum spinosum region, which is known to have the most desmosomes.
... lsmarshall made a comment on nbme24/block4/q#35 (An investigator is conducting a study of a novel...)
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submitted by lsmarshall(181)

"Desmosome (Macula adherens) - A cell-to-cell connection that provides structural support with intermediate filaments, particularly in tissues that undergo mechanical stress (e.g., skin, gastric tissue, bladder). Connects keratinocytes in the stratum spinosum of the epidermis." - AMBOSS

sympathetikey  This is why I was looking for some answer indicating keratinocytes in the stratum spinosum...instead they just gave a bunch of bs choices.
roygbiv  I'm confused because I also know that S. aureus cleaves desmoglein in the stratum granulosum, so why is it specifically this answer?
duat98  desomosomes connects cells to cells. hemidesmosome connects cells to basement membrane.
... fenestrated made a comment on nbme24/block4/q#35 (An investigator is conducting a study of a novel...)
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submitted by fenestrated(5)

Basically asking if you know Pemphigus Vulgaris. Separation of suprabasilar epidermis, intact basal keratinocytes vs Bollous pemphigoid--> includes separation of basal layer

subclaviansteele  This how I thought of the question...Classic histology photo of the "tomb stone" row of basal cells and the lifted keratinocytes.
... brethren_md made a comment on nbme24/block4/q#35 (An investigator is conducting a study of a novel...)
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submitted by brethren_md(39)

Stupid question, honestly just take your best guess and move on lol.

seagull  ░░░░░░░░░░░█▀▀░░█░░░░░░ ░░░░░░▄▀▀▀▀░░░░░█▄▄░░░░ ░░░░░░█░█░░░░░░░░░░▐░░░ ░░░░░░▐▐░░░░░░░░░▄░▐░░░ ░░░░░░█░░░░░░░░▄▀▀░▐░░░ ░░░░▄▀░░░░░░░░▐░▄▄▀░░░░ ░░▄▀░░░▐░░░░░█▄▀░▐░░░░░ ░░█░░░▐░░░░░░░░▄░█░░░░░ ░░░█▄░░▀▄░░░░▄▀▐░█░░░░░ ░░░█▐▀▀▀░▀▀▀▀░░▐░█░░░░░ ░░▐█▐▄░░▀░░░░░░▐░█▄▄░░░ ░░░▀▀▄░░░░░░░░▄▐▄▄▄▀░░░ THis Question ░░░░░░░░░░░░░░░░░░░░░░░
... rocmed made a comment on nbme24/block4/q#35 (An investigator is conducting a study of a novel...)
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submitted by rocmed(-3)

Desmoglein: Component of desmosomes, which connect keratinocytes in the stratum spinosum - FA 2018, p.467, Pemphigus Vulgaris

By this I can only assume that they mean that desmoglein connects keratinocytes to EACH OTHER, hence why the other options connecting keratinocytes to other structures are incorrect

charcot_bouchard  The epidermis primarily consists of keratinocytes[4] (proliferating basal and differentiated suprabasal), which comprise 90% of its cells. You are right. both are keratinocyte
... usmleuser007 made a comment on nbme24/block4/q#35 (An investigator is conducting a study of a novel...)
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submitted by usmleuser007(86)

Blistering diseases such as pemphigus vulgaris (PV) and pemphigus foliaceus (PF) are autoimmune diseases in which auto-antibodies target desmogleins.

  • PV is caused by circulating autoantibodies (IgG) that target Dsg3 (Desmoglein 3) and sometimes Dsg1.
  • PV is manifested by suprabasal acantholysis, or blisters in the mucous membrane and blisters in the epidermis.
  • PF patients have autoantibodies that target Dsg1 with superficial blisters on the epidermis with no mucous membrane issues.
  • Both disease result in a loss of keratinocyte adhesion.
  • Pemphigus can also be caused by a bacterial infection: bullous impetigo is an infection caused by a staphylococcus bacterium that releases a toxin that cleaves the Dsg1 extracellular domain.
... usmleuser007 made a comment on nbme24/block4/q#35 (An investigator is conducting a study of a novel...)
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submitted by usmleuser007(86)

