Outcome of treating thyrotoxic patients with a standard dose of radioactive iodine

This is a report of an audit exercise that was designed to study the effectiveness of treating thyrotoxic patients with a standard dose--370 MBq--of radioactive iodine (131l). This treatment was received by 183 patients in one centre between 1977 and 1989. The results were assessed from the answers to 114 questionnaires that had been completed by the patients' general practitioners. The patients were aged between 28 and 85 years; 86% were female; 42% had been treated previously with anti-thyroid drugs. Ninety-five of the patients (83%) became euthyroid after a single dose of 131l; 18 required one further dose; and one required two further doses. At the time of the survey, 32 (28%) were euthyroid, while 82 patients (72%) had become hypothyroid and required treatment with thyroxine. Within five years of treatment, 85% of the patients had become hypothyroid. These results are compared with those from two other centres.