How does desmopressin (DDAVP) help in von Willebrand disease?

• A. Inhibits fibrinolysis
• B. Replaces deficient platelets
• C. Stimulates release of endogenous vWF and factor VIII from endothelium
• D. Increases synthesis of fibrin

Answer: (C)

Desmopressin helps by triggering the release of von Willebrand factor and factor VIII from endothelial storage sites into the bloodstream. It acts on endothelial cells to exocytose Weibel-Palade bodies that contain vWF and FVIII, increasing their circulating levels. The rise in vWF enhances platelet adhesion to damaged vessels because vWF binds platelets (via GPIb) and collagen, promoting a more effective platelet plug. The effect is temporary, lasting only hours, and is particularly helpful in mild forms of von Willebrand disease. It does not replace platelets, does not promote fibrin synthesis, and does not inhibit fibrinolysis.