85% are A and 15% B; no racial or ethnic predisposition

• Hemophilia A: Deficiency/dysfxn in FVIII, 1/5,000 male births, 1/3 no FHx

• Hemophilia B: Deficiency/dysfxn in FIX, 1/30,000 male births

• Hemophilia C: Deficiency in FXI, 10 times less common than hemophilia A, usually mild bleeding tendency, bleeding risk not related to severity of deficiency

X-linked

Clot formation is delayed and not robust → slowing of rate of clot formation

• With crawling and walking—easy bruising

• Hallmark is hemarthrosis—earliest in ankles; in older child, knees and elbows

• Large-volume blood loss into iliopsoas muscle (inability to extend hip)—vague groin pain and hypovolemic shock

• Vital structure bleeding—life-threatening

Labs

• 2x to 3x increase in PTT (all others normal)

• Correction with mixing studies

• Specific assay confirms:

  • Ratio of VIII:vWF sometimes used to diagnose carrier state

  • Normal platelets, PT, bleeding time, and vW Factor

Treatment

• Replace specific factor

• Prophylaxis now recommended for young children with severe bleeding (intravenous via a central line every 2–3 days); prevents chronic joint disease

• For mild bleed—patient’s endogenous factor can be released with desmopressin (may use intranasal form)

• Avoid antiplatelet and aspirin medications

• DDAVP increases factor VIII levels in mild disease