need help with your account or subscription? click here to email us (or see the contact page)
join telegramNEW! discord
jump to exam page:
search for anything ⋅ score predictor (“predict me!”)
NBME Free 120 Answers

free120/Block 2/Question#34 (reveal difficulty score)
A 12-year-old girl is brought to the ...
Decreased activity of UDP glucuronosyltransferase 🔍 / 📺 / 🌳 / 📖

 Login (or register) to see more

 +4  upvote downvote
submitted by ashmash(4)

Why can’t we assume that the patient with an elevated direct bilirubin does not have some sort of obstruction where the alkaline phosphatase would be elevated (or even dubin johnson syndrome)? I didn’t think of Gilbert disease despite the intermittent course because I tend to look at direct and total bilirubin levels first to see if the direct bilirubin is elevated which in this case was elevated.

 Login (or register) to see more
bwdc  Few things. History always comes first. She also has even more indirect bili than direct. There’s also no other indication of obstruction clinically (such as pruritis), and you can’t infer an elevated lab value (alk phos) and rely on that in order to have everything come together. They have to give it to you. +10
morelife  I saw this question on Gilbert’s and also put down increased ALP. I noticed the relapsing-remitting history. However, my thoughts were that a direct bilirubinemia is a false finding in Gilberts (since it is due to lower UDP enzyme activity), and would more likely indicate obstruction. As you said, you would consciously neglect this finding in favor of the history? For these specific NBME style questions -- you know, the wishy/washy ones -- would you follow the principle of “history first”? +1
bwdc  @morelife, Plethora of evidence first. Here everything points in one direction except one small detail. If you were to make a list of pro/cons for each diagnosis using history, physical and objective data (labs, imaging, etc), the scales usually tip firmly in one direction. +3
wowo  also, unless I'm mistaken, it's not a direct bilirubinemia - tbili is 3 and direct is 1, so unconjugated is 2. They're both elevated. Even with a decrease in function of the enzyme, it still works, so if unconj bili increases, you'll get somewhat of an increase of conjugated bili +2
kindcomet  @wowo, that makes sense if the unconj bili is due to hemolysis but it doesn't make sense if pathophys is literally the conjugation step. I would have expected DECREASED conjugated bili, if anything. +3
sexymexican888  Also serum haptoglobin is normal, if it was a hemolytic anemia (intrinsic) it would be decreased +2
an1  All Uw resources have said that Gilbert is an unconjugated raise and A/S condition unless there is a stressor... +

 +2  upvote downvote
submitted by bwdc(697)

Intermittent hyperbilirubinemia/jaundice in an otherwise healthy individual is typical of Gilbert’s syndrome, which is caused by the decreased activity of UDP glucuronosyltransferase.

 Login (or register) to see more

 +1  upvote downvote
submitted by azibird(278)

This patient has a mixed hyperbilirubinemia. How could Gilbert syndrome, cause direct bilirubin to increase? The syndrome is caused by mildly decreased UDP-glucuronosyltransferase conjugation and impaired bilirubin uptake. So there's absolutely no way it could increase direct bilirubin! I thought this must mean that there was an obstruction or extravascular hemolysis.

 Login (or register) to see more

 +0  upvote downvote
submitted by divinedomain(1)

honestly fuck them. increased direct should point you to another dx.

 Login (or register) to see more

Must-See Comments from free120

sugaplum on It is a polymorphism
bwdc on Elaboration of proteases and urease with ...
bwdc on Hypercoagulability from advanced malignancy
bwdc on Ribosomal assembly
bwdc on Aspiration
bwdc on Amygdala
imnotarobotbut on von Willebrand disease
bwdc on Trinucleotide repeat expansion
bwdc on Mediation of cell entry via a fusion protein
bwdc on Metabolism
bwdc on Basement membrane
melchior on Aspiration
hungrybox on Immune complex deposition in tissues
aejinkim on Decreased activity in the enzyme that ...

search for anything NEW!