Research Identifies 4 Predictors of Epilepsy in Children With Complex Febrile Seizures

Four predictors of future epilepsy in children with complex febrile seizures (CFS) have been identified in new research published in Journal of Child Neurology.

These include experiencing more than 3 febrile seizures in 24 hours, interictal epileptiform discharges during post-CFS electroencephalogram (EEG), family history of afebrile seizures, and CFS onset at age 3 or later. Combined, having all 4 risk factors can raise the risk of epilepsy to over 75%, authors said.

“Early identification of children who will develop epilepsy after a CFS is essential to future management and counseling for parents/caregivers,” the researchers wrote.

Febrile seizures are the most common seizures in children and typically occur between ages 6 months and 5 years. The seizures can be characterized as simple or complex.

A CFS in children has at least 1 of the following features: focal onset or a seizure followed by a focal neurologic deficit, duration of 15 minutes or longer, or seizure recurrence during the same 24 hours, authors wrote. Although they can be stressful for parents, the seizures carry low risk for children.

Around 2% to 20% of children with febrile seizures go on to develop epilepsy. This risk tends to be heightened in those with a history of CFS. However, different results regarding the prognostic value of EEG after CFS exist, while practices employ varied recommendations on EEG attainment.

To better assess the predictive value of paroxysmal post-CFS EEG abnormalities for development of epilepsy, the researchers carried out a retrospective study of patients seen at Children’s Health Dallas between January 2009 and December 2019.

Patients were followed for 14 months to 11 years; the average follow-up time was 36 months. Of the 243 patients who completed follow-up of at least 1 year, 60 developed epilepsy after their CFS.

A total of 621 children had post-CFS EEGs. Data from the EEGs “identified an association between CFS and midline-vertex discharges, which were present in 52% of the 56 EEGs with interictal epileptiform discharges,” the authors wrote.

Additional findings include:

• Most patients had normal EEGs, but 20% had interictal epileptiform discharges
• Midline-vertex discharges were seen at a similar rate in children who did not develop epilepsy (55%) and those who developed epilepsy (45%)
• The development of epilepsy was not associated with any interictal epileptiform discharge localization
• 54% of the children who had interictal epileptiform discharges on the post-CFS EEG subsequently developed epilepsy
• Antiseizure medications were initiated for 20.6% of children after CFS, 38% of whom had interictal epileptiform discharges on the post-CFS EEG

The 20% of patients who developed epilepsy and had interictal epileptiform discharges on their post-CFS EEG is similar to rates reported in previous studies.

The current analysis’s retrospective nature and small sample size mark limitations. Because EEGs are often obtained in hospitalized children after CFS, particularly within a short time frame of the seizure, this practice could be a source of potential bias.

Furthermore, although the average follow-up time was 3 years, some patients who developed epilepsy may not have been captured in the data.

“A post-CFS EEG can provide value toward future counseling,” the authors said.

“Yet, until future prospective studies are performed, the presence of epileptiform discharges, particularly midline-vertex discharges, on post-CFS EEGs should be considered on an individual basis, in the context of clinical parameters, to guide counseling and management with antiseizure medications,” they concluded.

Reference

Choudhari PR, Lowden A, Dolce A. Exploring the age-old question: what is the predictive value of EEG for future epilepsy in children with complex febrile seizures. J Child Neurol. Published online May 7, 2023. doi:10.1177/08830738231171799