Inappropriate antidiuresis associated with pituitary adenoma--mechanisms not involving inappropriate secretion of vasopressin
Hung, S.C.; Wen, Y.K.; Ng, Y.Y.; Yang, W.C.
Clinical Nephrology 54(2): 157-160
2000
ISSN/ISBN: 0301-0430 PMID: 10968694 Document Number: 513104
We report an unusual case of inappropriate antidiuresis with undetectable vasopressin in an elderly man presenting with confusion due to severe hyponatremia. Further investigations led to the diagnosis of non-functional pituitary macroadenoma. The patient had normal thyroid and adrenal function. The abnormal water balance resolved promptly after transsphenoidal removal of the tumor, confirmed by a repeat water loading test. We conclude that inappropriate antidiuresis in the absence of excess vasopressin secretion may implicate mass effect from an underlying pituitary tumor.