Inherited bleeding disorder characterized by a reduced quantity or function of von Willebrand factor
Aetiology
The primary cause of VWD is a genetic mutation that results in a deficiency or dysfunction of VWF
The VWF gene is located on chromosome 12 and numerous mutations have been identified
Risk factors include a family history of VWD or a family history of bleeding
Pathophysiology
As VWF has a critical role as an adhesive protein in the platelet vessel wall interaction, the absence of VWF leads to impaired platelet adhesion to the subendothelium
Reduced VWF levels also lead to factor VIII deficiency, as factor VIII is not protected from premature degradation
Clinical features
Clinical features depend on mutation, ranging from mild to more severe bleeding:
Excess or prolonged bleeding from minor wounds
Excess or prolonged bleeding post-operatively
Easy bruising
Menorrhagia
Epistaxis
GI bleeding
Investigations
Bloods:
FBC: may be normal or may show microcytic anaemia or low platelet count
Coagulation tests: APTT may be normal or may be prolonged if factor VIII deficiency is present, PT will be normal
VWF antigen test, factor VIII clotting activity test
Specialised VWF testing e.g. von Willebrand factor multimer test