Clinical profile and outcome of children with Lennox Gastaut Syndrome: Retrospective single centre cohort (P2.087)

Objective: To determine the clinical profile and seizure outcome among children with Lennox-Gastaut-Syndrome (LGS) Background: LGS is a severe epileptic-encephalopathy featuring several types of intractable seizures and psychomotor arrest/regression. Design/Methods: All children with epilepsy presenting to a tertiary-care-centre in India between Jan-2014 to Aug-2017 were screened. LGS was diagnosed by(a) presence of ≥2 seizure types with one of the seizure types being tonic seizures, and (b)generalized slow-spike and wave discharges on EEG. Patients were then divided into structural, genetic and indeterminate sub-groups. Structural-LGS were defined by presence of pathogenic lesions on neuroimaging. Patients with unexplained etiology underwent next-generation-sequencing and they were classified as genetic-LGS if an underlying pathogenic mutation was identified. Patients were placed in the indeterminate-group if they failed to meet criteria for structural-or genetic-LGS. Results: Of the 2420 children with epilepsy, LGS was diagnosed in 261 children (194 males, 74.3%). These included 178(68.2%) structural-LGS, 66(25.3%) genetic-LGS and 17(6.5%)indeterminate-LGS. Mean(±SD) age of cohort was 64(±34) months. Mean(±SD) age of seizure onset was 9(±16) months. The frequency of seizure types included: tonic (n=261, 100%), myoclonic (n=173, 66.3%), absence (n=103, 39.5%), and generalised-tonic-clonic (n=66, 25.3%). Therapeutically, 24(9.2%) patients were receiving ≥5 anti-epileptic-drugs; 67(25.7%), 159(60.9%) and 11(4.2%) patients were being administered 4, 3, and 2 anti-epileptic-drugs respectively. Twenty-two (8.4%) patients were additionally receiving ketogenic diet. When last seen, 199(76.2%) children were having ≥1 seizure per week. Mean(±SD) age of seizure onset in structural-LGS (6±15months) was significantly less than that in genetic-LGS (12±12.9, p=0.007). Seizure frequency was ≥1/week in significantly greater proportion of children in structural-LGS (n=141/178, 79.2%) than in genetic-LGS (n=42/66, 63.6%; p=0.02). Mean(±SD) social quotient in structural-LGS subgroup (7.4±6.3) was significantly worse than genetic-LGS (51.6±17.2, p Conclusions: Majority of children with LGS have drug-resistant epilepsy. Children with structural-LGS have relatively worse neurocognitive outcome as compared with genetic-subgroup. Disclosure: Dr. Sondhi has nothing to disclose. Dr. Chakrabarty has nothing to disclose. Dr. Jauhari has nothing to disclose. Dr. Gupta has nothing to disclose. Dr. Gulati has nothing to disclose.