After some research this is why the other answers are incorrect:

  1. basal keratinocyte & lamina lucida
  2. Incorrect b/c lamina lucida is a component of the basement membrane which is found between the epithelium and underlying connective tissue (e.g., epidermis and dermis of the skin).
  3. It is a roughly 40 nanometre wide electron-lucent zone between the plasma membrane of the basal cells and the (electron-dense) lamina densa of the basement membrane. (WIKI)
  4. basal keratinocyte attaches to the basement membrane using hemidesmosome

  5. Granular keratinocyte & stratum corneum

  6. Stratum lucidum separates these two layers.
  7. there are no desmosome that connect these two layers
  8. Image for reference

  9. Lamina lucida & Lamina densa -- click for image

  10. both are part of the basement membrane and not the epidermis

  11. Melanocyte & basal kertinocyte --- click for image

  12. are both connected to eachoter via E-cadherins
  13. it is probably the damage to this connection that might lead to melanoma
... usmleuser007 made a comment on nbme24/block4/q#35 (An investigator is conducting a study of a novel...)
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submitted by usmleuser007(86)

After some research this is why the other answers are incorrect:

Basal keratinocyte & lamina lucida

  • Incorrect b/c lamina lucida is a component of the basement membrane which is found between the epithelium and underlying connective tissue (e.g., epidermis and dermis of the skin).
  • It is a roughly 40 nanometre wide electron-lucent zone between the plasma membrane of the basal cells and the (electron-dense) lamina densa of the basement membrane. (WIKI)
  • basal keratinocyte attaches to the basement membrane using hemidesmosome

Granular keratinocyte & stratum corneum

  • Stratum lucidum separates these two layers.
  • there are no desmosome that connect these two layers
  • Image for reference

Lamina lucida & Lamina densa -- click for image

  • both are part of the basement membrane and not the epidermis

Melanocyte & basal kertinocyte --- click for image

  • are both connected to eachoter via E-cadherins
  • it is probably the damage to this connection that
... mousie made a comment on nbme24/block4/q#36 (A 68-year-old woman comes to the emergency...)
 +3  upvote downvote
submitted by mousie(74)

"dronates" are Bisphosphonates, commonly used to prevent/treat osteoporosis. Most common adverse effects are Esophagitis (patients should take with water and be upright for at least 30minutes), Osteonecrosis of the jaw, and atypical femoral stress fractures. -taken right from FA 2018 pg 471

... lsmarshall made a comment on nbme24/block4/q#37 (A male newborn is delivered in the hospital at 40...)
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submitted by lsmarshall(181)

"Air droplets" sounds like respiratory (saliva or water) droplets. Inhalation of toxoplasma oocysts in cat feces isn't quite the same; not to say I know exactly what the oocysts are inhaled as (just microscopic dry cat poop particles?). Ingestion of undercooked meat to get the cysts is certainly a ROT for toxoplasma.

Toxoplasma as TORCH has triad of hydrocephalus, cerebral calcifications (intracerebral), and chorioretinitis. chorioretinitis can be in congenital CMV or toxoplasmosis. Periventricular calcifications are in CMV. Congenital CMV usually has hearing loss, seizures, petechial rash, “blueberry muffin” rash, chorioretinitis, and periventricular calcifications.

... majic made a comment on nbme24/block4/q#37 (A male newborn is delivered in the hospital at 40...)
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submitted by majic(0)

THE MOST COMMON route of Toxo transmission in adults in the USA is ingestion of undercooked pork. Even if cat litter is an option, undercooked pork is still more common.

yotsubato  Also another fun fact. Most people in France are infected by Toxo (like 80%) because of how they eat meat. (Very rare)
... sympathetikey made a comment on nbme24/block4/q#38 (A 33-year-old woman at 34 weeks' gestation has a...)
 +6  upvote downvote
submitted by sympathetikey(260)

Would've been nice if they told you "2nd intercostal space" on left or right...smh

