Iatrogenic Water Intoxication in Psychogenic Polydipsia

The case is reported of a 63-year-old female patient with psychogenic polydipsia. As part of investigations she received synthetic vasopressin, and developed severe hyponatraemia due to continued excessive intake of water. She became decorticate, but made a complete recovery on treatment with hypertonic saline. Careful monitoring is required when vasopressin is used in the investigation of polydipsia which may be psychogenic.