Cerebral salt wasting in a man with carcinomatous meningitis.

The purpose of this report is to alert the clinician that hyponatremic patients with CNS disease do not necessarily have a syndrome of inappropriate secretion of antidiuretic hormone. We describe a patient with hyponatremia and carcinomatous meningitis whose volume contraction resulted from striking urinary sodium losses. Although no longer even alluded to in reviews of hyponatremia, cerebral salt wasting appears to be a real clinical entity that warrants further investigation.