Autonomously functioning thyroid nodule
Sixty-seven patients with autonomously functioning thyroid nodule (AFTN) had either euthyroid or toxic nodules, according to clinical, biochemical, and dynamic studies. The subjects were residents of regions of Iran known to be iodine deficient. The prevalence of hyperthyroidism and T3 toxicosis was greater than in iodine-sufficient areas, and AFTN and toxic nodules occurred at a younger age range (74.6% of subjects were age 20–49 years) than in iodine-sufficient areas. One-fourth of the subjects had hyperthyroidism and 35.5% of the hyperthyroid patients had T3 toxicosis. The sex distribution showed a lower female-to-male ratio inpatients with AFTN (3.7:1) and in patients with toxic nodules (1.8:1) than earlier studies showed. There was some discrepancy in the results of T3 suppression and TRH tests; nine subjects with nonsuppressible nodules (T3 suppression) had normal TRH responses. Forty (81.6%) patients with euthyroid AFTN had no response to TRH stimulation. There was a good correlation between 1-131 and Tc-99m scans.