Hemophilias

(Lancet 2016;388:187)

• X-linked recessive factor VIII (hemophilia A) or factor IX (hemophilia B) deficiency
• Classification: mild (5–25% normal factor activity), moderate (1–5%), or severe (<1%)
• Clinical manifestations: hematomas, hemarthroses, bruising, bleeding (mucosal, GI, GU)
• Diagnosis: ↑ PTT (normalizes w/mixing study), normal PT & vWF, ↓ factor VIII or IX
• Prophylaxis indicated if <1% activity of factor VIII or IX
• Rx: purified/recomb. factor VIII or IX; desmopressin (mild disease); anti-fibrinolytics (aminocaproic acid; tranexamic acid); cryo (FVIII); emicizumab (bridges factor IX and X), effective for hemophilia A w/ and w/o inhibitors (NEJM 2017;377:809 & 2018;379:811)