Hyponatremia due to hypothyroidism: a pure renal mechanism

Hyponatremia is a common disorder. When hyponatremia is the result of hypothyroidism it can be successfully treated with thyroid hormone substitution. We followed cumulative sodium- and fluid balances of a patient with hyponatremia, resulting from hypothyroidism. We concluded that hyponatremia in hypothyroidism is due to a pure renal mechanism, and cannot be ascribed to inappropriate secretion of antidiuretic hormone.