A 14 year old boy presents to your clinic with a swollen and painful left knee. He said it was preceded by stiffness and followed by a warm sensation, then acute pain. There is no history of trauma; the boy just played a basketball game. You send off labs and get a normal platelet count and PT, and a prolonged aPTT. A mixing test corrects the abnormality. You send off a specific factor VIII assay; it's normal.
Challenge: What's the next most likely diagnosis? This disease has another name; who was it named after? What is its transmission?
1. What's the differential for a normal PT and a prolonged aPTT?
2. (Review) A normal aPTT and a prolonged PT?
3. (Review) A prolonged PT and aPTT?