Abstracts

Rationale: Seizures frequently occur in neonates with brain injury. Both clinical and subclinical neonatal seizures are reported to correlate with adverse neurodevelopmental outcome. Although neonatal ischemic stroke (NIS) frequently presents with manifested seizures, data are lacking regarding their subsequent evolution and impact on outcome as well as if acute recognition and early treatment of seizures could potentially improve the neurodevelopmental outcome from NIS. Our objectives were: 1)To determine the frequency of subclinical seizures in acute NIS 2)To evaluate the effect of seizures on radiographic progression of acute NIS 3)To assess the long term neurological outcome in this population (Paediatric Score Outcome Measure [PSOM] and Epilepsy) Methods: This is a retrospective single center study of neonates prospectively registered in the Canadian Paediatric Ischemic Stroke Registry (CPISR) (Toronto site) with acute NIS (arterial ischemic stroke [AIS] and/or cerebral sinus venous thrombosis [CSVT]) from January 1999 to December 2006. Inclusion required an electroencephalogram (EEG) performed within 7 days from confirmed NIS diagnosis. Patients were excluded if they were not term (<36 weeks or >46weeks CA) and if EEG trace was not available for review. Data were abstracted from the CPISR, Hospital Health Records and Neurophysiology Laboratory Database. EEG traces were reviewed by Board Certified Neurophysiologist (MC). Pre and Post EEG neuroimaging data were reviewed blinded by paediatric stroke neurologist (MM). Demographic data, PSOM, progression of ischemic lesions on neuroimaging and epilepsy outcome at last visit were compared between patients with and without seizures on EEG. Statistical analyses were performed using GraphPad 4 software. Significance was set at p<0.05 and trend when p<0.10. Results: There were 82 neonates with NIS. 29 were excluded due to incomplete data. Among 53 included patients, 18 (34%) had seizures on EEG recording that were only subclinical in 15 (83.3%) and clinical subclinical seizures in 3 (16.7%). Demographic data did not differ significantly in patients with (PS) or without (PWOS) seizures. There was no significant difference on stroke progression on neuroimaging follow-up. PSOM scores were significantly worse at follow up between PS (2.8 [95% CI 1.00 - 4.6]) versus PWOS (0.98 [95% CI 0.5 - 1.47]) (p=0.019). Epilepsy at follow up (63.0 months [95% CI 40.9 - 85.1] in PS and 58.2 months [95% CI 48.6 - 67.7] in PWOS, p=0.69) tended to be more frequent in neonates with seizures on EEG (5 out of 18 PS vs. 3 out of 35 PWOS, p=0.089). Conclusions: In our series, seizures occurred frequently, the majority being subclinical. Neurological outcome was significantly poor in PS. Close clinical and EEG monitoring to screen for clinical and subclinical seizures is desirable. Prophylactic treatment with anti-convulsant medications in acute NIS, in order to improve the long term prognosis and potentially diminish the chances of developing epilepsy is worth consideration. Prospective studies are needed to further address these issues.