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NBME 13 Answers

Block/Question (26.1 difficulty score)
A 77-year-old woman dies in the hospital ...
Interleukin-1 (IL-1)πŸ”

Block/Question (8.4 difficulty score)
An 18-month-old boy is brought to the ...
Iduronate sulfataseπŸ”

Block/Question (8.3 difficulty score)
A 22-year-old woman comes to the physician 3 ...
Anterior to the sternocleidomastoid muscleπŸ”

Block/Question (6.7 difficulty score)
A 3-year-old girl is found to have a grade ...
Ventricular septal defectπŸ”

Block/Question (6.2 difficulty score)
A 32-year-old woman comes to the physician ...
Myasthenia gravisπŸ”

Block/Question (6.5 difficulty score)
A 4-year-old boy is brought to the emergency ...
Reaction step labeled by the letter 'E'πŸ”


Block/Question (4.7 difficulty score)
A 43-year-old woman with metastatic colon ...
The agent being a humanized antibodyπŸ”

Block/Question (6.1 difficulty score)
A 43-year-old man comes to the physician for ...
Low-calorieπŸ”

Block/Question (5.1 difficulty score)
A 20-year-old man has cramping periumbilical ...
Interleukin-1 (IL-1)πŸ”

Block/Question (4.5 difficulty score)
An 18-year-old man has had temperatures to ...
T lymphocytesπŸ”

Block/Question (4.7 difficulty score)
A male newborn at 34 weeks' gestation is ...
EndotheliumπŸ”

Block/Question (4.4 difficulty score)
A 15-year-old boy is brought to the physician ...
Type I (immediate) hypersensitivityπŸ”

Block/Question (4.8 difficulty score)
A female newborn is delivered at 34 weeks' ...
Nitric oxideπŸ”

Block/Question (3.9 difficulty score)
A 5-month-old boy is brought to the physician ...
Thyroglossal ductπŸ”

Block/Question (3.7 difficulty score)
In order to determine risk factors for death ...
Observational cohort studyπŸ”

Block/Question (3.7 difficulty score)
A 36-year-old man who is seropositive for HIV ...
Pneumocystis jiroveci (formerly P. carinii)πŸ”

Block/Question (4.8 difficulty score)
A 47-year-old woman comes to the physician ...
Activation of nuclear gene transcriptionπŸ”

Block/Question (7.7 difficulty score)
A 5-year-old boy is brought to the physician ...
IschiumπŸ”

Block/Question (3.8 difficulty score)
A 23-year-old woman comes to the physician ...
DextromethorphanπŸ”

Block/Question (4.9 difficulty score)
A 54-year-old man has a squamous cell ...
Loss of heterozygosityπŸ”

Block/Question (5.5 difficulty score)
A previously healthy 42-year-old Asian woman ...
Induction of cytochrome P450πŸ”

Block/Question (4.7 difficulty score)
Homologous pairing of chromosomes in prophase ...
Crossing overπŸ”

Block/Question (6.4 difficulty score)
A 32-year-old woman comes to the physician ...
ClomipheneπŸ”

Block/Question (4.7 difficulty score)
A 31-year-old woman is brought to the ...
Desensitization of nicotinic receptorsπŸ”

Block/Question (4.3 difficulty score)
A previously healthy 40-year-old man is ...
Increased protein degradationπŸ”

Block/Question (6.1 difficulty score)
A 33-year-old woman who is right-handed is ...
Voltage-gated Na+ channelsπŸ”

Block/Question (6.2 difficulty score)
A study is conducted to evaluate the onset ...
Population-basedπŸ”

Block/Question (6.9 difficulty score)
An autopsy is done on a 46-year-old woman who ...
ParagangliomaπŸ”

Block/Question (4.2 difficulty score)
A cluster of three cases of nosocomial ...
Promote thorough hand cleansing before and after medical personnel visit each patientπŸ”