... neonem made a comment on nbme24/block4/q#38 (A 33-year-old woman at 34 weeks' gestation has a...)
 +0  upvote downvote
submitted by neonem(227)

My best guess is that this patient has a bicuspid aortic valve and has a murmur due to increased volume overload from the pregnancy.

charcot_bouchard  Can be congenital mild Tricuspid stenosis also. it also exaggerate during preg
... m-ice made a comment on nbme24/block4/q#38 (A 33-year-old woman at 34 weeks' gestation has a...)
 +2  upvote downvote
submitted by m-ice(116)

A soft systolic murmur is common in many pregnant women due to a high volume of flow (increased cardiac output). The murmur tends to go away within a few weeks of delivery once the cardiac output is closer to baseline.

... step420 made a comment on nbme24/block4/q#38 (A 33-year-old woman at 34 weeks' gestation has a...)
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submitted by step420(17)

I have a question: Since CO = SV * HR, and in pregnancy, women have an increased basal HR, why can't the answer be Pulse?

home_run_ball  I don't think HR would explain the grade 2/6 murmur, but SV would
... seagull made a comment on nbme24/block4/q#38 (A 33-year-old woman at 34 weeks' gestation has a...)
 +6  upvote downvote
submitted by seagull(355)

"Blood flow to various organs increases during pregnancy to meet the increased metabolic needs of tissues. Thus, venous return and cardiac output increases dramatically during pregnancy. Cardiac output gradually increases during the first 2 trimesters with the largest increase occurring by 16 weeks of gestation.3 The increase in cardiac output is well established by 5 weeks of gestation and increases to 50% above prepregnancy levels by 16 to 20 weeks of gestation. The rise in cardiac output typically plateaus after 20 weeks of gestation and remains elevated until term. The increases in cardiac output are associated with significant increases in stroke volume and heart rate (HR)"

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3802121/

... sattanki made a comment on nbme24/block4/q#39 (A 30-year-old woman comes to the physician because...)
 +4  upvote downvote
submitted by sattanki(27)

There are two mechanisms of regulating renal blood flow, the myogenic mechanism and tubulo-glomerular feedback. This question asks purely about the myogenic mechanism, which is where the afferent arteriole controls blood flow based purely off blood pressure entering the kidney, which is why decreased afferent arteriolar resistance is the best answer (the arteriole is dilating in response to the decreased blood flow in attempt to maintain normal blood flow to the kidney).

nwinkelmann  Man... I took this WAY TOO FAR, lol. I totally didn't recognize the clue of GFR and RPF as staying the same to tell me it was talking about normal, physiologic autoregulation. Silly mistake!
... ihavenolife made a comment on nbme24/block4/q#39 (A 30-year-old woman comes to the physician because...)
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submitted by ihavenolife(12)

Myogenic mechanism works in the afferent arteriole that supplies the glomerulus. When blood pressure increases, smooth muscle cells in the wall of the arteriole are stretched and respond by contracting to resist the pressure, resulting in little change in flow. When blood pressure drops, the same smooth muscle cells relax to lower resistance, allowing a continued even flow of blood.

Click the link to read about tuburoglomerular feedback as well. https://courses.lumenlearning.com/suny-ap2/chapter/regulation-of-renal-blood-flow/

... ankistruggles made a comment on nbme24/block4/q#40 (A 25-year-old woman is brought to the emergency...)
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submitted by ankistruggles(6)

How do you know her pulmonary symptoms are due to pulmonary capillary leakage and not hypoventilation? Is pulmonary capillary leakage just another way of saying pulmonary edema?

sattanki  Hypoventilation in no way leads to pulmonary edema.
fenestrated  Hypoventilation would increased the PCO2
... sattanki made a comment on nbme24/block4/q#40 (A 25-year-old woman is brought to the emergency...)
 +0  upvote downvote
submitted by sattanki(27)

The pt is having a severe case of pneumonia/sepsis (ARDS?), as that’s why her PO2 is low at 64. So in pneumonia there is increased capillary leakage leading to pulmonary edema.

