Some recent contributions

... ergogenic22 made a comment on nbme20/block2/q#16 (A 10-year-old boy with mild mental retardation is...)
 +0  upvote downvote
submitted by ergogenic22(0)

See the first aid entry on Tuberous sclerosis. It is associated with increased incidence of subependymal giant cell astrocytoma and many other conditions.


... ergogenic22 made a comment on nbme20/block2/q#5 (A 32-year-old woman has had fecal incontinence since...)
 +0  upvote downvote
submitted by ergogenic22(0)

A stretch injury during childbirth will result in damage to the external uretheral and anal sphincters and damage to the pudendal nerve (S2-S4). This can lead to decreased sensation in the perineal and genital area and fecal or urinary incontinence


... ergogenic22 made a comment on nbme20/block2/q#4 (A 56-year-old woman has frequently burned herself...)
 +0  upvote downvote
submitted by ergogenic22(0)

classic for Syringomyelia - results in bi-lateral loss of pain and temperature sensation in a "cape-like" distribution


... ergogenic22 made a comment on nbme20/block2/q#23 (Which of the following changes in the cardiovascular...)
 +0  upvote downvote
submitted by ergogenic22(0)

aging results in increased arterial stiffness (change in Extra Ccellular Mmatrix composition - decreased elastin, increased collagen deposition); ISH is responsible for 60-80% of HTN cases in patients > 60. Also, decreased compliance as a result of aging causes increased pulse pressure


... moloko270 made a comment on nbme22/block2/q#38 (Following a stroke, a patient is hoarse and cannot...)
 +0  upvote downvote
submitted by moloko270(0)

this is Wallenberg syndrome - stroke caused by obstruction of PICA - so thats why we get symptoms of dysphagia, hoarseness, absent gag reflex (p. 502 FA)


... mcl made a comment on nbme21/block1/q#30 (A newborn has female external genitalia and a 46,XY...)
 +0  upvote downvote
submitted by mcl(0)

Per p608 in FA 2019, SRY on Y chromosome results in development of testes. DHT results in development of male external genitalia (and the prostate).


... mcl made a comment on nbme21/block1/q#16 (A 43-year-old man comes to the physician for a...)
 +0  upvote downvote
submitted by mcl(0)

Labeled CXR showing position of different valves.


... mcl made a comment on nbme21/block1/q#36 (A 51-year-old woman comes to the physician because...)
 +0  upvote downvote
submitted by mcl(0)

This image is very helpful.


... mcl made a comment on nbme21/block1/q#17 (A 7-year-old girl is brought to a clinic in a...)
 +0  upvote downvote
submitted by mcl(0)

Methionine is an essential amino acid. All others listed are not.


... mcl made a comment on nbme21/block1/q#19 (A 22-year-old man has had frequent episodes of...)
 +0  upvote downvote
submitted by mcl(0)

Patient may have hereditary angioedema, which is associated with "recurrent attacks of intense, massive, localized subcutaneous edema involving the extremities, genitalia, face, or trunk, or submucosal edema of upper airway or bowels". The article goes on to say "C1-esterase inhibitor works directly on the complement and contact plasma cascades to reduce bradykinin release" which is also probably good to know.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3666183/


... mcl made a comment on nbme21/block1/q#12 (A 25-year-old nulligravid woman comes to the...)
 +0  upvote downvote
submitted by mcl(0)

PCOS is associated with abnormal production of sex steroids, including dysfunction of estrogen production and progesterone. Chronically elevated levels of estrogen can cause endometrial hyperplasia.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3917599/


... mcl made a comment on nbme21/block2/q#45 (A 3-year-old boy is brought to the emergency...)
 +0  upvote downvote
submitted by mcl(0)

Not sure if this is the right way to think about it, but if PT and PTT are both prolonged, this most likely means there is a problem with the common pathway (aka factor X).


... mcl made a comment on nbme21/block2/q#9 (A 40-year-old man is brought to the emergency...)
 +0  upvote downvote
submitted by mcl(0)

When working on acid/base disorders, it helps to look systematically at the following: (1) pH (which sadly was not given in this problem), (2) figure out which problem is primary by looking at PaCO2 and bicarb, and (3) look for any compensation (which the question doesn't ask but still).

Here, we see that the CO2 is high on the ABG. This means that patient is hypoventilating since levels of CO2 are ventilation dependent, and also that patient has respiratory acidosis. Also, bicarb is low, which implies that it's being "soaked up" by metabolic acidosis.


... mcl made a comment on nbme21/block2/q#30 (A 44-year-old man comes to the physician because of...)
 +0  upvote downvote
submitted by mcl(0)

This is a pretty good figure showing the conversion of membrane phospholipids to arachidonic acid/leukotrienes etc.

Blockade of COX enzyme by ibuprofen results in decreased production of prostaglandins H2 and E2, while causing the precursors to "back up" (increased arachidonic acid). This, in turn, results in increased production of leukotrienes.


... mcl made a comment on nbme21/block3/q#30 (A 41-year-old man comes to the physician because of...)
 +0  upvote downvote
submitted by mcl(0)

Deltoid is innervated by axillary nerve, which comes from roots C5/C6. Actions of the deltoid include abduction of the upper extremity.


... mcl made a comment on nbme21/block3/q#13 (A 40-year-old woman comes to the physician for an...)
 +0  upvote downvote
submitted by mcl(0)

Niacin (vitamin B3) antagonizes VLDL cholesterol secretion


... mcl made a comment on nbme21/block3/q#1 (A 30-year-old woman develops dimness of vision)
 +0  upvote downvote
submitted by mcl(0)

Page 250 FA - Ethambutol is associated with visual disturbances (changes in color vision).


... mcl made a comment on nbme21/block3/q#44 (A 23-year-old woman develops persistent sneezing...)
 +0  upvote downvote
submitted by mcl(0)

While antihistamines with action at H1 receptors are used for allergies, H2 antihistamines are typically used for ulcers. Therefore the best answer is stabilization of mast cell membranes. These drugs (cromolyn) prevent vesicles of histamine from fusing with the membrane.


... mcl made a comment on nbme21/block3/q#14 (A 35-year-old man is brought to the emergency...)
 +0  upvote downvote
submitted by mcl(0)

Vibrio cholerae is a gram-negative, comma shaped bacteria that can cause watery diarrhea. Cholera toxin functions by activating the Gs proteins --> increasing activity of adenylyl cyclase --> increased cAMP --> increased Na+ and Cl- efflux --> diarrhea.


... mcl made a comment on nbme21/block3/q#34 (A 39-year-old woman with rheumatoid arthritis...)
 +0  upvote downvote
submitted by mcl(0)

Membranous glomerulopephritis (aka membranous nephropathy, p 584 FA 2019) may occur secondary to drugs such as penicillamine. Immunofluorescence shows granular deposits due to immune complex deposition. Will also see diffuse capillary and GBM thickening, and SEM will show spike and dome appearance due to subepithelial deposits.


... mcl made a comment on nbme21/block4/q#44 (A 28-year-old woman with chronic renal failure...)
 +0  upvote downvote
submitted by mcl(0)

Furosemide and other loop diuretics are indicated for use in volume overload secondary to renal failure. Recall loop diuretics inhibit the Na+/K+/Cl- pump at the thick ascending loop of Henle, which messes with the hypertonicity of the medulla and therefore prevents urine from being concentrated. This results in increased fluid loss to urine, and is helpful in treating symptoms of edema.


... mcl made a comment on nbme21/block4/q#7 (A 14-year-old boy is brought to the physician by his...)
 +0  upvote downvote
submitted by mcl(0)

Gait problems raises suspicion for alcohol abuse or inhaled glue. However, onset of gait problems is relatively rapid (couple of months) and gait disturbance with regards to alcohol is either due to intoxication or chronic abuse. Alternative explanation available on SDN. Also see toluene toxicity on medscape.


... mcl made a comment on nbme21/block1/q#2 (A 6-month-old girl is brought to the physician...)
 +0  upvote downvote
submitted by mcl(0)

Patient most likely has Tay-Sachs disease. This figure nicely shows the biochemical pathway. Recall that both Tay-Sachs and Neimann Pick disease present with a cherry red spot on fundoscopy, but Tay Sachs lacks the hepatosplenomegaly seen in NP.


... mcl made a comment on nbme21/block4/q#46 (A 14-year-old girl is brought to the physician for a...)
 +0  upvote downvote
submitted by mcl(0)

Other way to get this question is by eliminating other options -- this figure is useful in listing some mutations and associated cancers.


... mcl made a comment on nbme21/block4/q#33 (A female newborn delivered at 26 weeks' gestation is...)
 +0  upvote downvote
submitted by mcl(0)

"chronic high oxygen saturations can adversely affect lung and eye outcomes of preterm infants." link


... welpdedelp made a comment on nbme22/block3/q#1 (A 35-year-old man comes to the physician because of...)
 +0  upvote downvote
submitted by welpdedelp(0)

So I think that issue of wrist extension and/or finger drop would be more radial nerve. However, there was more proximal weakness, so it would be C7.

"7-8 lay them straight", the pt couldn't "lay them straight" so it would be C7 root


... welpdedelp made a comment on nbme22/block3/q#4 (A 29-year-old woman has an inflammatory disease...)
 +0  upvote downvote
submitted by welpdedelp(0)

This was SLE. https://step1.medbullets.com/msk/112039/systemic-lupus-erythematosus

Think: 1,2,3= S-L-E

Using ACID: Type III is for Immune Complexes


... welpdedelp made a comment on nbme22/block3/q#38 (A 73-year-old man comes to the physician with his...)
 +0  upvote downvote
submitted by welpdedelp(0)

Increased intracranial pressure that results in Cushing's triad of increased blood pressure, irregular breathing, and bradycardia. Thus, high CO2 induces cushing triad and if you give PP then it will reduced CO2, and then down regulate the sympathetic vasoconstriction. Originally the brain had so much CO2 that it spazzed out and tried to increase the BP in order to push more oxygenated blood to the brain.

https://pbs.twimg.com/media/CK3J5kZUsAAqSf-.jpg:large


... welpdedelp made a comment on nbme22/block3/q#5 (A 72-year-old man with multiple myeloma agrees to...)
 +0  upvote downvote
submitted by welpdedelp(0)

https://www.reddit.com/r/step1/comments/b74znb/nbme_22_question_explanation_help_request_spoiler/


... welpdedelp made a comment on nbme22/block2/q#6 (A 52-year-old man is brought to the emergency...)
 +0  upvote downvote
submitted by welpdedelp(0)

It was just asking the lifespan of RBCs (120 days)


... jotajota94 made a comment on nbme21/block2/q#5 (A 2-week-old male newborn has a patent ductus...)
 +0  upvote downvote
submitted by jotajota94(0)

PDA flows from aorta to pulmonary artery decreasing afterload. Therefore cardiac output increases


... welpdedelp made a comment on nbme22/block4/q#5 (A new virus has been isolated that causes...)
 +0  upvote downvote
submitted by welpdedelp(0)

Ok, so RNA dependent DNA polymerase is for reverse transcriptase... single stranded + use RNA dependent RNA polymerase. Can someone explain?


... welpdedelp made a comment on nbme22/block4/q#3 (A 60-year-old man comes to the physician because of...)
 +0  upvote downvote
submitted by welpdedelp(0)

It was a Ferruginous bodies--> asbestosis. Ferruginous bodies are believed to be formed by macrophages that have phagocytosed and attempted to digest the fibers.


... welpdedelp made a comment on nbme22/block4/q#23 (A 57-year-old woman comes to the office because of a...)
 +0  upvote downvote
submitted by welpdedelp(0)

This is Lambert-Eaton, which improves with movement as compared to Myesthenia gracias whichh worsens with movement


... welpdedelp made a comment on nbme22/block1/q#22 (A previously healthy 6-year-old boy is brought to...)
 +0  upvote downvote
submitted by welpdedelp(0)

It was scabies, which is transmitted person-operon.


... chasingdreams101 made a comment on nbme23/block2/q#40 (A 22-year-old man is brought to the emergency...)
 +0  upvote downvote
submitted by chasingdreams101(0)

Can anyone explain how 10cm H20 positive PEEP leads to Peak Inspiratory PA, End Tidal PA, Peak Inspiratory Pip and End Tidal Pip all being positive?


... chasingdreams101 made a comment on nbme23/block2/q#32 (A 2-year-old girl is brought to the physician...)
 +0  upvote downvote
submitted by chasingdreams101(0)

I picked NMDA because it’s stimulatory, but is there any deeper reason for this?


... colonelred_ made a comment on nbme23/block1/q#42 (A 68-year-old woman comes to the office because of a...)
 +0  upvote downvote
submitted by colonelred_(0)

The patient had a total hysterectomy so a recurrence of cervical cancer is virtually not possible. Retroperitoneal fibrosis commonly results from radiation therapy to the pelvis, which can lead to bilateral hydronephrosis.


... colonelred_ made a comment on nbme23/block2/q#28 (A cohort study is conducted to examine the...)
 +0  upvote downvote
submitted by colonelred_(0)

Attributable risk = incidence in exposed – incidence in unexposed

= 30/1,000 (smokers) - 30/3,000 (nonsmokers)
= 0.03 - 0.01
= 0.02 (so the attributable risk is about 2%)

Applying it to a population of 10,000:

= 0.02 * 10,000
= 200


... realmedicmd made a comment on nbme23/block1/q#49 (Electrical stimulation of the stellate ganglion is...)
 +0  upvote downvote
submitted by realmedicmd(0)

I incorrectly chose vasodilation. Found out that it’s actually vasoconstriction (vasodilation is parasympathetic):

Autonomic nerve fibers are also crucially involved in the regulation of vascular effects in the skin. Sympathetic nerve fibers release norepinephrine and/or NPY to innervate arterioles, arteriovenous anastomoses, and venous sinusoids which results in vasoconstriction, whereas parasympathetic nerves mediate vasodilatation through activation of venous sinusoides by the release of ACh and VIP/peptide histidine methionine.

https://physiology.org/doi/full/10.1152/physrev.00026.2005


... real_rawgary made a comment on nbme23/block1/q#49 (Electrical stimulation of the stellate ganglion is...)
 +0  upvote downvote
submitted by real_rawgary(0)

The way I excluded vasodilation was this: the sympathetic receptor that dilates is β2, which is not stimulated by norepinephrine. So to stimulate the receptor, the stellate ganglion would have had to first stimulate the adrenal medulla to release epinephrine (stellate too high to stimulate the medulla).


... consistentwrongdoer3 made a comment on nbme23/block3/q#38 (A 5-year-old boy who has recently recovered from an...)
 +0  upvote downvote
submitted by consistentwrongdoer3(0)

What are we supposed to be looking at? I see multinucleated giant cells. I also see infiltrate (can’t tell if this is mononuclear or not).


... methylased made a comment on nbme23/block4/q#41 (Electrophysiology of the heart is studied in an...)
 +0  upvote downvote
submitted by methylased(0)

Regular rhythm (count the boxes, they're same), 1 unconducted p wave with regular rhythm --> atria and ventricles beating independently (likely ventricles ctrl by His-Purkinje) --> complete (3rd) heart block --> AVN ablation (this is actually done for pts with Afib sometimes)


... consistentwrongdoer3 made a comment on nbme23/block1/q#16 (Physical analysis of the isolated genomic DNA from a...)
 +0  upvote downvote
submitted by consistentwrongdoer3(0)

Why does methylation cause loss of resistance to GATC restriction endonuclease? Does this have to do with methylation of U to T?


... consistentwrongdoer3 made a comment on nbme23/block1/q#49 (Electrical stimulation of the stellate ganglion is...)
 +0  upvote downvote
submitted by consistentwrongdoer3(0)

I thought that the primary sympathetic innervation to the heart was through T1-T4. Why would stimulation of this ganglion not affect skin vessels in the upper limb?


... aladar50 made a comment on nbme23/block3/q#13 (A 65-year-old man with a history of gout comes to...)
 +0  upvote downvote
submitted by aladar50(0)

The important thing for most of the ethics questions are to look for the answer where you are being the nicest/most professional while respecting the patient’s autonomy, beneficence, non-maleficence, etc. Most of the choices here were either accusatory or basically being mean to the patient. The correct choice is to help the patient but also motivate them to continue physical therapy and to only use the permit as little as necessary. A similar question (which I think was on NBME 23 -- they are kind of blending together) was the one where the patient had test results that indicated he had cancer but the resident said not to (voluntarily) tell him until the oncologist came in later that day, and the patient asked you about the results. You don’t want to the lie to the patient and say you don’t know or that he doesn’t have cancer, but you also don’t want to be insubordinate to the resident’s (reasonable) request.


... aladar50 made a comment on nbme23/block4/q#41 (Electrophysiology of the heart is studied in an...)
 +0  upvote downvote
submitted by aladar50(0)

For the ECG, I initially thought it was 2nd degree Type 1 because it seemed that the PR intervals were increasing until a beat was dropped, but if you look at it closely, some of the P waves were hidden in the QRS complexes. If you notice that, then you can see that there were regular P waves and regular QRS complexes, but there was a complete dissociation between them which means it was 3rd degree heart block, so the answer was ablation near the AV node.


... jotajota94 made a comment on nbme21/block3/q#42 (A 27-year-old primigravid woman at 39 weeks'...)
 +0  upvote downvote
submitted by jotajota94(0)

High glucose leads to more insulin production in the fetus (recall that the hormone insulin is anabolic) ---> large fetus (9lb,1oz)---> problems in labor.


... aladar50 made a comment on nbme23/block1/q#13 (A researcher is asked to prospectively investigate...)
 +0  upvote downvote
submitted by aladar50(0)

So there’s 100 residents, and the prevalence after 2 years is =10 at the beginning, +5 in the first year, +10 second year, and -3 that healed, for a total prevalence of 22 residents or 22/100=22 percent. Thus, prevalence = above the standard. For incidence, it’s 15 new cases out of 90 residents over the 2 years (100 total residents – 10 that already had ulcers), or 15 new ulcers per 180 patient⋅years. This would be 83.3 new ulcers per 1000 patient⋅years if you extrapolated it out -- basically (1000/180) * 15 -- thus, incidence = above the standard.


... aladar50 made a comment on nbme23/block3/q#29 (A 50-kg (110-lb) experimental animal receives 1 L of...)
 +0  upvote downvote
submitted by aladar50(0)

I’m not the best at the calculations of ICF/ECF, but basically you are infusing a hypertonic solution into the animal. Initially, this is all going to go into the extracellular space, as any IV infusion will do. Since it is higher than isotonic solution, water is going to go from the intracellular space to the extracellular space to try to balance it out, so the intracellular space will have decreased volume and increased osmolality (since only water is leaving, making it more concentrated).

So you know for sure ICF volume is decreased and osmolality increased, and the extracellular volume will be increased. I think the osmolality of the extracellular space is the tricky part and the part where maybe someone else can help with the calculations but basically it’s hypertonic enough that the osmolality will still be increased.


... sakbarh made a comment on nbme23/block1/q#41 (A 62-year-old woman is brought to the emergency...)
 +0  upvote downvote
submitted by sakbarh(0)

She has many cardiovascular risk factors and likely suffered a stroke of the basilar artery causing locked in syndrome. According to FA this can cause a lesion at the pons, medullar, or lower midbrain -- however anatomically the basilar artery runs right on top of the pons so proximity most likely makes it the right answer.


... brolycow made a comment on nbme23/block2/q#19 (A 70-year-old man with severe congestive heart...)
 +0  upvote downvote
submitted by brolycow(0)

He has heart failure which leads to a decrease in renal blood flow and prerenal azotemia. In prerenal azotemia, BUN:Cr ratio is >= 20; Activation of the RAAS system due to the prerenal azotemia means that the spec grav is high at 1.025 and he is holding onto sodium so urinary sodium will be low (<20, FENa <1%).


... lostdinosaurs made a comment on nbme23/block2/q#19 (A 70-year-old man with severe congestive heart...)
 +0  upvote downvote
submitted by lostdinosaurs(0)

Hey can someone explain the renal findings? Physio is definitely not my strong suit.

Is it because he has fluid/Na+ retention that his specific gravity and Na+ are so low? Is there a reason for those specific BUN/creatinine over the others?


... tea-cats-biscuits made a comment on nbme23/block1/q#31 (A 16-month-old boy is brought to the physician for a...)
 +0  upvote downvote
submitted by tea-cats-biscuits(1)

I think I found what the disease was, though I honestly have no idea why they would test this rather than XLA. There’s a condition called Transient Hypogammaglobulinemia of Infancy. It presents w/low immunoglobulin levels post 6 months and can present w/small lymph nodes and tonsils in infancy BUT w/o any other findings of primary immunodeficiency including decreased counts.

Here’s an article about it: https://primaryimmune.org/about-primary-immunodeficiencies/specific-disease-types/transient-hypogammaglobulinemia-of-infancy/

You definitely don’t need to know the disease to get the correct answer since the link of lack of immunoglobulins would clue you into the lack of germinal centers, but I think this is more likely than XLA since every source I read implies that B cell counts are near 0 in the classic presentation (unless I’m missing a reason why leukocyte count w/diff wouldn’t show a significant decrease in lymphocytes due to near-zero B cells). Just wanted to put this here in case other people later came wondering, though I may still be wrong.


... hipster_do made a comment on nbme23/block1/q#31 (A 16-month-old boy is brought to the physician for a...)
 +0  upvote downvote
submitted by hipster_do(0)

I’m going to say it’s X linked agammaglobulinemia rather than SCID, but the difference between these two are tiny but this is why I think it’s the former:

SCID should be immediately because they just don’t have the IL2 receptors. CVID shows up when they’re 20-40 years old. You get absent germinal centers in both. No mention of absent thymic shadow which is in SCID.


... lilamk made a comment on nbme23/block1/q#31 (A 16-month-old boy is brought to the physician for a...)
 +0  upvote downvote
submitted by lilamk(0)

I made a lucky guess and chose this but I don’t think for the right reasons. I thought maybe he has BTK deficiency/Bruton’s Agammaglobinemia. But, now that I am going over it I wasn’t sure. Would that show a normal leukocyte differential? Is it CVID? Didn’t think CVID would have absent germinal centers in lymph nodes. What else could this be?


... masonkingcobra made a comment on nbme20/block4/q#8 (A 58-year-old man is brought to the emergency...)
 +0  upvote downvote
submitted by masonkingcobra(0)

Robbin's: The two most important causes of aortic aneurysms are atherosclerosis and hypertension. Atherosclerosis is the more dominant factor in abdominal aortic aneurysms, while hypertension is associated with ascending aortic aneurysms.


