Lithium and hypothyroidism.

There is general agreement that hypothyroidism is a possible consequence of lithium treatment but there is little agreement as to what the incidence of lithium related hypothyroidism is, or what clinical and laboratory tests could best be used to evaluate thyroid function. This study involved a survey of 70 clinicians, a chart review of 2,590 patients and a review of the pathophysiology of lithium-induced hypothyroidism. The major finding of this investigation is that lithium related thyroid dysfunction is not a common problem. Goiter during lithium therapy is 0.3%, clinical hypothyroidism is 1-2%, and TSH is the most specific laboratory test for evaluating thyroid function.