Etiological spectrum of symptomatic localization related epilepsies: a study from South India

Putative etiology was studied in 991 patients with symptomatic localization-related epilepsies seen in a university hospital in South India. They formed 39% of patients with various types of epilepsies and epileptic syndromes seen during the study period. Seizure occurred in close temporal association with an acute central nervous system (CNS) insult in 53% of patients. Infections of CNS including single CT enhancing lesion (SCTEL) accounted for 77% of patients with acute symptomatic epilepsy. Cerebrovascular diseases were the risk factors in 48% of patients with remote symptomatic epilepsy. Neurocysticercosis, SCTEL and small single cerebral calcific CT lesion (SSCCCTL) together accounted for 40% of etiological factors and neurotuberculosis for 10%. Infections of the central nervous system and SCTEL together were the putative risk factors in 52% of patients aged < or =40 years. Cerebrovascular diseases were the etiological factors in 64% of patients aged >40 years. Neurological handicaps from birth manifested by mental retardation and/or cerebral palsy was the feature in 21% of children. The type of seizure was either simple partial or complex partial with or without secondary generalization in 76% of patients. The remaining patients presented with either generalized tonic clonic seizures or unlocalized seizures. Localization to a single site of seizure origin proposed by the International League Against Epilepsy (ILAE) was possible in only 67.5% of patients. The most readily identifiable was motor cortex. In patients with unlocalized or generalized seizures the type of pathology was diffuse in 17% of patients and in 48.5% of patients, the lesion was located in the frontal brontoparietal lobe.