Overview
Definition
The most common inherited bleeding disorder, characterized by a quantitative deficiency or qualitative dysfunction of Von Willebrand Factor, impairing platelet adhesion and clotting cascade.
Epidemiology
Prevalence ~1% of the population. Autosomal dominant inheritance in most cases (Types 1 and 2); autosomal recessive in Type 3.
Etiology & Risk Factors
- Mutations in the VWF gene, leading to deficient platelet adhesion to damaged endothelium and decreased stabilization of circulating Factor VIII
Clinical Symptoms
- Mucocutaneous bleeding: Epistaxis, gingival bleeding, easy bruising
- Menorrhagia (heavy menstrual bleeding, extremely common presentation)
- Prolonged bleeding from minor cuts, dental procedures, or surgeries
- Hemarthrosis (rare, only in severe Type 3)
Clinical Approach
Diagnosis
- Normal or prolonged aPTT
- Normal PT and normal platelet count
- Decreased vWF antigen level
- Decreased Ristocetin cofactor activity (measures vWF platelet binding function)
- Decreased Factor VIII activity
Management
- Desmopressin (dDAVP) for Type 1 (stimulates release of stored endothelial vWF/Factor VIII)
- vWF-containing factor concentrates (Humate-P, Alphanate) for severe cases, surgeries, or Types 2/3
- Antifibrinolytic agents (Tranexamic acid) for mucosal bleeding
Complications
- Severe hemorrhage during childbirth, surgery, or major trauma
- Severe iron deficiency anemia from chronic mucosal bleeding