... neonem made a comment on nbme24/block4/q#40 (A 25-year-old woman is brought to the emergency...)
 +10  upvote downvote
submitted by neonem(227)

This patient isn't hypoventilating, they're HYPERventilating, hence the PCO2 < 40 mm Hg.

Let's walk it backwards: They are hyperventilating to compensate for the metabolic acidosis caused by widespread hypoxia. Hyperventilating allows you to blow off more CO2.

Why are they hypoxic? The person is hypoxic due to inflammation and acute respiratory distress syndrome from the pneumonia. All the cytokines from the inflammatory cells cause increased pulmonary capillary leakage, which blocks up the alveolar membrane so that O2 can't get through to the blood.

Why do they have metabolic acidosis in the first place? No oxygen --> no electron transport chain and no TCA --> lactic acidosis.

... famylife made a comment on nbme24/block4/q#40 (A 25-year-old woman is brought to the emergency...)
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submitted by famylife(32)

From AAFP:

"Acute respiratory distress syndrome is a manifestation of acute injury to the lung, commonly resulting from sepsis, trauma, and severe pulmonary infections. Clinically, it is characterized by dyspnea, profound hypoxemia, decreased lung compliance, and diffuse bilateral infiltrates on chest radiography...

In ARDS, the injured lung is believed to go through three phases: exudative, proliferative, and fibrotic, but the course of each phase and the overall disease progression is variable. In the exudative phase, damage to the alveolar epithelium and vascular endothelium produces leakage of water, protein, and inflammatory and red blood cells into the interstitium and alveolar lumen. These changes are induced by a complex interplay of proinflammatory and anti-inflammatory mediators."

https://www.aafp.org/afp/2003/0115/p315.html

... dbg made a comment on nbme24/block4/q#40 (A 25-year-old woman is brought to the emergency...)
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submitted by dbg(18)

Did anyone else wonder WHAT "PULMONARY SYMPTOMS" is the question referring to?? There is literally not a single symptom mentioned in the whole vignette. No "crackles heard over both lung fields" are not symptoms. They are signs found by the physician.

Seriously doubting the whole NBME board test writers right now. Do they adequately revise their work? This is not the first technical mistake I realize on the new forms.

nbmehelp  Yup. Looking back its clear what they were trying to get at, but this definitely threw me off when I was taking the test bc I kept rereading the question looking for a specific symptom the pt had that they wanted me to explain.
... jejunumjedi made a comment on nbme24/block4/q#41 (A 30-year-old man who is a migrant farm worker comes...)
 +4  upvote downvote
submitted by jejunumjedi(12)

The blood smear depicts Schuffner stippling. Found the exact image on the web with explanation:

http://spot.pcc.edu/~jvolpe/b/bi234/lec/2_parasites/images/P._vivax.htm

doctorboomboom  Hey thanks for finding the image! Do you know why the answer can’t be Chloroquine resistance? I was b/w that and formation of hypnozoites.
jejunumjedi  I think it's just that Schuffner stippling and hypnozoites are both specific to vivax and ovale species. These species could be chloroquine resistant or sensitive, but if you have Schuffner stippling or hypnozoites, you can definitively say that it's either vivax or ovale.
sherry  Species with hypnozoites is not called chloroquine resistant. Chloroquine-resistant species means trophozoite/schizont cant be killed by chloroquine. We dont have enough info to decide whether the spp in the q is resistant/sensitive. But we do know he moved from Honduras to USA 1 year ago.
soph  UW: in africa most malaria species are resistant to chloroquine. he is from hondruas
randios  Can anyone explain the 1-week history of fever? Ruled out vivax and ovale due to 48 hr cycles. Or did they just throw that in as an unspecific symptom.
... yotsubato made a comment on nbme24/block4/q#41 (A 30-year-old man who is a migrant farm worker comes...)
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submitted by yotsubato(214)

Kind of tricky question. The hypnozoites are chloroquine resistant. But the species may not be.

