Case Selection and Restrictions Recommended to Patients with Hyperthyroidism in South America

Abstract

Data from South America related to the use of radioiodine therapy indicate that radioiodine is prescribed only by physicians with special training and a license. A thyroid dose of ¹³¹I >29 mCi requires hospitalization of the patient. Members of the Latin American Thyroid Society (LATS) (235 physicians) were surveyed by a questionnaire on their management of Graves' disease, and the survey procedure was the same used by other thyroid societies. Thyroid uptake/scintigraphy was carried out by 60% of respondents and ¹³¹I was the isotope most used (chosen by 95% of respondents). Serum total T₄ and T₃ were requested by 97% of LATS members whereas measurement of free T₄ and TSH was employed less frequently (27% and 46.3%, respectively). The therapy of choice for 83% of responding members was antithyroid drugs. Radioiodine was chosen by 15.3% of respondents. For most respondents, the aim of ¹³¹I therapy was to restore euthyroidism. It was based on goiter size and thyroid uptake and administered in a single dose. For the radioiodine therapy, 55.5% of the respondents did not add any other medical treatment. The remaining group used antithyroid drugs before ¹³¹I (50%), and 77% employed it after the dose. There is a general consensus to provide the ¹³¹I treatment only to patients >18 years of age. ¹³¹I was overwhelmingly (64.2% versus 34% for drug therapy) the therapy seen as most appropriate for patients with recurrence or old age. The predominant use of antithyroid drugs for therapy of Graves' disease in South America was similar to that in Europe and Japan but different from the practice in North America.