Child with an maternal uncle with hemophilia who presents with joint swelling after minor trauma (concerning for hemarthrosis) with increased aPTT that corrects with mixing, concerning for hemophilia A (Factor VIII deficiency)
Key idea: Hemophilia A (X-linked, Factor 8 deficiency) > Hemophilia B (X-linked, Factor 9 deficiency) > Hemophilia C (Autosomal recessive, Factor 11 deficiency)
Key idea: If the coagulation studies are prolonged and do NOT correct with mixing, that should raise your suspicion for a coagulation factor inhibitor (often acquired in setting of recurrent transfusions, antiphospholipid syndrome, etc.)
etherbunnyInfrequent bleeding episodes in the uncle and a first presentation at the age of 5 sounded more like the milder hemophilia B (Factor IX) to me. Apparently not though!+
lindasmith462i thought so too but factor IX deficiency wasnt an answer option (I had to tripple check the main difficulty in this question is amking sure you cross out the right answer choices lol)+1
kstudyGot this one wrong cause I dyslexicly misread answer choice B as answer A. An NBME dilema when you know you're choosing the right answer but accidently bubble in the wrong one. +
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