P. Falciparum is resistant and looks like a banana, but you dont know if the malaria in the RBC is falciparum or not.

... leny123 made a comment on nbme24/block4/q#41 (A 30-year-old man who is a migrant farm worker comes...)
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submitted by leny123(2)

General rule - Chloroquine sensitive if from Caribbean or Central America west of Panama Canal, this patient immigrated from Honduras so you can eliminate chloroquine resistance as an answer choice (in addition to the vivax/ovale info above).

charcot_bouchard  Guys along with all intelligent discussion also keep in mind he immigrated 1 year back. So it must be hypnozoites which is causing this because Murica is Malaria free.
... nwinkelmann made a comment on nbme24/block4/q#41 (A 30-year-old man who is a migrant farm worker comes...)
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submitted by nwinkelmann(60)

Found this great document with slides about the different pathogens: http://ncasmbranch.org/meetings/2019SprPpts/2019-03_Spring_Garcia.pdf

... nwinkelmann made a comment on nbme24/block4/q#41 (A 30-year-old man who is a migrant farm worker comes...)
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submitted by nwinkelmann(60)

Does anyone know how to rule out E? I've never learned about microorganisms specifically activating a cell's CAMs, but when I looked it up, I found this article (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC395703/). The article doesn't specifically mention plasmodium as using it, but several of the resources for the article does.

... colonelred_ made a comment on nbme24/block4/q#42 (A 40-year-old man who recently immigrated to the USA...)
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submitted by colonelred_(44)

He’s presenting with classic signs of vitamin B3 deficiency (niacin); niacin is required to form the cofactor NAD+ (nicotinamide adenine dinucleotide).

bigjimbo  B3 Niacin deficiency = Pellegra = diarrhea, dermatitis, dementia death. = Niacin combines with adenine to become NAD+ https://www.aocd.org/page/Pellagra
... xxabi made a comment on nbme24/block4/q#43 (A 72-year-old woman with coronary artery disease...)
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submitted by xxabi(82)

Stent thrombosis vs re-stenosis. Stent thrombosis is an acute occlusion of a coronary artery stent, which often results in acute coronary syndrome. Can be prevented by dual antiplatelet therapy or drug-eluting stents. Re-stenosis is the gradual narrowing of the stent lumen due to neointimal proliferation, resulting in anginal symptoms.

... sweetmed made a comment on nbme24/block4/q#43 (A 72-year-old woman with coronary artery disease...)
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submitted by sweetmed(28)

Stent Restenosis occurs from scar tissue grows over stent causing “neointimal hyperplasia” and narrowing, ischemia symptoms return Tx: prevent by using drig eluting stents eg. Sirolimus. Thrombosis Post stenosis is Acute, stent serves as nidus for thrombus formation usually 2/2 missing mediation. Tx: prevent by using dual antiplatelet treatment [aspirin+clopidogrel/ticagrelor]. After 1 year, endothelization of stent occurs and there is a lower risk of thrombus, Tx lowered to just aspirin.

... medstruggle made a comment on nbme24/block4/q#44 (A 71-year-old woman with non-Hodgkin lymphoma is...)
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submitted by medstruggle(5)

Why do you give IV leucovorin with intrathecal methotrexate? Wouldn’t MTX lose its efficacy since leucovorin reverses the effects of MTX?

colonelred_  MTX will still work but yes some purine/pyrimidine synthesis can still occur. You often give leucovorin to decrease adverse effects of MTX.
welpdedelp  ok I have a question, leucovorin is the same as folic acid...so why give one over the other?
lsmarshall  Leucovorin, folinic acid, is a modified version of THF and enter folate metabolism where THF is, after the point where methotrexate takes its effect. I have a pharm. card that says "toxic effects on normal cells may be reduced by administration of folinic acid (a.k.a. leucovorin or citrovorum factor), which is **preferentially taken up by normal cells versus tumor cells**."
... sajaqua1 made a comment on nbme24/block4/q#44 (A 71-year-old woman with non-Hodgkin lymphoma is...)
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submitted by sajaqua1(171)

