Source:Ronen GM, Buckley D, Penney S, et al. Long-term prognosis in children with neonatal seizures.
–1822; doi: 10.1212/01.wnl.0000279335.85797.2c

In a population-based cohort from Newfoundland, researchers from Ontario and Newfoundland sought to determine the prognostic markers and functional status of school-aged youth who experienced clinical neonatal seizures (CLNESZ).

All children born in Newfoundland from 1990 through 1994 were prospectively followed. In 2004–2005 data on mortality, physical disability, cognitive impairment, learning disability during school age, other neurologic impairments, and postneonatal epilepsy were collected. Normal outcome was defined as the absence of intellectual and physical impairment.

Of the 34,615 infants in the study, follow-up data were available on 82 of 90 diagnosed with CLNESZ. The authors assumed that three infants with a benign neonatal course not available for follow-up were well and three others with a catastrophic neonatal course not available had died; thus 88 infants were included in the analysis. Of these, 62 were born at term and 26 prematurely.

The median gestational age (GA) of the preterm infants was 32 weeks. Median follow-up age for survivors was 10 years. Outcome was normal in 31 children (35%); 36 (41%) had neurodevelopmental impairments, and 21 (24%) had died. The median age at death was 13 months. GA was a better predictor of outcome than birth weight. Normal outcome occurred more often in term than preterm infants (P=.003). Postneonatal epilepsy developed in 27 (34%), including 29% of term and 48% of preterm infants. Median age at onset of epilepsy was nine months in term and four months in preterm infants. Epilepsy complicating mental retardation (MR) and cerebral palsy (CP) was associated with early death. CP occurred in 35% of those surviving infancy (25% of term and 63% of preterm infants), MR was present in 32% (25% of term and 53% of preterm infants), and learning disorders in 23%. Neonatal encephalopathy occurred in 42% of all infants, usually following hypoxic-ischemic events. All infants with severe encephalopathy either died or had MR, CP, and symptomatic epilepsy. Infections occurred in 19%; outcome was normal in term infants with infection, but poor in premature infants or those with CMV infection.

Neonatal interictal EEGs were available on 70 neonates >32 weeks GA; 34 were normal and 36 were abnormal. Abnormal neonatal EEG, usually an abnormal background activity, was associated with a poor outcome (P<.0001).

Other variables associated with a poor prognosis included cerebral dysgenesis, intraventricular hemorrhage, and need for multiple anti-epileptic drugs. Purely clonic seizures without facial involvement in term infants had a favorable prognosis, whereas generalized myoclonic seizures in preterm infants were associated with high mortality. Subtle seizures, generalized tonic seizures, and number of seizures were not predictive of outcome.

The authors conclude that the severity of the underlying disorder, probably in concert with the critical period of the brain injury, is the major determinant underlying outcome following neonatal seizures.

Dr. Millichap has disclosed no financial relationship relevant to this commentary. This commentary does not contain...

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