... masonkingcobra made a comment on nbme20/block2/q#20 (A 19-year-old man who is a college student is...)
 +0  upvote downvote
submitted by masonkingcobra(0)

Here is a fantastic picture to understand

https://www.semanticscholar.org/paper/Pneumomediastinum-in-the-neonate.-Cagle/7b235daea2488612a1917009afc849afc3e262e7/figure/4


... masonkingcobra made a comment on nbme20/block4/q#21 (A 47-year-old woman comes to the physician because...)
 +0  upvote downvote
submitted by masonkingcobra(0)

Page 2 has a great picture

https://www.jacionline.org/article/S0091-6749(18)31602-6/pdf


... masonkingcobra made a comment on nbme20/block4/q#16 (An investigator wishes to determine the...)
 +0  upvote downvote
submitted by masonkingcobra(0)

https://drawittoknowit.com/pop-quizzes/anatomy-physiology/at-a-high-flow-rate-how-does-saliva-compare-to-plasma


... masonkingcobra made a comment on nbme20/block3/q#38 (A 23-year-old man with a 3-year history of...)
 +0  upvote downvote
submitted by masonkingcobra(0)

In psychogenic polydipsia, serum sodium is low, and after water deprivation test, urine osmolality is increased. Urine osmolality does not increase with vasopressin injection

In nephrogenic diabetes insipidus, serum sodium is high and there is no change/mild increase in urine osmolality after water deprivation


... masonkingcobra made a comment on nbme20/block1/q#37 (A 1-month-old male newborn is brought to the...)
 +0  upvote downvote
submitted by masonkingcobra(0)

In metabolic alkalosis, potassium moves into the cells

The loss in volume through emesis triggers RAAS resulting in increased Aldosterone release and further potassium excretion

http://www.labpedia.net/test/116


... lispectedwumbologist made a comment on nbme20/block3/q#23 (A 50-year-old woman is brought to the emergency...)
 +1  upvote downvote
submitted by lispectedwumbologist(1)

Can somebody please explain why the pKa has to be 6 instead of 10?


... littletreetrunk made a comment on nbme22/block2/q#42 (A 75-year-old woman has taken 12 over-the-counter...)
 +0  upvote downvote
submitted by littletreetrunk(0)

I think the increase in plasma renin activity with NSAIDs has to do with inhibition of efferent artery dilation by prostaglandins (PGE2), since that's what NSAIDs do by inhibiting COX. This decreased renal blood flow leads to RAAS activation to conserve water and ultimately renin increases.


... mattnatomy made a comment on nbme22/block2/q#7 (A 66-year-old man comes to the physician because of...)
 +0  upvote downvote
submitted by mattnatomy(0)

Answer = Decreased libido; normal nocturnal erections

I believe what they were trying to indicate in this question was Psychological Sexual Dysfunction (aka - Performance Anxiety).

In this case, it wasn't so much the performance that worried the man, but he may be so focused on his health issues (post stroke), that he is unable to perform adequately. Therefore, his natural libido would be decreased. However, because it's psychogenic & not physiologic, he should still have normal nighttime erections.


... mattnatomy made a comment on nbme22/block2/q#11 (A 52-year-old man comes to the physician because a...)
 +0  upvote downvote
submitted by mattnatomy(0)

I believe they're referring to compression of branches of the Ilioinguinal Nerve (possibly the Anterior Scrotal Nerves.

Source: https://en.wikipedia.org/wiki/Anterior_scrotal_nerves


... mattnatomy made a comment on nbme22/block2/q#29 (A 79-year-old man is brought to the emergency...)
 +0  upvote downvote
submitted by mattnatomy(0)

A Pacemaker is the correct treatment for 3rd degree AV block. Makes it so the atria and ventricles beat in sync.


... mattnatomy made a comment on nbme22/block2/q#10 (A 56-year-old man with a palpable hard nodule on the...)
 +0  upvote downvote
submitted by mattnatomy(0)

Good picture diagram to explain: https://anatomy.elpaso.ttuhsc.edu/modules/pelvic_autonomic_module/Files/pelvic_page12p.jpg


... mattnatomy made a comment on nbme22/block2/q#9 (A 26-year-old woman develops hypotension and...)
 +0  upvote downvote
submitted by mattnatomy(0)

Diagnosis: Acute Hemolytic Transfusion Reaction

Pathogenesis:

Type II hypersensitivity reaction. Intravascular hemolysis (ABO blood group incompatibility) or extravascular hemolysis (host antibody reaction against foreign antigen on donor RBCs).

Presentation:

Fever, hypotension, tachypnea, tachycardia, flank pain, hemoglobinuria (intravascular hemolysis), jaundice (extravascular). Within 1 hour.


... mattnatomy made a comment on nbme22/block4/q#1 (A 2-day-old full-term female newborn suddenly...)
 +0  upvote downvote
submitted by mattnatomy(0)

I believe this is referring to midgut malrotation. Due to improper positioning of bowel (on the right side). Ladds bands connect the large intestine to the liver.

Can lead to:

  1. Volvulus

  2. Duodenal obstruction

3. SMA Occlusion -- I'm guessing based on the answer to the question


... mattnatomy made a comment on nbme22/block4/q#35 (Nicotinic acid acts at which of the following...)
 +0  upvote downvote
submitted by mattnatomy(0)

Answer = C. (Decreased hepatic VLDL synthesis)

Nicotinic acid = Niacin. Niacin works by:

  1. Inhibiting lipolysis (hormone sensitive lipase) in adipose tissue)

  2. Reducing hepatic VLDL synthesis


... mattnatomy made a comment on nbme22/block4/q#11 (A 26-year-old woman comes to the physician 5 weeks...)
 +0  upvote downvote
submitted by mattnatomy(0)

I thought initially we were dealing with post-partum psychosis, but on re-reading, this looks more like either Generalized Anxiety Disorder or OCD or both. Either way, treatment should be an SSRI (Sertraline).


... mattnatomy made a comment on nbme22/block4/q#22 (A 37-year-old man comes to the physician for a...)
 +0  upvote downvote
submitted by mattnatomy(0)

Severe hypertension often leads to hyperplastic arteriolosclerosis (onion-skin appearance). Also see proliferation of smooth muscle cells.


... drdoom made a comment on nbme24/block3/q#2 (A 28-year-old man has a blood pressure cuff placed...)
 +0  upvote downvote
submitted by drdoom(15)

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.


... mattnatomy made a comment on nbme22/block4/q#28 (A 48-year-old man comes to the emergency department...)
 +0  upvote downvote
submitted by mattnatomy(0)

Most common cause of splenic vein thrombosis is chronic pancreatitis, caused by perivenous inflammation.

Source: https://www.ncbi.nlm.nih.gov/pubmed/14502405


... mattnatomy made a comment on nbme22/block4/q#31 (A 65-year-old man comes to the emergency department...)
 +0  upvote downvote
submitted by mattnatomy(0)

Crackles either indicates chronic bronchitis or consolidation (from pneumonia or pulmonary edema).

Given that there's only a 1 day history of SOB, I'm leaning more towards lobar pneumonia. Maybe that's also what's causing the S3 at the LLSB? If it's Staph Aureus, I guess we could be looking at acute endocarditis + pneumonia? Or Q Fever? But that's just speculation. Could also just be that the lung consolidation is altering blood flow, leading to the back up into the Right Atrium & Ventricle.


... haliburton made a comment on nbme21/block1/q#20 (A 10-year-old girl develops fever, malaise, and loss...)
 +0  upvote downvote
submitted by haliburton(0)

Rabies attacks the nicotinic Acetylcholine receptor, and travels retrograde via dynein motors after binding AChR, according to FA.


... haliburton made a comment on nbme21/block1/q#31 (A 30-year-old woman comes to the office for a...)
 +1  upvote downvote
submitted by haliburton(0)

there are two essential fatty acids: linoleic = omega 6, and alpha-linoleic = omega 3.


... mattnatomy made a comment on nbme22/block4/q#44 (A 10-year-old boy has bruised easily since...)
 +0  upvote downvote
submitted by mattnatomy(0)

You can basically think of Dicumarol as warfarin. MOA: Depletes vitamin K stores Since Vitamin K is involved in gamma carboxylation of factors 2, 7, 9, & 10, you can use the Prothrombin Time to measure the response. Prothrombin time measures the extrinsic pathway of coagulation, which is mainly mediated via Factor 7.


... mattnatomy made a comment on nbme22/block4/q#38 (Patients with mucolipidosis II (I-cell disease) lack...)
 +0  upvote downvote
submitted by mattnatomy(0)

I-cell disease (inclusion cell disease/mucolipidosis type II)—inherited lysosomal storage disorder; defect in N-acetylglucosaminyl-1-phosphotransferase ; failure of the Golgi to phosphorylate ; mannose residues (mannose-6-phosphate) on glycoproteins --> proteins are secreted extracellularly rather than delivered to lysosomes. Results in coarse facial features, gingival hyperplasia, clouded corneas, restricted joint movements, claw hand deformities, kyphoscoliosis, and high plasma levels of lysosomal enzymes. Often fatal in childhood.


... haliburton made a comment on nbme21/block1/q#13 (A 25-year-old man develops shortness of breath after...)
 +0  upvote downvote
submitted by haliburton(0)

FA 2017: Chronic hypoxic pulmonary vasoconstriction results in pulmonary hypertension and RVH.


... haliburton made a comment on nbme21/block1/q#50 (A photograph is shown of a myelin-stained cross...)
 +0  upvote downvote
submitted by haliburton(0)

this is a cervical spinal cord section. the cuneate fasciculus is intact (UE) vibration and proprioception, but the white section is the gracile fasciculus (LE) and is damaged. I think the lateral portion that is uneven is just natural/artifact.


... haliburton made a comment on nbme21/block1/q#5 (A 45-year-old woman is brought to the emergency...)
 +0  upvote downvote
submitted by haliburton(0)

wikipedia (apologies): The atmosphere is composed of 78% nitrogen and 21% oxygen. Since oxygen is exchanged at the alveoli-capillary membrane, nitrogen is a major component for the alveoli's state of inflation. If a large volume of nitrogen in the lungs is replaced with oxygen, the oxygen may subsequently be absorbed into the blood, reducing the volume of the alveoli, resulting in a form of alveolar collapse known as absorption atelectasis.

I chose cardiogenic edema, but I believe this is incorrect because there is no heart failure risk at this time, so the purpose of the PEEP is certainly not to push out fluid.


... haliburton made a comment on nbme21/block1/q#4 (A 67-year-old man comes to the emergency department...)
 +0  upvote downvote
submitted by haliburton(0)

EF2 is translational elogation factor 2, which is necessary for protein synthesis.


... haliburton made a comment on nbme21/block2/q#2 (A 4-year-old girl is conscious but unable to breathe...)
 +0  upvote downvote
submitted by haliburton(0)

https://ghr.nlm.nih.gov/condition/pseudocholinesterase-deficiency

"People with pseudocholinesterase deficiency may not be able to move or breathe on their own for a few hours after [fast-acting drugs, such as succinylcholine and mivacurium] are administered.


... haliburton made a comment on nbme21/block2/q#28 (A 64-year-old woman with type 2 diabetes mellitus...)
 +0  upvote downvote
submitted by haliburton(0)

FA 2017: Fibrate ADRs include myopathy increased risk with statins, cholesterol gallstones


... haliburton made a comment on nbme21/block2/q#21 (A 35-year-old woman undergoes flexible...)
 +0  upvote downvote
submitted by haliburton(0)

link to cartoon diagram


... haliburton made a comment on nbme21/block2/q#35 (A 4-month-old female infant is brought to the...)
 +0  upvote downvote
submitted by haliburton(0)

This is water intoxication. https://www.ncbi.nlm.nih.gov/pubmed/1877579


... haliburton made a comment on nbme21/block2/q#33 (A 68-year-old man comes to the physician because of...)
 +0  upvote downvote
submitted by haliburton(0)

from AAFP ED of mixed organic and psychogenic origin is common. Psychogenic causes are more likely when the patient has normal erections with masturbation or when nocturnal penile tumescence is normal.


... haliburton made a comment on nbme21/block3/q#10 (A 30-year-old man has had intermittent severe lower...)
 +0  upvote downvote
submitted by haliburton(0)

FA 2017: Urinary cyanide-nitroprusside test is diagnostic. not sure how to know that it was a red color, but maybe just the fact that red seemed like a positive test result.

link to more background but not necessarily helpful for this question


... haliburton made a comment on nbme21/block3/q#18 (An 83-year-old man comes to the physician because of...)
 +0  upvote downvote
submitted by haliburton(0)

Bullous pemphigoid antigen must be hemidesmosome. FA: bulla are "bullow" the dermis (subepidermal blister). BP also yield "tense" bulla.


... haliburton made a comment on nbme21/block3/q#38 (A 28-year-old man develops a temperature of 39.9°C...)
 +0  upvote downvote
submitted by haliburton(0)

I chose G-CSF because the granulocytes seemed to me more of a risk than the moderate anemia. Erythropoietin seems like an appropriate choice as well but G-CSF more critical.


... haliburton made a comment on nbme21/block3/q#50 (A 32-year-old woman comes to the emergency...)
 +0  upvote downvote
submitted by haliburton(0)

my notes from UWORLD: andes aegypti mosquito = dengue south, southeast asia, pacific islands, carribean, americas HA, retro=orbital pain, joint pain, muscle ache. petechiae, purpura, epistaxis, melena, throbocytopenia leukpoenia, hemoconcentration


... haliburton made a comment on nbme21/block3/q#15 (A 47-year-old man has jaundice. Laboratory findings...)
 +0  upvote downvote
submitted by haliburton(0)

i think this is because bilirubin is a soluble liver breakdown product of heme, but has not entered the intestine/colon for gut bacteria conversion to stercobilin or urobilin. urobilin in urine is normal.


... haliburton made a comment on nbme21/block3/q#19 (A 25-year-old woman develops increasing shortness of...)
 +0  upvote downvote
submitted by haliburton(0)

Peri- or postpartum cardiomyopathy (PPCM) is a rare, life-threatening heart disease of unclear origin and is characterized by heart failure of sudden onset between the final weeks of pregnancy and 6 months after delivery. link to pubmed The clinical picture of PPCM corresponds to a dilated cardiomyopathy (DCM) with signs of severe heart failure.


... haliburton made a comment on nbme21/block4/q#16 (A 40-year-old woman who had pneumonia due to...)
 +0  upvote downvote
submitted by haliburton(0)

FA 2017: Secrete surfactant from lamellar bodies. Also serve as precursors to type I cells and other type II cells. Proliferate during lung damage.


... haliburton made a comment on nbme21/block4/q#10 (A 64-year-old man is evaluated for cough, dyspnea,...)
 +0  upvote downvote
submitted by haliburton(0)

Small cell lung cancer causes SIADH. Location + exclusionary clues.


... pmnbp made a comment on nbme24/block3/q#2 (A 28-year-old man has a blood pressure cuff placed...)
 +0  upvote downvote
submitted by pmnbp(0)

could someone please explain why adenosine is correct?


... monoloco made a comment on nbme24/block3/q#11 (The pedigrees of patients with schizophrenia most...)
 +0  upvote downvote
submitted by monoloco(11)

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.


... sattanki made a comment on nbme24/block2/q#35 (A 55-year-old woman comes to the physician because...)
 +0  upvote downvote
submitted by sattanki(0)

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


... medstudied made a comment on nbme24/block4/q#31 (In a study of antibiotic resistance, a strain of...)
 +0  upvote downvote
submitted by medstudied(0)

Can someone explain why the correct answer for the question here is conjugation but can’t be transposition?


... gainsgutsglory made a comment on nbme24/block3/q#35 (A 4-year-old girl has a history of multiple bone...)
 +0  upvote downvote
submitted by gainsgutsglory(0)

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).


... itsdrgoodwood made a comment on nbme24/block3/q#35 (A 4-year-old girl has a history of multiple bone...)
 +0  upvote downvote
submitted by itsdrgoodwood(0)

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.


... bobson150 made a comment on nbme22/block3/q#35 (A 4-year-old boy is brought to the physician by his...)
 +0  upvote downvote
submitted by bobson150(0)

Is this saying there is vesicoureteral reflux? I could have sworm this same image was on form 20 or 21 and the answer was Wilms tumor


... bobson150 made a comment on nbme22/block4/q#18 (A 10-year-old girl has a slightly painful 2-mm...)
 +0  upvote downvote
submitted by bobson150(0)

Is the grey supposed to be a suture? If not why would this not be wound healing therefore granulation tissue?


... bobson150 made a comment on nbme22/block1/q#44 (A 52-year-old man with a history of alcoholic...)
 +0  upvote downvote
submitted by bobson150(0)

The wording of this question confused me. This is asking "which of these vessels is the high pressure system" right? So the high pressure superior rectal is causing increased pressure into the inferior rectal?


... justgettinby made a comment on nbme20/block1/q#24 (A 50-year-old man comes to the physician because of...)
 +0  upvote downvote
submitted by justgettinby(0)

Itraconazole requires the acidic environment of the stomach to be absorbed. Omeprazole inhibits the H+/K+ pump of the stomach, thereby decreasing the acidity of the stomach. So when the patient takes Omeprazole and Itraconazole together, Itraconazole won't be absorbed into the body. That's why it has no effect.

It's recommended to take medications at least 2 hours prior to taking an antacid.


... zelderonmorningstar made a comment on nbme24/block3/q#36 (A 1-month-old male newborn is brought to the...)
 +0  upvote downvote
submitted by zelderonmorningstar(0)

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


... drdoom made a comment on nbme24/block2/q#48 (The breakdown of dipeptides and tripeptides to free...)
 +0  upvote downvote
submitted by drdoom(15)

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:


... medstruggle made a comment on nbme24/block4/q#44 (A 71-year-old woman with non-Hodgkin lymphoma is...)
 +0  upvote downvote
submitted by medstruggle(0)

Why do you give IV leucovorin with intrathecal methotrexate? Wouldn’t MTX lose its efficacy since leucovorin reverses the effects of MTX?


... colonelred_ 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 colonelred_(0)

The diagnosis is strawberry hemangioma, commonly happens in kids, often resolves on its own as they get older.


... colonelred_ made a comment on nbme24/block4/q#17 (A 63-year-old woman undergoes operative repair of a...)
 +0  upvote downvote
submitted by colonelred_(0)

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.


... colonelred_ made a comment on nbme24/block4/q#42 (A 40-year-old man who recently immigrated to the USA...)
 +0  upvote downvote
submitted by colonelred_(0)

He’s presenting with classic signs of vitamin B3 deficiency (niacin); niacin is required to form the cofactor NAD+ (nicotinamide adenine dinucleotide).


... medstruggle made a comment on nbme24/block4/q#27 (A 19-year-old man has had weakness of the muscles of...)
 +0  upvote downvote
submitted by medstruggle(0)

Can someone please explain this? What is the diagnosis here?


... medstruggle made a comment on nbme24/block4/q#4 (A 63-year-old woman develops flank pain,...)
 +0  upvote downvote
submitted by medstruggle(0)

Why was the acute hemolytic transfusion reaction due to ABO incompatibility, but not Rh incompatibility?


... medstruggle made a comment on nbme24/block4/q#21 (An otherwise healthy 45-year-old man comes to the...)
 +0  upvote downvote
submitted by medstruggle(0)

Why is it aphthous ulcers if there are no GI symptoms? Why can’t it be herpes zoster?


... medstruggle made a comment on nbme24/block4/q#26 (A 10-year-old girl is brought to the physician by...)
 +0  upvote downvote
submitted by medstruggle(0)

Why is it not ovarian follicle cells? I thought the female analog of Sertoli and Leydig is theca/granulosa cells.


... medstruggle made a comment on nbme24/block2/q#26 (A 35-year-old man is brought to the emergency...)
 +0  upvote downvote
submitted by medstruggle(0)

Can someone explain why does this patient have hypokalemia?


... medstruggle made a comment on nbme24/block2/q#20 (A 52-year-old man is admitted to the hospital for...)
 +0  upvote downvote
submitted by medstruggle(0)

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


... medstruggle made a comment on nbme24/block2/q#48 (The breakdown of dipeptides and tripeptides to free...)
 +0  upvote downvote
submitted by medstruggle(0)

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


... neonem made a comment on nbme20/block2/q#21 (A 25-year-old woman comes to the physician 2 days...)
 +1  upvote downvote
submitted by neonem(2)

Cat scratch disease (Bartonella infection in immunocompetent hosts) causes lymphadenitis (especially in the axillary region) characterized by sarcoid-like non-caseating granulomas filled with neutrophils.


... hayayah made a comment on nbme21/block1/q#11 (A 27-year-old primigravid woman at 34 weeks'...)
 +0  upvote downvote
submitted by hayayah(54)

HELLP syndrome: Hemolysis Elevated Liver enzymes Low Platelets.

A manifestation of severe preeclampsia. Blood smear shows schistocytes. Can lead to DIC and hepatic subcapsular hematomas Ž rupture Ž severe hypotension.


... neonem made a comment on nbme20/block3/q#6 (A new drug has the following effects on the activity...)
 +0  upvote downvote
submitted by neonem(2)

Leukotriene B4 is a potent chemotactic molecule for neutrophils. Selective loss of this would have no effect on platelets, mast cells, or endothelium - these are more responsive to changes in TXA2, complement/arachidonic acid, and PGI2, respectively.


... hayayah made a comment on nbme21/block1/q#22 (A 36-year-old man with AIDS elects to participate in...)
 +0  upvote downvote
submitted by hayayah(54)

Cysteine-cysteine chemokine receptor 5 (CCR5) is a protein found on the surface of CD4 cells.


... neonem made a comment on nbme20/block3/q#43 (A 71-year-old man comes to the physician because of...)
 +0  upvote downvote
submitted by neonem(2)

Cilostazol is a phosphodiesterase inhibitor; leads to increased cAMP which inhibits platelet degranulation/activation while also causing vasodilation. All of the other options work on either vasculature or platelets but not both.


... neonem made a comment on nbme20/block3/q#5 (A 35-year-old man comes to the physician because of...)
 +0  upvote downvote
submitted by neonem(2)

Methotrexate would be a drug of choice for psoriasis refractory to topical creams and light therapy; inhibits dihydrofolate reductase in order to decrease skin cell proliferation and reduce inflammatory response.


... neonem made a comment on nbme20/block3/q#36 (A 4-year-old boy has had fever, abdominal cramping,...)
 +1  upvote downvote
submitted by neonem(2)

Shigella causes an inflammatory diarrhea; it produces a toxin and can invade tissue directly. In addition, it is resistant to acid, so it has a characteristically low infective dose (~10 organisms), which facilitates its fecal-oral (person-to-person) spread especially in settings where hygiene may be compromised, such as in daycare or institutional housing. It can be differentiated from E. Coli (EHEC) because E Coli doesn't have as much person-to-person spread and only causes GI damage by the shiga-like toxin, not direct invasion. Therefore, EHEC wouldn't facilitate as strong of a neutrophilic response.


... hayayah made a comment on nbme21/block1/q#28 (A 47-year-old man is brought to the emergency...)
 +0  upvote downvote
submitted by hayayah(54)

Mixed venous oxygen saturation (SvO2) is measured in the pulmonary artery. SvO2 samples the true mixed venous blood leaving the right heart. Measurement of mixed venous oxygen saturation (SvO2) from the pulmonary artery has been advocated as an indirect index of tissue oxygenation.