This answer rests on the difference between Folate and Leucovorin. Intrathecal methotrexate is given to block dihydrofolate reductase (DHFR) from making folic acid into DHF, and then turning that DHF into THF. This is done to prevent the production of downstreamn products necessary for metabolism including DNA synthesis. Leucovorin (also called 5-formy-lTHF) can be used to sidestep this product by being put into play downstream. See the diagram here: https://www.emed.com.au/folic-acid-and-fertility-doing-more-harm-than-good/ Folate is listed as Folic Acid, methotrexate interferes with DHFR, and Leucovorin is 5-formyl-THF. There is also further description here: https://www.drugbank.ca/drugs/DB00158

Why does this not simply undo the action of methotrexate? This is because many cancers do not have the reduced folate carrier. So the cancers pick up folate and methotrexate, and their DNA synthesis is reduced. Meanwhile other healthy cells can pick up the Leucovorin and stave off some of the worst effects. Remember, leucovorin cannot be given intrathecally.

https://www.d.umn.edu/~jfitzake/Lectures/DMED/Antineoplastics/DNASynthesisInhibitors/Methotrexate/LeucovorinRescue.html

... xxabi made a comment on nbme24/block4/q#45 (A 40-year-old woman with a 25-year history of type 1...)
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submitted by xxabi(82)

Creatinine clearance slightly overestimates GFR because creatinine is moderately secreted by PCT

... usmleuser007 made a comment on nbme24/block4/q#45 (A 40-year-old woman with a 25-year history of type 1...)
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submitted by usmleuser007(86)

Most absorption ad secretion is done at the PCT. It is this reason why the PCT is the most metabolically active portion of the nephron.

As this image shows, you can see that reabsorption & secretion occurs at the PCT

this means that both PAH & creatinine are secreted for elimination at the PCT along with the additional volume freely filtered through the bowman's capsule.

Furthermore; Inulin is neither secreted nor reabsorbed.

hence Inulin is better for GFR. But, creatinine is normally used for GFR as an estimate (probably d/t ease)

... brethren_md made a comment on nbme24/block4/q#46 (A 22-year-old woman comes to the physician because...)
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submitted by brethren_md(39)

tumor of Pineal Gland (Pinealoma) causes Parinaud Syndrome (vertical gaze palsy)

neonem  Due to compression of the superior colliculus in the tectum, I believe
wowo  FA2019 p516
... neonem made a comment on nbme24/block4/q#47 (A 40-year-old man comes to the physician because of...)
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submitted by neonem(227)

This patient case sounds like he has iron deficiency anemia (anemia, low hematocrit, microcytic) from a GI bleed. To get this question right, you had to remember that the two major inherited GI cancer syndromes are FAP (due to mutation in APC gene, which is a tumor suppressor gene) and Lynch syndrome AKA hereditary non-polyposis colorectal carcinoma (HNPCC), caused by a mutation in a number DNA mismatch repair genes, of with MHS2 is a more common one.

The mechanisms of their carcinoma development are different; in FAP, tumors arise from a normal --> adenoma --> carcinoma sequence while in HNPCC, tumors arise from what's known as a microsatellite instability pathway, leading to spontaneous formation of a carcinoma (not preceded by a benign lesion like an adenoma)... You didn't need to know this to get this question right, but definitely good to know.

medpsychosis  To make it even simpler, if you narrowed it down to FAP vs HNPCC and looked at the image provided in the question, you'd see it's less likely to be FAP due to absence of numerous polyps which would be expected. So HNPCC would be your best choice!
yb_26  I always get Li-Fraumeni and Lynch syndromes confused :/
... lsmarshall made a comment on nbme24/block4/q#48 (A 55-year-old woman is brought to the physician by...)
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submitted by lsmarshall(181)

PCA stroke can cause "prosopagnosia" which is the inability to recognize familiar faces. Caused by bilateral lesions of visual association areas, which are situated in the inferior occipitotemporal cortex (fusiform gyrus). The ability to name parts of the face (e.g., nose, mouth) or identify individuals by other cues (e.g., clothing, voices) is left intact.

