Acquired von Willebrand Syndrome.

Acquired von Willebrand syndrome is a rare hemorrhagic diathesis, with clinical symptoms similar to those associated with the inherited form von Willebrand disease. This syndrome is characterized by a lack of previous bleeding symptoms, negative familial history, and occurrence in a relatively older age. Most commonly, acquired von Willebrand syndrome develops in the course of other conditions, such as lymphoproliferative, myeloproliferative, cardiovascular and autoimmune disorders; additionally, it can be associated with some non-hematological malignancies and use of certain prescription drugs. Pathogenesis of von Willebrand syndrome is complex and not fully understood. Deficiency or impaired activity of von Willebrand factor can result from the presence of specific antibodies against this factor, its adsorption onto the surfaces of neoplastic cells, mechanic injury or proteolysis. Diagnosis is based on the measurements of plasma concentration and the activity of von Willebrand factor and multimer analysis. Management of acquired von Willebrand syndrome includes the therapy of the underlying disease and the control or prevention of bleeding. Hemostatic drugs that are most commonly prescribed in this syndrome include desmopressin, von Willebrand factor concentrates, recombinant activated factor VII, intravenous immunoglobulin and adjunctive antifibrinolytic therapy. Additionally, plasmapheresis is required in some cases.