Abstracts

Rationale: Childhood convulsive status epilepticus (CSE) is associated with significant short-term morbidity and mortality. However, little is known about the long-term outcome following an episode of CSE in childhood from a population-based perspective. Determining morbidity following CSE and their predictors will be useful for prognostication and planning resource allocation. Our group 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 investigating this unique cohort to determine their outcomes within 10 years after an episode of CSE, and in this abstract report preliminary data on neurological and neuroimaging outcomes. Methods: The current study, the Status Epilepticus Outcomes Study (STEPSOUT), involves follow-up of children ascertained during NLSTEPSS. All children enrolled in STEPSOUT are invited to have a clinical neurological evaluation and brain MR Imaging (MRI) on a 1.5T scanner. An experienced paediatric neuroradiologist qualitatively analysed the MRI scans, and reported each as either normal, having clinically significant abnormalities, or abnormal but the abnormalities are unlikely to be clinically significant. Results: 34 children (20 male) have been enrolled to date. Median follow-up from their initial CSE episode was 7.36 (range 6.3-9) years. The diagnostic category of CSE was prolonged febrile seizures (PFS) in 10, and non-PFS in 24 (4 acute symptomatic (AS), 14 remote symptomatic (RS), 3 idiopathic and 3 unclassified). MRIs could not be performed in 15 children in the non-PFS category (14 of which had severe developmental delay and/or behavioural problems), due to either lack of subject cooperation (4), or parents not consenting for the scans (11). At follow-up, all children with previous PFS were neurologically normal and did not have epilepsy. None of the children with previous AS or unclassified CSE had subsequent epilepsy or motor deficits, except one child with previous AS who had epilepsy for 2 years after CSE, but was in remission off medication at last follow-up. All children with previous RS and idiopathic CSE were reported to have cognitive and/or motor impairments by their carers, and also had epilepsy with ongoing seizures on treatment. Neuroimaging was normal with no evidence of mesial temporal sclerosis (MTS) in all children with previous PFS, AS and idiopathic CSE, except non-specific white matter changes unlikely to be of clinical significance in one and an incidental right choroid fissure cyst in another. In the 4 with previous RS, neuroimaging was suggestive of hypoxic ischemic injury in 2, hypoglycaemic injury in 1 and perinatal middle cerebral artery infarction in 1. Conclusions: Our preliminary data suggest children with PFS have good neurological outcome within 10 years after CSE with no evidence of MTS on neuroimaging. Children with prior neurological insult and/or epilepsy at the time of CSE have poor outcome with ongoing epilepsy and neurological co-morbidity.