Researchers at Nihon University School of Medicine, Tokyo, Japan, report 11 children with intractable epilepsy (West syndrome in 6 and myoclonic seizures in 5) who showed clinical and electrographic improvement following acute viral infection. Seizure remission occurred following exanthem subitum in 5 patients, rotavirus gastroenteritis in 2, measles in 2, herpetic stomatitis in 1, and common cold in 1. In patients with West syndrome, salaam and/or tonic spasms resolved within 6 days after onset of viral infection, and hypsarrhythmia was modified and evolved to localized spikes. Myoclonic seizures resolved rapidly and completely and the EEG gradually normalized or improved. Four of the 11 patients became seizure free for 5 to 20 years, 1 child remained seizure free for 12 months after viral infection, and 6 relapsed and had seizure recurrence within 14 days to 1 month after remission. Characteristic findings in the 4 patients with prolonged remission included: 1) normal brain CT/MRI, 2) normal development prior to onset of epilepsy, and 3) a short duration of epilepsy before occurrence of viral infection. One mechanism for seizure remission proposed is a change in immune state following viral infection similar to the effect of immunoglobulin therapy. Alternative hypotheses include: 1) direct suppression of seizures by virus, 2) elevation of serum Cortisol level, or 3) anti-inflammatory cytokine response to viral infection. 
COMMENT. Several reports of seizure remission following viral infection have involved patients with West syndrome, and some cases have a spontaneous remission. Among cases of viral-induced remission of epilepsy, exanthem subitum and human herpes virus-6 appear to be involved most commonly, and West syndrome is the most susceptible epilepsy. Previous reports of viral-induced seizure remission have described the clinical findings but have lacked the details of electrographic and hypsarrhythmia modification. The mechanism and therapeutic possibilities of this report deserve further study.