Thrombotic thrombocytopenic purpura precipitated by thyrotoxicosis.

Thrombotic thrombocytopenic purpura (TTP) may be seen in association with autoimmune disorders such as immune hemolytic anemia and systemic lupus erythematosus, but rarely has it been associated with Graves' disease. We report one such case of a woman with new-onset thyrotoxicosis caused by Graves' disease, who abruptly developed TTP, confirmed by low serum ADAMTS-13 value. She had a dramatic response to plasma exchange, with remission of TTP. Definitive treatment with radioactive iodine resulted in euthyroidism and has prevented recurrence of TTP.