TY - JOUR T1 - Thyroid dysfunction following a kelp-containing marketed diet JF - BMJ Case Reports DO - 10.1136/bcr-2014-206330 VL - 2014 SP - bcr2014206330 AU - Tiziana Di Matola AU - Pio Zeppa AU - Maurizio Gasperi AU - Mario Vitale Y1 - 2014/10/29 UR - http://casereports.bmj.com/content/2014/bcr-2014-206330.abstract N2 - Complementary medications and herbal medicine for weight loss have become very popular. We report a case of thyroid dysfunction following the ingestion of a kelp-containing marketed diet in a 45-year-old woman with no previous thyroid disease. Signs of hyperthyroidism occurred shortly after a kelp-containing diet. Hyperthyroidism lasted 2 months and was followed by an overt hypothyroidism. The thyroid scintiscan exhibited an extremely low uptake and colour-Doppler ultrasonography revealed multiple small areas of pulsatile flow. After 3 months of levothyroxine substitutive therapy, normal thyroid function was recovered after levothyroxine discontinuation. This clinical history is compatible with a case of iodine-induced thyrotoxicosis followed by prolonged block of the sodium–iodide symporter activity as a consequence of excessive iodine consumption from kelp. Consumers of marketed diets containing kelp or other iodine-rich ingredients should be advised of the risk to develop a thyroid dysfunction also in the absence of underlying thyroid disease. ER -