Childhood refractory focal epilepsy following acute febrile encephalopathy

Background: we describe a group of previously normal children who developed severe focal epilepsy after an acute/sub-acute illness resembling encephalitis. Methods: this is a retrospective study. An acute phase (encephalitis/encephalopathy period) and a chronic phase (chronic focal resistant epilepsy) were defined. Results: eight patients were enrolled. The median age at onset was 6.6 years (range 8 months-17.6 years). In the acute phase, fever was the first symptom in all cases and was associated with seizures and status epilepticus. All patients had focal seizures arising in both hemispheres. Seizure onset occurred in the frontal and temporal regions. EEGs showed slowing background activity associated with focal or diffuse slow waves with rare epileptiform abnormalities. Cerebrospinal fluid oligoclonal bands were observed in four out of six patients tested. MRI images showed bilateral peri-insular hyperintensity in four cases. Five patients received corticosteroids, and in four cases, they were given along with intravenous immunoglobulins. The median duration of the acute phase was 19 days (range 15-30 days). During the chronic phase, which followed the acute phase without interval, patients presented with drug-resistant focal seizures and neuropsychological deficits, which ranged from hyperactivity and attention deficits to short-term verbal memory deficit, pervasive developmental disorders, and language delay. Conclusion: considering the clinical presentations, EEG findings, and the associated occurrence of non-specific immunological activations, a possible immune-mediated pathogenesis can be hypothesized, although firm conclusions cannot be drawn out.