Enhanced susceptibility to iodide myxedema in patients with hashimoto’s disease

Abstract

Studies were performed in 6 patients with proven Hashimoto’s disease and one patient with probable Hashimoto’s disease who were initially euthyroid, as judged from clinical findings, serum thyroxine (T4) and serum TSH concentrations. When these patients were given saturated solution of potassium iodide (5 drops containing approximately 180 mg of iodide daily), 4 of the 7 developed hypothyroidism within 4 to 6 weeks as evidenced by clinical findings, subnormal values for serum T4, and elevated values for serum TSH concentration. Values quickly returned to normal when iodides were withdrawn. In the remaining 3 patients, evidence of hypothyroidism did not develop despite continuation of iodide administration for as long as 17-30 weeks. No obvious differences between the 4 patients who developed iodide myxedema and the 3 who did not were evident in respect to known duration of the disease, size of goiter, initial level of thyroid function or intensity of the auto-immune process as judged by circulating autoantibody titers. The possible similarities between Hashimoto’s disease and Graves’ disease with respect to the occurrence of enhanced sensitivity to iodide induced myxedema in the 2 disorders is considered. © 1971 by The Endocrine Society.