Lithium toxicity with hypothyroidism as a possible determinant.

A case of a woman with severe lithium toxicity and hypothyroidism with persistent hyponatremia and hypokalemia is presented. The mechanisms of the development of lithium toxicity by alterations in fluid and sodium metabolism, including those induced by lithium itself, are reviewed. The possibility that hypothyroidism may have been a significant determinant in the development of this case of lithium toxicity is considered and discussed. This is of special interest given that lithium can induce hypothyroidism. In addition, the safe reinstitution of lithium prophylaxis in this woman can be reported.