Block/Question (4.8 difficulty score)
A 23-year-old woman with type 1 diabetes ...
Inability to produce hydroxy-halide radicalsπŸ”

Block/Question (3.6 difficulty score)
A 25-year-old woman undergoes a radical ...
Compression sleeveπŸ”

Block/Question (5.2 difficulty score)
A young adult couple has been unable to ...
Seminal vesiclesπŸ”

Block/Question (5.3 difficulty score)
A 25-year-old man with cystic fibrosis comes ...
Biofilm formation in the lower respiratory tractπŸ”

Block/Question (5.1 difficulty score)
An 18-year-old woman with mild mental ...
Apo BπŸ”

Block/Question (10.1 difficulty score)
A mouse melanoma, B-16, is highly metastatic. ...
HomingπŸ”

Block/Question (4.1 difficulty score)
A 22-year-old woman comes to the physician ...
Antiphospholipid antibody syndromeπŸ”

Block/Question (9.5 difficulty score)
A previously healthy 32-year-old man is ...
Alcohol dehydrogenaseπŸ”

Block/Question (5.2 difficulty score)
A 40-year-old woman is brought to the ...
Vascular malformationπŸ”

Block/Question (4.6 difficulty score)
A 33-year-old woman comes to the physician ...
Cortical hyperplasiaπŸ”

Block/Question (4.0 difficulty score)
A 55-year-old man with hepatic encephalopathy ...
LactuloseπŸ”

Block/Question (4.4 difficulty score)
A previously healthy 25-year-old man is ...
Alveolar hyaline membraneπŸ”

Block/Question (5.1 difficulty score)
A 64-year-old woman comes to the physician ...
Esophageal peristalsis: decreased; Lower esophageal sphincter tone: decreasedπŸ”

Block/Question (4.9 difficulty score)
A 62-year-old man is brought to the emergency ...
Pulmonary edemaπŸ”

Block/Question (2.3 difficulty score)
an investigator is studying the human immune ...
cancer type cervical cancer human papilloma virus type 16 E6πŸ”

Recent comments ...

... drjungly made a comment on nbme13/block3/q#7 (32 yo woman, 5 years inability to conceive)
 +6 
submitted by drjungly(10)
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laNmor ehnmnaoroo,mrl male rspme dstuy adn rnmaol snmese: tilsl ca’nt ccineevo hent igev YTR tiwh ecepmn,olhi ahtt is Asaotntnig ta nGHR ropercte ta ylhaH,ompsaat cBolk nroEsetg eidmtaed iihnnbioit fo RnHG neceh cIernesa leserea fo g;;;g&t;g&gntg&G&tt;gcn&t&H;tiR. HL eursg uiBecoolntoiprvna morti - oulwd be pflhleu fi hte pt has riinttfiyle ude ot REESCIAN SNLIEOC. PRATD - is etspdpo ni US due to larce ellc omcancrai in uogny eamlfe nrbo ot thleho.yirtnmE troaedlsi - indb entegosr gtct&e;te&pngti&;ori>gt;it;&b;hg RnGH ;gg&n&;tgto&g&tt;; LH r:segu on c(usne.i sikR of troadlmeine ocde egci)oeorertaaMnmpsrnrxy - si gnotirpesr bdn-β€”i nootpeseegrr .irsrep.ee.ott(pcono.cnm fo imgrnno efrat pill)

... jsmoov made a comment on nbme13/block4/q#2 (18 yo woman, mild mental retardation, 3 days decreased ability to see in reduced light)
 +6 
submitted by jsmoov(13)

This baby has abetalipoproteinemia. ("without Beta apolipoproteins"). Thus they will lack B-48 and B-100 and have absent levels of chylomicrons, VLDL, and LDL. Infants present with severe fat malabsorption and deficiencies of all fat soluble vitamins (ADEK). Lack of vitamin A renders them vulnerable to Retinitis pigmentosa and lack of VitE leads to spinocerebellar degeneration.

