Acute EEG findings in children with febrile status epilepticus

Abstract

Objective: The FEBSTAT (Consequences of Prolonged Febrile Seizures) study is prospectively addressing the relationships among serial EEG, MRI, and clinical follow-up in a cohort of children followed from the time of presentation with febrile status epilepticus (FSE). Methods:We recruited 199 children with FSE within 72 hours of presentation. Children underwent a detailed history, physical examination, MRI, and EEG within 72 hours. All EEGs were read by 2 teams and then conferenced. Associations with abnormal EEG were determined using logistic regression. Interrater reliability was assessed using the k statistic.Results: Of the 199 EEGs, 90 (45.2%) were abnormal with the most common abnormality being focal slowing (n 5 47) or attenuation (n 5 25); these were maximal over the temporal areas in almost all cases. Epileptiform abnormalities were present in 13 EEGs (6.5%). In adjusted analysis, the odds of focal slowing were significantly increased by focal FSE (odds ratio [OR] 5 5.08) and hippocampal T2 signal abnormality (OR 5 3.50) and significantly decreased with high peak temperature (OR 5 0.18). Focal EEG attenuation was also associated with hippocampal T2 signal abnormality (OR 5 3.3).Conclusions: Focal EEG slowing or attenuation are present in EEGs obtained within 72 hours of FSE in a substantial proportion of children and are highly associated with MRI evidence of acute hippocampal injury. These findings may be a sensitive and readily obtainable marker of acute injury associated with FSE. Neurology Febrile status epilepticus (FSE) is an important neurologic emergency and the most severe type of complex febrile seizure. Acute morbidity and mortality are low, 1 but the long-term consequences of FSE and risks of specific epilepsies, such as mesial temporal epilepsy, are not well established. Retrospective studies report that approximately 30% of patients with medically refractory temporal lobe epilepsy being evaluated for surgery have a history of prolonged febrile seizures, but prospective studies failed to confirm the association.2-9 The Consequences of Prolonged Febrile Seizures (FEB-STAT) study is designed to prospectively examine the outcome of FSE and predictors of outcome. 10Both MRI and EEG data are collected within 72 hours and then at later intervals to evaluate the possible relationship of FSE to subsequent mesial temporal lobe epilepsy. The methodology of assembling the cohort and a description of the clinical semiology and phenomenology of the first 119 subjects were previously published. 10 In this report, we describe the acute EEG findings and their relationship to characteristics of the episode of FSE as well as to the acute imaging findings. 11,13 A febrile seizure was defined as a provoked seizure in which the sole acute provocation was fever (temperature .38.4°C, 101.0°F) without history of a febrile seizure and with no evidence of an acute CNS infection or insult.11,13 Children with known severe neurologic disability before entry were excluded from the FEBSTAT study. Subjects were e...

Origins of Temporal Lobe Epilepsy: Febrile Seizures and Febrile Status Epilepticus

“…A limitation of the prior studies is that they lacked imaging data to correlate with the EEG findings. In the FEBSTAT study, both EEG and MRI were performed in the postictal state [76,117]. Overt epileptiform abnormalities were uncommon, however focal slowing or attenuation or both (usually maximal over the temporal area) were present in over 30 % of the cases.…”

Continuous EEG monitoring in children in the intensive care unit (ICU)

“…In one study, EEG performed within the 72 hours following febrile status epilepticus revealed the presence of focal abnormalities (90 out of 199 EEGs), and rarely focal spikes (13 EEGs). These focal abnormalities were significantly more frequent in focal seizures, when MRI evidenced hippocampal T2 signal abnormality and when the fever was not very high [25]. In another study on 119 children presenting with febrile seizures, EEG abnormalities (EEG performed between 7 and 21 days later) were seen in 26 cases (21.8%) and 9 children (7.6%) developed epilepsy later on.…”

Seizures and Epilepsies due to Channelopathies and Neurotransmitter Receptor Dysfunction: A Parallel between Genetic and Immune Aspects

“…They concern 2-5% of affected children, mostly aged between 6 months and 5 years [Stafstrom, 2002]. A recent multicentric prospective study evaluated long-term consequences of febrile status epilepticus on 200 children and showed MRI (hippocampal and temporal lobe) and EEG abnormalities (1/3 presented focal temporal slowing) [Nordli et al, 2012] within the first 72 h, while CSF analysis was unremarkable [Frank et al, 2012].…”