Febrile status epilepticus and epileptogenesis: The FEBSTAT study.

Area of Science:

• Pediatric Neurology
• Neuroimaging
• Epileptology

Background:

• Febrile status epilepticus (FSE) is a prolonged seizure in infants triggered by fever.
• The long-term neurological consequences of FSE, particularly hippocampal injury and subsequent epilepsy, require further elucidation.

Purpose of the Study:

• To investigate the incidence and evolution of hippocampal injury following FSE.
• To determine the association between acute FSE-related hippocampal injury and the development of epilepsy, specifically temporal lobe epilepsy.

Main Methods:

• Prospective enrollment of over 200 infants experiencing FSE in the multicenter FEBSTAT study.
• Serial magnetic resonance imaging (MRI) including initial scans within days of FSE and follow-ups at 1, 5, and 10 years.
• Electroencephalography (EEG) to assess post-ictal abnormalities.
• Hippocampal volume and apparent diffusion constant measurements.

Main Results:

• Acute unilateral hyperintense hippocampal T2 signal on MRI was observed in 10% of infants post-FSE.
• A significant association was found between focal EEG abnormalities and hippocampal T2 hyperintensity.
• Follow-up MRIs revealed marked hippocampal volume loss by 1 year, evolving into hippocampal sclerosis in 70% of those with initial T2 hyperintensity.
• Ten-year cumulative epilepsy incidence was 30% overall, but 71% in those with acute hippocampal T2 hyperintensity.
• Medial temporal lobe epilepsy incidence was 39% in those with acute hippocampal T2 hyperintensity, versus 4% in the entire cohort.

Conclusions:

• Acute hippocampal injury following FSE is identifiable via MRI and EEG.
• This injury leads to significant hippocampal volume loss and sclerosis over time.
• Infants with FSE-induced hippocampal injury have a substantially elevated risk of developing epilepsy, particularly temporal lobe epilepsy.