Recurrent hyponatremia in an elderly patient with a cystic pituitary gland.

A 71-year-old male with a long history of diabetes and hypertension was admitted with mild azotemia and recurrent hyponatremia. He was diagnosed with a pituitary gland cystic tumor. On careful evaluation, his hyponatremia was found to be due to cerebral salt wasting. The patient made a full recovery following treatment for cerebral salt wasting.