NBME Step 2 CK Form 7 Bone marrow aspiration (NBME Answers)

Retired NBME Step 2 CK Form 7 Answers

step2ck_form7/Block 1/Question#6 (reveal difficulty score)
A 4-year-old boy has had increasing fatigue ...
Bone marrow aspiration 🔍 / 📺 / 🌳 / 📖
tags: hemeonc

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submitted by study_dude_guy(14)

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This question is actually a lot deeper than it looks. It is not about "when do you treat thrombocytopenia", which you DO treat when they have bleeding like in the question. This question is about management of ALL which has specific guidelines. According to uptodate, as long as platelet levels are about 20,000 in ALL, you are good to go for a bone biopsy.

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drdoom very nice +

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submitted by ∗buttercup(18)

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Bone marrow examination is generally not required for the initial evaluation in most cases of unexplained isolated thrombocytopenia in children. This child has pancytopenia and therefore requires a bone marrow aspiration.

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jesusisking Why wouldn't it be platelet transfusion 1st? +

jesusisking Just found the answer. Patient was stable and not actively bleeding w/ 30K platelet count. For this type of patient, start transfusing at <10K: https://www.aafp.org/afp/2011/0315/hi-res/afp20110315p719-t2.gif +4

deathbystep1 well the question said "his gums started bleeding when he brushed his teeth". So wouldn't that be considered active bleeding? I was aware about the aafp guidelines as there was a similar question in Uworld as well. The only reason i chose platelet transfusion was because he was "actively" bleeding from the gums. Otherwise it was clear that he had pancytopenia and you need to do a bone marrow biopsy. +

zalzale96 Isn't bone marrow aspiration considered an invasive procedure and thus we should transfuse since his platelets level is below 50k? +

osler_weber_rendu Acc to UW, in children transfuse ivig, steroids, anti D only if child has more than mucocutaneous bleeds. In adults it is done if the count is below 30k irrespective. +

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submitted by ∗step_prep5(246)

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Young child with a recent URI who is presenting with pancytopenia and lymphadenopathy and hepatomegaly, concerning for acute lymphoblastic leukemia
Key idea: Viral infections are known for causing pancytopenia, but in this patient who fits the correct demographic and has lymphadenopathy and hepatomegaly (signs of lymphoid hyperplasia) fit well with a diagnosis of acute lymphoblastic leukemia, which would have at least 20% blast cells on bone marrow aspiration

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