Coagulation Disorders USMLE Step 1 Practice Question
A 3-year-old boy is brought to the emergency department with a 2-day history of fever (38.5°C), petechial rash, and lethargy. His parents report he was in his usual state of health until yesterday. Vital signs show HR 118/min, RR 30/min, and BP 95/62 mmHg. Physical examination reveals generalized petechiae, hepatosplenomegaly, and no lymphadenopathy. Laboratory studies show: hemoglobin 7.2 g/dL, platelets 18,000/μL, INR 2.4, aPTT 58 seconds (normal 25-35), fibrinogen 85 mg/dL (normal 200-400), and elevated D-dimer. Peripheral blood smear shows schistocytes. Bone marrow biopsy demonstrates adequate megakaryocytes. Which of the following is the most likely diagnosis?
Answer choices
- AImmune thrombocytopenia with secondary coagulopathy
- BDisseminated intravascular coagulation secondary to sepsisCorrect answer
- CThrombotic thrombocytopenic purpura
- DAcute leukemia with tumor lysis syndrome
- EHemophilia A with secondary hypofibrinogenemia
- FVitamin K deficiency with thrombocytopenia
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