Abstracts

Rationale: Hypoxic-ischemic encephalopathy (HIE) is one of the most common causes of neonatal encephalopathy and the leading cause of seizures in the neonatal period. Therapeutic hypothermia (TH) is now standard of care for full term infants with HIE, given that it is associated with improved neurodevelopmental outcomes. Although HIE is a risk factor for the later development of epilepsy, in particular infantile spasms, there is limited data regarding the incidence in infants who underwent TH.  Our aim was to determine the incidence of later onset seizures following hospital discharge in term infants with HIE who underwent TH. Methods: A single center, retrospective study was performed on neonates who underwent whole body TH between 2011-2014.  All patients were monitored with continuous electroencephalography (EEG) during TH.  Routine follow up EEGs were also collected after hospital discharge.  Data was collected through the electronic medical record.  Follow up data was obtained regarding later epilepsy based on subsequent outpatient visits.     Results: Follow up data were available for 25 (81%) of 31 neonates who received TH.  Median age at follow up was 24 months with interquartile range of 19-36 months.  Acute seizures occurred during TH in 11 (44%) patients, 7 (64%) of whom had electrographic-only seizures.  Later seizures occurred in 2 (18%) out of the cohort with acute seizures, with 1 patient developing epileptic spasms and 1 with febrile seizures.  None of the infants without seizures went on to subsequently develop later seizures. Follow up EEG data was collected in 9 (82%) out of the 11 patients with acute seizures and 7 (50%) of 14 patients without acute seizures.  Median age of follow up EEG was 6 months with interquartile range of 5-9.25 months.  Three (33%) of the 11 patients with acute seizures had abnormal EEGs on follow up.  One (33%) of 3 patients with an abnormal follow up EEG developed later seizures.  None of the patients without acute seizures had a follow up EEG that was abnormal.                     Conclusions: Acute seizures are common in neonates with HIE, but later seizures are uncommon following hospital discharge.  Although limited by small sample size, in our cohort, only patients with acute seizures developed later seizures.  Of the 2 patients with later seizures, only one developed epilepsy with infantile spasms.  Neonates with acute seizures were also more likely to have an abnormal follow up EEG.  However, even in these patients with acute seizures, the majority had normal follow up EEGs.  The incidence of later seizures in neonates who received TH appears to be low, and follow up EEGs could serve as a marker for assessing later seizure risk in this population.           Funding: No funding sources