NBME 22 Herpes encephalitis (NBME Answers)

need help with your account or subscription? click here to email us (or see the contact page)

search for anything ⋅ score predictor (“predict me!”)

Retired NBME 22 Answers

nbme22/Block 3/Question#50 (reveal difficulty score)
A 56-year-old woman is brought to the ...
Herpes encephalitis 🔍 / 📺 / 🌳 / 📖
tags: infectious_disease

+19 upvote downvote
submitted by ∗drzed(333)

get full access to all content ⋅ pick a username

I'm a simple man, I see encephalitis and temporal lobe involvment, I click herpes.

get full access to all content ⋅ pick a username

asharm10 hahaha true that, overthinking is the reason for getting so many questions wrong +

chaosawaits So the protein level is high based solely on the invading lymphocytes? That and the borderline low glucose had me thinking bacterial. +

l0ud_minority But why does it have a preference for the temporal lobe I wonder???? +

sunnyside @chaosawaits I think of LP labs this way: Bacteria eat CSF glucose (low CSF glucose) and poop it out as proteins (high CSF protein). Viruses don't eat CSF glucose (normal CSF glucose) and are composed of proteins (high CSF protein). Tho I did get this question wrong because the CSF glucose was annoyingly borderline... should've just gone with the buzzword +

+6 upvote downvote
submitted by ∗imnotarobotbut(184)

get full access to all content ⋅ pick a username

Although there are no specific herpes indicators, a CSF panel with mostly leukocytes indicates a viral infection (as well as the normal glucose). So you can rule out TB, neurosarcoidosis and bacterial. Brudzinski/kernig sign are related to meningitis, but even if you don't know what those are, the question says that there is an abnormality in the TEMPORAL lobe (meningitis = meninges). Encephalitis would be the best answer, especially because Herpes Encephalitis affects the temporal lobe.

get full access to all content ⋅ pick a username

taediggity Also look for Kluver-Bucy like symptoms in the stem +1

mambaforstep why? +

b1ackcoffee I agree with everything but normal glucose. Glucose here is NOT normal. to quote wiki "The glucose level in CSF is proportional to the blood glucose level and corresponds to 60-70% of the concentration in blood. Therefore, normal CSF glucose levels lie between 2.5 and 4.4 mmol/L (45–80 mg/dL)." +

baja_blast NBME reference table gives normal CSF glucose to be 40-70 mg/dL. As far as I'm concerned, for the purposes of the exam the reference table is probably a better source than wiki. +5

Must-See Comments from nbme22

sacredazn on Unrearranged immunoglobulin gene
seagull on Decreased binding of RNA polymerase
seagull on Anticholinergic
mcl on Area labeled ‘D’
liverdietrying on Release of stored thyroid hormone from a ...
kernicterusthefrog on Displacement
keycompany on Negative nitrogen balance
joha961 on Displacement
imgdoc on Area labeled ‘C’ (Abducens nucleus, right)
alwaysanonymous on 25 mL/cm H2O
drdoom on 1 in 600
seagull on Glutamine
yotsubato on Phase variation
bubbles on Acute retroviral infection