Autoimmune thrombocytopenic purpura associated with hyperthyroidism in a single individual.

An association between thrombocytopenia and thyrotoxicosis has been previously documented. In addition, a familial association between thrombocytopenia and thyrotoxicosis has also been reported. Theories for etiology include a common immunologic cause, a thyrotoxic-induced decrease in platelet survival, and a genetic predisposition for underlying autoimmune disease. We report a case of autoimmune thrombocytopenic purpura associated with hyperthyroidism in which the patient's thrombocytopenia and thyrotoxicosis resolved concomitantly. We recommend testing for hyperthyroidism in all patients with unexplained thrombocytopenia and that family members of patients be evaluated, screened, and observed for thrombocytopenia and hyperthyroidism.