A Case of Hypothyroid Graves' Disease with Extremely High Titers of TSAb

Graves' ophthalmopathy in hypothyroid state is called Hypothyroid Graves' Disease, which is a comparatively rare disease. We experienced a case of a 57 year old man with severe exophthalmos and diplopia, which are typical symptoms of Graves' opthalmopathy, and with an extremely high thyroid-stimulating antibody(TSAb) level. He also had a firm diffuse goiter and hypothyroidism with positive anti-thyroglobulin and anti-thyroid microsomal antigen. These findings suggested Hashimoto's thyroiditis. Severity of ophthalmopathy and TSAb level were improved during replacement therapy with T4. Although a thyroid stimulation-blocking antibody was also detected in this patient, we thought that hypothyroidism in this case was based on destructive change in the thyroid with Hashimoto's thyroiditis. Therefore, we should be aware of the fact that there are cases of hypothyroidism with Graves' ophthalmopathy and a high level of TSAb.