THE PREVENTION AND MANAGEMENT OF IODINE-INDUCED HYPERTHYROIDISM AND ITS CARDIAC FEATURES

Review of available literature and experience supports a recommended d aily iodine intake of 150 mu g for adults, 200 mu g during pregnancy, 50 mu g for the first year of life, 90 mu g for ages 1 to 6, and 120 m u g for ages 7 to 12. The amount of iodine added to salt in fortificat ion programs should be adjusted to achieve these intakes. Iodine-induc ed hyperthyroidism (IIH) is an occasional consequence of the correctio n of iodine deficiency, occurring most frequently in older subjects wi th multinodular goiter. This complication is usually mild and self-lim ited, but may be serious and occasionally lethal. The most important c linical manifestations are cardiovascular. Thyrotoxicosis can aggravat e pre-existing cardiac disease and can also lead to atrial fibrillatio n, congestive heart failure, worsening of angina, thromboembolism, and rarely, death. In the absence of pre-existing cardiac disease, treatm ent of thyrotoxicosis usually returns cardiac function to normal. Heig htened awareness on the part of the health sector will promote early d etection and prompt treatment of IIH. Monitoring should be an importan t part of a successful program of iodization, and in addition it offer s the best opportunity for recognizing and treating IIH. Further resea rch to improve the characterization and prevention of IIH is strongly encouraged. The most important conclusion is that IIH, while an issue that needs serious address, is not a reason to stop iodine supplementa tion in deficient regions. The benefits to the community from correcti ng iodine deficiency and avoiding its associated disorders far outweig h the damage from IIH.