Predictors of one-year seizure remission--a clinicoradiological and electroencephalographic study

BACKGROUND and AIMS: In epileptic patients, the requirement of number of antiepileptic drug (AED) to achieve seizure remission may be different in different geographic location and races. This study aims at evaluating the requirement of AEDs for one-year seizure remission of Indian epileptic patients and their predictors with special reference to ring enhancing lesion. SUBJECTS and METHODS: Consecutive epileptic patients from neurology out patients department of a tertiary care center were included who completed one year follow up. Children < 12 years of age were excluded. A detailed history, neurological examination, CT scan and EEG were carried out. Patients were classified into idiopathic, symptomatic and cryptogenic epilepsy. Symptomatic epilepsies were further classified into patients with ring lesion and without it. Patients were prescribed appropriate AEDs, initially monotherapy then duo and later even more than 2 AEDs if seizures were not controlled. The relationship of various clinical, radiological and EEG changes with requirement of number of AEDs for seizure remission was compared employing Chi square test. RESULTS: There were 120 patients whose mean age was 26.8 (13-71) years and 34 females. 48(40%) patients were classified into idiopathic, 53(44%) symptomatic and 19(15.80%) cryptogenic. After commencement of AEDs, 90(75%) patients were seizure free at 1 year; 78(65%) on monotherapy, 12(10%) on duotherapy and none on more than 2 drugs. The frequency of remission was higher in idiopathic (79%) and symptomatic (79%) compared to cryptogenic (52%). The seizure remission and requirement of number of AEDs were related to type of epilepsy, seizure frequency, neurological deficit and EEG abnormality. Symptomatic patients in non-ring lesion group were younger, had more frequent seizure, neurological deficit and EEG abnormality than ring lesion. Seizure remission was better in patients with ring lesion (87%) compared to without it (44%). CONCLUSION: 75% epileptic patients had one year seizure remission; majority achieved on monotherapy, occasionally on duotherapy and none on more than 2 AEDs. Symptomatic epilepsy due to ring lesion had higher seizure remission rate followed by idiopathic. Cryptogenic epilepsy, frequent seizure, neurological deficit and EEG abnormalities were related to poor remission and requirement of more number of AEDs.