Results of treatment of thyrotoxicosis following relapse after antithyroid drug therapy.

One hundred and thirty patients who relapsed after a full course of treatment with antithyroid drugs have been reviewed. Of 22 patients receiving a second course of antithyroid drugs, 17 (77%) relapsed. In contrast, only 2 out of 44 patients treated by surgery relapsed and seven became hypothyroid. Nevertheless, local complications, in particular parathyroid insufficiency, were especially common in this group. Eighty patients received radioiodine, 11 (14%) requiring more than three doses before finally being rendered euthyroid. Postradiation hypothyroidism developed in 39 (49%) patients.