In cardiogenic shock you have decreased CO --> decreased O2 delivery --> decreased SvO2.


... neonem made a comment on nbme20/block3/q#50 (A 62-year-old man comes to the physician because of...)
 +0  upvote downvote
submitted by neonem(2)

This patient likely has some form of upper motor neuron lesion or disease - UMN lesions are characterized by weakness, increased deep tendon reflexes, and spastic paresis. Baclofen is a GABA-B agonist specific to the spinal cord, used ot treat muscle spasticity, dystonia, and MS. GABA-B is a G-protein coupled receptor coupled to Gi, so agonism of this receptor causes hyperpolarization of the neurons and decreased release of excitatory glutamate.


... hayayah made a comment on nbme21/block3/q#8 (A 55-year-old woman is brought to the emergency...)
 +0  upvote downvote
submitted by hayayah(54)

Wernicke-Korsakoff syndrome. Don't have to be an alcoholic to get this, just usually is related to alcoholism / thiamine deficiency.


... neonem made a comment on nbme20/block4/q#6 (A 51-year-old man develops diaphoresis, tachycardia,...)
 +0  upvote downvote
submitted by neonem(2)

Alcohol withdrawal leads to a sympathetic-hyperactivity-like syndrome with tremors, HTN, insomnia, GI upset, diaphoresis, and mild agitation 3-36 hours after the last drink. There is a similar, but usually slightly later, overlap of withdrawal seizures 6-48 hours after the last drink.


... hayayah made a comment on nbme21/block3/q#27 (A 55-year-old woman with a benign nodule in the left...)
 +0  upvote downvote
submitted by hayayah(54)

The thyroid is supplied with arterial blood from the superior thyroid artery, a branch of the external carotid artery, and the inferior thyroid artery, a branch of the thyrocervical trunk.


... neonem made a comment on nbme20/block4/q#24 (A 27-year-old man comes to the physician because of...)
 +0  upvote downvote
submitted by neonem(2)

Most of intrinsic muscles of the hand are innervated by ulnar nerve - chronic compression at the hook of hamate could lead to nerve ischemia


... hayayah made a comment on nbme21/block3/q#40 (A 65-year-old woman undergoes surgical repair of an...)
 +0  upvote downvote
submitted by hayayah(54)

Note: The abducens n. is actually the nerve most likely to be damaged by an expanding internal carotid aneurysm in the cavernous sinus but they give you specific CN3 function in this question.


... hayayah made a comment on nbme21/block3/q#33 (Left radial arterial and venous blood samples are...)
 +0  upvote downvote
submitted by hayayah(54)

the majority of carbon dioxide molecules are carried as part of the bicarbonate buffer system. In this system, carbon dioxide diffuses into the RBCs. Carbonic anhydrase (CA) within RBCs quickly converts the carbon dioxide into carbonic acid (H2CO3). Carbonic acid is an unstable intermediate molecule that immediately dissociates into bicarbonate ions (HCO3-) and hydrogen (H+) ions.

The newly synthesized bicarbonate ion is transported out of the RBC into the plasma in exchange for a chloride ion (Cl−); this is called the chloride shift. When the blood reaches the lungs, the bicarbonate ion is transported back into the RBC in exchange for the chloride ion. The H+ ion dissociates from the hemoglobin and binds to the bicarbonate ion. This produces the carbonic acid intermediate, which is converted back into carbon dioxide through the enzymatic action of CA. The carbon dioxide produced is expelled through the lungs during exhalation.


... neonem made a comment on nbme20/block4/q#46 (A 28-year-old woman at 32 weeks' gestation comes to...)
 +0  upvote downvote
submitted by neonem(2)

Obstructive uropathy causes a postrenal azotemia --> when prolonged, tubular damage ensues. This leads to an acute tubular necrosis, characterized by necrotic plugs in the tubular system as seen in the image


... hayayah made a comment on nbme21/block4/q#46 (A 14-year-old girl is brought to the physician for a...)
 +0  upvote downvote
submitted by hayayah(54)

Most human cancers are d/t a loss of function of TP53 gene.


... hayayah made a comment on nbme21/block4/q#1 (A 50-year-old woman has azotemia. Renal...)
 +0  upvote downvote
submitted by hayayah(54)

Invasive cervical carcinoma is associated with hydronephrosis and renal failure d/t CA spreading through uterine wall and into the bladder.


... hayayah made a comment on nbme21/block4/q#28 (A 56-year-old man undergoes surgical resection of...)
 +0  upvote downvote
submitted by hayayah(54)

Although half these hormones can actually also be secreted from the duodenum, the duodenum is associated the most with CCK release.


... hayayah made a comment on nbme21/block4/q#23 (An investigator is studying the regulation of...)
 +2  upvote downvote
submitted by hayayah(54)

Lymph flow rate is usually low. It is influenced primarily by the rate of lymph formation. For example, if blood capillary pressure is increased by arterial vasodilation or venous constriction, the flow rate of lymph increases. Also, the flow rate is affected by compression of lymphatics by contraction of neighboring musculature and by negative intrathoracic pressure (breathing).

Interstitial pressure (so pressure in the ECF, which would increase if given IV saline) and lymph flow are positively related. A small increase in interstitial volume greatly increases its pressure, promoting lymph flow that acts to restore the interstitial volume to normal.

more on this topic: https://www.ncbi.nlm.nih.gov/books/NBK53448/


... hayayah made a comment on nbme21/block4/q#24 (A 56-year-old man undergoes a renal transplant. Five...)
 +0  upvote downvote
submitted by hayayah(54)

Hyperacute transplant rejection occurs within minutes d/t pre-existing recipient antibodies that react to donor antigen (type II hypersensitivity reaction), activate complement.


... colonelred_ made a comment on nbme24/block2/q#42 (A 3-week-old female newborn is brought to the...)
 +0  upvote downvote
submitted by colonelred_(0)

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.


... jejunumjedi made a comment on nbme24/block4/q#41 (A 30-year-old man who is a migrant farm worker comes...)
 +0  upvote downvote
submitted by jejunumjedi(0)

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


... 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(0)

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.


... ankistruggles made a comment on nbme24/block4/q#13 (A 90-year-old man has a 1-week history of...)
 +0  upvote downvote
submitted by ankistruggles(0)

How do you know he has an incarcerated inguinal hernia and not fecal impaction?


... 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(0)

Why are the IMA and SMA most likely to be affected in her condition?


... ankistruggles made a comment on nbme24/block4/q#35 (An investigator is conducting a study of a novel...)
 +0  upvote downvote
submitted by ankistruggles(0)

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 made a comment on nbme24/block4/q#30 (An investigator is studying an outbreak of...)
 +0  upvote downvote
submitted by sattanki(0)

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.


... ankistruggles made a comment on nbme24/block4/q#40 (A 25-year-old woman is brought to the emergency...)
 +0  upvote downvote
submitted by ankistruggles(0)

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 made a comment on nbme24/block4/q#5 (A 45-year-old man comes to the physician because of...)
 +0  upvote downvote
submitted by sattanki(0)

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.


... sattanki made a comment on nbme24/block4/q#49 (A 27-year-old man sustains a spinal cord transection...)
 +0  upvote downvote
submitted by sattanki(0)

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.


... sattanki made a comment on nbme24/block4/q#8 (A 1-week-old newborn is brought to the physician...)
 +0  upvote downvote
submitted by sattanki(0)

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.


... sattanki made a comment on nbme24/block4/q#39 (A 30-year-old woman comes to the physician because...)
 +0  upvote downvote
submitted by sattanki(0)

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).


... consistentwrongdoer3 made a comment on nbme24/block4/q#10 (A 60-year-old woman is receiving cisplatin therapy...)
 +0  upvote downvote
submitted by consistentwrongdoer3(0)

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.


... skinnynomore made a comment on nbme24/block2/q#12 (An 80-year-old man is admitted to the hospital...)
 +0  upvote downvote
submitted by skinnynomore(0)

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.


... zelderonmorningstar made a comment on nbme24/block3/q#34 (An otherwise healthy 35-year-old man sustains a...)
 +0  upvote downvote
submitted by zelderonmorningstar(0)

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


... colonelred_ made a comment on nbme24/block3/q#34 (An otherwise healthy 35-year-old man sustains a...)
 +0  upvote downvote
submitted by colonelred_(0)

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.


... stapes2big made a comment on nbme24/block3/q#14 (A cohort study is done to evaluate the association...)
 +0  upvote downvote
submitted by stapes2big(0)

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


... drdoom made a comment on nbme24/block3/q#25 (An investigator is studying a new virus isolated...)
 +0  upvote downvote
submitted by drdoom(15)

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


... tea-cats-biscuits made a comment on nbme24/block3/q#25 (An investigator is studying a new virus isolated...)
 +0  upvote downvote
submitted by tea-cats-biscuits(1)

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.


... tea-cats-biscuits made a comment on nbme24/block3/q#34 (An otherwise healthy 35-year-old man sustains a...)
 +0  upvote downvote
submitted by tea-cats-biscuits(1)

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.


... tea-cats-biscuits made a comment on nbme24/block1/q#30 (A 55-year-old man is brought to the emergency...)
 +0  upvote downvote
submitted by tea-cats-biscuits(1)

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


... tea-cats-biscuits made a comment on nbme24/block3/q#29 (Drug X is given to a 25-year-old normal subject....)
 +0  upvote downvote
submitted by tea-cats-biscuits(1)

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).


... tea-cats-biscuits made a comment on nbme24/block3/q#42 (Which of the following terms best describes the...)
 +0  upvote downvote
submitted by tea-cats-biscuits(1)

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.


... tea-cats-biscuits made a comment on nbme24/block3/q#24 (A 3-month-old boy is brought to the emergency...)
 +0  upvote downvote
submitted by tea-cats-biscuits(1)

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.


... medstruggle made a comment on nbme24/block1/q#40 (A 26-year-old man and his 25-year-old wife come to...)
 +0  upvote downvote
submitted by medstruggle(0)

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”?


... medstruggle made a comment on nbme24/block1/q#31 (An experimental study is conducted to examine the...)
 +0  upvote downvote
submitted by medstruggle(0)

Why is alternative splicing or post-transcriptional modification incorrect?


... tea-cats-biscuits made a comment on nbme24/block1/q#28 (A 32-year-old woman comes to the physician because...)
 +1  upvote downvote
submitted by tea-cats-biscuits(1)

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.


... beeip made a comment on nbme23/block1/q#35 (A 42-year-old woman comes to the physician because...)
 +0  upvote downvote
submitted by beeip(7)

The best I can understand, they're describing endometrial hyperplasia, a result of excess estrogen, a steroid hormone that translocates to the nucleus and binds its transcription factor.


... surely_not_a_robot_ made a comment on nbme22/block2/q#45 (An 86-year-old man who lives in a skilled nursing...)
 +0  upvote downvote
submitted by surely_not_a_robot_(0)

Per first aid. Dextromethorphan = “Antitussive (antagonizes NMDA glutamate receptors). Synthetic codeine analog. Has mild opioid effect when used in excess.”

I guess the key is that the opioid effect is mild. Seems like they’re asking which would treat the symptoms and reduce the side effects, not necessarily get rid of the side effects completely. Agree that it is a challenging one for Step 1.


... rockediny made a comment on nbme22/block2/q#45 (An 86-year-old man who lives in a skilled nursing...)
 +1  upvote downvote
submitted by rockediny(1)

Dextro is the correct answer here. From the choices given, dextro is the least likely to cause constipation since its main mechanism of action is NMDA antagonism w/some opioid activity -- it can cause constipation but the other choices are MUCH MORE likely to. As for diphenhydramine = it is not appropriate for elderly patients and it isn’t an antitussive.


... calcium196 made a comment on nbme22/block2/q#45 (An 86-year-old man who lives in a skilled nursing...)
 +0  upvote downvote
submitted by calcium196(2)

NBME 20 has a question with a guy taking over the counter cough medication and now he has constipation. Want to guess the answer? It was dextro! -> https://nbmeanswers.com/exam/nbme20/458

So I’m pretty sure the NBME 22 question is just straight up wrong.


... noselex made a comment on nbme22/block2/q#45 (An 86-year-old man who lives in a skilled nursing...)
 +0  upvote downvote
submitted by noselex(0)

Dextro vs Codeine: Both are antitussives, but dextro is more of NMDA agonist that also has opioid agonist activity. Dextro is often abused to get a similar out of body feeling due to its NMDA agonist effect. Codeine on the other other is a full-on opioid agonist. It’s also used as anti-diarrheal, so constipation is very common adverse effect.

Tiotropium is wrong because it’s not an antitussive. Also, it’s an anticholinergic which is (1) contraindicated in elderly unless really indicated, (2) a well-documented anticholinergic effect is constipation.


... lodododo made a comment on nbme22/block2/q#32 (A 54-year-old man who works in a delicatessen comes...)
 +1  upvote downvote
submitted by lodododo(1)

There’s a UWorld question on this. Once the healthy axon retracts and the distal (injured) axon degenerates, there’s a bunch of myelin debris in the way that remains there for a long time. This blocks regeneration of the axon.


... bhangradoc made a comment on nbme22/block2/q#32 (A 54-year-old man who works in a delicatessen comes...)
 +0  upvote downvote
submitted by bhangradoc(0)

Schwann cells: they are supposed to degrade residual myelin sheath during the neuronal degeneration. Without that degeneration, I guess you can’t re-innervate properly. Not totally sure.


... calcium196 made a comment on nbme22/block2/q#45 (An 86-year-old man who lives in a skilled nursing...)
 +0  upvote downvote
submitted by calcium196(2)

How is a synthetic opioid (dextromethorphan) that you can find with a 2 second google search as causing constipation the correct answer? Is it just because tiotropium wouldn’t treat the cough?


... hayayah made a comment on nbme21/block2/q#14 (A 30-year-old woman comes to the office because she...)
 +0  upvote downvote
submitted by hayayah(54)

Cretinism (congenital hypothyroidism) is the most common cause of treatable mental disability. Causes poor brain development.


... hayayah made a comment on nbme21/block2/q#50 (A 65-year-old woman comes to the emergency...)
 +1  upvote downvote
submitted by hayayah(54)

Catheter placement:

https://aneskey.com/wp-content/uploads/2016/08/image00804.jpeg

Recall that the lung apex extends above the first rib.


... hayayah made a comment on nbme21/block2/q#26 (A healthy 32-year-old woman at 35 weeks' gestation...)
 +1  upvote downvote
submitted by hayayah(54)

Stretch or dilation of the cervix and vagina are strong stimuli for oxytocin secretion, mediated by neural pathways called the Ferguson reflex.

Article: https://www.sciencedirect.com/topics/neuroscience/ferguson-reflex


... joha961 made a comment on nbme22/block4/q#33 (A 38-year-old single woman with a history of chronic...)
 +1  upvote downvote
submitted by joha961(1)

Like others have said, I think sublimation would have been better, but displacement from first aid says that it is, “redirection of emotions or impulses to a neutral person or object” so she’s kicking her family by kicking the bag.


... hayayah made a comment on nbme21/block2/q#16 (A 34-year-old woman comes to the physician because...)
 +0  upvote downvote
submitted by hayayah(54)

This pt has an ASD which is a "hole" between the LA and RA. Fixing it could damage the AV bundles.


... borborygnoramus made a comment on nbme22/block4/q#33 (A 38-year-old single woman with a history of chronic...)
 +1  upvote downvote
submitted by borborygnoramus(1)

As best as I could tell, it was displacement because the other choices were definitely wrong, not b/c displacement was a good choice. Felt like there were lots of this type of question on this exam.


... hayayah made a comment on nbme21/block2/q#8 (A 55-year-old man is diagnosed with renal artery...)
 +1  upvote downvote
submitted by hayayah(54)

Renal artery stenosis is going to decrease blood flow to the kidney. JG cells sense the decrease in perfusion pressure and secrete renin.

Renin is produced by the JG cells, JG cells are in the cortex (they are modified smooth muscle of the afferent arteriole).


... hayayah made a comment on nbme21/block2/q#47 (A 55-year-old woman comes to the physician because...)
 +1  upvote downvote
submitted by hayayah(54)

Secondary hyperparathyroidism (usually d/t chronic renal failure).

Lab findings include ↑ PTH (response to low calcium), ↓ serum calcium (renal failure), ↑ serum phosphate (renal failure), and ↑ alkaline phosphatase (PTH activating osteoBlasts).


... hayayah made a comment on nbme21/block2/q#44 (A 75-year-old man has the sudden onset of partial...)
 +0  upvote downvote
submitted by hayayah(54)

lower quadrantanopia: parietal lesion

vs upper quadrantanopia = temporal lesion


... hayayah made a comment on nbme21/block2/q#29 (A healthy 25-year-old man is participating in a...)
 +0  upvote downvote
submitted by hayayah(54)

P. 91 of FA has a quick explanation for this!

Basically once you're in a starving state there's still hepatic gluconeogenesis going on (as well as using FFA) but the gluconeogenesis is coming from peripheral tissue lactate and alanine.


... hayayah made a comment on nbme21/block2/q#19 (A 3-year-old boy who recently immigrated to the USA...)
 +0  upvote downvote
submitted by hayayah(54)

This pt has osteomalacia / rickets (since he's a kiddo). Caused by defective mineralization of osteoid (osteomalacia) or cartilaginous growth plates (rickets, only in children).

Most commonly d/t Vitamin D deficiency.

Children with rickets have pathologic bow legs (genu varum), bead-like costochondral junctions (rachitic rosary), craniotabes (soft skull).


... thomas made a comment on nbme20/block1/q#12 (72 yo woman with dysphagia)
 +0  upvote downvote
submitted by thomas(1)

headshot

https://slideplayer.com/slide/10842513/39/images/24/Drainage+territory+Drains+lymphatics+from+whole+of+the+body+except.jpg


... thomas made a comment on nbme20/block2/q#35 (A 36-year-old woman comes to the office because of a...)
 +0  upvote downvote
submitted by thomas(1)

Looked like hepatosplenomegaly, but I went with liver b/c the edema could be due to liver dysfunction.


... thomas made a comment on nbme20/block2/q#25 (A 14-year-old girl is brought to the physician...)
 +0  upvote downvote
submitted by thomas(1)

It's a mitochondrial disease. - present in successive generations, always with maternal transmission - damage to high-energy tissues - CSF lactic acidosis (due to increased anaerobic metabolism due to impaired oxidative phosphorylation)


... thomas made a comment on nbme20/block2/q#36 (A 31-year-old man has a large, yellow, soft mass...)
 +1  upvote downvote
submitted by thomas(1)

Lipomas/Liposarcomas are the commonest soft-tissue tumors in adults. The high mitotic index & infiltrative nature indicate that the mass is malignant.


... thomas made a comment on nbme20/block2/q#32 (A 12-year-old girl is brought to the physician by...)
 +0  upvote downvote
submitted by thomas(1)

They tell you that the kid has no clavicle. This means the defect is in membranous ossification, NOT endochondral, so the pathology is NOT going to involve the chondro-whatever cells. decreased ALK is consistent with osteoblast defect.


... thomas made a comment on nbme20/block4/q#34 (A 20-year-old man is brought to the physician by his...)
 +0  upvote downvote
submitted by thomas(1)

The first sentence acknowledges the patient's emotions, which is always good. The second sentence is good because it begins the interview with an open-ended question.


... thomas made a comment on nbme20/block4/q#42 (A 65-year-old woman dies 6 months after the onset of...)
 +0  upvote downvote
submitted by thomas(1)

Answer is Astrocyte. Patient has glioblastoma multiforme. Although meningiomas may occur at convexities, meningiomas are benign and often asymptomatic. They may cause h/a seizures, but would be unlikely to cause death w/in 6m of onset of h/a. The size of tumor and course of illness is consistent with the course of GBM


... thomas made a comment on nbme20/block3/q#47 (A 60-year-old woman has prolonged apnea following...)
 +0  upvote downvote
submitted by thomas(1)

Not sure about this, but it seems to me that this is referring to "pseudocholinesterase inhibitor deficiency. It's an enzyme defect that is triggered by NMJ blockers - succinylcholine or curare's.

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


... hayayah made a comment on nbme21/block2/q#31 (A 37-year-old man is brought to the emergency...)
 +1  upvote downvote
submitted by hayayah(54)

With this question, I think they want you to recognize that the patient isn't having chest pain related to the heart. They emphasize several rib fractures and a pneumothorax but don't indicate any heart damage (lack of adventitious sounds = no pulmonary edema indicated or a lung issue related to heart problem).

The pericarditis is what's innervated by the phrenic n. Seeing as how his heart is fine, the fractured ribs are probably what are causing him pain via the intercostal nerves.


... celeste made a comment on nbme20/block4/q#3 (A 23-year-old woman comes to the physician for a...)
 +1  upvote downvote
submitted by celeste(10)

Sounds like a hypertrophic scar. "Hypertrophic scars contain primarily type III collagen oriented parallel to the epidermal surface with abundant nodules containing myofibroblasts, large extracellular collagen filaments and plentiful acidic mucopolysaccharides." https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3022978/


... celeste made a comment on nbme20/block4/q#20 (A 5-year-old boy is brought to the physician for a...)
 +2  upvote downvote
submitted by celeste(10)

This sounds like Fanconi syndrome. The proximal tubular epithelial cells have a hard time reabsorbing filtrate, so you'll see a loss of phosphate, amino acids, bicarbonate, and glucose.


... celeste made a comment on nbme20/block4/q#24 (A 27-year-old man comes to the physician because of...)
 +3  upvote downvote
submitted by celeste(10)

The adductor pollicis muscle is innervated by the ulnar nerve, giving this guy a difficult time holding a sheet of paper.


... celeste made a comment on nbme20/block2/q#6 (An 18-year-old boy has just been diagnosed with...)
 +4  upvote downvote
submitted by celeste(10)

While the lifetime risk in the general population is just below 1%, it is 6.5% in first-degree relatives of patients and it rises to more than 40% in monozygotic twins of affected people. Analyzing classic studies of the genetics of schizophrenia done as early as in 1930s, Fischer concludes that a concordance rate for psychosis of about 50% in monozygotic twins seems to be a realistic estimate, which is significantly higher than that in dizygotic twins of about 10–19% (ncbi.nlm.nih.gov/pmc/articles/PMC4623659/#ref3)


... celeste made a comment on nbme20/block2/q#15 (A 55-year-old man comes to the physician because of...)
 +0  upvote downvote
submitted by celeste(10)

Dextromethorphan is an opium alkaloid derivative. Dextromethorphan is a drug of abuse. The main risks associated with dextromethorphan are ataxia, central nervous system (CNS) stimulation, dizziness, lethargy and psychotic behavior. Less frequently with large doses seizures and respiratory depression can occur. Nausea, vomiting, constipation and tachycardia may also occur. (toxnet.nlm.nih.gov)


... celeste made a comment on nbme20/block3/q#31 (A 62-year-old woman comes to the physician because...)
 +0  upvote downvote
submitted by celeste(10)

Beta-Tubulin is a subunit of tubulin. Tubulin is one of several members of a small family of globular proteins. It is the major constituent of microtubules. There are two of most common members of the tubulin family: alpha-tubulin and beta-tubulin, and together their dimers form microtubules. (origene.com)


... celeste made a comment on nbme20/block3/q#48 (A 48-year-old woman comes to the physician because...)
 +0  upvote downvote
submitted by celeste(10)

Amiodarone, a class III antiarrhythmic drug, has multiple effects on myocardial depolarization and repolarization that make it an extremely effective antiarrhythmic drug. However, amiodarone is associated with a number of side effects, including thyroid dysfunction (both hypo- and hyperthyroidism), which is due to amiodarone's high iodine content and its direct toxic effect on the thyroid. (uptodate.com)


... celeste made a comment on nbme20/block3/q#9 (A 62-year-old man comes to the physician because of...)
 +0  upvote downvote
submitted by celeste(10)

If prostate cancer spreads to other parts of the body, it nearly always goes to the bones first (cancer.org/cancer/prostate-cancer/treating/treating-pain.html)


... allinthistogether made a comment on nbme20/block2/q#8 (Three elderly residents of an assisted living...)
 +1  upvote downvote
submitted by allinthistogether(1)

Legionella is common causes of pneumonia superimposed on chronic obstructive pulmonary disease.


