A 12 yo male presents with c/o easy bruising, recurrent epistaxis and bleeding gums. He has previously been healthy, has not had any recent illnesses. The family history is essentially negative.
Physical exam reveals a well-developed, well-nourished child with multiple petechiae and purpura on the extremities, as well as several on his torso. HEENT exam reveals mild gingivitis. He has some bloody drainage in the right nostril. His heart and lung exam is normal. The abdominal exam is normal. No organomegaly noted.
CBC: RBC 4.62, Hgb 13.8, Hct 38.2, MCV 83, MCH 30, MCHC 36, RDW 12.4, WBC 5.8, N 46, L38, M 13, E 1, B 2, platelet count <5000. Platelet morphology- increased in size. INR 0.91 (RI 0.85-1.15), PTT 24.8 sec (RI 23-34), TT 15.8 sec (RI 13-18) Bone Marrow Aspirate: Erythrocyte and granulocyte maturation within normal limits. Megakaryocytes appear normal in number and morphology. Sections: Slightly hypocellular for his age, with abundant megakaryocytes. 1. What is the differential diagnosis? 2. What is the most likely diagnosis? 3. Discuss the pathophysiology of this disorder. 4. What are some other disorders that can result in decreased clotting?