Seizures and magnetic resonance imaging-detected brain injury in newborns cooled for hypoxic-ischemic encephalopathy

Abstract

Objective: To describe the association between electrographically detected seizures and brain injury evaluated by magnetic resonance imaging in newborns treated with hypothermia.

Study design: A total of 56 newborns treated with hypothermia were monitored using video electroencephalography through cooling and rewarming, and then imaged at a median of 5 days. The electroencephalograms were reviewed for indications of seizure and status epilepticus. Moderate-severe injury detected on magnetic resonance imaging was measured using a classification scheme similar to one predicting abnormal outcome in an analogous population.

Results: Seizures were recorded in 17 newborns (30%), 5 with status epilepticus. Moderate-severe injury was more common in newborns with seizures (relative risk, 2.9; 95% CI, 1.2-4.5; P=.02), and was present in all 5 newborns with status epilepticus. Newborns with moderate-severe injury had seizures that were multifocal and of later onset, and they were more likely to experience recurrent seizures after treatment with 20 mg/kg phenobarbital. Newborns with only subclinical seizures were as likely to have injury as those with seizures with a clinical correlate (57% vs 60%).

Conclusion: Seizures represent a risk factor for brain injury in the setting of therapeutic hypothermia, especially in neonates with status epilepticus, multifocal-onset seizures, and a need for multiple medications. However, 40% of our neonates were spared from brain injury, suggesting that the outcome after seizures is not uniformly poor in children treated with therapeutic hypothermia.