Is "cerebral hyponatraemia" iatrogenic?

Hyponatraemia and hypoosmolality in patients with central nervous system (CNS) disease or trauma are often ascribed to inappropriate secretion of antidiuretic hormone. A "cerebral" aetiology has been postulated. A review of published reports and data from the present study indicate that the increase in antidiuretic activity in these conditions is generally to be expected and is therefore appropriate. It is suggested that the hyponatraemia observed is the result of excessive administration of fluids. In patients with CNS disease or injured brains intravenous fluid intake should be limited to about 1 litre (of 2.5% glucose in 0.45% saline for a 70 kg adult) per day during the acute stress.