Anemias USMLE Step 1 Practice Question
A 31-year-old woman is brought to the emergency department because of confusion and severe fatigue. She has petechiae on her legs. Laboratory studies show hemoglobin 8.1 g/dL, platelets 22,000/mm3, creatinine mildly elevated, lactate dehydrogenase elevated, and numerous schistocytes on peripheral smear. PT and PTT are normal. Which of the following is the most likely underlying abnormality?
Answer choices
- AShiga toxin-mediated endothelial injury
- BAutoantibody-mediated inhibition of ADAMTS13Correct answer
- CAutoimmune destruction of GpIIb/IIIa on platelets
- DActivation of the extrinsic coagulation pathway by tissue factor
- EDeficiency of factor VIII
- FComplement-mediated thrombotic microangiopathy due to mutations in complement regulatory proteins
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