Von Willebrand’s disease
A hereditary bleeding disorder, von Willebrand’s disease is characterized by prolonged bleeding time, moderate deficiency of clotting Factor VIIIAHF (antihemophilic factor), and impaired platelet function.
This disease commonly causes bleeding from the skin or mucosal surfaces and, in females, excessive uterine bleeding. Bleeding may range from mild and asymptomatic to severe, potentially fatal hemorrhage. Prognosis, however, is usually good.
Unlike hemophilia, von Willebrand’s disease is inherited as an autosomal dominant trait and occurs more often in females. One theory of pathophysiology holds that mild to moderate deficiency of Factor VIII and defective platelet adhesion prolong coagulation time. Specifically, this results from a deficiency of the von Willebrand factor (VWF), which stabilizes the Factor VIII molecule and is needed for proper platelet function.
Defective platelet function is characterized by:
decreased agglutination and adhesion at the bleeding site
reduced platelet retention when filtered through a column of packed glass beads
diminished ristocetin-induced platelet aggregation.
Recently, an acquired form has been identified in patients with cancer and immune disorders.