Association between thyrotoxicosis and thrombocytopenia. A case report and review of the literature.

In a young woman who presented with hyperthyroidism and autoimmune thrombocytopenic purpura, the platelet count returned to normal following successful treatment of the hyperthyroidism. Thromboagglutinins were present, the titer declining as the patient became euthyroid. A survey of the literature revealed 48 reports of hyperthyroidism and thrombocytopenia, these disorders coexisting in 37 patients and there being no apparent cause for the lowered platelet counts in 28 of them. The clinical features and response to treatment in the latter group and in our patient are reviewed, comprising a series of 29. Of 22 patients whose hyperthyroidism was adequately treated, platelet counts returned to normal in 18 (82%). In three patients the purpura remitted despite persistent thrombocytopenia. It is estimated that in 7% of patients with autoimmune thrombocytopenic purpura, thrombocytopenia responds to treatment of an underlying thyrotoxicosis and in many of these patients the thrombocytopenia will prove resistant to other forms of therapy.