Continuous Electroencephalographic Monitoring of Status Epilepticus in Dogs and Cats: 10 Patients (2004-2005)

Objective: To describe the use of continuous electroencephalographic (EEG) monitoring for management of status epilepticus (SE) in dogs and cats.

Design: Retrospective study.

Setting: University teaching hospital.

Animals: Ten patients (7 dogs, 3 cats) with SE of differing etiology (idiopathic epilepsy, n=3; toxicity, n=4; meningoencephalitis, n=2; undefined, n=1).

Interventions: The EEG was recorded continuously from 5 stainless-steel needle electrodes inserted SC. Animals were treated with diazepam and phenobarbital followed by either propofol (n=3) or pentobarbital (n=7) as a continuous rate of infusion.

Measurements And Main Results: Clinical seizures stopped after induction of anesthesia in each animal. The EEG, however, still showed distinct epileptiform patterns (spikes, polyspikes) in all animals. Paroxysms were suppressed by increasing the infusion rate of either pentobarbital or propofol. A burst-suppression pattern was achieved in 5 animals. EEG epileptiform activity reappeared in 4 animals when attempting to taper the dose after >6 hours of anesthesia. This was interpreted as ongoing EEG seizure activity and an increased risk for clinical seizures, and the anesthetic dosage was adjusted accordingly.

Conclusion: Continuous EEG monitoring appears to be a useful tool for therapeutic monitoring of SE in dogs and cats. It allows the detection of EEG seizures without the appearance of clinical seizures. Further investigations with blinded investigators and homogeneous animal groups to define therapeutic endpoints are warranted.