... skip_lesions made a comment on nbme13/block2/q#38 (5 yo boy, 6 months progressive clumsiness and fatigue)
 +3 
submitted by skip_lesions(10)

Muscle: Adductor magnus

Origin: Pubis, tuberosity of ischium

Insertion: Femur

Action: Adducts the thigh at the hip

... thegooddoctor2 made a comment on nbme13/block1/q#1 (77 yo woman, dies in hospital after long illness)
 +2 
submitted by thegooddoctor2(1)

Remember, HOT T Bone Steak. IL-1 causes severe inflammation and is directly involved in the creation of the lytic lesion.

... jsmoov made a comment on nbme13/block3/q#21 (Autopsy of 46 yo woman, adenocarcinoma of colon)
 +2 
submitted by jsmoov(13)

Positive staining for synaptophysin and chromogranin are immediate buzzwords for neuroendocrine tumors. Paragangliomas are the only type listed here.

Others would be small cell carcinoma of lung, carcinoid tumor, gastrinomas/insulinomas/etc, pheos, medullary carcinoma of thyroid.

... jsmoov made a comment on nbme13/block3/q#31 (23 yo woman, type 1 diabetes mellitus, follow-up examination)
 +2 
submitted by jsmoov(13)

Halides are the elements in the 2nd the last column of the periodic table (F, Cl, Br, I, etc). Defective MPO prevents conversion of H2O2 into HOCl (a hydroxy-halide) which is aka bleach and the most powerful antimicrobial our phagocytes can synthesize

... skip_lesions made a comment on nbme13/block3/q#45 (25 yo man, cystic fibrosis, 3 days fever, cough, progressive shortness of breath)
 +2 
submitted by skip_lesions(10)

P. aeruginosa has been shown to form biofilm-like microcolonies in the lungs of CF patients making it difficult to treat with antibiotics.

... jsmoov made a comment on nbme13/block1/q#19 (22 yo woman, 3 months painless, slowly enlarging mass on left neck)
 +1 
submitted by jsmoov(13)

Branchial cleft cysts typically occur due to failure of the 2nd branchial cleft to obliterate resulting in a persistent cervical sinus. Branchial cleft cysts will not move with swallowing and classically occur anterior to the sternocleidomastoid muscle

... iceberglettuce made a comment on nbme13/block3/q#15 (33 yo woman, right-handed, 3 days progressive weakness, numbness of arms and legs)
 +1 
submitted by iceberglettuce(8)

This one was a doozy. I think by saying "nerve studies show slow conduction velocity," they are referencing saltatory conduction impairment. Therefore they are asking us which channels are necessary for saltatory conduction - which would be voltage-gated Na+ channels.

... drjungly made a comment on nbme13/block3/q#19 (Study of onset and course of cardiovascular disease in African American men and women)
 +1 
submitted by drjungly(10)
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scserehaerr want ot nowk CV kisr abtuo icafnrA aAcmiren otasipulpno btu od nto ahve daat ofr eyrev spofenIr. a arerchsere awtend ot enrla erwehth gbnie tanicre hitetcniy rceeaisn a riks fo raticlaupr iadees,s it duowl otn be catlicpra to usdyt yeevr vdniliadui rfmo atht eiyintcth . atsdne,I eth eaerhrrecs might ecestl a aslpem of teh apioptu.lno A mealsp si a lrsmlea opgur fo mmerseb fo a npupaotlio eecsltde to peerntser het nlpoao.itup In eodrr to eus scisstaitt to lnrea ntshig atuob eht natpioplou, hte laspme smut eb nro.mad A mronda smlape is eon ni chwhi yvree rememb fo a tlnaipuoop ahs an lqeua acnhec fo nbegi ese.dtelc heT msot lnocommy udes splmae is a mlspie rodanm .lamspe It esequrri ttah revey seolspbi epsmal fo eth esltceed zise ahs an elaqu ahencc fo nibge du.se

