1FC1.5 Interstitial radiosurgery for gelastic epilepsy due to hypothalamic hamartomas: tolerability and efficacy in childhood and adolescence

Abstract

Study aim: Our objective was to examine the demography, clinical features and prognostic factors predicting developmental outcome in a United Kingdom cohort of children with Dravet Syndrome. Methods: In the study period, 12/2005 to 2/2010, we prospectively collected data on individuals with Dravet syndrome referred to the only UK centre offering genetic testing. We analysed demographic information based on UK population and birth data. From structured referral data we examined a range of clinical characteristics including epilepsy phenotype, seizure precipitants, EEG data, imaging studies, mutation class and response to medication. Predictors of developmental outcome were determined by logistic regression. Results: We identified 241 SCN1A mutation-positive Dravet syndrome cases of which 207 are UK-based. The incidence of Dravet Syndrome is at least one in every 40,900 UK births. Clinical features predicting a worse developmental outcome included status epilepticus (OR=3.1; CI=1.5−6.3; p = 0.003), interictal EEG abnormalities in the first year of life (OR=5.7; CI=1.9 16.8; p = 0.002) and motor disorder (OR=3.3; CI=1.7−6.4; p<0.001). No significant effect was seen for seizure precipitants, MRI abnormalities or mutation class (truncating vs. missense). Abnormal MRI imaging was documented in 11% of cases, principally with findings of non-specific brain atrophy or hippocampal changes. Valproate, benzodiazepines and topiramate were reported the most helpful medications at time of referral. Aggravation of seizures was reported for carbamazepine (60%) and lamotrigine (43%). Conclusions: Identification of factors influencing prognosis both aids counselling and encourages early, syndrome specific therapy. Prevention of status epilepticus with regular medication and emergency protocols is important and may influence developmental outcome.