Nonfebrile seizures after febrile convulsions: possible role of chronic cytomegalovirus infection.

Twelve hundred children with convulsions when feverish were studied during a period of five years. Among them 52 subjects (4.33%) developed nonfebrile seizures after a period of eight months to five years from the first febrile convulsion (group A). Twenty-three children had neither afebrile seizures nor EEG abnormalities during the period of observation (group B). The two groups were comparable for age of the first febrile convulsion onset, sex, and socioeconomic status. None had risk factors for subsequent epilepsy or clinical signs of congenital cytomegalovirus infection. The isolation rate of CMV from urine was 53.84% in patients of group A, 26.09% in children of group B, and 26.83% in healthy control children. Twelve CMV-positive children from group A were followed for one to more than three years. In five of seven children with persisting EEG abnormalities, cytomegaloviruria was still present 13 to 41 months after the first isolation, whereas none of five patients with normal electroencephalograms had viruria after a comparable period. We found that CMV-positive children generally lacked cell-mediated immunity to the virus, whereas CMV-negative patients had positive reactions. Our data suggest a correlation between persistence of neurologic abnormalities and CMV excretion in children with nonfebrile seizures and CMV infection.