Coagulation Disorders USMLE Step 1 Practice Question
A 19-year-old woman presents with lifelong menorrhagia requiring frequent transfusions and recurrent epistaxis. She reports prolonged bleeding for 3 hours after dental extraction last month. Vital signs: BP 108/72, HR 92, RR 16, Temp 37°C, SpO2 98%. Laboratory studies show platelet count 245,000/μL, PT 12 seconds, PTT 38 seconds (normal <35), fibrinogen 280 mg/dL, and normal bleeding time. She denies family history of bleeding disorders. Which of the following is the most likely explanation for her disorder?
Answer choices
- AAbsence of factor XIII preventing fibrin cross linking
- BDeficiency of von Willebrand factor causing impaired platelet adhesion and reduced factor VIII stabilityCorrect answer
- CMutation in factor V causing activated protein C resistance
- DDefect of glycoprotein IIb IIIa causing impaired platelet aggregation
- EAutoantibody to ADAMTS13
- FDeficiency of factor XI causing impaired contact activation and thrombin generation
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