Cyclical edema and hypokalemia due to occult episodic hypercorticism.

Yearly episodes of edema, hypokalemia, anxiety, and depression were found to be due to cortisol and deoxycorticosterone surges secondary to a pituitary adenoma in a woman without any of the usual clinical features of Cushing's syndrome. During the long clinical remissions, she had no recognizable laboratory abnormality. She had two episodes in the year following incomplete transphenoidal pituitary tumor resection, but has had none in 2 yr since receiving radiotherapy. The episodes were caused by mineralocorticoid actions of large ACTH-induced increases in cortisol and deoxycorticosterone secretion. A history of episodic edema and hypokalemia, often attributed in women to surreptitious diuretic abuse, requires a careful search for hypercorticism even in the absence of clinical Cushing's syndrome.