Hypercalcemia in Adrenocortical Insufficiency

Serum calcium has been examined in 4 patients with Addison's disease and in 5 with symptoms of manifest adrenocortical insufficiency after adrenalectomy for Cushing's syndrome. In each group hypercalcemia was found in 3 patients, and the incidence of hypercalcemia was the same as that of hyponatremia. Hypercalcemia alone occurred in 3 patients, as also did hyponatremia. Hypercalcemia without other disturbances of serum electrolytes led, in one of the patients, to surgical exploration of the neck in the search for a parathyroid adenoma. Determination of serum calcium should be a routine procedure in patients with suspicion of adrenocortical insufficiency, and this diagnosis should not be forgotten in cases with hypercalcemia. Possible mechanisms for the hypercalcemia in adrenocortical insufficiency are discussed.