A woman with postoperative hyponatremia related to desmopressin acetate

A patient was referred to the intensive care unit with sudden delirium and a serum sodium level of 111 mEq/L (mmol/L). A computerized tomographic scan revealed marked cerebral edema. Laboratory values were highly consistent with the action of the antidiuretic hormone. She had received desmopressin acetate (DDAVP) for 4 days preoperatively and postoperatively for putative van Willebrand's disease. Hyponatremia as a sequel to DDAVP treatment is an unusual complication and the medication is generally safe. However, our patient nevertheless teaches that vigilance equals avoidance.