povidone-iodine and Goiter--Nodular

In a 63-year-old woman with a multinodular goiter who was receiving suppressive therapy with levothyroxine sodium, iodine-induced thyrotoxicosis developed after povidone-iodine was applied to the surface of a granulating hip wound. Signs and symptoms of apathetic thyrotoxicosis developed on two occasions, once within a week after exposure of the wound to povidone-iodine soaks and again following repeated Hubbard tank debridement with added povidone-iodine. Iodine-induced thyrotoxicosis was confirmed by markedly elevated serum thyroxine and serum and urine iodine levels. On eliminating the sources of exogenous iodine and inhibiting thyroxine biosynthesis with propylthiouracil, the process was gradually controlled. A year later the patient was taking no medication and was clinically and chemically euthyroid. Apparently, iodine-induced thyrotoxicosis can result from passive diffusion of iodine into autonomous thyroid tissue. Iodine-containing preparations given to patients with multinodular goiters may result in thyrotoxicosis even if thyrotropin is suppressed with exogenous thyroxine.

Topics: Female; Goiter, Nodular; Humans; Hyperthyroidism; Iodine; Middle Aged; Povidone-Iodine; Thyroxine

Iodine-induced hyperthyroidism has been frequently described when iodine is introduced into an iodine-deficient area. However, it may also occur in patients with and without previous thyroid disease residing in iodine-sufficient areas. Five patients with iodine-induced hyperthyroidism seen in a 12-month period are described. All were exposed to iodine in the form of commonly used drugs (Betadine, Iodo-Niacin, amiodarone, and radiographic contrast dyes). The cause of iodine-induced hyperthyroidism is unclear, but it is probably more common in patients with goiters containing previously existing areas of autonomous function or iodine-poor thyroglobulin. Iodine-induced hyperthyroidism usually abates after iodine withdrawal in patients with multinodular goiters or normal thyroid glands. The hyperthyroidism is usually treated with beta-blockers and antithyroid thionamide drugs, although reinstitution of iodine to block thyroid hormone release or corticosteroids occasionally may be necessary. Iodine-containing drugs should be given with caution to patients with underlying thyroid disease.

Topics: Adult; Amiodarone; Chlorobutanol; Coloring Agents; Coronary Artery Bypass; Drug Combinations; Female; Goiter, Nodular; Graves Disease; Humans; Hyperthyroidism; Iodine; Iodine Radioisotopes; Male; Middle Aged; Niacinamide; Postoperative Complications; Povidone-Iodine; Propylthiouracil; Radiographic Image Enhancement; Sodium Iodide; Thyroid Hormones