... thechillhill made a comment on nbme20/block3/q#1 (The frequency of an autosomal recessive disease in a...)
 +0  upvote downvote
submitted by thechillhill(0)

p + q = 1 p^2 + 2pq + q^2 = 1 if q^2 = 1/1600 = 0.00063 then q = sqrt(q^2) = 0.025 solve for p to get p = 1 - r = 1 - 0.025 = 0.975 the heterozygous carriers = 2pq = 1 - p^2 = 1 - 0.95 = 0.5 q^2 can be dropped b/c it's much smaller than p^2. The deletion is responsible for 80% of the mutations. 0.8 x 0.5 = 0.04 = 4/100 = 1/25

There might be an easier way to do this, but it worked for me.


... sklawpirt made a comment on nbme21/block4/q#13 (A 4-month-old boy is diagnosed with a rare autosomal...)
 +0  upvote downvote
submitted by sklawpirt(0)

I think the idea here is simply that one should think about where vesicles are coming from on their way to the golgi complex.

"Two steps forward and one step back." Specfically the question may be referring to a rare craniofacial disorder. an awarenesss of that disease is not necessary. What is necessary is understanding the origin from where vesicles are traficked to the Golgi apparatus.

COPI protein is needed to coat vescles from the RER to send to golgi. Thus, with a mutation in that protein, the packaged proteins that should bleb off and be sent to the golgi, instead accumulate in the RER and dilate it. Thus the answer.

https://www.cell.com/ajhg/pdf/S0002-9297(16)30214-2.pdf


... haliburton made a comment on nbme20/block4/q#8 (A 58-year-old man is brought to the emergency...)
 -1  upvote downvote
submitted by haliburton(0)

FA 2017: 3° syphilis disrupts the vasa vasorum of the aorta with consequent atrophy of vessel wall and dilatation of aorta and valve ring. May see calcification of aortic root, ascending aortic arch, and thoracic aorta. Leads to “tree bark” appearance of aorta. Can result in aneurysm of ascending aorta or aortic arch, aortic insufficiency.


... haliburton made a comment on nbme20/block4/q#19 (A 55-year-old man with severe emphysema comes to the...)
 +0  upvote downvote
submitted by haliburton(0)

resonant sound is normal. hyperresonant with overexpansion. tactile fremitus is increased /c solid mass or fluid, and decreased with air/fluid level or overexpansion. prolonged expiratory phase -> obstructive conditions.


... drdoom made a comment on nbme21/block3/q#39 (A 74-year-old woman with mild dementia is admitted...)
 +0  upvote downvote
submitted by drdoom(15)

Stem actually states, “On questioning, the patient does not know the date [time], the name of the hospital [place], or the name of her nurse who had just introduced himself [person].” So, pt is disoriented to time and place (Choice A); that is definitely concerning -- as would be depressed mood (Choice E) and the other choices -- but “inability to understand severity and prognosis” is the most concerning since that is the very definition of capacity. Inability to understand = lack of capacity.


... haliburton made a comment on nbme20/block2/q#39 (A 29-year-old man comes to the physician because of...)
 +0  upvote downvote
submitted by haliburton(0)

Mycoplasma pneumoniae cold agglutinins, no response to amoxicillin.

FA 2017: Classic cause of atypical “walking” pneumonia (insidious onset, headache, nonproductive cough, patchy or diffuse interstitial infiltrate). X-ray looks worse than patient. High titer of cold agglutinins (IgM), which can agglutinate or lyse RBCs. Grown on Eaton agar. Treatment: macrolides, doxycycline, or fluoroquinolone (penicillin ineffective since Mycoplasma have no cell wall). ABC = Africa, Blindness, Chronic infection. D–K = everything else. Neonatal disease can be acquired during passage through infected birth canal. No cell wall. Not seen on Gram stain. Pleomorphic A. Bacterial membrane contains sterols for stability. Mycoplasmal pneumonia is more common in patients < 30 years old. Frequent outbreaks in military recruits and prisons. Mycoplasma gets cold without a coat (cell wall).


... drdoom made a comment on nbme20/block4/q#29 (A 15-year-old girl is brought to the physician by...)
 +0  upvote downvote
submitted by drdoom(15)

[deleted]


... haliburton made a comment on nbme20/block3/q#4 (An 18-year-old woman comes to the physician because...)
 +0  upvote downvote
submitted by haliburton(0)

FA 2017: Infects B cells through CD21. Atypical lymphocytes on peripheral blood smear G —not infected B cells but reactive cytotoxic T cells. ⊕ Monospot test—heterophile antibodies detected by agglutination of sheep or horse RBCs. Use of amoxicillin in mononucleosis can cause characteristic maculopapular rash.


... haliburton made a comment on nbme20/block3/q#23 (A 50-year-old woman is brought to the emergency...)
 +0  upvote downvote
submitted by haliburton(0)

[comment moved to subcomment]


... hayayah made a comment on nbme20/block4/q#29 (A 15-year-old girl is brought to the physician by...)
 +0  upvote downvote
submitted by hayayah(54)

An adverse effect of doxycycline is photosensitivity.


... hayayah made a comment on nbme20/block4/q#48 (A 24-year-old man comes to the emergency department...)
 +0  upvote downvote
submitted by hayayah(54)

Pt. has Familial dyslipidemias. Type I—Hyperchylomicronemia.


... hayayah made a comment on nbme20/block4/q#15 (45 yo man undergoing surgical procedure)
 +0  upvote downvote
submitted by hayayah(54)

Hyperventilation causes decreased PaCO2 which subsequently leads to arterial vasoconstriction thus lowering cerebral blood flow (CBF), cerebral blood volume, and ICP.

He wants to increase ICP (cerebral vasodilation) which he can do by decreasing the respiratory rate (hypoventilation).


... hayayah made a comment on nbme20/block4/q#21 (A 47-year-old woman comes to the physician because...)
 +0  upvote downvote
submitted by hayayah(54)

Hypersensitivity pneumonitis—mixed type III/IV hypersensitivity reaction to environmental antigen. Causes dyspnea, cough, chest tightness, headache. Often seen in farmers and those exposed to birds. Reversible in early stages if stimulus is avoided.

It's a type of restrictive lung disease.


... hayayah made a comment on nbme20/block4/q#32 (A 55-year-old man comes to the physician because of...)
 +0  upvote downvote
submitted by hayayah(54)

Glucagonoma: Tumor of pancreatic α cells Žcausing an overproduction of glucagon.

Presents with 5D’s:


... hayayah made a comment on nbme20/block4/q#18 (A 35-year-old man comes to the physician because of...)
 +0  upvote downvote
submitted by hayayah(54)

Zollinger-Ellison syndrome: Gastrin-secreting tumor (gastrinoma) of pancreas or duodenum.


... hayayah made a comment on nbme20/block4/q#10 (A 65-year-old woman who has a 25-year history of...)
 +0  upvote downvote
submitted by hayayah(54)

She has a vitamin C deficiency. Scurvy features swollen gums, easy bruising, petechiae, perifollicular and subperiosteal hemorrhages.


... hayayah made a comment on nbme20/block4/q#31 (A 48-year-old man is brought to the emergency...)
 +1  upvote downvote
submitted by hayayah(54)

Iron overdose is a cause of a high anion gap metabolic acidosis.


... hayayah made a comment on nbme20/block4/q#7 (33 yo woman with HIV, generalized tonic-clonic seizure)
 +0  upvote downvote
submitted by hayayah(54)

This is a primary central nervous system lymphoma. Most commonly associated with HIV/AIDS; pathogenesis involves EBV infection.

Considered an AIDS-defining illness. Variable presentation: confusion, memory loss, seizures. Mass lesion(s) (may be ring-enhancing in immunocompromised patient) on MRI, needs to be distinguished from toxoplasmosis via CSF analysis or other lab tests. Toxo usually has multiple ring enhancing lesions.


... hayayah made a comment on nbme20/block4/q#17 (A previously healthy 55-year-old man has recently...)
 +0  upvote downvote
submitted by hayayah(54)

Also, you shouldn't be seeing end-organ damage or increased renin / kidney response with a previously healthy patient that just developed essential HTN. The body doesn't want to increase renin when it has HTN. However, if you have stenosis, the kidneys freak out because they're not getting enough flow and think the whole body isn't either, so they activate the RAAS system. When you give them an ACE-I, the renin is still being produced by the kidney, it just isn't being converted to angiotensin-II.

To eliminate other choices:


... hayayah made a comment on nbme20/block4/q#4 (A 20-year-old man comes to the physician stating...)
 +0  upvote downvote
submitted by hayayah(54)

A fractured cribriform plate (anterior skull trauma) can result in leaking of cerebrospinal fluid into the nose and loss of sense of smell. Smell plays a large role in the perception of taste. So, in practice, a patient may complain of loss of taste rather than of smell.


... hayayah made a comment on nbme20/block2/q#47 (A 35-year-old man comes to the physician to discuss...)
 +1  upvote downvote
submitted by hayayah(54)

You have a 25% chance of inheriting the same HLA markers as your siblings.


... hayayah made a comment on nbme20/block2/q#36 (A 31-year-old man has a large, yellow, soft mass...)
 +1  upvote downvote
submitted by hayayah(54)

Benign tumors are usually well-differentiated and well-demarcated, with low mitotic activity, no metastases, and no necrosis.

Malignant tumors (cancers) may show poor differentiation, erratic growth, local invasion, metastasis, and apoptosis. High mitotic activity.

Fat tumors:


... hayayah made a comment on nbme20/block2/q#49 (An 82-year-old woman is brought to the physician...)
 +0  upvote downvote
submitted by hayayah(54)

Beta blockers as antiarrhythmics suppress abnormal pacemakers by decreasing the slope of phase 4 --> prolonging phase 4.


... hayayah made a comment on nbme20/block2/q#12 (An 80-year-old man with type 2 diabetes mellitus is...)
 -1  upvote downvote
submitted by hayayah(54)

Pelvic splanchnic nerves are part of the parasympathetic system.


... hayayah made a comment on nbme20/block2/q#44 (A 43-year-old woman, gravida 2, para 1, at 10 weeks'...)
 +3  upvote downvote
submitted by hayayah(54)

Down Syndrome Labs:


... hayayah made a comment on nbme20/block2/q#44 (A 43-year-old woman, gravida 2, para 1, at 10 weeks'...)
 +0  upvote downvote
submitted by hayayah(54)

[revised]


... hayayah made a comment on nbme20/block2/q#19 (A 66-year-old man is brought to the emergency...)
 +1  upvote downvote
submitted by hayayah(54)

It's transitional cell carcinoma, which smoking is a common risk factor for; it can involve the renal pelvis/calyces. The histo image shows the papillary nature of the tumor (however it can also be flat or nodular according to Pathoma).

Also known as urothelial carcinoma. Most common tumor of urinary tract system (can occur in renal calyces, renal pelvis, ureters, and bladder). Can be suggested by painless hematuria (no casts).


... hayayah made a comment on nbme20/block2/q#13 (A 25-year-old woman comes to the physician because...)
 +1  upvote downvote
submitted by hayayah(54)

Diagnosis of Syph: Visualized by immunofluorescence or dark-field microscopy; serology is important – two types of antibodies:


... hayayah made a comment on nbme20/block2/q#17 (A 57-year old man has a hemoglobin concentration of...)
 +2  upvote downvote
submitted by hayayah(54)

This is reactive polycythemia vera, which is due to high altitude or lung disease. SaO2 is low, and EPO is increased.

Another way to approach the question is looking at the blood smear. It's pretty normal (no megakaryocytes, no increased number of platelets, no rods, nothing blue, etc). A blood smear from a COPD patient will be normal. Just an increased number of RBCs due to the increased EPO leading to increased Hgb.


... hayayah made a comment on nbme20/block2/q#30 (A 78-year-old man is brought to the emergency...)
 +0  upvote downvote
submitted by hayayah(54)

He's not eating enough.

One of cortisol's functions is to increase gluconeogenesis, lipolysis, and proteolysis.


... hayayah made a comment on nbme20/block2/q#25 (A 14-year-old girl is brought to the physician...)
 +1  upvote downvote
submitted by hayayah(54)

This is a presentation of mitochondrial myopathy. They often present with myopathy, lactic acidosis, and CNS disease. 2° to failure in oxidative phosphorylation. Muscle biopsy often shows “ragged red fibers”.

There is variable expression in a population or even within a family due to heteroplasmy in mitochondrial inheritance.


... hayayah made a comment on nbme20/block2/q#18 (A 65-year-old man is brought to the emergency...)
 +1  upvote downvote
submitted by hayayah(54)

This man is showing sxs of an MI.

Initial phase of myocardial infarction leads to subendocardial necrosis involving < 50% of the myocardial thickness (subendocardial infarction); EKG shows ST-segment depression.

Continued or severe ischemia (>20 minutes) leads to transmural necrosis involving most of the myocardial wall (transmural infarction); EKG shows ST-segment elevation.


... hayayah made a comment on nbme20/block2/q#37 (A 28-year-old woman of Eastern European Jewish...)
 +1  upvote downvote
submitted by hayayah(54)

Defective homologous recombination is seen in breast/ovarian cancers with the BRCA1 gene mutation.


... hayayah made a comment on nbme20/block3/q#18 (An 18-year-old woman comes to the physician to...)
 +0  upvote downvote
submitted by hayayah(54)

Familial adenomatous polyposis is an autosomal dominant mutation. Thousands of polyps arise starting after puberty; pancolonic; always involves rectum. Prophylactic colectomy or else 100% progress to CRC.

Autosomal dominant diseases have, on average, 50% chance of being passed down to offspring.


... hayayah made a comment on nbme20/block2/q#32 (A 12-year-old girl is brought to the physician by...)
 +1  upvote downvote
submitted by hayayah(54)

A big thing here too is noticing that the ALP is decreased. Osteoblast activity is measured by bone ALP. I think that was the main focus here and not that you necessarily need to know the CBFA1 gene mutation.


... hayayah made a comment on nbme20/block2/q#29 (A 25-year-old woman has a flu-like illness (fever,...)
 +0  upvote downvote
submitted by hayayah(54)

Most important cause of viral myocarditis is Coxsackie (picornavirus).


... hayayah made a comment on nbme20/block2/q#3 (An investigator compares the DNA sequences of a...)
 +0  upvote downvote
submitted by hayayah(54)

Most restriction enzymes bind palindromes.

So both 5'CCGG or 3'GGCC would have been acceptable in this scenario.


... hayayah made a comment on nbme20/block2/q#22 (A 44-year-old woman comes to the physician for a...)
 +1  upvote downvote
submitted by hayayah(54)

In eukaryotic cells, two major pathways—the ubiquitin-proteasome pathway and lysosomal proteolysis—mediate protein degradation.

The major pathway of selective protein degradation in eukaryotic cells uses ubiquitin as a marker that targets cytosolic and nuclear proteins for rapid proteolysis.

The other major pathway of protein degradation in eukaryotic cells involves the uptake of proteins by lysosomes and digestion by proteases.


... hayayah made a comment on nbme20/block2/q#34 (A 28-year-old man has excessive thirst and polyuria....)
 +0  upvote downvote
submitted by hayayah(54)

Pt has diabetes inspidus.

If urine concentrates with administration of ADH analog, the kidneys are responsive and the problem is with ADH production in the hypothalamus or release in the post. pituitary.


... hayayah made a comment on nbme20/block2/q#24 (A patient with a 1-week history of diarrhea has...)
 +0  upvote downvote
submitted by hayayah(54)

Patient has chronic diarrhea leading to metabolic acidosis. Respiratory compensation will lead to decreased CO2 (respiratory alkalosis via hyperventilation).


... hayayah made a comment on nbme20/block2/q#40 (A 70-year-old man has a 3-month history of weakness...)
 +1  upvote downvote
submitted by hayayah(54)

Squamous cell carcinoma characteristics: cavitation, hypercalcemia, associated with smoking.

Small cell may actually produce antibodies against presynaptic Ca channels.


... hayayah made a comment on nbme20/block2/q#45 (A new antiplatelet agent is developed for the...)
 +0  upvote downvote
submitted by hayayah(54)

Absolute risk: the difference in risk (not the proportion) attributable to the intervention as compared to a control.

(.12) - (.04) = .08

ARR = 8%


... hayayah made a comment on nbme20/block3/q#29 (An 83-year-old man is brought to the emergency...)
 +0  upvote downvote
submitted by hayayah(54)

Septic shock is a type of distributive shock which is marked by massive vasodilation (d/t inflammatory response) causing decreased SVR, decreased preload / PCWP, and increased CO.


... hayayah made a comment on nbme20/block3/q#2 (A 23-year-old woman is brought to the emergency...)
 +0  upvote downvote
submitted by hayayah(54)

Allopurinol inhibits xanthine oxidase. It is used for chronic gout as well as prevention of tumor-lysis associated urate nephropathy.


... hayayah made a comment on nbme20/block3/q#40 (Two days after admission to the hospital because of...)
 +0  upvote downvote
submitted by hayayah(54)

The only time you transfuse a Jehovah's Witness patient is when the patient is a minor (<18 years old).


... hayayah made a comment on nbme20/block3/q#20 (A 67-year-old woman comes to the physician for a...)
 +0  upvote downvote
submitted by hayayah(54)

Sensitivity tests are used for screening. Specificity tests are used for confirmation after positive screenings.

Sensitivity tests are used for seeing how many people truly have the disease. Specificity tests are for those who do not have the disease.

A highly sensitive test, when negative, rules OUT disease. A highly specific test, when positive, rules IN disease. So, a test with with low sensitivity cannot rule out a disease. A test with low specificity can't rule in disease.

The doctor and patient want to screen for colon cancer and rule it out. The doctor would want a test with high sensitivity to be able to do that. He knows that testing her stool for blood will not rule out the possibility of colon CA.


... hayayah made a comment on nbme20/block3/q#46 (Removal of the thymus at birth results in severely...)
 +0  upvote downvote
submitted by hayayah(54)

By age 75, the thymus is little more than fatty tissue. Fortunately, the thymus produces all of your T cells by the time you reach puberty. They are long-lived and that's why you can lose your thymus without impairment of your immune system.


... hayayah made a comment on nbme20/block3/q#22 (In patients with breast cancer, metabolically stable...)
 +0  upvote downvote
submitted by hayayah(54)

GnRH agonists like Leuprolide are effective for patients with breast CA because if given in a continuous fashion, they downregulate the GnRH receptor in the pituitary and ultimately decrease FSH and LH.


... vlodkadrinker made a comment on nbme21/block4/q#45 (During an experiment, an investigator observes that...)
 +0  upvote downvote
submitted by vlodkadrinker(1)

don't forget about the Mg block! . . . . . .


... vlodkadrinker made a comment on nbme21/block3/q#39 (A 74-year-old woman with mild dementia is admitted...)
 +0  upvote downvote
submitted by vlodkadrinker(1)

I obviously thought that the main thing for capacity is to understand the severity and prognosis of her medical condition BUT I thought this was a trick question because they asked "if the mental examination finding showed..." and the stem failed to mention anything about her orientation to place or time. dumb


... hayayah made a comment on nbme20/block3/q#37 (A 62-year-old man with alcohol-induced liver disease...)
 +0  upvote downvote
submitted by hayayah(54)

Clinical use of K-sparing diuretics:


... hayayah made a comment on nbme20/block3/q#15 (A 23-year-old woman, who was diagnosed with Sjögren...)
 +0  upvote downvote
submitted by hayayah(54)

Substance P (SP) is an undecapeptide present in the CNS and the peripheral nervous system. A compound thought to be involved in the synaptic transmission of pain and other nerve impulses.


... hayayah made a comment on nbme20/block3/q#28 (A 23-year-old woman who is 6 months pregnant...)
 +1  upvote downvote
submitted by hayayah(54)

Heparin-induced thrombocytopenia (HIT) is the development of IgG antibodies against heparin bound platelet factor 4 (PF4). Antibody-heparin-PF4 complex activates platelets Ž thrombosis and thrombocytopenia. Highest risk with unfractionated heparin.


... vlodkadrinker made a comment on nbme21/block2/q#31 (A 37-year-old man is brought to the emergency...)
 +0  upvote downvote
submitted by vlodkadrinker(1)

why? like does my med school suck or am I just that dumb cuz we never learned anything like this


... hayayah made a comment on nbme20/block3/q#44 (A 56-year-old man is brought to the emergency...)
 +2  upvote downvote
submitted by hayayah(54)

LV stopped working, pressure backed up into pulm circuit. Pulm circuit roughly is made of 3 "parts" - the capillaries, interstitial space, and the alveoli.

In cardiogenic shock, the extra blood increases capillary hydrostatic pressure, driving fluid into the interstitial space. Compared to the alveoli, the interstitial space now has more fluid (thus more interstitial hydrostatic pressure and less oncotic pressure due to ratio of fluid to protein), and as a result of this unbalancing of forces, fluid moves into the alveoli --> pulmonary edema.


... hayayah made a comment on nbme20/block3/q#8 (A 12-year-old girl is brought to the physician for a...)
 +0  upvote downvote
submitted by hayayah(54)

Atrophy is decrease in tissue mass due to decrease in size (increased cytoskeleton degradation via ubiquitin-proteasome pathway and autophagy;  decreased protein synthesis) and/or number of cells (apoptosis). Causes include disuse, denervation, loss of blood supply, loss of hormonal stimulation, poor nutrition.


... hayayah made a comment on nbme20/block3/q#25 (A 4-week-old infant is brought to the emergency...)
 +0  upvote downvote
submitted by hayayah(54)

Most common cause of gastric outlet obstruction in infants. Palpable olive-shaped mass in epigastric region, visible peristaltic waves, and nonbilious projectile vomiting at ∼2–6 weeks old.

