A disorder resulting from excessive retention of water in the brain. Main symptoms are dizziness, headaches, confusion and nausea. In severe cases the patient may have fits (see SEIZURE) or lose consciousness due to cerebral OEDEMA; the condition may be fatal. Several conditions can disturb the body's water balance, causing accumulation of water in the tissues. Heart or kidney failure, CIRRHOSIS of the liver, disorders of the ADRENAL GLANDS and diabetic ketoacidosis can all result in water retention. Other causes are stress as a result of surgery, when increased secretion of antidiuretic hormone (VASOPRESSIN) by the adrenal gland may occur. It may arise during intravenous therapy, if an excessive volume of a too dilute fluid is given, leading to HYPONATRAEMIA. Treatment is of the underlying condition, restricting fluids and possibly the judicious use of DIURETICS, with careful monitoring of the body's ELECTROLYTES. Where cerebral oedema is suspected, drugs such as mannitol may be used.