Without knowing that, remembering occipital lobe is involved in 'visual stuff' broadly, including image processing and this patient is having issues with understanding images should be enough to get to the answer.

gonyyong  Lol I guessed it exactly because of that
sympathetikey  Never heard of that one before. Thanks!
karthvee  This is not prosopagnosia, but instead a case of apperceptive agnosia. Wiki: "...patients are more effective at naming two attributes from a single object than they are able to name one attribute on each of the two superimposed objects. In addition they are still able to describe objects in detail and recognize objects by touch." Although, lesions tend to be in the occipito-parietal area so PCA again is the answer!
... sweetmed made a comment on nbme24/block4/q#48 (A 55-year-old woman is brought to the physician by...)
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submitted by sweetmed(28)

PCA stroke: Visual Agnosia [can see, but not recognize objects] and Hallucinations, Contralateral hemianopia with macular sparing, Alexia without agraphia[if dominant hemispehere involved].

... sattanki made a comment on nbme24/block4/q#49 (A 27-year-old man sustains a spinal cord transection...)
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submitted by sattanki(27)

Apparently there is a completely separate spinal cord reflex where direct penile stimulation leads to an erection. This reflex only needs an intact arc in S2-S4, so as long as this region is not injured, an erection can still occur. However, with transection at C8, then the psychogenic erection reflex cannot occur, as this requires descending fibers from the cortex.

lsmarshall  Just saw a good summary of nerves/vessels involved saying, "pelvic parasympathetic fibers from S2-S4 can cause cavernous arteriole vasodilation via the cavernous nerve without of central stimulation."
seagull  S2-3-4 keeps the penis off the floor
drdoom  Modifying @seagull into iambic pentameter: “S2, S3, and Number 4 / keeps the big ole penis / off the floor”
... charcot_bouchard made a comment on nbme24/block4/q#49 (A 27-year-old man sustains a spinal cord transection...)
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submitted by charcot_bouchard(42)

Apparently theres role of sympathetic system in psychogenic erection and its comes from T11-L2. So if patient have transaction at L5 they lose reflex erection but still retain psychogenic one.

ABove T9 transaction cause loss of psychogenic erection

charcot_bouchard  Below L5* (Not at)
... cinnapie made a comment on nbme24/block4/q#49 (A 27-year-old man sustains a spinal cord transection...)
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submitted by cinnapie(2)

Why does every NBME have one or two erection related questions??

youssefa  Cause we all know what bout to happen to us in this exam :D
... ihavenolife made a comment on nbme24/block4/q#50 (A 47-year-old man comes to the physician because of...)
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submitted by ihavenolife(12)

Pg 360 First Aid 2019

Internal Hemorrhoids

-Visceral innervation (no pain felt), Superior rectal a., Superior rectal vein (drains to IMV), Internal iliac lymph nodes

versus

External Hemorrhoids

-Somatic innervation (they hurt), Inferior rectal a., Inferior rectal vein (drains to internal pudendal vein), Superficial inguinal lymph nodes

kateinwonderland  Above pectinate -V:sup. rectal v -> inf. mesenteric v. -> splenic v. -> portal v -internal iliac LN Below pectinate -V:inf. rectal v -> internal pudendal v->internal iliac v->common iliac v->IVC -superficial inguinal LN (FA 2018 p360)
sherry  Venous drainage above pectinate, most to the portal vein, some to internal iliac v via middle rectal vein. I think the real solid key here is that the clinical vignette suggests hepatic cirrhosis.
... m-ice made a comment on nbme24/block4/q#50 (A 47-year-old man comes to the physician because of...)
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submitted by m-ice(116)

This patient shows signs of cirrhosis, which is likely associated with portal hypertension. Portal hypertension will cause increased pressure in all veins draining into the portal vein, and can cause bulging of these veins at areas where they meet those that drain to the vena cava. One area is the rectum and anus, where the superior rectal vein (from the portal system) meets up with the middle and inferior rectal veins (which drain to the caval system). Increased pressure in the superior rectal vein will cause hemorrhoids at this location.

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