Epilepsy and West syndrome in neonates with hypoxic-ischemic encephalopathy

Perinatal hypoxic-ischemic encephalopathy (HIE) has been linked to the development of late-onset seizures. The aim of the present study was to determine the incidence of epilepsy and West syndrome in children with perinatal HIE and identify factors associated with the development of postnatal seizure disorders.

We retrospectively enrolled 208 term and late-preterm infants diagnosed with perinatal HIE from April 2000 to March 2009 at Saitama Children's Medical Center. Children with obvious multiple anomalies and known chromosomal abnormalities were excluded. A questionnaire was distributed to parents to determine seizure-related outcomes. Medical records were retrospectively reviewed and relevant clinical parameters were analyzed.

In total, 162 questionnaires were answered (77.9%). Of the 162 subjects, 26 (16.0%) developed epilepsy, and eight subjects (4.9%) were diagnosed with West syndrome. Neonatal seizures occurred in 72 subjects (44.4%). The incidence of epilepsy and West syndrome was significantly higher in infants who experienced neonatal seizures than in those without seizure history. A total of 82 subjects were diagnosed with moderate (n = 52) or severe HIE (n = 30), of whom 57 subjects (69.5%) received therapeutic hypothermia. The incidence of epilepsy was significantly lower in these treated subjects. In addition, subjects with moderate or severe HIE were significantly more likely to develop late-onset epilepsy and West syndrome than those with mild HIE.

The severity of perinatal HIE and neonatal seizures is a potential risk factor for the development of late-onset seizures. Therapeutic hypothermia may reduce the risk of the development of epilepsy in such cases.