The syndrome of inappropriate secretion of antidiuretic hormone. A case report.

A 72-year-old woman with the syndrome of inappropriate secretion of antidiuretic hormone of unknown cause during more than one year of observation is reported. Plasma vasopressin levels were excessively elevated, even during a water load test. Her serum electrolyte abnormalities and general state were ameliorated after fluid restriction. During treatment with demeclocycline the patient was able to increase fluid without deterioration.