The Treatment of Thyrotoxicosis with Radioiodine

Abstract

Although the literature now contains many reports dealing with various aspects of the treatment of thyrotoxicosis with radioiodine, the persistence of several important unsolved problems seems to justify the presentation of additional experience acquired with statistically significant groups of cases. It is our purpose here to report such a group of patients. Although our experience to date has comprised more than 400 cases, we have included in this report only 180 of the first 228 patients treated by us. Material During the period from November 1947 to December 1952, 228 patients were treated for thyrotoxicosis with radioiodine 131.2 From these we selected 180 who have been followed for one year or more after treatment, and in whom the diagnosis was established beyond reasonable doubt on the basis of the clinical picture and standard diagnostic procedures. This group consisted of 37 males and 143 females, a ratio of approximately 1 to 4. The age range for men was from twenty-two to seventy-two years and for women from twenty to seventy-three. In patients below the age of forty, we have not considered I131 the treatment of choice unless previous thyroidectomy or other unusual circumstances dictated otherwise. In Figure 1 is shown the age distribution by decades, the largest group of 53 patients (29.4 per cent) being in the sixth decade. The general age incidence of thyrotoxicosis is also shown for the sake of comparison. In addition to 42 patients with postoperative recurrence there were 138 previously untreated or who had received antithyroid medication without permanent remission. Fifteen of the latter were classified as having toxic nodular goiters and the other 123 as having toxic diffuse goiters. Results The results of therapy with radioiodine in the entire group are shown in Figure 2. Almost 80 per cent of the patients were relieved of their thyrotoxic symptoms following an initial dose of I131, and in more than 97 per cent thyrotoxicosis disappeared after one or more treatments. When last evaluated, 142 patients (78.9 per cent) were euthyroid, 33 (18.3 per cent) were hypothyroid, and 5 (2.8 per cent) were considered as having shown unsatisfactory responses to I131. The unsatisfactory group included 4 women with large goiters, who subsequently underwent thyroidectomy, and 1 who died in thyroid storm. These cases are briefly summarized below. Case I: J. G., a 24-year-old Negro female with a large toxic diffuse goiter, had received two prolonged courses of thiouracil compounds. She relapsed into her former thyrotoxic state following withdrawal of medication. Four months later she received 7 millicuries of I131, with subsequent gradual partial improvement. Her basal metabolism rate declined from +41 to +28 per cent two months after treatment. A second dose of I131 was refused, and thyroidectomy was later performed, followed by a satisfactory remission.