Coagulation Factor Inhibitor

Introduction

• Autoantibody against a coagulation factor
• Anti-Factor VIII is the most common
• recall factor VIII is deficient in hemophilia A

Presentation

• Symptoms
  • hemarthroses
  • intramuscular bleeding
  • GI bleeding
  • excessive bleeding in response to minor trauma
• indistinguishable from hemophilia

Evaluation

• Labs
  • ↑ PTT
  • normal PT, bleeding time
• Mixing studies 
  • supplied factor does not result in clot formation
    • antibody inhibits supplied factors
• used to distinguish from hemophilia, which would clot when supplied normal plasma