Lithium Therapy and Thyroid Disorders

Lithium carbonate is used as a first-line treatment for bipolar disorder and is given to approximately 1 in every 200 patients with this psychiatric disease. Lithium, an element in the alkali metal group, has a variety of anti-thyroid effects, primarily goiter formation and hypothyroidism. Rarely, lithium may cause hyperthyroidism secondary to thyroiditis or through possible autoimmune actions. Since this cation can inhibit thyroid hormone release and increase retention of radioactive iodine, it can be used as an adjunct therapy in the treatment of hyperthyroidism and thyroid cancer. There are many proposed mechanisms for lithium’s actions on thyroid hormone secretion, thyrocyte proliferation, and effects on the immune system, but more research is still required. We will review the pathophysiological mechanisms and clinical manifestations of lithium therapy on the thyroid gland.