Lithium toxicity and myxedema coma in an elderly woman.

The development of hypothyroidism as a side effect of lithium therapy is a well recognized phenomenon. However, the presentation of myxedema coma after lithium intoxication has not been previously documented. In this case lithium toxicity may have exacerbated preexisting hypothyroidism to the point of respiratory arrest. Based on this case, we recommend periodic monitoring of thyroid function in an effort to detect preexisting hypothyroidism or lithium-induced hypothyroidism.