Long-term prognosis in children with neonatal seizures: a population-based study.

OBJECTIVE: To examine outcome and explore for prognostic markers in a cohort <10 years following neonatal seizures.
METHODS: We prospectively diagnosed clinical neonatal seizures with high specificity for true epileptic seizures in a population-based setting of all live newborns in the province of Newfoundland, Canada, between 1990 and 1995. Children with neonatal seizures were followed by specialized provincial health services. Follow-up data were collected on epilepsy, physical and cognitive impairments, and other heath issues.
RESULTS: Data were available on 82 out of 90 subjects. We added information on six others whose outcome was clearly predictable from earlier information. Prognosis was better for term than for preterm infants (p = 0.003): term: 28 (45%) normal, 10 (16%) deaths, and 24 (39%) with impairments; preterm: 3 (12%) normal, 11 (42%) deaths, and 12 (46%) with impairments. Of survivors, 17 (27%) developed epilepsy, 16 (25%) had cerebral palsy, 13 (20%) had mental retardation, and 17 (27%) had learning disorders. Variables associated with poor prognosis were Sarnat stage III or equivalent severe encephalopathy, cerebral dysgenesis, complicated intraventricular hemorrhage, infections in the preterm infants, abnormal neonatal EEGs, and the need for multiple drugs to treat the neonatal seizures. Pure clonic seizures without facial involvement in term infants suggested favorable outcome, whereas generalized myoclonic seizures in preterm infants were associated with mortality.
CONCLUSIONS: Poor prognosis for premature infants with seizures is reflected in high rates of subsequent long-term disability and mortality. The severity and timing of the pathologic process continue to be the major determinants for outcome.