Ultrasound shows thickened and lengthened pylorus. Treatment is surgical incision (pyloromyotomy).


... hayayah made a comment on nbme20/block3/q#39 (A 19-year-old woman has severe refractory pustular...)
 +1  upvote downvote
submitted by hayayah(54)

Isotretinoin is used to treat severe cystic acne. It is a teratogen. Can cause multiple severe birth defects. Contraception is mandatory. RXR is a retinoid X receptor.

IsoTERATinoin


... vlodkadrinker made a comment on nbme21/block4/q#29 (A 22-year-old man comes to the physician because of...)
 +1  upvote downvote
submitted by vlodkadrinker(1)

tinidazole preferred due to single dose


... hayayah made a comment on nbme20/block3/q#24 (A 2-month-old girl is brought to the emergency...)
 +0  upvote downvote
submitted by hayayah(54)

Patient has congenital hypothyroidism (cretinism). Findings: pot belly, pale, puffy-faced, umbilical hernia, macroglossia, hypotonia, poor brain development (MC cause of treatable mental retardation), large anterior fontanelles.


... hayayah made a comment on nbme20/block3/q#45 (A 39-year-old man reports bright red spots on the...)
 +0  upvote downvote
submitted by hayayah(54)

Large swollen rectal veins --> patient has external hemorrhoids. Swollen and inflamed veins in the rectum and anus that cause discomfort and bleeding. The most common cause of external hemorrhoids is repeated straining while having a bowel movement.


... hayayah made a comment on nbme20/block3/q#35 (A 51-year-old man has the acute onset of fever and...)
 +1  upvote downvote
submitted by hayayah(54)

CMV is associated with infecting organ transplant patients. CMV is transmitted via sexual contact, organ transplant, or vertically via placenta. Reactivation of CMV occurs in the immunosuppressed.

Organ transplant patients are at an increased risk of CMV pneumonia.


... hayayah made a comment on nbme20/block3/q#23 (A 50-year-old woman is brought to the emergency...)
 +1  upvote downvote
submitted by hayayah(54)

In order for a drug to be cleared by the kidney, it must first be filtered in the glomeruli. Drugs with a high VD have more of the drug in the tissue that are not available to filtered by the kidney. Drugs with high protein binding won't be filtered either. So you want a drug with low Vd and low binding if you want it cleared via the kidneys and urine.


... hayayah made a comment on nbme20/block3/q#13 (A 45-year-old woman develops proteinuria and...)
 +0  upvote downvote
submitted by hayayah(54)

Acute interstitial renal inflammation. Pyuria (classically eosinophils) and azotemia occurring after administration of drugs that act as haptens, inducing hypersensitivity (eg, diuretics, NSAIDs, penicillin derivatives, proton pump inhibitors, rifampin, quinolones, sulfonamides).


... hayayah made a comment on nbme20/block3/q#30 (A 22-year-old woman who recently emigrated from...)
 +0  upvote downvote
submitted by hayayah(54)

The right and left ventricle are drained by separate parts of the foramen of monro. (Left side is drained by left monro, right side by right monro). An obstruction of the right foramen of monro will enlarge the right ventricle.


... hayayah made a comment on nbme20/block3/q#27 (A 55-year-old man with type 2 diabetes mellitus,...)
 +0  upvote downvote
submitted by hayayah(54)

Statins can have a side effect of rhabdomyolysis.


... hayayah made a comment on nbme20/block3/q#3 (A 45-year-old woman has a thyroidectomy because of...)
 +0  upvote downvote
submitted by hayayah(54)

Patient has medullary carcinoma. Malignant proliferation of parafollicular "C" cells that produce calcitonin and have sheets of cells in an amyloid stroma.


... hayayah made a comment on nbme20/block3/q#34 (A 22-year-old woman comes to the emergency...)
 +2  upvote downvote
submitted by hayayah(54)

Administration of Penicillin for Syphilis may lead to the Jarisch-Herxheimer reaction hours after treatment. Occurs due to lysis of spirochetes (so it can occur with Borrelia and Leptospirosis as well). The reaction is characterized by fever and chills.

The classical explanation of the Herxheimer reaction is that treatment results in the sudden death and destruction of large numbers of treponemes, with the liberation of protein products and toxins.


... hayayah made a comment on nbme20/block1/q#9 (A 50-year-old man is brought to the physician by his...)
 +1  upvote downvote
submitted by hayayah(54)

Frontotemporal dementia (formerly known as Pick disease): Early changes in personality and behavior (behavioral variant), or aphasia (primary progressive aphasia). May have associated movement disorders (eg, parkinsonism).

While this presents very similiarly to Hungtington's, you can differentiate it because in this stem it says "atrophy of the frontal lobes bilaterally" whereas Huntington's has atrophy of caudate and putamen with ex vacuo ventriculomegaly.


... hayayah made a comment on nbme20/block1/q#23 (A 34-year-old man who is HIV positive is brought to...)
 +0  upvote downvote
submitted by hayayah(54)

Mycobacterium avium complex infections are a common opportunistic infection in patients with advanced AIDS (CD4 count <50).


... hayayah made a comment on nbme20/block1/q#46 (A 55-year-old woman comes to the physician for a...)
 +2  upvote downvote
submitted by hayayah(54)

Notice, the stem says "precorsors in the skin"

D3 (cholecalciferol) from exposure of skin (stratum basale) to sun, ingestion of fish, milk, plants.

D2 (ergocalciferol) from ingestion of plants, fungi, yeasts.

Both converted to 25-OH D3 (storage form) in liver and to the active form 1,25-(OH)2 D3 (calcitriol) in kidney.


... hayayah made a comment on nbme20/block1/q#1 (A 37-year-old nurse is accidentally stuck with a...)
 +1  upvote downvote
submitted by hayayah(54)

NRTI's are associated with possible side effects of anemia, granulocytopenia, and myelosuppression.


... hayayah made a comment on nbme20/block1/q#45 (A 2-year-old boy is brought to the physician because...)
 +1  upvote downvote
submitted by hayayah(54)

Fanconi's is a generalized reabsorption defect in PCT causing increased excretion of amino acids, glucose, HCO3–, and PO43–, and all substances reabsorbed by the PCT.


... hayayah made a comment on nbme20/block1/q#25 (A 25-year-old primigravid woman at 42 weeks’...)
 +0  upvote downvote
submitted by hayayah(54)

Oxytocin uses IP3 signaling pathway.

GnRH, Oxytocin, ADH (V1-receptor), TRH, Histamine (H1-receptor), Angiotensin II, Gastrin.

FA mnemonic: "GOAT HAG"


... hayayah made a comment on nbme20/block1/q#30 (A 33-year-old woman comes to the emergency...)
 +0  upvote downvote
submitted by hayayah(54)

Capitate and lunate are in the center of the palm. Capitate is not an option, so lunate is the answer.

Dislocation of lunate may cause acute carpal tunnel syndrome.


... hayayah made a comment on nbme20/block1/q#18 (A 36-year-old man comes to the physician because he...)
 +1  upvote downvote
submitted by hayayah(54)

The tubes are catheters put in for urine to flow into a bag. So urine output is going to increase. The patient is also hyperkalemic. Aldosterone responds to hyperkalemia by increasing K+ excretion.

Hyperkalemia will stimulate aldosterone secretion even if renin is suppressed due to his hypertension. Although Na+ will be reabsorbed, this will be transient (should resolve once the potassium levels normalized) and since his urine output will most likely return to normal, his blood pressure should also normalize.


... hayayah made a comment on nbme20/block1/q#49 (A 56-year-old man comes to the physician because of...)
 +1  upvote downvote
submitted by hayayah(54)

Case of arteriolosclerosis.

Hyperplastic arteriolosclerosis involves thickening of vessel wall by hyperplasia of smooth muscle ('onion-skin appearance')


... hayayah made a comment on nbme20/block1/q#13 (A 6-week-old girl is brought to the physician by her...)
 +1  upvote downvote
submitted by hayayah(54)

No abnormalities, only some vomiting, looks well w/ no failure to thrive. Most likely immature LES.


... hayayah made a comment on nbme20/block1/q#50 (A 26-year-old man undergoes an abdominal exploratory...)
 +0  upvote downvote
submitted by hayayah(54)

Short gastric a. branch from the splenic a.

Branches of the celiac trunk that constitute the blood supply to the stomach: common hepatic, splenic, and left gastric.


... hayayah made a comment on nbme20/block1/q#37 (A 1-month-old male newborn is brought to the...)
 +1  upvote downvote
submitted by hayayah(54)

With chronic vomiting, you lose electrolytes and a lot of acid. It triggers metabolic alkalosis which is why all the serum values are low (or on the lower end of the normal range) except for bicarbonate.


... hayayah made a comment on nbme20/block1/q#8 (A 10-year-old girl is brought to the physician by...)
 +1  upvote downvote
submitted by hayayah(54)

Earliest detectable secondary sexual characteristic is breast bud development in girls, testicular enlargement in boys.


... hayayah made a comment on nbme20/block1/q#28 (A previously healthy 16-year-old girl comes to the...)
 +0  upvote downvote
submitted by hayayah(54)

Trichomonas:

Clinical findings: thin, yellow-green, malodorous, frothy discharge and vaginal inflammation / itching.

Lab findings: pH >4.5 and motile trichomonads.


... hayayah made a comment on nbme20/block1/q#4 (A 50-year-old man is brought to the emergency...)
 +1  upvote downvote
submitted by hayayah(54)

Methanol is toxic by two mechanisms:

First, methanol can be fatal due to its CNS depressant properties in the same manner as ethanol poisoning.

Second, in a process of toxication, it is metabolized to formic acid via formaldehyde in a process initiated by the enzyme alcohol dehydrogenase in the liver. Methanol is converted to formaldehyde via alcohol dehydrogenase (ADH) and formaldehyde is converted to formic acid (formate) via aldehyde dehydrogenase (ALDH).

Formate is toxic because it inhibits mitochondrial cytochrome c oxidase, causing hypoxia at the cellular level, and metabolic acidosis, among a variety of other metabolic disturbances.


... hayayah made a comment on nbme20/block1/q#38 (A 9-year-old girl is brought to the physician...)
 +0  upvote downvote
submitted by hayayah(54)

Patient has a craniopharyngioma. Most common childhood supratentorial tumor. Derived from remnants of Rathke pouch (oral ectoderm). Calcification is common. Cholesterol crystals found in “motor oil”-like fluid within tumor.

A cystic suprasellar mass with calcifications and enhancement of the wall or solid portions in a child or adolescent is almost always a craniopharyngioma.

May be confused with pituitary adenoma (both cause bitemporal hemianopia).


... hayayah made a comment on nbme20/block1/q#7 (A 5-year-old girl with AIDS develops a progressive...)
 +2  upvote downvote
submitted by hayayah(54)

Acyclovir, famciclovir, valacyclovir are guanosine analogs. They undergo conversion to acyclovir monophosphate via virus encoded thymidine-kinase. Ultimately, they inhibit viral DNA polymerase by chain termination.

Mutated viral thymidine kinase can cause resistance.


... hayayah made a comment on nbme20/block1/q#39 (A 3-month-old boy is brought to the office by his...)
 +1  upvote downvote
submitted by hayayah(54)

Inguinal hernias are usually reducible, femoral hernias are not.

This is an indirect inguinal hernia. It enters internal inguinal ring lateral to inferior epigastric vessels and is superior to the inguinal ligament.

Caused by failure of processus vaginalis to close (can form hydrocele). May be noticed in infants or discovered in adulthood. Much more common in males.


... hayayah made a comment on nbme20/block1/q#34 (A strain of Escherichia coli produces a...)
 +1  upvote downvote
submitted by hayayah(54)

Missense mutations involve a nucleotide substitution resulting in changed amino acids. Sometimes the effects of missense mutations may be only apparent under certain environmental conditions; such missense mutations are called conditional mutations. Many missense mutations result in proteins that are still functional, at least to some degree.

Also, all the other answers would probably leave you with either a greatly altered or non-functional protein.


... hayayah made a comment on nbme20/block1/q#35 (A 70-year-old man dies of coronary artery disease....)
 +0  upvote downvote
submitted by hayayah(54)

The damage is in the L midbrain in the area affecting the corticospinal tract. Because it is in the midbrain, decussation in the pyramids (medulla) so it will show ipsilateral dysfunctional motor signs.

Photo of midbrain and important areas: shorturl.at/myHLR


... hayayah made a comment on nbme20/block1/q#10 (A 77-year-old woman has been having difficulty...)
 +0  upvote downvote
submitted by hayayah(54)

Little finger = ulnar nerve.

C8-T1 are the roots of the ulnar nerve, which is a branch of the medial cord. The ulnar nerve is not found in the carpal tunnel (the medial nerve is).

Ulnar n. damage can lead to loss of wrist flexion and adduction, flexion of medial fingers, abduction and adduction of fingers (interossei), actions of medial 2 lumbrical muscles. Loss of sensation over medial 1 1/2 fingers, including hypothenar eminence.


... hayayah made a comment on nbme20/block1/q#40 (Monoclonality of neoplastic cells in endometrial...)
 +0  upvote downvote
submitted by hayayah(54)

Neoplasia is new tissue growth that is unregulated, irreversible, and monoclonal.

Clonality can be determined by glucose-6-phosphate dehydrogenase (G6PD) enzyme isoforms. G6PD is X-linked.

*For more information check out Ch. 3 Neoplasia in Pathoma


... hayayah made a comment on nbme20/block1/q#12 (72 yo woman with dysphagia)
 +0  upvote downvote
submitted by hayayah(54)

The left upper extremity and breast are drained by the axillary lymph node. The kidney is drained by the thoracic duct. The heart has its own lymph system going on surrounding the heart.


... hayayah made a comment on nbme20/block1/q#14 (A 28-year-old man who is a migrant worker comes to...)
 +0  upvote downvote
submitted by hayayah(54)

Of all the options, psoas major is the only one that is really associated with the lumbar vertebrae.

Q. Lumborum involves the transverse process of L1 but Psoas Major originates from L1-L5


... hayayah made a comment on nbme20/block1/q#15 (A 30-year-old man who completed a successful course...)
 +0  upvote downvote
submitted by hayayah(54)

Definition of adjustment disorder:

Emotional symptoms (eg, anxiety, depression) that occur within 3 months of an identifiable psychosocial stressor (eg, divorce, illness) lasting < 6 months once the stressor has ended.

If symptoms persist > 6 months after stressor ends, it is GAD.


... hayayah made a comment on nbme20/block1/q#47 (A 60-year-old woman with type 2 diabetes mellitus is...)
 +1  upvote downvote
submitted by hayayah(54)

The two most important MI complications that occur within a 2-5 day span are papillary muscle rupture and interventricular septum ruture.

Papillary muscle rupture leads to severe mitral regurgitation, heard as a systolic murmur at the apex.


... hayayah made a comment on nbme20/block1/q#20 (An 8-year-old boy is evaluated for ventricular...)
 +0  upvote downvote
submitted by hayayah(54)

Coarctation of the aorta leads to increased LV overload causing LV hypertrophy and a L axis deviation.


... hayayah made a comment on nbme20/block1/q#19 (A 60-year-old man comes to the physician because of...)
 +1  upvote downvote
submitted by hayayah(54)

This patient has small cell carcinoma. This type of cancer is associated with paraneoplastic syndromes such as: Cushing Syndrome, SIADH, or antibodies against Ca2+ channels (Lambert-Eaton) or neurons. Amplification of myc oncogenes is also common.

SIADH (Syndrome of inappropriate antidiuretic hormone secretion) is characterized by:

Body responds to water retention with aldosterone and ANP and BNP. That is what causes the increased urinary Na+ secretion Žwhich leads to normalization of extracellular fluid volume Žand the euvolemic hyponatremia.


... hayayah made a comment on nbme20/block1/q#36 (A 56-year-old man is admitted to the hospital after...)
 +0  upvote downvote
submitted by hayayah(54)

Rhabdomyolysis can present looking like a kidney injury (it can lead to acute tubular necrosis as well). The electrolyte findings are just like renal failure (Inc. K+, inc. PO4-, dec. Ca)

To differentiate between rhabdomyolysis and kidney injury, you check the urine to see if there are any RBCs. In rhabdomyolysis there are no free RBCs in the urine.


... hayayah made a comment on nbme20/block1/q#2 (A mother who has toxoplasmosis gives birth to an...)
 +1  upvote downvote
submitted by hayayah(54)

The baby does not get any maternal IgM, IgA or IgE as they do not cross the placenta, so if IgM is found it may suggest the baby has encountered an infection in utero.

IgG is passed down to the baby as a means of passive immunity until the baby can form their own antibodies of different types. So if you see anything other than IgG (e.g. IgM) you know it must be d/t an infection.


... hayayah made a comment on nbme20/block1/q#24 (A 50-year-old man comes to the physician because of...)
 +1  upvote downvote
submitted by hayayah(54)

Add on to the other comment: SICKFACES.COM (when I Am drinking Grapefruit juice) is the mnemonic for remembering the CYP450 Inhibitors:


... hayayah made a comment on nbme20/block1/q#6 (A 16-year-old student has uncontrollable sleepiness,...)
 +2  upvote downvote
submitted by hayayah(54)

In narcolepsy, there is a direct transition from wakefulness to REM sleep. Basically instead of going through the early stages and gradually falling into a deep sleep, you just suddenly go from being awake to being in a deep sleep.


... hayayah made a comment on nbme20/block1/q#41 (A 45-year-old man has fever, chills, dysuria, and a...)
 +1  upvote downvote
submitted by hayayah(54)

Prostatitis is characterized by dysuria, frequency, urgency, low back pain. Warm, tender, enlarged prostate.

Acute bacterial prostatitis—in older men most common bacterium is E. coli.


... hayayah made a comment on nbme20/block1/q#5 (A 24-year-old African American man comes to the...)
 +0  upvote downvote
submitted by hayayah(54)

Foreign body inflammatory facial skin disorder characterized by firm, hyper-pigmented papules and pustules that are painful and pruritic. Located on cheeks, jawline, and neck.

Commonly occurs as a result of shaving (“razor bumps”), primarily affects African-American males.

Images: shorturl.at/fpwY1


... hayayah made a comment on nbme20/block1/q#42 (A 60-year-old man has two-pillow orthopnea, severe...)
 +0  upvote downvote
submitted by hayayah(54)

This patient has heart failure. Normal JVP is 6-8 mmHg.

Signs of heart failure are based on cardiac pump dysfunction, Žcongestion, and low perfusion.

Symptoms: include dyspnea, orthopnea, fatigue; signs include S3 heart sound, rales, jugular venous distention (JVD), and pitting edema.


... hayayah made a comment on nbme20/block1/q#21 (A 75-year-old woman comes to the physician because...)
 +0  upvote downvote
submitted by hayayah(54)

This is an example of Shingles. Herpes simplex and herpes zoster viruses cause abnormal cell division in epidermal cells, and this creates multinucleated giant cells.

A Tzank smear showing multinucleated giant cells is characteristic of Varicella Zoster Virus infections. (HSV will have similar findings).


... halux made a comment on nbme21/block1/q#42 (A 36-year-old woman undergoes a total hysterectomy...)
 +0  upvote downvote
submitted by halux(1)

[moved to subcomment]


... beeip made a comment on nbme21/block1/q#42 (A 36-year-old woman undergoes a total hysterectomy...)
 +1  upvote downvote
submitted by beeip(7)

[moved to subcomment]


... halux made a comment on nbme21/block1/q#42 (A 36-year-old woman undergoes a total hysterectomy...)
 +1  upvote downvote
submitted by halux(1)

can some one please explain why is the hyperplasia?


... est88 made a comment on nbme21/block1/q#20 (A 10-year-old girl develops fever, malaise, and loss...)
 +1  upvote downvote
submitted by est88(4)

Rabies Virus (rhabdoviridae)

Fever, encephalitis, drooling


... est88 made a comment on nbme21/block1/q#23 (A 59-year-old man comes to the physician because of...)
 +1  upvote downvote
submitted by est88(4)

I believe its Squamous cell carcinoma. Its centrally located, smoker, and its a hilar mass. Keratin pearls.


... est88 made a comment on nbme21/block1/q#45 (An 18-year-old man comes to the physician because of...)
 +1  upvote downvote
submitted by est88(4)

Pyruvate Kinase defect leads to decreased ATP leading to rigid RBCs and extra vascular hydrolysis. Increased levels of 2,3-BPG decreases hemoglobin affinity for O2.


... est88 made a comment on nbme21/block3/q#26 (A 19-year-old woman comes to the office because of a...)
 +1  upvote downvote
submitted by est88(4)

Retroperitoneal structures: SAD PUCKER.

Only the descending colon is part of this.


... hayayah made a comment on nbme20/block1/q#44 (A 35-year-old woman with newly diagnosed...)
 +1  upvote downvote
submitted by hayayah(54)

Renovascular disease is the most common cause of 2° HTN in adults. Can be d/t ischemia from renal stenosis or microvascular disease. Can hear renal bruits lateral to umbilicus.

Main causes of renal artery stenosis:

Lab values based off:

  1. Stenosis decreases blood flow to glomerulus.
  2. Juxtaglomerular apparatus (JGA) responds by secreting renin, which converts angiotensinogen to angiotensin I.
  3. Angiotensin I is converted to angiotensin II (ATII) by angiotensin converting enzyme (ACE --in lungs)
  4. ATII raises blood pressure by (1) contracting arteriolar smooth muscle, increasing total peripheral resistance and (2) promoting adrenal release of aldosterone, which increases reabsorption of sodium (where Na+ goes H2O will follow) in the distal convoluted tubule (expanding plasma volume). Can lead to hypokalemia (seen in the labs for this question)
  5. Leads to HTN with increased plasma renin and unilateral atrophy (due to low blood flow) of the affected kidney; neither feature is seen in primary hypertension

... thechurchofbobbyhill made a comment on nbme21/block1/q#23 (A 59-year-old man comes to the physician because of...)
 +0  upvote downvote
submitted by thechurchofbobbyhill(0)

Hi- I don't have an explanation for this but I am also curious as to why this was the answer.


... louisville made a comment on nbme20/block3/q#36 (A 4-year-old boy has had fever, abdominal cramping,...)
 +1  upvote downvote
submitted by louisville(1)

Methylene-blue stained fecal smear reveled numerous neutrophils (but not any organisms). Shigella is colorless when stained with methylene blue; E coli stains blue with methylene blue because it ferments lactose.


... mrmassador made a comment on nbme20/block2/q#25 (A 14-year-old girl is brought to the physician...)
 +1  upvote downvote
submitted by mrmassador(1)

I think the point of the question is to recognize that this is a mitochondrial disease (mother and maternal grandmother were affected). Produces wide range of effects, but muscle weakness and some neurologic deficits stood out to me. Also this: https://ghr.nlm.nih.gov/gene/MT-TL1#conditions


... step420 made a comment on nbme20/block2/q#43 (An 18-year-old woman comes to the physician because...)
 +1  upvote downvote
submitted by step420(1)

This is mullerian agenesis. Normal ovaries but absent uterus.


