Von Willebrand disease

Background

• Most common inherited bleeding disorder
• vWF has two roles:
  • 1. Acts as cofactor for platelet adhesion
  • 2. Acts as carrier protein for factor VIII extending its half life
• vWD results from quantitative or qualitative dysfunction of Von Willebrand factor

Clinical Features

• Skin and mucosal bleeding
  • Epistaxis, gingival bleeding, menorrhagia
• Hemarthrosis is unusual

Diagnosis

• Bleeding time: prolonged
• PT: normal
• PTT: normal-mildly prolonged
• vWF activity level: low

Treatment

• Avoid ASA, NSAIDs, heparin
• Intermediate purity factor VIII
  • Goal to increase VWF activity by 50-100%
  • Initial infusion of 20-40 IU/Kg
  • High replacement doses may be indicated in more severe disease
• Platelet transfusion
  • consider if replacement therapy instituted and persistent bleeding
• Desmopressin
  • Induces release of vWF from endothelial storage sites
  • 0.3mcg/kg IV (max 20mcg) over 30min
• Aminocaproic acid
• Recombinant Factor VIIa
  • Consider in type 3 VWD patients who have developed antibodies to VWF replacement
  • Increased risk of thrombosis, especially in patients with coronary artery disease

Source

Tintinalli's Emergency Medicine: A Comprehensive Study Guide, 7e (2010), Chapter 230. Hemophilias and Von Willebrand Disease

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