Improvement of intractable childhood epilepsy following acute viral infection

In this study, we report 11 patients with intractable childhood epilepsy that improved following acute viral infection. The patients were 8 boys and 3 girls. Six of the 11 children were diagnosed as West syndrome (5 of the symptomatic type and 1 of the cryptogenic type). The remaining 5 children were myoclonic seizures. The patients became seizure free within 6 days following acute viral infections without an exchange or addition of antiepileptic drugs (AEDs). The types of acute viral infections were Exanthema subitum (Roseola infantum) in 5 patients, Rotavirus gastroenteritis in 2 patients, Measles infection in 2 patients, Herpetic stomatitis in 1 patient and Common cold in the remaining patient. Salaam seizures and/or tonic spasms disappeared within 6 days after the onset of viral infections, and hypsarrhythmia evolved to localized spikes on electroencephalography (EEG) in the patients with West syndrome. Epileptic seizures disappeared rapidly and EEG gradually normalized or improved in patients with myoclonic seizures. Four patients became seizure free for 5 years to 20 years. In 6 patients, seizures relapsed within 14 days to 1 month after the disappearance of seizures. One child remained seizure free for 12 months after viral infection. Common factors in 4 children who were continuously seizure free include (1) normal or almost normal findings of brain CT/MRI, (2) normal development prior to the onset of epileptic seizures, and (3) a short time interval between the onset of seizures and the acute viral infection. We propose several hypotheses including an immunological effect for the improvement of intractable childhood epilepsy following acute viral infection. Further study may provide important information concerning the mechanism of seizure control and the applicable to treatment for intractable childhood epilepsy.