Inappropriate Secretion of Antidiuretic Hormone Due to Myxedema

Abstract

HYPONATREMIA is a frequent finding in severe hypothyroidism^{1 2 3 4 5 6} and is associated with a significant mortality. Interest in the mechanism of the electrolyte changes has focused on the inability to excrete a water load and on the pituitary-adrenocortical axis.^7,8 In 1962 a case of myxedema was reported in which the hyponatremia was attributed to inappropriate secretion of antidiuretic hormone.⁹ A patient with clinical and laboratory evidence of recurrent hypothyroidism and severe hyponatremia probably due to inappropriate secretion of antidiuretic hormone was recently seen at the Grace—New Haven Community Hospital. The fluid and electrolyte abnormality responded to thyroid replacement alone, thus . . .