Effect of Graves' disease on idiopathic thrombocytopenic purpura.

The association between hyperthyroidism and thrombocytopenia is a known although infrequent clinical condition. Distinct mechanisms are probably active in each particular case, but the thyrotoxic state has been implicated as having a key effect on the fall in the number of platelets. We describe a patient with coexisting Graves' disease and idiopathic thrombocytopenic purpura who showed special refractoriness to treatment of the bleeding condition in the thyrotoxic state, but who promptly responded to treatment when the thrombocytopenia relapsed 2 1/2 years later, while he was euthyroid. Thus, in this case, a clear exacerbating effect of the thyrotoxic state on the thrombocytopenia was observed. We suggest evaluation of the thyroid condition in patients suffering from refractory thrombocytopenia.