... step420 made a comment on nbme20/block3/q#41 (A 2-year-old child undergoes resection of the right...)
 +0  upvote downvote
submitted by step420(1)

Other kidney Hypertrophies due to increased stress --> not hyperplasia bc not cancerous


... step420 made a comment on nbme20/block4/q#8 (A 58-year-old man is brought to the emergency...)
 +0  upvote downvote
submitted by step420(1)

Hypertension can lead to aneurysms like in this patient. Not syphilis because not thoracic aorta.


... step420 made a comment on nbme20/block4/q#1 (A 32-year-old man comes to the physician because of...)
 +0  upvote downvote
submitted by step420(1)

B-HCG and LH,FSH,TSH share same alpha subunit, so HCG can activate those receptors if its in high enough quantity. Activating LH receptor will lead to more Testosterone from the Leydig cells. More testosterone can lead to more estrogen formation via aromatase.


... drdoom made a comment on nbme21/block3/q#21 (A screening program is instituted for detection of...)
 +0  upvote downvote
submitted by drdoom(15)

Also consider this great description from the NIH’s MeSH database:

INCIDENCE: The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from PREVALENCE, which refers to all cases, new or old, in the population at a given time.

https://meshb.nlm.nih.gov/record/ui?ui=D015994


... drdoom made a comment on nbme21/block3/q#21 (A screening program is instituted for detection of...)
 +2  upvote downvote
submitted by drdoom(15)

Don’t forget that incidence is the number of new cases which emerge in an unaffected population. Incidence is trying to get at the question -> “In a given year, how many new people develop this disease?”

In other words, you cannot count people who already have the disease. You have to exclude those people from your calculation. You want to know, among all the people out there who DO NOT have the disease, how many times this year was someone (newly) diagnosed?

Said differently still, you don’t want to “double-count” people who developed the disease before your study. As an epidemiologist, that would screw up your sense of how infective or transmissible a disease is. You want to know, “from time1 to time2 how many new cases emerged?”


... drdoom made a comment on nbme21/block3/q#21 (A screening program is instituted for detection of...)
 +2  upvote downvote
submitted by drdoom(15)

2,500 students ... but you find out during your initial screen that 500 already have the disease. So, strikeout those people. That leaves 2,000 students who don’t have the disease.

Over the course of 1 year, you discover 200 students developed the infection. Thus:

200 new cases / 2,000 people who didn’t have the disease when you started your study = 10 percent

Tricky, tricky NBME ...


... drdoom made a comment on nbme21/block3/q#49 (The gene that codes for a protein normally found in...)
 +2  upvote downvote
submitted by drdoom(15)

The synthesis of virtually all proteins (mRNA->peptide) occurs in the cytoplasm.[1] That’s where all ribosomes reside, after all. Ribosomes, which are mostly just rRNA (~2/3 rRNA + 1/3 protein*, by weight), are assembled in the nucleus but only do their stuff once they get to the cytoplasm.

For a protein to leave its original hometown of the cytosol and become a resident of the nucleus or, sayyyyyy, the endoplasmic reticulum, it needs to have a little string of amino acids which shout “I belong in the nucleus!” or “I belong in the endoplasmic reticulum!”

Proteins ultimately destined for the ER contain an unimaginatively named string of amino acids known as “signal sequence,” which, for the purposes of the Step 1, is always at the N-terminus. The signal sequence tells other cytosolic proteins, “Hey! Take me (and the rest of the peptide of which I am part) to the ER!”

In the absence of this signal, a protein will remain in its “default” home of the cytosol.

Here’s a nice schematic showing the flow of proteins from initial synthesis to final destinations:


Endnotes

  1. “The synthesis of virtually all proteins in the cell begins on ribosomes in the cytosol.” (Essential Cell Biology, Alberts et al., 2014, p. 492)

*If you really want your mind blown, consider that even the protein subunits that make up that 1/3 of a ribosome are themselves initially synthesized in the cytosol; later, they are transported back into the nucleus via the nuclear pore.


... jejunumjedi made a comment on nbme21/block3/q#49 (The gene that codes for a protein normally found in...)
 +0  upvote downvote
submitted by jejunumjedi(0)

I think this is describing a signal peptide (hydrophobic at N-terminus). Without signal peptide => can’t be transported into endoplasmic reticulum.


... _pusheen_ made a comment on nbme21/block2/q#8 (A 55-year-old man is diagnosed with renal artery...)
 +0  upvote downvote
submitted by _pusheen_(0)

I think this one is literally just asking what part of the kidney will be the most poorly perfused. That part would have the most renin. Also, the medulla doesn’t have JG cells so I guess that’s another reason why it couldn’t have the most renin.


... cellgamesgojan made a comment on nbme21/block4/q#5 (An 11-year-old boy has had persistent pain in his...)
 +0  upvote downvote
submitted by cellgamesgojan(3)

Jambo is right. I was reading through Goljan Rapid Review and he states that the lungs are the most common site of metastasis for osteosarcoma.


... jambo2222 made a comment on nbme21/block4/q#5 (An 11-year-old boy has had persistent pain in his...)
 +1  upvote downvote
submitted by jambo2222(1)

It’s an osteosarcoma. Sarcoma = hematogenous mets. It’s in the legs so think how a DVT goes to lung. Same idea.


... vonhippelindau made a comment on nbme21/block2/q#12 (A 66-year-old woman comes to the physician because...)
 +0  upvote downvote
submitted by vonhippelindau(0)

I picked Crohn’s too. I think the severe constipation over 5 years distracted me.


... logical_champion made a comment on nbme21/block2/q#12 (A 66-year-old woman comes to the physician because...)
 +0  upvote downvote
submitted by logical_champion(0)

I think it is good to note the demographics. The patient is female and old. That, along with the constipation, made me lean more towards diverticulitis. IBD usually develops in younger persons.


... lnsetick made a comment on nbme21/block2/q#3 (A 17-year-old boy returns to the locker room after...)
 +1  upvote downvote
submitted by lnsetick(1)

... krazyglue5 made a comment on nbme21/block4/q#14 (A 25-year-old woman has a 3-week history of bleeding...)
 +1  upvote downvote
submitted by krazyglue5(1)

She has ITP/immune thrombocytopenia, so she has autoantibodies against her platelets, specifically GPIIb/IIIa. She has the large megakaryocytes because her bone marrow is trying to churn out platelets. She’s a woman of child-bearing age with increased bleeding time but no other neurologic abnormalities/renal issues/fever, so think ITP.


... cellgamesgojan made a comment on nbme21/block4/q#14 (A 25-year-old woman has a 3-week history of bleeding...)
 +1  upvote downvote
submitted by cellgamesgojan(3)

The patient suffered from Immune Thrombocytopenia. autoantibodies against the glycoproteins GP2B/3A.

On labs, you’ll see: increase in megakaryocytes; on the question stem they’re described as “rare but large.” Megakaryocytes are not suppressed.


... cellgamesgojan made a comment on nbme21/block3/q#28 (A 1-year-old girl is admitted to the hospital...)
 +1  upvote downvote
submitted by cellgamesgojan(3)

I figured, glycine-X-Y is technically considered a “primary amino acid structure of a protein” since the definition of a Primary structure of a protein is “a linear chain of amino acids.” If you mess with the Primary structure, as in the question stem, you cannot form the Secondary structure of the protein, which is determined by the hydrogen-bonding which occurs between the peptide backbone, independent of the R groups. I hope this made sense.

From wikipedia: “Secondary structure is formally defined by the pattern of hydrogen bonds between the amino hydrogen and carboxyl oxygen atoms in the peptide backbone.” (emphasis mine)


... drdoom made a comment on nbme21/block3/q#28 (A 1-year-old girl is admitted to the hospital...)
 +0  upvote downvote
submitted by drdoom(15)

Here’s one way to process-of-eliminate “decreased hydrogen-bond formation”: I’m not a big fan of this line of reasoning, but technically alanine as a side group has more hydrogens* for potential hydrogen bonding than glycine:

alanine: —CH3
glycine: —H

So, “technically,” alanine would permit more hydrogen-bond formation, which might allow you to eliminate that choice.

That said, it seems almost impossible to rule out (without very technical knowledge or some provided experimental data) that the slightly larger alanine does not impair hydrogen bonding between collagen molecules via steric (spatial) interference. In simpler terms, since alanine is larger, you would think that it must somehow interfere with the hydrogen-bonding that occurs with the wild-type glycine.

---
*Strictly speaking, it’s not the number of hydrogens but also the strength of the dipole that facilitates hydrogen bonding: a hydrogen bound to a strongly electronegative molecule like fluorine will “appear” more positive and, thus, hydrogen-bond more strongly with a nearby oxygen (compared with a hydrogen connected to carbon, for example).

Further reading:

  1. https://www.chem.purdue.edu/gchelp/liquids/hbond.html

... wasabilateral made a comment on nbme21/block3/q#28 (A 1-year-old girl is admitted to the hospital...)
 +0  upvote downvote
submitted by wasabilateral(0)

I think it has something to do with glycine (due to its small size it can fit in many places where other amino acids can not and hence it provides “structural compactness” to the collagen, i.e. put a kink in the alpha helix). If glycine is misplaced by something else, I don’t think pro-collagen can form its correct secondary structure.


... nuts4med made a comment on nbme21/block2/q#12 (A 66-year-old woman comes to the physician because...)
 +0  upvote downvote
submitted by nuts4med(0)

I was thinking Chron’s because of the narrowing of the lumen and the picture seemed like there was creeping fat. Now that I think about it though, the LLQ and constipation should have led towards diverticulitis pretty quickly.


... beeip made a comment on nbme21/block3/q#4 (A clinical trial is conducted to compare the...)
 +0  upvote downvote
submitted by beeip(7)

I might be the only person on earth who got this one wrong, but regardless:

"ITT analysis includes every subject who is randomized according to randomized treatment assignment. It ignores noncompliance, protocol deviations, withdrawal, and anything that happens after randomization."[1]


... porky_pork_chop made a comment on nbme21/block3/q#28 (A 1-year-old girl is admitted to the hospital...)
 +0  upvote downvote
submitted by porky_pork_chop(0)

Why would it be a disruption of the secondary structure of collagen molecules? I thought to form the tropocollagen triple helix hydrogen bonds are needed; and FA says failure of formation of the triple helix results in Osteogenesis Imperfecta.


... 5thgencephalosporin made a comment on nbme21/block2/q#39 (A 64-year-old man with bronchospastic pulmonary...)
 +0  upvote downvote
submitted by 5thgencephalosporin(0)

“The combination of a long-acting beta 2 agonist (LABA) and an inhaled corticosteroid is more efficacious in asthma and [COPD] than [...] either alone. Corticosteroids may regulate beta 2 receptor function by increasing expression of the receptor, restoring G-protein/beta 2 receptor coupling, and inhibiting beta 2 receptor downregulation.”

https://www.ncbi.nlm.nih.gov/pubmed/16113435


... drdoom made a comment on nbme21/block4/q#23 (An investigator is studying the regulation of...)
 +1  upvote downvote
submitted by drdoom(15)

Vasoconstriction (narrowing of a tube) will cause the flow rate to increase through that tube, which decreases radial/outward pressure. The faster a fluid moves through a tube, the less “outward” force it exerts. (This is known as the Venturi effect.)


... assoplasty made a comment on nbme21/block4/q#23 (An investigator is studying the regulation of...)
 +0  upvote downvote
submitted by assoplasty(3)

Vasoconstriction decreases blood flow and thus decreases hydrostatic pressure. Seems counter intuitive but I had to look this up after I got it wrong, too.


... wasabilateral made a comment on nbme21/block2/q#39 (A 64-year-old man with bronchospastic pulmonary...)
 +0  upvote downvote
submitted by wasabilateral(0)

This is what I thought but not sure if it’s correct. There is a UWorld q where it describes co-administration of cortisol and epinephrine. Cortisol significantly enhances the effect of epi because cortisol has a permissive effect on maintaining the adrenergic receptors.


... porky_pork_chop made a comment on nbme21/block2/q#12 (A 66-year-old woman comes to the physician because...)
 +0  upvote downvote
submitted by porky_pork_chop(0)

My reasoning was that it’d be diverticulitis due to the more acute history of presentation: “fever, chills, LLQ pain for 1 day.” Crohn’s should have a longer timeline of presentation; although the skip lesions made this one really tricky. Not sure how the gross pathology photograph plays in though ...


... calcium196 made a comment on nbme21/block4/q#4 (The FOXO transcription factor responds to insulin...)
 +2  upvote downvote
submitted by calcium196(2)

Ubiquitin-mediated proteolysis is not reversibly affected by insulin. The question asks for reversible ways that insulin affects it, and ubiquitination would lead to degradation via proteases, which is not reversible. Nuclear/cytoplasmic shunting makes sense because FOXO is a transcription factor, so it can’t do its job if it is in the cytoplasm!


... cytocoins made a comment on nbme21/block3/q#7 (A 65-year-old man comes to the physician because of...)
 +0  upvote downvote
submitted by cytocoins(0)

With the drop in testosterone (and therefore DHT), some of the prostate cells will undergo apoptosis. Apoptosis = DNA fragmentation (180 bp segments).


... _pusheen_ made a comment on nbme21/block3/q#7 (A 65-year-old man comes to the physician because of...)
 +0  upvote downvote
submitted by _pusheen_(0)

Alternatively, all the other options pointed to things that would actually increase testosterone production and its effects; orchiectomy would obviously not do that.


... feronie made a comment on nbme21/block3/q#7 (A 65-year-old man comes to the physician because of...)
 +1  upvote downvote
submitted by feronie(1)

Orchiectomy = ↓ testosterone production = ↓ DHT => prostate cells undergo apoptosis. (This mechanism is similar to using 5α-reductase blockers to treat BPH.)

Apoptosis is characterized by DNA fragmentation (pyknosis, karyorrhexis, karyolysis).


... liltr made a comment on nbme21/block3/q#16 (A 16-year-old boy is brought to the physician...)
 +0  upvote downvote
submitted by liltr(0)

I choose MVP too, but this patient’s main symptom is cough only during exercise. This is more indicative of exercised associated asthma. You could see shortness of breath in MVP during exercise, but choosing MVP leaves the cough unaccounted for.


... lnsetick made a comment on nbme21/block3/q#16 (A 16-year-old boy is brought to the physician...)
 +0  upvote downvote
submitted by lnsetick(1)

I just remember Sattar saying MVP tends to be asymptomatic. Also, I think the kid complained specifically of coughing, and that made me really lean away from MVP.


... lnsetick made a comment on nbme21/block2/q#24 (A 65-year-old man dies in a motor vehicle collision....)
 +0  upvote downvote
submitted by lnsetick(1)

I don’t think it was cavitary; I think that was just the bronchus. I think abscesses tend to be smaller, and wouldn’t affect the surrounding parenchyma much. I wasn’t super confident in picking squamous cell carcinoma, but I did know that squamous cell carcinoma tends to be a centrally-located lung tumor.


... mattfoley_govtcheese made a comment on nbme21/block2/q#24 (A 65-year-old man dies in a motor vehicle collision....)
 +0  upvote downvote
submitted by mattfoley_govtcheese(1)

My choice for Squamous Cell Carcinoma was guided by the central location of the tumor. To me, that didn’t look like the cavity you’d get with abscess but a huge tumor.


... mattfoley_govtcheese made a comment on nbme21/block2/q#20 (A 14-year-old girl is brought to the physician by...)
 +1  upvote downvote
submitted by mattfoley_govtcheese(1)

The clues for trichotillomania were the death of her grandmother suddenly, since trichotillomania is often stress-induced. I also narrowed it down by it saying the hair was in different growth stages in the patchy areas, which makes sense if she’s plucking them out at different times.

Telogen effluvium is most common in middle-aged women, so she doesn’t fit the profile (but you’re right about it being caused by stress).


... wasabilateral made a comment on nbme21/block4/q#2 (A 23-year-old woman comes to the student health...)
 +0  upvote downvote
submitted by wasabilateral(0)

Syphilis pathogenesis is the inflammation and obliteration of the vasa vasorum (small blood vessels) that feeds bigger blood vessels like aorta, arteries, arterioles. It does not matter what the stage is, T. pallidum infects the vasa vasorum and, in the process, obliterates the nerves and blood vessels. This kills blood supply to those areas = ischemia but no pain (painless chancre). More localized in earlier stages, and in later stage, the spirochetes disseminate, so you have the aorta and spinal cord involvement but same pathogenesis. (Edit: Goljan explained this somewhere.)


... liltr made a comment on nbme21/block4/q#2 (A 23-year-old woman comes to the student health...)
 +0  upvote downvote
submitted by liltr(0)

It is syphilis. Syphilis is an endarteritis! :)

“The pathologic changes associated with syphilis are characterized by obliterative endarteritis that is found in all stages of the disease.”
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2811633/


... flashvoyger made a comment on nbme21/block4/q#25 (An 80-year-old woman cannot concentrate her urine...)
 +3  upvote downvote
submitted by flashvoyger(3)

The question is asking you how much water must the woman take in to maintain the same osmolality. This woman takes in 450 mOsm of solute per day. This is a unit of measurement -- think of it like grams.

For her to keep the same osmolality she must excrete 450 mOsm per day. The only way for her to excrete the solute is via the kidneys. The only way for her kidneys to excrete 450 mOsm is if they excrete 1 liter of water also. This is the max concentration that her kidneys can produce. (Her kidneys are not “powerful enough” to make her urine any more concentrated than that.)

This woman is also losing another liter of water to feces, sweating and respiration. This is the “insensible water loss”. That means if she losing 1 liter of water to sweat, respiration and feces per day plus 1 liter of water to urine (because she needs to dissolve her solute in something!), for her blood to stay the same osmolality, she must replace the water she lost thus must, at minimum, drink 2 liters of water per day.


... cantaloupe5 made a comment on nbme21/block4/q#25 (An 80-year-old woman cannot concentrate her urine...)
 +3  upvote downvote
submitted by cantaloupe5(5)

She’s intaking 450 mOsm per day so she needs to excrete 450 mOsm per day to maintain equilibrium. You can’t just excrete mOsm’s by themselves -- they have to be dissolved in some amount of water.

Let’s say you excrete 450 mOsm with 500 mL of water -- that means your kidneys are concentrating urine to:

450 mOsm ÷ 500 mL = 900 mOsm/L

But the maximum this lady’s kidneys can concentrate urine to is 450 mOsm/L, so she has to excrete more water to get it that dilute. That amount of water is 1 L, because 450 mOsm/1 L = 450 mOsm/L.

Now there’s nothing stopping her from excreting the 450 mOsms in an even more dilute urine -- for example if she drank an extra L of water one day, the kidneys could get rid of that extra L with the same amount of 450 mOsm by diluting the urine to 450 mOsm ÷ 2 L = 225 mOsm/L. But the question asks for the minimum amount of water -- which is 1 L by the kidneys (+ 1 L from the other stuff for a total of 2 L).


... madeforupvoting2 made a comment on nbme21/block4/q#25 (An 80-year-old woman cannot concentrate her urine...)
 +0  upvote downvote
submitted by madeforupvoting2(0)

To maintain plasma osmolality -> Need to exactly replace all the fluids lost in the day

She cannot concentrate urine above 450 mOsm/kg , so the minimum amount of water required to be excreted by kidneys is 1 (to excrete the 450 mOsm she accumulates per day). The minimum excretion water required is necessarily at max concentration; if you were to say produce diluter urine, say 225mOsm/kg, this would require 2 L of water. The question wants the minimum possible water volume, so we assume she’s concentrating to the max.

1 L losses from kidney + 900 mL insensible + 100 mL in sweat and feces = 2L losses -> need to ingest 2 L of water to replace.


... drmantistoboggan4 made a comment on nbme21/block1/q#47 (A 26-year-old woman (III-2) comes to the physician...)
 +1  upvote downvote
submitted by drmantistoboggan4(1)

It said it was fatal to males in utero, and the question asked about live born offspring. Since the males aren’t being born in the first place, I said 50% females and 0% males.


... assoplasty made a comment on nbme21/block2/q#29 (A healthy 25-year-old man is participating in a...)
 +2  upvote downvote
submitted by assoplasty(3)

Fats are ketogenic (except odd chain FA), so they produce ketones for energy production (Acetyl-CoA) rather than glucose. If the question asked what the primary source of energy production was, it would still be glycogen (and not ketones), because this is within 24 hours. However after 24 hours the answer could be ketone bodies. Regardless, the question specifically said the pt had a serum glucose of 100, indicating that we are looking for something that provides a substrate for gluconeogenesis.

During periods of starvation, substrates for gluconeogenesis come from two sources: (1) breakdown of existing muscle, or (2) via odd-chain FA through propionyl-CoA. (*Valine also feeds into propionyl CoA, but is not involved during starvation --> see below)

(1) The alanine-pyruvate cycle provides this (glutamine in muscle + pyruvate --> alanine --> goes to liver --> transamination to alpha-ketoglutorate --> pyruvate is separated from glutamine --> glutamine goes to urea cycle, pyruvate goes on to gluconeogenesis). Lactate can also be used (this could have been a right answer if it were listed).

(2) Odd chain FAs are also glucogenic, but stearic acid (provided in the answer choice) isn’t odd chain, so it is only ketogenic and can be ruled out.

Although valine (and other branched a.a.) feed into Propionyl-CoA, they are not used in starvation because starvation strictly relies on hepatic gluconeogenesis. These a.a. are not metabolized in the liver because the liver lacks branched-chain a.a. transferase enzyme. In First Aid, Biochem section, under Fasting/Starvation, in both the “fasting state” (which is within the time frame of this question), or the “starvation state,” both utilize hepatic gluconeogenesis. My assumption is that valine is used during regular metabolism, and not during periods of starvation.


... volcanobuns made a comment on nbme21/block2/q#29 (A healthy 25-year-old man is participating in a...)
 +0  upvote downvote
submitted by volcanobuns(0)

@frimmy_11 Why would protein break down after only 20 hours? Shouldn’t fat be the major contributor now? Also if protein is being used, then why isn’t valine the choice? It’s also glucogenic.


... frimmy_11 made a comment on nbme21/block2/q#29 (A healthy 25-year-old man is participating in a...)
 -2  upvote downvote
submitted by frimmy_11(-2)

Muscle protein breaks down into the amino acid alanine which enters Cahill Cycle to form glucose ...


... danger_rave made a comment on nbme21/block3/q#32 (A 72-year-old man comes to the physician because of...)
 +1  upvote downvote
submitted by danger_rave(1)

@infundibidum6 So, I got to bleomycin due to SketchyMicro. Bleomycin can cause hyperpigmentation and pulmonary fibrosis, and I didn’t have any connections to chlorambucil. Anthracyclines can be used for all sorts of malignancies (free radicals kill lots of stuff), so the exact indications did less for me to get to the answer than it might have with another category. n=1, but it’s not a magic memorization answer at least.


