Abstracts

Rationale: Convulsive status epilepticus (CSE) is the most common medical neurological emergency in childhood. There are limited population-based data on the medium/long-term outcomes of childhood CSE. Having carried out the first prospective pediatric population-based study on CSE, the north London convulsive status epilepticus in childhood surveillance study (NLSTEPSS), we are now following up this unique, well-phenotyped cohort 5-8 years following their episode of CSE to: 1) determine prevalence and types of epilepsy, behavioural and cognitive outcomes; 2) characterise structural substrates for outcomes; 3) evaluate the relationships between clinical and structural characteristics and outcomes; 4) estimate all-cause mortality Methods: 226 children with CSE (176 with first-ever CSE) were enrolled in NLSTEPSS between May 2002 and April 2004 by paediatricians from 21 hospitals in north London. Of the original 226 children, 7 died during hospitalisation for their CSE. Information about each episode of CSE and patient details, including developmental status prior to the acute episode are available. Since April 1, 2009 the original cohort are being traced and surviving members are being invited for follow-up. All enrolled children will have detailed clinical neurological evaluation, psychology assessment and Magnetic Resonance Imaging of their brain. They will initially be screened for behavioural and cognitive problems using the Strengths and Difficulties Questionnaire (SDQ), Swanson, Nolan, and Pelham, version IV Questionnaire (SNAP -IV) for ADHD and oppositional defiant disorders, the Autistic Spectrum Screening Questionnaire (ASSQ), obsessive compulsive disorder, Tourette and depression screen scales, Sunderland Memory Questionnaire and Behaviour Rating Inventory of Executive Function (BRIEF). The 4 subtest Wechsler Abbreviated Scale of Intelligence (WASI) will be used to obtain a full scale IQ as well as performance and verbal IQ. Children's Memory Scale and the visual paired comparison test will be used to identify memory impairment. In addition to conventional sequences, MR Imaging will include qualitative and quantitative hippocampal assessments using volumetry, T2 relaxometry, apparent diffusion coefficient measurements and fractional anisotropy on diffusion tensor imaging. Focal abnormalities in brain structure outside of the hippocampus not identified on visual assessment will be investigated using voxel based morphometry in Statistical Parametric Mapping (SPM, version 8). The results of all assessments will be used as the basis for any formal diagnoses of adverse outcomes. Results: Of the original 219 survivors, 33 (15%, 95%CI 11-20%) have been traced so far. Of these, four (12%, 95%CI 5-27%) have died during the follow-up period. Data collection is ongoing and further results will be presented. Conclusions: STEPSOUT is the first prospective pediatric population-based study to investigate outcomes 5-8 years following an episode of childhood CSE. Preliminary results suggest that outcome may not be benign.