... jsmoov made a comment on nbme13/block3/q#30 (Cluster of three cases of nosocomial pneumonia caused by <i>Klebsiella pneumonia</i>)
 +1 
submitted by jsmoov(13)

Klebsiella has a capsule and is spread through person-to-person contact (e.g. from patient to patient via the contaminated hands of healthcare personnel). "The bacteria are not spread through the air"

... skip_lesions made a comment on nbme13/block3/q#39 (Young adult couple, 2 years unable to conceive)
 +1 
submitted by skip_lesions(10)

Seminal vesicles contribute fructose to the ejaculate. Decreased fructose concentration may indicate an ejaculatory duct obstruction.

... mario made a comment on nbme13/block4/q#7 (Mouse melanoma, B-16, highly metastatic)
 +1 
submitted by mario(1)
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isth slcel soluhd be mest lecl pntl,ntrasa so hgnoim si hte eonnnmvriet tath aptecc hmet nda uhnirso hmte htwi rhtgwo tsroafc to areumt

... iceberglettuce made a comment on nbme13/block4/q#36 (25 yo man, admitted to hospital for viral pneumonia)
 +1 
submitted by iceberglettuce(8)

Diffuse alveolar damage = ARDS -> alveolar hyaline membranes

... meryen13 made a comment on nbme13/block2/q#20 (an investigator is studying the human immune response)
 +1 
submitted by meryen13(12)

i was so confused by this question. is this because the rest are human antigens, so why would we have antibodies against them? but HPV is antibody toward E6 is foreign...?

topgunber  im going with this explanation. the rest : cd19, her2, Prostate acid phosph, tyrosinase are all endogenous molecules. makes sense that viral protein e6 has the highest immunogenicity. +1
... pharmtomed made a comment on nbme13/block1/q#1 (77 yo woman, dies in hospital after long illness)
 +0 
submitted by pharmtomed(1)

So I think where I got tripped up is that she does, indeed, have multiple myeloma (so there will be increased serum IgG), but the thing that is actually causing her bones to show the osteoclastic lesions shown in the image is IL-1 (osteoclast activating factor). Weird wording. Thanks NBME.

... schep made a comment on nbme13/block1/q#1 (77 yo woman, dies in hospital after long illness)
 +0 
submitted by schep(13)

I thought lytic bone lesion-->multiple myeloma-->hypercalcemia

but I suppose that calcium isn't involved in the process of creating the lytic lesion, that would be IL-1 and TNF

... athenathefirst made a comment on nbme13/block1/q#20 (3 yo girl, grade 4/6, loud, harsh, high-pitched holosystolic murmur)
 +0 
submitted by athenathefirst(5)

Why is this VSD? Is it just because she is 3 years old? I was stuck between MVP, VSD.

schep  I picked VSD because of the description of the murmur-loud, harsh, holosystolic, radiates over precordium and palpable thrill at left sternal border (I think because high pressure blood is moving from LV-->RV so you can feel a thrill) MVP is late systolic, crescendo murmur with midsystolic click +
castlblack  rule out all diastolic murmurs including -aortic regurg, -mitral stenosis, -PDA (no sound in diastole so cant be continuous). Rule out all murmurs that are heard on A and M sites, -aortic stenosis, -mitral regurg. Coarctation of the aorta is heard between the scapula I read so rule that out too. Rule out crescendo decrescendo murmurs, because holosystolic murmurs are like they sound: the same throughout systole. -pulmonic stenosis, -atrial septal defect. (AS has already been ruled out) You are now left with tricuspid regurg and VSD. Use harsh, high pitched descriptors to pick VSD. Tricuspid is described as blowing just like mitral regurg. Tricuspid regurg is a close candidate because it is heard in the same place as VSD, can be due to congenital malformation e.g. ebstein anomaly. It is also seen in rheumatic fever and endocarditis, but no other symptoms are mentioned so this question is leaning toward congenital malformation. +
... schep made a comment on nbme13/block1/q#26 (4 yo boy, brought to ER, 1 hour headache, nausea, vomiting, dizziness)
 +0 
submitted by schep(13)

carbon monoxide inhibits the final step of ETC, cytochrome oxidase

... skip_lesions made a comment on nbme13/block1/q#30 (43 yo man, routine health maintenance examination)
 +0 
submitted by skip_lesions(10)

