Coags

Hemophilia A

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Hemophilia A, Hemophilia, Factor VIII Deficiency

  • Epidemiology
  1. Most common hereditary Coagulation Disorder (1:10,000)
  2. Accounts for 80-90% of Hemophilia cases (remainder are Hemophilia B which is a Factor IX Deficiency)
  • Pathophysiology
  1. Sex linked recessive deficiency of factor VIII
  • Symptoms
  1. Excessive bleeding from slight Trauma
    1. Dental extraction
    2. Surgery
  2. Visceral bleeding
  3. Hemarthrosis
    1. Contractures
    2. Degenerative Arthritis
  • Labs
  1. Partial Thromboplastin Time (PTT) elevated
  2. ProTime (INR/PT) normal
  • Management
  • Recombinant Factor VIII replacement
  1. Indications
    1. Acute Bleeding
    2. Preoperative prophylaxis
  2. Dosing basic regimen
    1. Typical dosing
      1. Factor VIII 50 units/kg every 8-12 hours OR
      2. Factor VIII (desired concentration - current concentration) * wtKg every 8-12 hours
    2. Factor VIII Infusion
      1. Load: 50 units/kg
      2. Infusion: 4-5 units/hour (directed by Factor VIII levels)
  3. Dosing in major bleeding (directed by involved region and target Factor VIII levels)
    1. Major injury with active bleeding or preoperative and perioperative prophylaxis and management
      1. Target: 100% initially, then 80-100% until wound healed, then 30% of normal Factor VIII Level until Suture removal
      2. Recombinant Factor VIII 50 units/kg every 12 hours (adjusted for healing)
    2. Joint bleeding (hemarthrosis)
      1. Target: 80% in acute period, then 40% every other day of normal Factor VIII Level
      2. Recombinant Factor VIII 40 units/kg initially, then 20 units/kg every other day until healed
    3. Gastrointestinal Bleeding
      1. Target: 100% initially, then 50% of normal Factor VIII Level until healed
      2. Recombinant Factor VIII 50 units/kg initially, then 30-40 units/kg daily
    4. Genitourinary bleeding
      1. Target: 100% initially, then 30% of normal Factor VIII Level until healed
      2. Recombinant Factor VIII 50 units/kg initially, then 30-40 units/kg daily
    5. CNS Bleeding
      1. Target: 80-100% initially, then 50-100% of normal Factor VIII Level for 14 days
      2. Recombinant Factor VIII 50 units/kg initially, then 25 units/kg every 12 hours
    6. Oral Bleeding
      1. Target: 100% of normal Factor VIII Level
      2. Recombinant Factor VIII 50 units/kg
      3. Consider topical fibrinolytic agents
    7. Epistaxis
      1. Target: 80-100% initially, then 30% of normal Factor VIII Level until healed
      2. Recombinant Factor VIII 40-50 units/kg then 30-40 units/kg daily
    8. Muscle bleeding
      1. Target: 50% of normal Factor VIII Level
      2. Recombinant Factor VIII 20-40 units/kg daily until healed
  4. Alternative agents when Factor VIII is not available
    1. Cryoprecipitate 10 units
      1. Increases Factor VIII to over 100%
  5. References
    1. Deloughery and Orman in Majoewsky (2013) EM:Rap 13(9): 1-4
    2. DiMichele (1996) Pediatr Clin North Am 43(3): 709-36 [PubMed]