Hypo-osmolal syndrome due to prolonged nausea.

Hyponatremia and hypo-osmolality developed in a 70-year-old patient. It was probably mediated by hypersecretion of antidiuretic hormone, which, in turn, was due to prolonged nausea and vomiting. Severe esophagitis was the cause of the nausea. The patient was not given large amounts of fluids intravenously, and it is likely that she continued to drink for nondipsetic reasons. In view of her medical history of neurosyphilis, the possibility of a disturbance in the mechanism of thirst regulation is discussed, but remains unproved.