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Hippocampal volumes and diffusion-weighted image findings in children with prolonged febrile seizures
J Natsume1, N Bernasconi, M Miyauchi
1Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan. junnatsu@med.nagoya-u.ac.jp
Insights
Prolonged febrile seizures (PFS) lasting over 60 minutes in children can lead to larger hippocampal volumes and signal changes on diffusion-weighted imaging (DWI), suggesting potential structural damage and future epilepsy risk.
Area of Science:
- Pediatric Neurology
- Neuroimaging
- Epileptology
Background:
- Prolonged febrile seizures (PFS) are a critical concern in pediatric neurology.
- Understanding the neurobiological impact of PFS is essential for predicting long-term outcomes.
- Hippocampal volume (HV) and diffusion-weighted imaging (DWI) are key neuroimaging markers.
Purpose of the Study:
- To evaluate hippocampal volumes (HV) and DWI signal changes in children following PFS.
- To correlate these findings with PFS duration and electroencephalogram (EEG) abnormalities.
- To compare HV in patients with neurologically normal controls.
Main Methods:
- Studied 12 children with a first episode of PFS (≥30 min).
- Assessed HV using high-resolution MRI and DWI signal abnormalities visually.
- Compared patient HV with 13 age-matched controls and correlated with PFS duration and EEG.
Main Results:
- Children with PFS ≥60 min had significantly larger HV than controls.
- A positive correlation was observed between HV and seizure duration in all patients.
- DWI revealed hippocampal hyperintensity in three patients with intractable seizures, correlating with temporal EEG abnormalities.
Conclusions:
- Refractory PFS (≥60 min) is associated with enlarged hippocampal volumes and DWI abnormalities.
- These findings suggest that prolonged, medically refractory PFS may induce structural changes in limbic areas.
- Such structural alterations could potentially contribute to the development of future epileptogenesis.
Objectives:
To assess hippocampal volumes (HV) and signal changes on diffusion-weighted imaging (DWI) within 5 days of prolonged febrile seizures (PFS) and compare them with the PFS duration and EEG.
Methods:
We studied 12 children (mean age: 32 +/- 21 months, range 10 months-5 years) within 5 days of a first episode of PFS (a seizure or series of seizures lasting for 30 min or longer, without return of consciousness between the seizures). The HV measurements were carried out using high-resolution magnetic resonance imaging and signal intensity abnormalities were evaluated visually on DWI. HV in patients were compared with those of 13 neurologically normal controls (mean age 31 +/- 16 months, range 15 months-5 years). HV abnormalities correlated with PFS duration. HV and DWI abnormalities were compared with EEG abnormalities.
Results:
Seizure duration ranged from 40 to 95 min. In seven out of twelve patients, seizures were refractory and lasted for 60 min or longer despite intravenous infusion of diazepam. In the patients with PFS for 60 min or longer, HV were significantly larger than that of controls. In all patients, there was a positive correlation between HV and seizure duration. DWI showed hyperintensity in unilateral hippocampus in three patients with intractable seizures, ipsilateral thalamus in two, and cingulate in one. EEG showed abnormalities in temporal areas ipsilateral to the DWI abnormalities in these patients.
Conclusions:
Large HV and hippocampal hyperintensity on DWI were seen in patients with refractory PFS. Our results suggest that medically refractory PFS lasting for 60 min or longer may cause structural changes in limbic structures that could promote later epileptogenesis.
