Hypernatremic psychosis in the elderly: case reports

Paranoid Adipsia-induced Severe Hypernatremia and Uremia treated with Hemodialysis

We describe a patient with severe hypernatremia and uremia caused by paranoid adipsia who was treated successfully with hydration and hemodialysis. A previously healthy 40-year-old woman developed the paranoid idea that her water was poisoned, so she refused to drink any water. On admission, her blood urea nitrogen was 208mg/dL, creatinine 4.90mg/dL, serum osmolality 452mOsm/L, serum sodium 172mEq/L, urine specific gravity ≥1.030, urine osmolality 698mOsm/L, and urine sodium/potassium/chloride 34/85.6/8mEq/L. We diagnosed her with uremic encephalopathy and started intravenous dextrose, but the sodium correction was incomplete. She underwent two sessions of hemodialysis to treat the uremic encephalopathy and hypernatremia, and recovered fully without neurological sequelae. Although the standard treatment for severe hypernatremia is hydration, hemodialysis can be an additional treatment in cases of combined uremic encephalopathy.

Drinking, thirst and water intoxication

Drinking is an activity determined partly by oropharyngeal stimulation and gastrointestinal sensations as well as biochemical changes, and thirst need not be involved. It is sometimes disturbed in mania or depression. Overdrinking (polydipsia) is common in long-stay in-patients, but only gives rise to water intoxication when there is a variable functional renal abnormality such as SIADH causing water retention. In contrast, in affective disorders, disturbance of sodium retention may be seen, possibly representing failure of nervous vascular control as part of the mental illness.