Etiological spectrum of localization-related epilepsies in childhood and the need for CT scan in children with partial seizures with no obvious causation--a study from south India.

The etiological spectrum of 558 children (< 16 years) with partial seizures seen in a university hospital in south India, was analysed using syndromic classification proposed by the International League Against Epilepsy (ILAE). Partial seizures accounted for 57 per cent of childhood epilepsies. Idiopathic localization-related epilepsies accounted for 3 per cent, symptomatic localization-related epilepsies for 48 per cent and cryptogenic localization-related epilepsies for 49 per cent. Single CT enhancing lesion (SCTEL; solitary cysticercal granuloma), single small cerebral calcific CT lesion (SSCCCTL), and multiple small cerebral calcific CT lesions together accounted for 51 per cent of patients categorized under symptomatic localization-related epilepsies. Of the 138 patients with these CT lesions, only four patients with SCTEL had focal signs to suggest symptomatic etiology and in the remaining the putative etiology was established only after CT scan was obtained. A CT scan was carried out in 247 children with localization-related epilepsies with no obvious causation, and the proportion of CT scans showing one of these three etiologies was 0.54 [95 per cent confidence intervals (CI), 49-60]. Our observations suggest that in India a child with partial seizures with no obvious causation has a high probability of harboring one of these three lesions. In these patients, a CT scan should be the initial structural imaging investigation and will be cost effective.