Metabolic disturbances after head injury: abnormalities of sodium and water balance with special reference to the effects of alcohol intoxication.

Eighty-eight patients with craniocerebral trauma were studied prospectively to assess the effects of the injury on sodium and water balance. Abnormalities of serum sodium and osmolality occurred in 11 of the 76 patients who were on the study more than 24 hours, and the incidence of these abnormalities was directly related to the severity of the craniocerebral injury. Hyponatremic hypo-osmolar states were as frequent as were hypernatremia and serum hyperosmolality. The major cause of the hyponatremia was inappropriate antidiuretic hormone secretion; hypernatremia was due to dehydration and occurred predominantly in comatose patients with increased insensible fluid losses associated with pyrexia. We recommend that the initial fluid intake after craniocerebral trauma be kept between 1500 and 1800 ml/24 hours and that further fluid management be dictated by repeated serum electrolyte determinations. The electrolyte balance should be monitored continuously after a significant head injury for up to 2 weeks, because hyponatremic states sometimes develop more than 1 week after injury. The serum alcohol was measured on admission, and the level of serum alcohol correlated well with the serum osmolality on admission; thus, the degree of elevation of serum osmolality was a very good guide to the serum alcohol level. However, there was no statistically significant correlation between alcohol intoxication or chronic alcoholism and the late development of serum sodium and osmolality disturbances.