Iatrogenic thyrotoxicosis: Causal circumstances, pathophysiology, and principles of treatment - Review of the literature

Thyrotoxicosis is the clinical syndrome that results when tissues are expos ed to high levels of circulating thyroid hormones. In most instances thyrot oxicosis is due to hyperthyroidism, a term reserved for disorders character ized by overproduction of thyroid hormones by the thyroid gland. Neverthele ss, thyrotoxicosis may also result from a variety of conditions other than thyroid hyperfunction. The present report focuses on the etiologies, pathop hysiology, and treatment of iatrogenic thyrotoxicosis. Iatrogenic thyrotoxi cosis may be caused by (1) subacute thyroiditis (a result of lymphocytic in filtration, cellular injury, trauma, irradiation) with release of preformed hormones into circulation; (2) excessive ingestion of thyroid hormones ("t hyrotoxicosis factitia"); (3) iodine-induced hyperthyroidism (radiologic co ntrast agents, topical antiseptics, other medications). Among these causes of iatrogenic thyrotoxicosis, that induced by the iodine overload and cytot oxicity associated with amiodarone represents a significant challenge. Succ essful management of amiodarone-induced thyrotoxicosis requires close coope ration between endocrinologists and endocrine surgeons. Surgical treatment may have a leading yet often underestimated role in view of the potential l ife-threatening severity of this disease, whereas others kinds of iatrogeni c thyrotoxicosis are usually treated conservatively.