Surgical Treatment of Postencephalitic Epilepsy

ABSTRACT

Encephalitis is often followed by chronic intractable epilepsy. Many of these patients pose significant challenges to the localization of seizure generators and to the strateges for management of intractable epilepsy. The authors analysed 17 patients with postencephalitic epilepsy(PEE), who underwent resective surgeries. Most patients had been accompanied by coma, convulsive status epilepticus, and focal motor deficit at the time of encephalitis. MRI studies showed variable degree of brain damage hippocampal sclerosis only(n=5), neocortical gliosis only(n=6), and both(n=5). Analysis of ictal semiology revealed a predominant temporo-limbic seizure pattern in 7, a variable extralimbic patterns in 6, and unclassified in 4 patients. Surgical resection includes temporal(n=11), frontal(n=3), centroparietal(n=1), multilobar(n=2), and callosotomy(n=2). Surgical outcome was graded as class 1(n=8), class 2(n=2), class 3(n=4), and class 4(n=3). It is concluded that surgical result was promising despite the traditional concerns about localizing problem in the setting of PEE. Surgical treatment should be, therefore, considered if localizing information is persistent. Intracranial EEG recording was very useful to delineate the area of seizure onset. MRI abnormalities were not always correlated with ictal onset zone in the patients with PEE.