... infundibidum6 made a comment on nbme21/block3/q#32 (A 72-year-old man comes to the physician because of...)
 +0  upvote downvote
submitted by infundibidum6(0)

I got it down to bleomycin & chlorambucil and went with chlorambucil (sounded like “bu”sulfan ... lol) because I thought bleomycin was for testicular cancer/Hodgkins lymphoma. I later found out that chlorambucil is actually a preferred treatment for CLL! Is it because chlorambucil causes severe immunosuppression? So you wouldn’t be giving it to a 72 yo man in the first place?


... beeip made a comment on nbme21/block4/q#36 (A 45-year-old man comes to the physician because of...)
 +0  upvote downvote
submitted by beeip(7)

This review suggests that enchondroma and chondrosarcoma are unable to be differentiated on histology alone. According to Orthobullets:

"unlike enchondroma, most chondrosarcomas have non-mechanical pain (rest pain and nocturnal pain)"

Guess this diagnosis is made on history.


... beeip made a comment on nbme21/block4/q#34 (A healthy 8-year-old boy is brought to the physician...)
 +1  upvote downvote
submitted by beeip(7)

"Excitatory amino acids" refers to glutamate, while "Biogenic" apparently refers to tyrosine, the precursor AA to dopamine and norepi.


... beeip made a comment on nbme21/block4/q#6 (A 55-year-old man comes to the physician because of...)
 +1  upvote downvote
submitted by beeip(7)

This has been a tough concept for me to get, but I think I'm finally there:

The stem is describing primary adrenal insufficiency, or Addison's.


... beeip made a comment on nbme20/block2/q#2 (Following a wedding reception that was attended by...)
 +0  upvote downvote
submitted by beeip(7)

[moved to subcomment]


... strugglebus made a comment on nbme20/block1/q#17 (A 50-year-old woman comes to the physician because...)
 +2  upvote downvote
submitted by strugglebus(14)

As an edit: 108,001 people reported to have side effects when taking Hydrochlorothiazide. Among them, 25 people (0.02%) have Breast discharge


... strugglebus made a comment on nbme20/block3/q#50 (A 62-year-old man comes to the physician because of...)
 +0  upvote downvote
submitted by strugglebus(14)

They are talking about Baclofen, a GABA-B agonist known to treat muscle spasticity


... strugglebus made a comment on nbme20/block1/q#17 (A 50-year-old woman comes to the physician because...)
 +3  upvote downvote
submitted by strugglebus(14)

Nowhere have I been able to find why the hell this is a thing.


... strugglebus made a comment on nbme20/block4/q#50 (A previously healthy 16-year-old girl is brought to...)
 +0  upvote downvote
submitted by strugglebus(14)

There are certain situations in which you don't need to notify parents about anything when treating a child--STIs are one of them. The reason being that untreated STIs will cause more spread as well as can lead to PID


... strugglebus made a comment on nbme20/block2/q#46 (A physician prescribes a newly marketed drug to 45...)
 +1  upvote downvote
submitted by strugglebus(14)

I chose this solely because it was so damn specific


... strugglebus made a comment on nbme20/block3/q#14 (During a clinical study, an investigator tests a new...)
 +0  upvote downvote
submitted by strugglebus(14)

You are aiming to increase power and you can do so by increasing sample size (reduce B error).


... strugglebus made a comment on nbme20/block1/q#26 (Serum cholesterol concentrations are measured as...)
 +0  upvote downvote
submitted by strugglebus(14)

So you know that 65% of the data will fall within 1SD of the mean. So if you subtract 100-65 you will get 35. Which means that about 16% will fall above and 16% will fall below 1 SD. They are asking for how many will fall above 1 SD. I'm sure there is a better way of doing this, but thats how I got it lol.


... strugglebus made a comment on nbme20/block3/q#23 (A 50-year-old woman is brought to the emergency...)
 +0  upvote downvote
submitted by strugglebus(14)

I was wondering if it was to allow for partial CNS penetration since the drug is supposedly supposed to have CNS effect


... strugglebus made a comment on nbme20/block4/q#11 (A 37-year-old man who is HIV positive comes to the...)
 +1  upvote downvote
submitted by strugglebus(14)

Hydrocodone/Methadone can lead to dependence--you avoid in long term use. NSAIDs you also avoid due to partial ineffectiveness in neuropathic pain as well as ulcer risk. TCA's are known to treat neuropathic pain very well (i.e. diabetes, ART therapy)


... strugglebus made a comment on nbme20/block4/q#22 (A 35-year-old man is given cyclosporine following a...)
 +0  upvote downvote
submitted by strugglebus(14)

As a side note, the phosphatase would have activated calcineurin https://www.ecosia.org/images?q=calcineurin+phosphatase#id=2E5AEA65CD7AADC5FADD1C144FFFAD3B7068FDAA


... strugglebus made a comment on nbme20/block4/q#22 (A 35-year-old man is given cyclosporine following a...)
 +0  upvote downvote
submitted by strugglebus(14)

Cyclosporine is a calcineurin inhibitor, which aims to decrease IL-2


... strugglebus made a comment on nbme20/block4/q#25 (A 52-year-old man is brought to the emergency...)
 +0  upvote downvote
submitted by strugglebus(14)

Propanolol is a non-selective Beta blocker. So your HR will decrease (B1), which will cause a compensatory increase in TPR.


... strugglebus made a comment on nbme20/block1/q#24 (A 50-year-old man comes to the physician because of...)
 +0  upvote downvote
submitted by strugglebus(14)

This a CYP 450 inhibitor (SICKFACES.COM); its the O.


... strugglebus made a comment on nbme20/block2/q#48 (A sedentary 50-year-old man with hypertension comes...)
 +0  upvote downvote
submitted by strugglebus(14)

Most of the pts values were normal. Drinking wasn't outrageous, LDL was mild, BMI has fine. He did have HTN though. The biggest risk factors are the fact that he had suffered an MI and started suffering severe depression (weight loss/anxiety). Thus, he is more at risk for suicide.


... strugglebus made a comment on nbme20/block2/q#35 (A 36-year-old woman comes to the office because of a...)
 +0  upvote downvote
submitted by strugglebus(14)

I thought the liver looked huge af too lol which made me requisition the whole radiograph


... strugglebus made a comment on nbme20/block2/q#2 (Following a wedding reception that was attended by...)
 +0  upvote downvote
submitted by strugglebus(14)

[moved to subcomment]


... strugglebus made a comment on nbme20/block2/q#2 (Following a wedding reception that was attended by...)
 +1  upvote downvote
submitted by strugglebus(14)

[moved to subcomment]


... strugglebus made a comment on nbme20/block2/q#18 (A 65-year-old man is brought to the emergency...)
 +0  upvote downvote
submitted by strugglebus(14)

ST will first decrease; however, after 20 min it will increase (elevate)


... strugglebus made a comment on nbme20/block2/q#38 (A 50-year-old woman with a restrictive pulmonary...)
 +0  upvote downvote
submitted by strugglebus(14)

Ok, so you can reason this by drawing out REIT (sorry I can't draw it here). Anywho, you know its a restrictive disorder and will have a decreased RV, so automatically you know that RV is a component of FRC (FRC= RV+ERV). Thus, FRC should also be decreased. You also know that restrictive diseases are characterized by a steady decrease in FEV1/FVC since both components are decreasing. This leaves you with VC decreasing since FVC= forced vital capacity.


... strugglebus made a comment on nbme20/block2/q#17 (A 57-year old man has a hemoglobin concentration of...)
 +1  upvote downvote
submitted by strugglebus(14)

Pt has polycythemia vera (myeloproliferative disorder) due to chronic hypoxia induced by COPD. Myeloid metaplasia is extra medullary hematopoiesis due to myelofibrosis. Hereditary hemochromatosis would have been proven by a prussian blue stain. Hypersplenism would have caused decreased RBCs, and myelodysplasic syndrome would have shown Auer rods or blasts.


... strugglebus made a comment on nbme20/block2/q#28 (At a postnatal checkup, a 6-week-old female newborn...)
 +0  upvote downvote
submitted by strugglebus(14)

Also, Meckels would have describe hematochezia or failure to pass meconium


... strugglebus made a comment on nbme20/block1/q#48 (An otherwise healthy 4-month-old girl is brought to...)
 +0  upvote downvote
submitted by strugglebus(14)

The strawberry hemangiomas tend to grow and then randomly involute.


... strugglebus made a comment on nbme20/block1/q#27 (A 53-year-old woman comes to the physician because...)
 +0  upvote downvote
submitted by strugglebus(14)

It also looked exactly like schistosome on the slide--it had the little spine. Entamoeba would have had a bunch of RBCs inside.


... strugglebus made a comment on nbme20/block2/q#20 (A 19-year-old man who is a college student is...)
 +3  upvote downvote
submitted by strugglebus(14)

Bronchophony= pneumonia Expiratory stridor= tracheobronchial obstruction (mass/foreign body) Inspiratory stridor = laryngeal obstruction Succussion splash= test for pyloric stenosis

When there is a fractured rib it will cause a trauma pnemothorax which can cause air to escape and become trapped under the skin leading to crepitus.


... strugglebus made a comment on nbme20/block2/q#13 (A 25-year-old woman comes to the physician because...)
 +1  upvote downvote
submitted by strugglebus(14)

Any answer with treponemes is used to syphilus only and is very specific. That only leaves cardiolipin, which is also elevated in SLE; this is why its sensitive but not specific in Syph.


... strugglebus made a comment on nbme20/block3/q#11 (A 3-year-old boy is brought to the physician because...)
 +0  upvote downvote
submitted by strugglebus(14)

Auto dom disease are usually heterozygous (or so they want us to assume)


... strugglebus made a comment on nbme20/block1/q#35 (A 70-year-old man dies of coronary artery disease....)
 +0  upvote downvote
submitted by strugglebus(14)

It affected the corticospinal tract in the crus cerebri on the L


... strugglebus made a comment on nbme20/block1/q#33 (A 17-year-old girl comes to the emergency department...)
 +0  upvote downvote
submitted by strugglebus(14)

OK, so if I remember correctly this is the one that shows the inheritance pattern. mitochondrial is also passed by the mother; however, it can have variable expressivity and incomplete penetrance, which is why some members were not affected.


... strugglebus made a comment on nbme20/block1/q#9 (A 50-year-old man is brought to the physician by his...)
 +0  upvote downvote
submitted by strugglebus(14)

Fronto-temporal dementia characterized by personality change is usually Picks


... strugglebus made a comment on nbme20/block1/q#29 (During an experiment, an investigator isolates an...)
 +0  upvote downvote
submitted by strugglebus(14)

Lysine is used in elastin and collagen cross linking; it is cross linked by lysyl oxidase to make collagen fibers


... strugglebus made a comment on nbme20/block1/q#43 (A randomized clinical trial is conducted to compare...)
 +0  upvote downvote
submitted by strugglebus(14)

The CI value contained 1, which means that its insignificant


... strugglebus made a comment on nbme20/block1/q#16 (A 30-year-old woman with multiple sclerosis comes to...)
 +0  upvote downvote
submitted by strugglebus(14)

The pons has nerves 5-8, so the trigeminal would be affected here


... strugglebus made a comment on nbme20/block4/q#44 (A 45-year-old man comes to the office for counseling...)
 +0  upvote downvote
submitted by strugglebus(14)

I had put "starches" b/c pts that undergo bariatric surgery are only supposed to eat complex carbs (fruits/vegetables) and avoid simple carbs (i.e. breakfast cereal/baked goods)


... strugglebus made a comment on nbme20/block4/q#43 (A physician is assigned to a search and rescue team...)
 +1  upvote downvote
submitted by strugglebus(14)

You have negative Nitrogen balance in starvation (lack of protein) and positive Nitrogen in muscle building states (i.e. children/athletes)


... vonhippelindau made a comment on nbme21/block1/q#24 (A 23-year-old man drinks alcohol heavily on a...)
 +0  upvote downvote
submitted by vonhippelindau(0)

It’s acute alcohol consumption so fatty change more likely. Cellular swelling indicates alcoholic hepatitis which requires chronic alcohol consumption (See FA 2019 pg 385). At least that’s the logic I used to pick fatty change.


... stapes2big made a comment on nbme21/block3/q#37 (A 5-year-old boy who has homocystinuria improves...)
 +0  upvote downvote
submitted by stapes2big(0)

The question is basically setting up a situation similar to that of a competitive inhibitor. They say that higher concentrations of pyridoxal phosphate increases the activity of the enzyme to normal levels. Similarly, when you have a competitive inhibitor and increase the concentration of substrate, the enzyme can achieve the same Vmax as if without the inhibitor.


... navevan3 made a comment on nbme21/block3/q#37 (A 5-year-old boy who has homocystinuria improves...)
 +0  upvote downvote
submitted by navevan3(0)

For this question, I was thinking that they asked you compare to a “normal” person, so the Vmax wouldn’t change since they state that his activity returns to a normal level. Only the x-axis would since it would be at increased concentrations in comparison.


... volcanobuns made a comment on nbme21/block3/q#11 (A 50-year-old man is found dead in bed at home. His...)
 +0  upvote downvote
submitted by volcanobuns(0)

MI sudden death -> arrhythmia. The order of commonness is arrhythmia > cardiogenic shock > rupture.


... frimmy_11 made a comment on nbme21/block3/q#11 (A 50-year-old man is found dead in bed at home. His...)
 +0  upvote downvote
submitted by frimmy_11(-2)

Mottling and softening of anterior wall on autopsy suggests it was not older than 24 hrs. Death from fatal arrhythmia like V-fib most commonly occurs within one day of the MI. That said, once scar has formed in myocardial tissue it, too, can cause arrhythmia.


... danger_rave made a comment on nbme21/block3/q#36 (Which of the following best explains why the use of...)
 +0  upvote downvote
submitted by danger_rave(1)

Multiple myeloma is an neoplastic proliferation of plasma cells, and since plasma cells don’t have surface Ig bound innately, that was the only “true” option.


... wasabilateral made a comment on nbme21/block1/q#3 (An investigator is studying the efficacy of distinct...)
 +0  upvote downvote
submitted by wasabilateral(0)

I think they want you to think about how conjugate vaccine is made: polysaccharide + protein fragment (to induce T dependent immune response). Only flagellin is a protein (or at least sounds like one) in the option list.


... assoplasty made a comment on nbme21/block3/q#31 (A 28-year-old woman at 18 weeks' gestation has...)
 +1  upvote downvote
submitted by assoplasty(3)

I think the concept they’re testing is the increased TBG levels in pregnancy, and not just hyperthyroidism in general.

When screening for hypo/hyperthyroidism, TSH levels are ALWAYS preferentially checked because they are more sensitive to minute differences in T3/T4. Often times TSH levels can demonstrate a change even when T3/T4 levels are in the subclinical range. The only exception to this would be in pregnancy (and I guess maybe liver failure? I doubt they would ask this though). High estrogen levels prevents the liver from breaking down TBG, leading to increased TBG levels in the serum. This binds to free T4, decreasing the amount of available free T4. As a compensatory mechanism, TSH levels are transiently increased and the RATE of T4 production is increased to replenish baseline free T4 levels. However the TOTAL amount of T4 is increased.

The question is asking how to confirm hyperthyroidism in a pregnant woman --> you need to check FREE T4 levels (because they should be normal due to compensatory response). You cannot check TSH (usually elevated in pregnancy to compensate for increased TBG), and you cannot check total T4 levels (will be increased). You got the answer right either way but I think this is a different reasoning worth considering, because they can ask this concept in other contexts of hyper-estrogenism, and if they listed “TSH” as an answer choice that would be incorrect.


... cantaloupe5 made a comment on nbme21/block2/q#6 (A 38-year-old woman comes to the physician because...)
 +2  upvote downvote
submitted by cantaloupe5(5)

Recurrent kidney stones should include hyperparathyroidism on your differential, couple that with gastrinoma and you’re looking at MEN 1. Lipomas are also associated with MEN 1.


... cantaloupe5 made a comment on nbme21/block3/q#31 (A 28-year-old woman at 18 weeks' gestation has...)
 +0  upvote downvote
submitted by cantaloupe5(5)

Hypo/hyperthyroidism is diagnosed with TSH w/ reflex to T4 (this just tells the lab if TSH is normal don’t check T4 but if TSH is abnormal, check T4 too). TSH wasn’t an option so T4 is the best answer.


... cantaloupe5 made a comment on nbme21/block4/q#15 (A 5-year-old boy is brought to the physician for a...)
 +0  upvote downvote
submitted by cantaloupe5(5)

Proccess of elimination for this one. Two you can eliminate immediately just from looking at the biochemical pathway chart. The other two required knowledge that eumelanin is more protective than pheomelanin (this is why redheads burn more easily). Because pheomelanin is less protective, there would be more not less ROS from sunlight.


... cantaloupe5 made a comment on nbme21/block4/q#45 (During an experiment, an investigator observes that...)
 +0  upvote downvote
submitted by cantaloupe5(5)

This one was tricky but I think you could’ve done this one without knowledge of NMDA receptors. Stem told you that glutamate activates both non-NMDA and NMDA receptors but it activated only non-NMDA receptors in the early phase. That means NMDA receptors activate after non-NMDA receptors. That means something was delaying NMDA receptor activating and the only answer that made sense as the Mg inhibiting NMDA at resting potential. Once the cell is depolarized by non-NMDA receptors, NMDA receptors can be activated.


... cantaloupe5 made a comment on nbme21/block3/q#11 (A 50-year-old man is found dead in bed at home. His...)
 +0  upvote downvote
submitted by cantaloupe5(5)

Histology showed coagulative necrosis (preserved architecture of myocardial fibers) with neutrophil infiltration which hinted that the MI was within 24 hours. Most likely cause of death within first 24 hours of MI is arrhythmia. Myocardial rupture would also be visible on gross appearance of the heart, which they described in the stem.


... cantaloupe5 made a comment on nbme21/block1/q#3 (An investigator is studying the efficacy of distinct...)
 +0  upvote downvote
submitted by cantaloupe5(5)

Capsular polysaccharide vaccines are often conjugated to proteins to improve immunogenicity. Flagellin is the only answer choice that's a protein.


... nuts4med made a comment on nbme21/block3/q#35 (A 63-year-old woman comes to the physician because...)
 +0  upvote downvote
submitted by nuts4med(0)

Anyone have an idea why the decreased arterial O2 saturation is incorrect? Assuming she has pulm edema since she has LE edema, wouldn't a lower O2 sat be expected too?


... cellgamesgojan made a comment on nbme21/block3/q#35 (A 63-year-old woman comes to the physician because...)
 +1  upvote downvote
submitted by cellgamesgojan(3)

AV Fistulas re-rout blood from the arterial system to the venous system, by-passing the Arterioles = Increase PL ---> INCREASE VR. All in all = Increase CO.

According to UWorld, the arterioles are a major source of resistance ... so bypassing the arterioles results in a decrease in Total Peripheral Resistance ... causing an increase in the rate and volume of blood returning to the heart. I am pretty sure there is more to the physiology behind this, but I hope this explained a little.


... heavy_neighborhood made a comment on nbme21/block2/q#5 (A 2-week-old male newborn has a patent ductus...)
 +1  upvote downvote
submitted by heavy_neighborhood(1)

PDA flows from the Aorta ==> Pulmonary arteries, by passing the RV so there is no change in O2 in the RV.


... moneysacs made a comment on nbme21/block2/q#5 (A 2-week-old male newborn has a patent ductus...)
 +0  upvote downvote
submitted by moneysacs(0)

Why is does a PDA after birth result in "higher than normal left ventricular cardiac output" over increased "right ventricular PO2"? Does the pulm artery --> aorta shunt become reversed after birth, so higher oxygen aorta blood would flow back into the right ventricle? I get that more blood would be pumped to the left ventricle, resulting in RVH/LVH, but don't understand the O2 bit.


... cantaloupe5 made a comment on nbme21/block1/q#45 (An 18-year-old man comes to the physician because of...)
 +0  upvote downvote
submitted by cantaloupe5(5)

For this one you just had to know the glycolysis pathway. Stem told you 2,3-BPG is elevated, which is upstream of pyruvate kinase.


... kingtime9119 made a comment on nbme20/block3/q#23 (A 50-year-old woman is brought to the emergency...)
 +0  upvote downvote
submitted by kingtime9119(0)

[comment moved to subcomment]


... beeip made a comment on nbme20/block2/q#2 (Following a wedding reception that was attended by...)
 +2  upvote downvote
submitted by beeip(7)

How to differentiate between Norovirus and Rotavirus here? Must be related to the the contagious nature of the illness?


... beeip made a comment on nbme20/block2/q#35 (A 36-year-old woman comes to the office because of a...)
 +1  upvote downvote
submitted by beeip(7)

Liver looks pretty normal-sized to me. Pic here for comparison


... beeip made a comment on nbme20/block3/q#36 (A 4-year-old boy has had fever, abdominal cramping,...)
 +1  upvote downvote
submitted by beeip(7)

Apart from the line in FA referencing PMN infiltrate in Shigella, there is no way to differentiate here between it and E. Coli. Cheap shot.


... beeip made a comment on nbme20/block4/q#21 (A 47-year-old woman comes to the physician because...)
 +0  upvote downvote
submitted by beeip(7)

I also was thinking M. avium here, but hypersensitivity pneumonitis seems to fit with the reticulogranular changes.


... beeip made a comment on nbme20/block4/q#44 (A 45-year-old man comes to the office for counseling...)
 +0  upvote downvote
submitted by beeip(7)

Thought this would be something regarding "bariatric surgery," but nope, just "no starchy foods, because you're pre-diabetic."


... medbitch94 made a comment on nbme20/block3/q#42 (A 13-year-old girl has an episode of severe cellular...)
 +0  upvote downvote
submitted by medbitch94(1)

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4946499/


... medbitch94 made a comment on nbme20/block3/q#26 (A 3-month-old boy is brought to the physician...)
 +1  upvote downvote
submitted by medbitch94(1)

FA2019 page 47: I-cell disease (inclusion cell disease/mucolipidosis type II)—inherited lysosomal storage disorder; defect in N-acetylglucosaminyl-1-phosphotransferase → failure of the Golgi to phosphorylate mannose residues (forming mannose-6-phosphate) on glycoproteins → proteins are secreted extracellularly rather than delivered to lysosomes. Results in coarse facial features, gingival hyperplasia, clouded corneas, restricted joint movements, claw hand deformities, kyphoscoliosis, and high plasma levels of lysosomal enzymes. Often fatal in childhood.


... medbitch94 made a comment on nbme20/block3/q#49 (A 92-year-old woman who was recently admitted to a...)
 +0  upvote downvote
submitted by medbitch94(1)

Full article: https://www.ncbi.nlm.nih.gov/books/NBK448130/


... medbitch94 made a comment on nbme20/block3/q#49 (A 92-year-old woman who was recently admitted to a...)
 +0  upvote downvote
submitted by medbitch94(1)

Actinic purpura results from extravasation of blood into the dermis. This phenomenon is due to the skin atrophy and the fragility of the blood vessels in elderly individuals, which is exacerbated by chronic sun exposure. Actinic purpura lesions are located on sun-exposed areas, like the arms, face, and neck.

