Serum enzyme activity of hydroxybutyric dehydrogenase (HBD) and heat inactivated lactate dehydrogenase (LD) after operations on intracranial aneurysms.

The relation between clinical signs of parenchymatous cell damage after brain surgery and the serum activity of the LD-isoenzymes determined either as HBD or as heat inactivated LD, has been studied in 44 patients operated upon for intracranial aneurysms. Seven patients had a postoperative increase of the serum enzyme activity above the upper normal limit. All these showed neurological symptoms as compared to only 14% of those who had a postoperative enzyme level within normal limits. This speaks strongly in favour of a relation between the brain cell damage and the increase of the serum activity of the LD-isoenzyme. Since only 15% of the patients had a pathological enzyme level, it is further suggested that an uncomplicated operation for intracranial aneurysm should not cause an increase of the HBD or heat inactivated LD above the upper normal limit.