The background of the study. Patients with hyperthyroidism caused by Graves’ disease who are treated with an antithyroid drug may remain well thereafter, but some have recurrent hyperthyroidism. This study describes the occurrence of recurrent hyperthyroidism that subsided spontaneously in patients previously treated for Graves’ hyperthyroidism.
How the study was done. The study subjects were 22 patients, 20 women and 2 men, with Graves’ hyperthyroidism who had mild transient hyperthyroidism after completion of a course of antithyroid drug therapy (mean duration, 39 months) and who were followed without resumption of therapy. All had normal serum thyrotropin (TSH), free thyroxine (T4), and thyroid-stimulating antibody (TSH-like Ab) values when therapy was stopped. Patients who had “unbearable” symptoms of hyperthyroidism or were elderly were excluded.
The results of the study. The interval between when antithyroid drug therapy stopped to the onset of recurrent hyperthyroidism averaged 6 months (range, 1 to 12). At that time, all the patients had undetectable serum TSH values and high serum free T4 values. Thyroid radioiodine uptake was low in two patients, indicating thyroiditis, and was normal or high in four others, indicating Graves’ disease. The patients became euthyroid without therapy an average of 6 months later, and none had later recurrence of hyperthyroidism.
The conclusions of the study. Patients with Graves’ hyperthyroidism who are treated with an antithyroid drug may later have recurrent hyperthyroidism that subsides spontaneously.
The original article. Kubota S, Tamai H, Ohye H, Fukata S, Kuma K, Miyauchi A. Transient hyperthyroidism after withdrawal of antithyroid drugs in patients with Graves’ disease. Endocr J 2004;51:213-7.