Skin atrophy in dermatoporosis is due to an alteration of collagen, similar to that which is seen in osteoporosis. This pronounced skin atrophy caused by the photo-aging makes the dermal vascular network very sensitive to the slightest trauma or shearing force.


... medbitch94 made a comment on nbme20/block2/q#35 (A 36-year-old woman comes to the office because of a...)
 +0  upvote downvote
submitted by medbitch94(1)

WHY she has a huge ass liver too? I don't understand how you can choose big spleen over big liver or visa versa


... monoloco made a comment on nbme20/block1/q#27 (A 53-year-old woman comes to the physician because...)
 +0  upvote downvote
submitted by monoloco(11)

When you have a traveler who has intermittent abdominal symptoms and diarrhea, and who has traveled to the likes of northern Africa and such, Schistosomiasis needs to be on your radar. At least, that’s how I’ve incorporated this nugget into my mental space.


... drdoom made a comment on nbme20/block1/q#6 (A 16-year-old student has uncontrollable sleepiness,...)
 +1  upvote downvote
submitted by drdoom(15)

This is an interesting one. I like to remember it this way: in people with narcolepsy, all the “right kinds” of sleep are happening at all the “wrong times” of day. During the day, when a power nap would typically throw you immediately into REM, this kid is only entering Stage 1 or 2 (lightest sleep = slightest noises jar him back to reality). At night, when he should peacefully drift into Stage 1, 2, and so on, he instead completely zonks out. Classic narcolepsy.

From UpToDate: “Narcolepsy can be conceptualized as a disorder of sleep-wake control in which elements of sleep intrude into wakefulness and elements of wakefulness intrude into sleep.”


... drdoom made a comment on nbme20/block1/q#11 (The sequence surrounding the first two exons of the...)
 +0  upvote downvote
submitted by drdoom(15)

As described in the question stem, this mutation occurs within an intron (a gene segment which is transcribed [DNA->RNA] but not translated). RNA splicing enzyme(s) grab RNA and “loop it”; an intron is cut out and the exons on either side of the intron are adjoined, like this:

exon1—intron—exon2 => exon1—exon2

Typically, this splicing occurs at the very edges of the intron (what I denoted with the “—” character). But in our case, a mutation within the intron is causing RNA splicing enzyme to recognize a new site: the splicer cuts within the intron (instead of at the very edge, as it should). So, we get something that looks like this:

exon1—intr—exon2

That’s a totally different mRNA molecule, and it's going to make our β-globin protein look (and behave) awfully strange.


... monoloco made a comment on nbme20/block1/q#11 (The sequence surrounding the first two exons of the...)
 +0  upvote downvote
submitted by monoloco(11)

This has to do with intron splicing. Remember GTAG. This mutation induced an AG closer where it was supposed to be, so some of that intron just became an exon.


... monoloco made a comment on nbme20/block1/q#32 (A 56-year-old woman is brought to the emergency...)
 +1  upvote downvote
submitted by monoloco(11)

This is the only choice that comes close to nicking the thoracic duct, specifically at its inlet, the left subclavian.


... monoloco made a comment on nbme20/block2/q#14 (A 23-year-old woman has had fever, hypotension, and...)
 +0  upvote downvote
submitted by monoloco(11)

Encapsulated organisms run rampant in patients who have no spleen, whether physically or functionally. (Recall the wide-array of sequalae sickle cell patients experience thanks to their functional autosplenectomy.)


... monoloco made a comment on nbme20/block2/q#28 (At a postnatal checkup, a 6-week-old female newborn...)
 +0  upvote downvote
submitted by monoloco(11)

Annular pancreas is the only answer that accounts for the bile in the vomit; of the choices, it is the only obstruction distal to where bile enters the GI tract.


... monoloco made a comment on nbme20/block2/q#10 (A 70-year-old woman is transferred to a...)
 +2  upvote downvote
submitted by monoloco(11)

This is indirectly asking about peak bone density. That whole thing about weight-bearing exercises, eating right, yada yada, before and during that down-slope phase of life for bone density. All about reducing that 1% per year age-related bone density loss as best as we can. Level of activity is precisely like weight-bearing exercise. (Consider: no activity, bed-ridden -- say goodbye to your bones; highly active, runs every other day -- good amount of weight-bearing / stress to induce remodeling and maintain integrity of the bones.)


... monoloco made a comment on nbme20/block2/q#26 (A male newborn is found to have a decreased blood...)
 -1  upvote downvote
submitted by monoloco(11)

Decreased total, normal free (unbound) = Thyroid hormone-binding globulin deficiency


... monoloco made a comment on nbme20/block2/q#32 (A 12-year-old girl is brought to the physician by...)
 +3  upvote downvote
submitted by monoloco(11)

This is a conditional called craniocleidodysplasia. The kid on Stranger Things with the lisp has the disorder. No collar bones, too many teeth, frontal bossing => craniocleidodysplasia. CBFA1 is a gene highly implicated in osteoblast function.


... monoloco made a comment on nbme20/block2/q#11 (A female newborn delivered at 36 weeks' gestation is...)
 +0  upvote downvote
submitted by monoloco(11)

This is a hypoplasia of the pleuroperitoneal membrane. The guts herniate into the thorax, usually on the left side, and result in hypoplasia of the lungs (because they're horribly compressed).


... monoloco made a comment on nbme20/block2/q#19 (A 66-year-old man is brought to the emergency...)
 +0  upvote downvote
submitted by monoloco(11)

Is this the one with the poor kidney that was cut in half against its will and has a dilated distal ureter? If so, probably showing us transitional carcinoma with mild invasion into that distal ureter. Pathoma does a pretty awesome job of talking about GU cancers (and most cancers) ((and most medicine)) IMO.


... monoloco made a comment on nbme20/block2/q#20 (A 19-year-old man who is a college student is...)
 +1  upvote downvote
submitted by monoloco(11)

I have regarded crepitus as the rubbing of bone-on-bone. My study partner and I think this is a purely definitional question. Yes, crepitus could also be trapped air. Context, I guess.


... monoloco made a comment on nbme20/block3/q#36 (A 4-year-old boy has had fever, abdominal cramping,...)
 +3  upvote downvote
submitted by monoloco(11)

I think Shigella is the most appropriate, as it is actually regarded as highly inflammatory. Yes, E. coli can be of the EHEC/STEC variety, but E. coli could also be of the ETEC variety or whatever other strains it has. Ergo, E. coli may be plausible, but it is not the 'most likely.' Bleh to these kinds of questions.


... monoloco made a comment on nbme20/block3/q#23 (A 50-year-old woman is brought to the emergency...)
 +1  upvote downvote
submitted by monoloco(11)

If you want to clear a drug, it is probably best that it not be bound to proteins (so that it gets filtered) and it has a low volume of distribution (so it isn't in the deep, hard to reach tissues).


... monoloco made a comment on nbme20/block4/q#21 (A 47-year-old woman comes to the physician because...)
 +1  upvote downvote
submitted by monoloco(11)

This patient is experiencing hypersensitivity pneumonitis from the parakeets. I was thinking M. Avium when I selected parakeets -- I think my logic was flawed given the specifics of the patient's story.


... monoloco made a comment on nbme20/block4/q#17 (A previously healthy 55-year-old man has recently...)
 +0  upvote downvote
submitted by monoloco(11)

As a rule of thumb, if you give someone an ACE inhibitor and they get a problem, they had renal artery stenosis (usually bilaterally, or so we were taught at our med school). Probably has to do with decreased GFR thanks to decreased Angiotensin II–selective vasoconstriction of the efferent arteriole => decreased sodium delivery to macula densa => increased renin release.


... monoloco made a comment on nbme20/block4/q#30 (A 32-year-old woman is brought to the emergency...)
 +0  upvote downvote
submitted by monoloco(11)

Anytime you have a person who bumps their head, gets back up, and then has severe issues or dies like 6 hours later -- you have yourself an epidural hematoma from laceration to the middle MENINGEAL artery. (Goljan really emphasizes that you don't screw up and select middle cerebral.) You know it has to be an arterial laceration since the dura is tightly adhered to the skull's inner surface. Goljan referred to his experience with it as needing pliers to remove the dura from the skull; graphic, but it drives the point home. Tenting seen on CT is because the epidural hematoma gets stuck between the suture lines. When it manages to break past one of the suture lines, it is my understanding that then is when you get severe sequelae, like death or whatever.


... onyx made a comment on nbme20/block1/q#12 (72 yo woman with dysphagia)
 +0  upvote downvote
submitted by onyx(4)

Thoracic duct relations.


... onyx made a comment on nbme20/block1/q#12 (72 yo woman with dysphagia)
 +2  upvote downvote
submitted by onyx(4)

Thoracic duct relations.


... onyx made a comment on nbme20/block1/q#12 (72 yo woman with dysphagia)
 +0  upvote downvote
submitted by onyx(4)

Mediastinal relations.


... onyx made a comment on nbme20/block1/q#12 (72 yo woman with dysphagia)
 +0  upvote downvote
submitted by onyx(4)

The mass described is in the posterior mediastinum (see images below). The thoracic duct is damaged “near the mass”, hence drainage of organs distal to that point will be affected. The images below should clarify.


... onyx made a comment on nbme20/block1/q#31 (66 yo man, cavitary lesion in right lower lobe of lung)
 +2  upvote downvote
submitted by onyx(4)

A radiographically visible air-fluid level suggests a pretty large lesion (hence, “cavitary”). That's not going to become normal tissue again. Six months following resolution of symptoms you can expect healing in the form of a scar; that is, fibrosis but only in a single spot.


... radion made a comment on nbme20/block4/q#7 (33 yo woman with HIV, generalized tonic-clonic seizure)
 +0  upvote downvote
submitted by radion(0)

Single enhancing lesion points more towards lymphoma than toxo. Toxo is usually multi-ring enhancing lesions.


... drdoom made a comment on nbme20/block4/q#15 (45 yo man undergoing surgical procedure)
 +0  upvote downvote
submitted by drdoom(15)

The more general principle: endothelia vasodilate in the presence of high CO2; you gotta get rid of that acid somehow! Can’t let it accumulate, as lower pH within a “micro-environment” affects structure/efficiency of enzymes, proteins, etc. The more acidic a local environment, the more you expect nearby vasculature to dilate (as a means of increasing flow rate, thereby ferrying off accumulate acid).

The anesthesiologist can exploit this mechanism. By hyperventilating (blowing off CO2), the brain vasculature senses a low CO2 / “hunky-dory state,” which requires no vasodilation. In other words, the vasculature does not need to continue the ATP-consuming practice of synthesizing Nitric Oxide (NO).


... radion made a comment on nbme20/block4/q#15 (45 yo man undergoing surgical procedure)
 +0  upvote downvote
submitted by radion(0)

Hypercarbia causes cerebral vasodilation. If you have ever seen an intra- or acute post-op neurosurgical patient, or really any patient about to herniate, you can remember this because they will be hyperventilated to pCO2 around 25-30 to decrease ICP via cerebral vasoconstriction; in this case, we have the opposite. The curve of pCO2 vs cerebral blood flow is quite steep in the physiologic range meaning small changes in ventilation make a significant difference in CBF.


... metformality made a comment on nbme19/block0/q#0 (Isolated skeletal muscle contracted with electrical stimulation)
 +0  upvote downvote
submitted by metformality(0)

When a muscle runs out of fuel (eg, glucose) and/or producing less ATP and “increased” accumulation of metabolites (all other options besides the correct choice), it is a sign of onset of muscle fatigue. The stem is asking which of the following will “decrease?”, and it is the pH that will decrease (acidosis) due to the accumulation of lactic acid (remember glycolysis pathway where pyruvate gets converted to lactic acid).


... metformality made a comment on nbme19/block3/q#12 (23 yo woman engages in 30 minutes of strenuous exercise)
 +0  upvote downvote
submitted by metformality(0)

High cardiac output to the pulmonary circulation during exercise will cause the distension and recruitment of micovessels and that would cause the increase in total cross-sectional area.

Here are two images that illustrate this principle nicely:


... metformality made a comment on nbme19/block4/q#17 (60 yo man, 20-year history of hypertension; shortness of breath and fatigue for 3 months)
 +0  upvote downvote
submitted by metformality(0)

This patient with a history chronic hypertension is most likely suffering from left heart failure (decreased cardiac outpout), causing the blood to back up in the lungs (Crackles are heard bilaterally, shortness of breath) and that resulting into increased afterload for the right side of the heart, raising the pressure in the right heart chambers, which get transmitted back to central vein.


... drdoom made a comment on nbme19/block1/q#13 (Mechanism of action of tumor suppressor genes)
 +0  upvote downvote
submitted by drdoom(15)

This is essentially a formal logic question. Logically speaking, the question asks us to identify a mechanism that tumor suppressors have which proto-oncogenes do not. In other words, what is a mechanism shared by all known tumor suppressors but not shared by any known proto-oncogenes? For that reason, it can’t be phosphorylation; sure, phosphorylation is a mechanism of tumor suppressors but it’s also a mechanism of many known proto-oncogenes.


... picodemolar made a comment on nbme19/block1/q#13 (Mechanism of action of tumor suppressor genes)
 +0  upvote downvote
submitted by picodemolar(0)

Oncogenes with gain of function mutation lead to increased transcription, etc., whereas tumor suppressor genes block G1-->S phase. NF1 gene product has RAS GTPase activity which works by phosphorylating and activating protein (neurofibromin). So there is at least 1 tumor suppressor gene that works through phosphorylation.


... quackster made a comment on nbme19/block1/q#4 (66 yo man, 2 months no erection)
 +0  upvote downvote
submitted by quackster(0)

This is a controversial one, but it seems the consensus is that pt had sxs of major depression, and thus his libido was most likely down. But structurally/blood flow–wise, he was fine, so nocturnal erections were normal. So, concept NBME wants us to realize is that we should screen for depression in pts who complain of sexual dysfunction? Or ask about sex in pts who display sxs of depression, like that patient had in the stem of the Q.


... shadowbox made a comment on nbme19/block3/q#40 (25 yo woman requests prenatal diagnosis at 12 weeks gestation)
 +0  upvote downvote
submitted by shadowbox(0)

The stem states that the mother is 12 weeks gestation. CVS is performed 1st trimester, usually b/t 10-14 weeks gestation according to Up-to-Date. Amnio is performed after 15 weeks. From Up-to-Date: “Amniocentesis should be performed after 15 weeks of gestation because earlier procedures are less likely to be successful, are associated with higher rates of cell culture failure, and carry greater fetal risks.”


... shadowbox made a comment on nbme19/block3/q#19 (30 yo man and 24 yo woman; best estimate that child will have oculocutaneous albinism?)
 +0  upvote downvote
submitted by shadowbox(0)

Since the father's sibling is affected, we know that the father's parents are both carriers. That means the possible genotypes of the father are AA, Aa, aA, or aa.

We know the father is unaffected, so that means he cannot be aa, and must be either AA, Aa, or aA.

Since there are only 3 different genotypes he could have, with 2 of them being carrier genotypes, there is a 2/3 probability he is a carrier.

So we obtain the probability of the father passing on a recessive allele as 2/3 (probability of being a carrier) x 1/2 (probability of passing on a recessive allele if he is a carrier). The 2/3 is not relevant to the probability that the mother is a carrier.

We know the frequency of affected individuals in the population at large is 1/40,000 (=q^2), so q=1/200.

P+q=1, so p=199/200 and 2pq=2(199/200)(1/200).

To make multiplication easier we assume 199/200=1, so:

2pq=2*(1/200)=1/100 --> this is the carrier frequency (a.k.a., heterozygotes) in the population, which we can assume for the mother.

So, to answer the entire question we multiply the probability that father is a carrier (2/3) and passes on the allele (1/2) times the probability that mother is a carrier (1/100) and passes on the allele (1/2); putting it all together we have:

(2/3)*(1/2)*(1/100)*(1/2) = 2/1200 = 1/600


... shadowbox made a comment on nbme19/block1/q#4 (66 yo man, 2 months no erection)
 +0  upvote downvote
submitted by shadowbox(0)

The amount of nocturnal erections is decreased, I think (atherosclerotic problem); but I thought that it was a typical case of a patient suffering from depression after a serious illness, therefore => decreased libido.


... aliyah made a comment on nbme19/block1/q#17 (29 yo man untreated HIV)
 +0  upvote downvote
submitted by aliyah(3)

After the CD4+ cells become infected, the CD8+ cells kill them.


... aliyah made a comment on nbme19/block1/q#35 (5 yo boy, right eye pain 1 week)
 +1  upvote downvote
submitted by aliyah(3)

If a germ cell or somatic cell had the original mutation, then there's an increased risk for cancer in other parts of the body too. If only retinal cells in one eye is mutated, only that one eye is at risk for cancer.


... aliyah made a comment on nbme19/block3/q#5 (30 yo woman, 1 week of visual difficulty)
 +2  upvote downvote
submitted by aliyah(3)

The right eye's efferent nerves are working, as left eye stimulation causes a change in the right eye. The right eye optic n. damage causes it's afferent n. to be damaged. It can't carry info to brain, so right and left eye can't constrict to light.


... ajguard26 made a comment on nbme19/block2/q#16 (40 yo woman, chorionic villus sampling)
 +1  upvote downvote
submitted by ajguard26(8)

Chorionic villi sampling is the taking of genetic material within in the chorionic villi of the placenta. Chorionic sampling is done when a patient is at high risk for chromosomal abnormalities (previous pos. tests, 35yo or older, family hx.) during the 10-13 weeks of pregnancy.

Confined placental mosaicism results when the C.V.S. testing comes back back showing a trisomy, but all subsequent testing (and the fetus itself) have normal chromosomal counts. This may be due to either a trophoblastic mutation, or by "trisomic rescue," in which trisomic cells that were supposed to be in the fetus are confined to the placenta to prevent an abnormal fetus.


... ajguard26 made a comment on nbme19/block2/q#13 (25 yo man, exercise test. Most likely physiologic changes)
 +1  upvote downvote
submitted by ajguard26(8)

As the muscle works and breaks down ATP, adenosine is produced, leading to an increase in the tissues. This increased adenosine causes vasodilation, which in turn increases vascular conductance (the flow of a volume of blood through the vasculature).

Although you may think muscle contraction may lead to a decrease in flow through the vessel(s) by squeezing down on them, this mechanism is overcome by the increased cardiac output from the heart.


... ajguard26 made a comment on nbme19/block1/q#24 (62 yo woman sudden weakness of left leg)
 +2  upvote downvote
submitted by ajguard26(8)

This patient presents with classic upper motor neuron lesion symptoms: weakness, hyperreflexia, and decreased sensation. However, the question states she "cannot tell whether her left great toe is raised or depressed" when her eyes are closed, which may make you reconsider and think there may be some proprioceptive issues they are trying to hint at. This is not the case. Especially once they mention there are no other abnormalities (i.e., no upper limb abnormalities or right sided abnormalities). If this is the case, there is no damage to the tracts at all (which are still considered UMN).

Therefore, the damage is purely motor and sensory in the left leg, which is on the medial aspect of the frontal and parietal lobes respectively. This area is supplied by the anterior cerebral artery.


... ajguard26 made a comment on nbme19/block1/q#48 (62 yo man, decreased speech fluency after cerebral infarct)
 +1  upvote downvote
submitted by ajguard26(8)

Obviously no picture here, but "A" in the picture represents Broca's area, which would cause the expressive aphasia this patient is experiencing.

However, the question also states the patient has weakness of the lower two-thirds of his face. This may cause you to think there is maybe a lesion in the pre-central motor area (thinking humonculus), but realize that the motor area travels all the way down to the bottom of the frontal lobe, RIGHT BEHIND THE BROCA'S AREA. In fact, Broca's area encompasses that part of the humonculus. And since the upper part of the face is controlled by the upper part of the facial motor cortex, and the lower part is controlled by the lower part of the facial motor cortex, you can have paralysis of the lower part of the face and have expressive aphasia if the lesion is in that specific area (does not need to be a lower motor lesion to spare the upper face/forehead).


... ajguard26 made a comment on nbme19/block1/q#42 (Advantage of randomized controlled studies)
 +1  upvote downvote
submitted by ajguard26(8)

"Confounding variables" here means "confounding bias," essentially. And this is true because a prospective cohort looks at a specific exposure to a substance (environmental toxin, drug, etc.), and asks "Who will develop this disease if exposed?" PCS's look attempt to find a relative risk associated with an exposure. They do not take into account the affects other exposures. This is your confounding bias. FA gives the example of confounding bias as "Pulmonary disease is more common in workers in a coal mine; however, miners are more likely to smoke," and since smoking can also lead to pulmonary disease, you can't really say whether the smoking (first or second hand) or the coal dust causes the problem. A clinical trial, on the other hand, contains a test group and a control group, so variables such as the confounding variable mentioned above are limited.


... ajguard26 made a comment on nbme19/block1/q#1 (53 yo woman with GERD.)
 +2  upvote downvote
submitted by ajguard26(8)

So although Misoprostol DOES increase mucus production and is gastro-protective (and in FA does state that it decreases acid production), thereby decreasing symptoms and aiding in healing, omeprazole is the "more correct" choice. This is because omeprazole is a proton-pump inhibitor, which will act directly on the proton pumps of the stomach and decrease the offending agent more than the misoprostol will. Therefore, it is the first line drug for GERD.


... doofusmd made a comment on nbme19/block1/q#35 (5 yo boy, right eye pain 1 week)
 +4  upvote downvote
submitted by doofusmd(5)

This is what is known as a somatic mutation: a mutation that occurs in non-germline cells and, therefore, only effects daughter cells derived from the parent cell with the mutation. So, a mutation occurred in a differentiated parent cell that gave rise to a set of daughter cells (which, in this case, were destined to become retinal tissue).


... drdoom made a comment on nbme19/block1/q#4 (66 yo man, 2 months no erection)
 +14  upvote downvote
submitted by drdoom(15)

Inability to maintain an erection = erectile dysfunction. So now the question is "Why?"

Fatigue, difficulty sleeping, difficulty concentrating is starting to sound like depression. "Difficulty concentrating" might be interpreted as impaired executive function or the beginnings of vascular-related dementia (dementia related to small but numerous cerebral infarcts), but on Step 1 dementia will be blatant (i.e., "lost his way home," "wandering," etc.).

Depression is actually common after a debilitating event like stroke, as you might expect. With depression comes a loss of sexual interest and desire—that is decreased libido.

One can make the argument that a "vascular patient" might have some issues with his "pipes" (arteriosclerosis, parasympathetic/sympathetic dysfunction) and, for this reason, nocturnal erection should be decreased; but note that nothing is mentioned about long-standing vascular disease (no hx of hypertension).

As a result, the best answer choice here is C. (Libido decreased but nocturnal erections normal.) The big question I have is, how the heck does this guy know he's hard when he's asleep!!? :p