THE SYNDROMIC CLASSIFICATION OF THE INTERNATIONAL LEAGUE AGAINST EPILEPSY - A HOSPITAL-BASED STUDY FROM SOUTH-INDIA

Purpose: To determine the distribution of various epilepsies and epile ptic syndromes in the epileptic population treated in a university hos pital in a developing country. Methods: Data concerning 2,531 patients with epilepsy seen between January 1989 and June 1994 were analyzed u sing the International League Against Epilepsy (ILAE) classification. Results: Of 2,531 cases, 48% fell into ILAE categories 1.3, 3.2, or 4. 1 (cryptogenic, without unequivocal generalized or focal seizures; or situation-related seizures, respectively). Localization-related epilep sies (LREs) and epileptic syndromes (1.1, 1.2, 1.3) were found in 1,59 1 (62.9%) patients; of these patients, symptomatic localization-relate d epilepsies totaled 62.7%, and idiopathic localization-related epilep sies accounted for only 0.7%. Juvenile myoclonic epilepsy was the most common type of idiopathic generalized epilepsy (IGE), comprising 4.9% of the total study population and 7.7% of patients registered in the epilepsy clinic. A combination of childhood and juvenile absence epile psies were found in only 0.4% of the total study population. Single co mputed tomography (CT) enhancing lesion (SCTEL) and focal cerebral cal cification (FCC) accounted for 22% of the etiologic factors for locali zation-related epilepsies. Neurologic deficits were found in 9.5% of p atients with SCTEL; none were found with FCC. None of the patients wit h these lesions had any history of antecedent events that suggested CN S involvement. In patients with localization-related epilepsies with u nremarkable clinical data, the proportion of CT scans showing SCTELs w as 39 (95% confidence interval [CI], 0.35-0.43) and 0.18 (95% CI, 15-0 .21) for FCCs. The proportion for both lesions together was 0.57 (95% CI, 0.53-0.61). Seizures did not recur once the lesion resolved in pat ients with SCTELs. In patients with FCCs, seizure remission was 71.5% (95% CI, 53.7-85.4) at 3 years. Conclusions: This study illustrates th e rarity in one patient population of some of the syndromes and catego ries described in the ILAE classification. Childhood and juvenile abse nce epilepsies together formed a small proportion. SCTEL and FCC were important etiologic factors for localization related epilepsies. The e pilepsy associated with SCTEL was a form of benign epilepsy; epilepsy associated with FCC had remission rates similar to other remote sympto matic epilepsies. Without neuroimaging evidence, these 2 lesions would have been missed and the patients might have been grouped under crypt ogenic localization related epilepsy. For this reason, we emphasize th e need for neuroimaging in patients with localization related epilepsi es with unremarkable clinical findings, before classification into the cryptogenic category. In the absence of neuroimaging, such patients s hould be classified as ''probably cryptogenic.''