Teaching Pearls:

• Intrinsic Coagulation Pathway
  • XII, XI, IX, VIII
  • Manifested by PTT
• Extrinsic Coagulation Pathway
  • Factor VII
  • Coumadin decreases production of Factors 2, 7, 9, and 10. Factor VII has the shortest half-life so PT/INR changes are seen first.
  • Manifested by PT/INR
• Factor VIII Deficiency (Hemophilia A)
  • Genetic
    • X-link recessive trait
      • Present mostly in males at younger age
    • Due to decreased ability to produce factor VIII
    • Elevated PTT due to factor VIII deficiency
    • Treated with prophylactic Factor XIII infusion
    • Clinically presents with hemarthrosis, which can be very severe causing chronic disabling joint disease.
  • Acquired
    • Can be seen in malignancy, post-partum state, or with other autoimmune diseases
    • Can also be idiopathic
    • Elevated PTT due to inhibitor protein against factor VIII
    • Treatment depends on concentration of inhibitor
      • Fast Responder (high inhibitor) – treat with PCC/FFP if actively bleeding, and immunosuppression.
      • Slow Responder (low inhibitor)  – can be treated with factor VIII infusion.
    • Clinical bleeding can manifest in a variety of ways as compared to congenital factor VIII deficiency.
• Von Willebrand’s Disease (vWF)
  • Most common genetic cause of bleeding.
  • vWF protects factor VIII from being degraded.
    • vWF deficiency can lead to PTT prolongation.
  • vWF binds to a receptor G1b on the platelets to achieve primary hemostasis.
    • vWF disease results in increased bleeding time, which is a result of poor platelet binding and aggregation.