Hypothyroidism as a cause of acquired von Willebrand's disease.

Three patients with bleeding tendency who met the criteria for type 1 von Willebrand's disease are described. In two patients, hypothyroidism was suspected and confirmed at presentation, and in the third hypothyroidism became apparent 4 years later. In all three, the history and clinical course after treatment with thyroxine indicated acquired von Willebrand's disease secondary to hypothyroidism. The possibility of hypothyroidism should be considered in patients presenting with von Willebrand's disease.