Evaluation of Radioiodine Therapy in the Refractory Hyperthyroidism

Background: Thyrotoxicosis is a clinical state with potentially multiple etiologies, clinical presentations, and treatments. Thyrotoxicosis is a clinical condition that results from inappropriate function of thyroid hormone in the body tissues. During the early 1950s, radioactive iodine was used as a definitive treatment method. During the last two decades, radioactive iodine has been recognized as an effective treatment for thyrotoxicosis because of its simplicity, repeatability, inexpensiveness, and low recurrence rate. Method and materials: One hundred patients with refractory hyperthyroidism (40 men and 60 women) were enrolled according to the inclusion criteria from 2017 to 2021. The data was extracted considering the ethical principles of examining patients' medical files. Patients' information including age, gender, type of hyperthyroidism, serum levels of TSH, and free T4 were collected before and 2, 6, and 12 months after treatment. Results: The results showed that 61% of the patients had toxic nodular goiter and 39% had diffuse toxic goiter. The mean ± standard deviation values of patient’s TSH and free T4 before treatment were 0.91±0.07 and 2.9±0.8, respectively. Six months after treatment, 49% of the patients became hypothyroid. Also 43% revealed euthyroid state and 5% showed no response (recurrence). One year follow-up of these patients after repetitive radioiodine therapy showed 6% hypothyroidism and 2% euthyroidism. Conclusion: Our results indicated that radioactive iodine therapy is an effective and definitive treatment for patients with refractory hyperthyroidism.