Graves Disease After Thyroid Hormone Treatment for Thyroid Nodule

Abstract

Nodularity of the thyroid gland is extremely common, and suppression of thyroid-stimulating hormone secretion by thyroxin is one of the treatment options most often employed. However, exogenous thyroid hormone could be a precipitating factor for autoimmune hyperthyroidism. We studied a 39-year-old woman for a thyroid nodule found by sonogram. She had no palpable mass in the thyroid gland. She had no tremor. Thyroid function tests were normal. After 4 weeks of thyroxin 0.1-mg daily treatment, Graves disease was diagnosed by thyrotoxicosis and combined with diffuse increased radioactive iodine uptake in thyroid gland. The thyroxin was discontinued and the symptoms of thyrotoxicosis improved. Thyroid function test returned to normal. Physicians should be aware of the possibility of precipitating autoimmune hyperthyroidism with thyroxine suppressive therapy for thyroid nodules.