Destructive effects of prolonged status epilepticus.

Abstract

Convulsive seizures were initiated by 3 methods, penicillin, metrazol and electroshock in a series of cats. Side effects of the convulsive agents were compared. All animals were tracheotomized and a respirator was used to maintain adequate pulmonary ventilation while cerebral activity was monitored by the electroencephalogram throughout the seizures. In one group individual Betz cells were removed and O2 uptake studied. The remaining animals were allowed to recover from the muscle relaxant and studied clinically. Despite muscular relaxation and adequate oxygenation the animals suffered irreversible damage and expired 48 hr. following termination of the convulsions. All the Betz cells studied from the seizure animals showed a serious alteration in metabolic potential. Since the necropsied brains in this study did show a moderate degree of swelling it is possible that prolonged seizure eventually leads to cerebral edema which is exacerbated by the resulting venous stasis. In addition, relative anoxia exists during a seizure which may result in temporary or permanent damage to cerebral tissue. It might well be that supportive oxygenation interferes with a normal cerebral protective mechanism. Considerable changes occur in the neurons following prolonged seizures and the results suggest that they are related to the electrical activity during that period.