A case of Graves' disease associated with polymyositis.

A patient with Graves' disease associated with severe muscle weakness who was finally diagnosed as polymyositis by pathological examination of the muscle is reported. A 28-year-old women was incidentally found to have hyperthyroidism when she consulted a hospital for the evaluation and treatment of anemia in 1979. She was treated with methimazole for approximately a month when she stopped the medication by herself. Approximately two yr later (Nov. 4, 1981) she consulted another hospital with complaints of palpitation and muscle weakness. Diagnosis of hyperthyroidism due to Graves' disease and thyrotoxic myopathy were made, followed by the treatment with radioiodine (4 mCi of 131I). She was further treated with propylthiouracil (PTU). Four yr after the treatment, serum thyroid hormone concentration declined to the lower level than normal and serum TSH concentration increased. She was subsequently treated with synthetic I-T4. Despite the fact she became euthyroid with the treatment, muscle weakness as well as elevated concentrations of muscle enzymes were not improved. Muscle biopsy was made in July 1983, and she was diagnosed as immune polymyositis and treatment with prednisolone and cyclophosphamide in addition to PTU or I-T4, was started. With the treatment, serum LDH decreased to the normal range. However she still has muscle weakness and serum concentrations of CPK and aldolase are still in higher levels than normal range.