A case of Graves' disease associated with painful thyroiditis.

We report on a 61-year-old woman with untreated Graves' disease associated with painful thyroiditis. On examination, the left lobe of the thyroid gland was firm and tender but the right lobe was not. A diagnosis of Graves' disease was made based on the results of thyroid function tests including the percentage of thyroidal radioactive iodine uptake (RAIU) and the presence of thyroid-stimulating antibodies (TSAb). However, ultrasonogram results and inflammatory findings (C-reactive protein concentration and erythrocyte sedimentation rate) also indicated the presence of inflammation in the thyroid gland. She was first treated with aspirin, and later with prednisolone. Her clinical course was similar to that in cases of subacute thyroiditis, but neither her HLA type nor aspiration cytology findings indicated the type of thyroiditis. With the resolution of the thyroiditis, her serum levels of thyroid hormone and TSAb decreased, although RAIU increased. Finally, she became euthyroid without antithyroid drug treatment. The serum levels of antithyroid antibodies, TSH-binding inhibitor immunoglobulins (TBII) and TSAb increased transiently and then decreased during the course of the illness, indicating that the mechanism(s) of the production and/or degradation of TBII and TSAb is similar to that for antithyroid antibodies in the present case. The present findings also indicate that remission may occur in some patients with Graves' disease after painful thyroiditis is resolved.