Coagulation Disorders USMLE Step 1 Practice Question
A 9-year-old boy is brought to the pediatric clinic by his mother for evaluation of recurrent nosebleeds and easy bruising over the past 2 years. His maternal grandmother and mother both experienced heavy menstrual bleeding requiring iron supplementation. The patient denies joint pain or swelling. Vital signs are within normal limits. Physical examination reveals scattered petechiae on the lower extremities and scattered ecchymoses on the shins; there is no hepatosplenomegaly, lymphadenopathy, or signs of joint bleeding. Laboratory results:
- Platelet count: 248,000/μL
- PT: 12 seconds (normal)
- PTT: 39 seconds (normal <35 seconds)
- Fibrinogen: 320 mg/dL (normal)
- von Willebrand factor antigen: 38% (normal >50%)
- Factor VIII activity: 42% (normal 50-150%)
- Bleeding time: prolonged Which of the following is the most likely diagnosis?
Answer choices
- AHemophilia A with von Willebrand factor deficiency
- BType 2 von Willebrand disease
- CPlatelet dysfunction (Bernard-Soulier syndrome)
- DFactor XI deficiency
- EType 1 von Willebrand diseaseCorrect answer
- FImmune thrombocytopenia
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