Why are patients with von Willebrand disease prone to mucosal bleeding?

• A. Defective platelet adhesion due to deficient vWF mediated binding to subendothelial collagen.
• B. Increased platelet production.
• C. Increased fibrin formation.
• D. Enhanced vitamin K activity.

Answer: (A)

Mucosal bleeding in von Willebrand disease results from impaired primary hemostasis due to lack of functional von Willebrand factor that normally ties platelets to damaged vessel walls. vWF acts as a bridge between exposed subendothelial collagen and platelet GPIb, promoting firm platelet adhesion and the formation of the initial platelet plug. When vWF is deficient or dysfunctional, platelets fail to adhere effectively, especially in the high-shear environment of mucosal surfaces, leading to easy and recurrent mucosal bleeding. vWF also stabilizes factor VIII, so levels of FVIII can be reduced as well, which can worsen bleeding, but the core problem driving mucosal bleeding is defective platelet adhesion from insufficient vWF.