NBME 23 Immune destruction of platelets (NBME Answers)

NBME 23 Answers ↦

nbme23/Block 3/Question#38 (46.8 difficulty score)
A 5-year-old boy who has recently recovered ...
Immune destruction of platelets🔍
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+18
submitted by sajaqua1(524),

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hTe mroawr wssho urorcspsre to ey,cyehortrst as lwel sa keameayogt.scyr Tsih is ot owhs uyo ttha eth eussi ti'sn d,onprdceonrituu hcwhi anems htta we era oglsni RCB adn epettslla eohmewres ie ceotnid.tusr htaT seulr uto D adn .E rTehe si ghontni ot ctdieian aht hte iclhd sha tassiniddeme suotbsruclie .)(B At sthi oipnt we rea telf htiw A or C. A louwd dtianice mdsasDteenii trsaaancIrlvu ogoilaauCtn C(D)I or onshetmig mii,alsr which dowlu sretlu ni wol lsetelatp nad CBR ubt ew lwudo alos ees oranlmba BCR eikl ctiheostcyss etl"eh"m( s)ecll. We ear tixpeyclli tlod hatt the eeorrhytcyst are hrnmocomroic and rn.cycomiot ,Hoverew eumimn durotnitces fo eteatsllp naplsexi it lla- teh utcerdisont of tepaletls delas to esmo rhehaimrggon nad so a rpdo ni R,BC nad ITP lcalslasicy aresis areft a cneert reupp oarrrtyepsi tatcr rivla tncen.fioi

meningitis Just in case anyone is wondering like I did, the low platelet count explains thethose multinucleated cells. They are Megakaryocytes in Bone Marrow Biopsy. +12

nwinkelmann Also, don't forget that autoimmune thrombocytopenia purpura has 2 demographics: young kids, which generally resolves spontaneously fairly quickly, and then young adult females which is a true autoimmune condition that doesn't resolve. Patient's age + thrombocytopenia + essentially normal rest of heme pannel = autoimmune thrombocytopenia purprua in child. +6

abhishek021196 That is exactly how I approached this question. Normal heme panel and a decreased Platelet count in a young boy after an infection just made me intuitively select ITP. +

+2
submitted by seagull(1444),

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Wyh si shit tno U?SH wHo idd uyo guys cpporaah eth ont?suiqe

joonam I think if this was HUS (d/t a bacterial infection) the leukocyte count would be abnormal (11k<) +

yotsubato normochromic normocytic RBC thats why. You would see schistocytes +9

vulcania Also for HUS I would expect mention of h/o bloody diarrhea, or at least diarrhea (not URI), and mention of something to do with kidney damage. +

+0
submitted by consistentwrongdoer3(17),

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aWth are ew odppesus to eb okoglni ?ta I ees imutleenutalcd ignat selc.l I oasl see eialnfrtti ct(na’ letl if ihst si oceumnnlrao ro .t)no

methylased Young child following URI with TCP is pretty classic ITP. Sometimes they throw in extra stuff on purpose, but I didn’t see much on the bone marrow aspirate either. +7

mousie I was also thinking ITP but the bone marrow image kind of threw me off too, not sure what I'm supposed to see but still think ITP is best choice ... +

meningitis It also almost threw me off, but then I remembered he had low platelet count and I guessed those multinucleated cells were Megakaryocytes (I looked for Megakaryocyte Bone Marrow Biopsy in google and they are the same). +1

what Bone marrow shows increased megakaryocytes -> ITP +