Patient is obese with a BMI of 30 and a major risk factor for T2DM is obesity and high-calorie diet.

castlblack  what is wrong with low carbohydrate? Carbs raise insulin after all +2
... meryen13 made a comment on nbme13/block1/q#43 (18 yo man, 8 days temperature of 38.3 C, sore throat, cervical lymph node enlargement)
 +0 
submitted by meryen13(12)

https://www.slideshare.net/csbrprasad/imn-csbrp-54556104 i found this link helpful. the atypical cd8+ lymphocytes are diagnostic for EBV

castlblack  Despite being dormant in monocytes (premature macrophages), causing B cell immortality and B cell lymphomas, EBV causes atypical T cells in the blood. +
... victor_abdullatif made a comment on nbme13/block1/q#48 (Male newborn at 34 weeks gestation delivered vaginally)
 +0 
submitted by victor_abdullatif(0)

Diagnosis: strawberry hemangioma

Heme = blood -ang- = vessel -oma = benign mass

A benign tumor of capillaries, therefore the origin is endothelium

... schep made a comment on nbme13/block2/q#6 (Female newborn, delivered at 34 weeks gestation, advanced-care setting)
 +0 
submitted by schep(13)

FYI since I didn't know the difference

Nitric oxide=NO

Nitrous oxide=N2O

... jsmoov made a comment on nbme13/block2/q#8 (5-month-old boy, 5 days difficulty feeding)
 +0 
submitted by jsmoov(13)

Midline mass that moves with swallowing = thyroglossal duct cyst

... iceberglettuce made a comment on nbme13/block3/q#5 (42 yo Asian woman, brought to ER, 24 hours nausea, vomiting, progressive lethargy)
 +0 
submitted by iceberglettuce(8)

Chronic EtOH induces CytP450. Acetaminophen metabolism yields NAPQI, which is highly hepatotoxic.

CytP450 inducers: CRAP GPS

Carbamazepine Rifampin Alcohol (chronic) Phenytoin

Griseofulvin Phenobarbitol St. John's wart

... skip_lesions made a comment on nbme13/block4/q#35 (55 yo man, hepatic encephalopathy, 24 hours of confusion and lethargy)
 +0 
submitted by skip_lesions(10)

Colonic bacteria convert lactulose into lactic acid and acetic acid, which acidifies colonic contents. This leads to the conversion of ammonia (NH3), which is a weak base, into its nonabsorbable protonated form, ammonium (NH4+). Once protonated, the positive charge prevents ammonium from crossing cell membranes, keeping the molecule in the colon. As the levels of ammonia in circulation gradually declines, the symptoms of hepatic encephalopathy improve

... scoresloth made a comment on nbme13/block4/q#42 (64 yo woman, 6 months heartburn, difficulty swallowing solid food and liquid)
... ergogenic22 made a comment on nbme13/block4/q#20 (32 yo man, brought to ER, 1 day intermittent flashing spots, blurred vision, vomiting, confusion, difficulty walking)
 -2 
submitted by ergogenic22(300)
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I levieeb that the tionqeus si iesngutsgg eht tnipeta ahs a maonlhet dvr.oseoe

rstiF diA 8120 eapg Mh"t elzi:OoipnE2bFisi7β€” aoclhol ndrydsoeeghae nda si an ioetdnta orF vesedoOsr fo olnhaetM or heentyE l .lyoc"gl

Teh raoens I ma snueur si ttah daipiekwi assett sotm pitan nhsitner rea tesekno ro horsrbaydonc

lae  that's correct, I don't know about what the thinner has but the clinics is methanol toxicity for sure +1