Clinical implications of status epilepticus in children
Authors: Shavonne Massey, Brenda Banwell
Journal: The Lancet Child & Adolescent Health (2017)

Status epilepticus (SE) is the most common neurological emergency encountered in childhood; therefore, care providers need to be aware of the acute and chronic implications to accurately counsel patients and their families.1Ng YT Maganti R Status epilepticus in childhood.J Paediatr Child Health. 2013; 49: 432-437Crossref PubMed Scopus (6) Google Scholar The umbrella diagnosis of SE includes numerous subtypes: electrographic SE, convulsive SE, focal SE with impaired consciousness, and absence SE. The most recent guidelines from the International League Against Epilepsy (ILAE) provide two convulsive SE timepoints: the time at which continuous seizure activity requiring the administration of an emergency medication is likely (5 min), and the time at which a continued seizure might lead to permanent neuronal damage (30 min).2Brigo F Tinazzi M Trinka E In response: terminology of PNES over time—the terms they are a-changin'.Epilepsia. 2015; 56: 979-980Crossref PubMed Scopus (2) Google Scholar Unfavorable short-term outcomes after SE, such as in-hospital mortality and neurological morbidity at hospital discharge, have been shown across several paediatric cohorts, in both convulsive and non-convulsive SE.3Topjian AA Gutierrez-Colina AM Sanchez SM et al.Electrographic status epilepticus is associated with mortality and worse short-term outcome in critically ill children.Crit Care Med. 2013; 41: 215-223Crossref PubMed Scopus (127) Google Scholar, 4Maegaki Y Kurozawa Y Tamasaki A et al.Early predictors of status epilepticus-associated mortality and morbidity in children.Brain Dev. 2015; 37: 478-486Summary Full Text Full Text PDF PubMed Scopus (23) Google Scholar Suresh Pujar and colleagues5Pujar SS Martinos MM Cortina-Borja M et al.Long-term prognosis after childhood convulsive status epilepticus: a prospective cohort study.Lancet Child Adolesc Health. 2017; (published online Dec 5.)http://dx.doi.org/10.1016/S2352-4642(17)30174-8Summary Full Text Full Text PDF Scopus (37) Google Scholar describe long-term neurological outcomes (including development of epilepsy, motor and intellectual disability, and educational difficulties) for a cohort of children with convulsive SE followed for a median of 8·9 years. In this population-based study that prospectively monitored the natural course of paediatric patients with convulsive SE, 66% of survivors from their original cohort6Chin RF Neville BG Peckham C et al.Incidence, cause, and short-term outcome of convulsive status epilepticus in childhood: prospective population-based study.Lancet. 2006; 368: 222-229Summary Full Text Full Text PDF PubMed Scopus (413) Google Scholar participated, and there were no significant difference in baseline demographic characteristics between participants with and without follow up. The primary take-away point from the study is that long-term neurological outcomes in children after convulsive SE are quite varied and highly correlated with baseline neurological status. The data from this study suggest that previously neurologically intact children presenting with an acute febrile illness or acute symptomatic cause of convulsive SE who survive have a low risk of developing new, long-term neurological morbidity. The cumulative incidence of epilepsy in the cohort was 24·7%, with all epilepsies presenting within the first 5 years following the episode of SE. The lowest incidence of epilepsy was in prolonged febrile SE (14·3%) and the highest incidences of epilepsy were in remote symptomatic SE (45·5%) and unclassified SE (50·0%). There was also a small risk for incident development of motor and intellectual disability in the total cohort, with a cumulative incidence of 2·1% for motor disability and 8·8% for intellectual disability. The presence of pre-existing epilepsy served as the only significant predictor of intellectual disability. Educational support has had varied use in the cohort; 5·7% of patients with prolonged febrile SE and no patients with acute symptomatic SE used educational supports compared with 89·5% of patients with idiopathic convulsive SE and 86·8% of patients with remote symptomatic convulsive SE. By contrast, children who develop SE in the context of an established neurological disorder are at significantly increased risk for neurological morbidity, including worsening neurological status. Although this study was able to stratify patients by baseline neurological status, future studies could assess the burden of pre-convulsive SE neurological disease so that the degree of worsening conferred by an episode of convulsive SE is better defined. Future studies could focus on the effects of seizure burden (which might carry various definitions—total number of minutes with seizure, maximal hour percentage with seizure, or refractoriness to treatment) in long-term outcomes of children with SE. A single study7Payne ET Zhao XY Frndova H et al.Seizure burden is independently associated with short term outcome in critically ill children.Brain. 2014; 137: 1429-1438Crossref PubMed Scopus (203) Google Scholar of the relationship between electrographic seizure burden and short-term outcomes in neonates and children with electrographic SE showed no association between seizure burden (defined as maximum percentage of any hour occupied by electrographic seizure) and mortality, but escalating seizure burden was associated with increased probability of neurological decline (defined as a worsening Pediatric Cerebral Performance Category score at hospital discharge). This work has not yet been replicated in convulsive SE. Given that timely antiseizure medication administration results in improved efficacy of the medication in children who are critically ill,8Williams RP Banwell B Berg RA et al.Impact of an ICU EEG monitoring pathway on timeliness of therapeutic intervention and electrographic seizure termination.Epilepsia. 2016; 57: 786-795Crossref PubMed Scopus (34) Google Scholar future studies could determine whether earlier initiation of treatment for convulsive SE would result in decreased seizure burden, and whether such a reduction was associated with improved long-term neurological outcomes. The current study focused on clinically detected convulsive SE, but concordant EEG data was not consistently recorded or reported. Future studies of convulsive SE could also include EEG analysis after the initial convulsive period, because additional information such as the presence of subclinical seizures or the persistence of an abnormal EEG background might offer additional prognostic information. Important differences in long-term outcomes might be explained not only by SE causes, but also by SE type. Previous work has suggested unfavourable long-term neurobehavioral outcomes among previously neurologically intact children after electrographic SE,9Abend NS Wagenman KL Blake TP et al.Electrographic status epilepticus and neurobehavioral outcomes in critically ill children.Epilepsy Behav. 2015; 49: 238-244Summary Full Text Full Text PDF PubMed Scopus (34) Google Scholar a finding that diverges from the results of the current study of convulsive SE. With growing evidence of the link between abnormal cerebral metabolites and unfavourable outcomes in critically ill adult populations with acute brain injury,10Hutchinson PJ Jalloh I Helmy A et al.Consensus statement from the 2014 International Microdialysis Forum.Intensive Care Med. 2015; 41: 1517-1528Crossref PubMed Scopus (196) Google Scholar a potential future goal of neuromonitoring in children with SE could also include microdialysis of CSF obtained both during and after SE. The evolution of neurometabolites (eg, glucose, lactate, pyruvate, neurofilament light chain) during and after an episode of SE might provide additional functional data, which is currently unavailable with standard EEG analysis, that could inform differences in outcomes experienced by different paediatric SE strata. We declare no competing interests. Long-term prognosis after childhood convulsive status epilepticus: a prospective cohort studyChildhood CSE is associated with substantial long-term neurological morbidity, but primarily in those who have epilepsy, neurological abnormalities, or both before the episode of CSE. Survivors without neurological abnormalities before CSE have favourable outcomes. Full-Text PDF Open Access