Objectives: To determine incidence rates and risk factors of remote seizure after perinatal arterial ischemic stroke.
Methods:We retrospectively identified a population-based cohort of children with perinatal arterial ischemic stroke (presenting acutely or in a delayed fashion) from a large Northern Californian integrated health care system. We determined incidence and predictors of a remote seizure (unprovoked seizure after neonatal period, defined as 28 days of life) by survival analyses, and measured epilepsy severity in those with active epilepsy ($1 remote seizure and maintenance anticonvulsant treatment) at last follow-up.Results: Among 87 children with perinatal stroke, 40 (46%) had a seizure in the neonatal period.During a median follow-up of 7.1 years (interquartile range 3.2-10.5), 37 children had $1 remote seizure. Remote seizure risk was highest during the first year of life, with a 20% (95% confidence interval [CI] 13%-30%) cumulative incidence by 1 year of age, 46% (CI 35%-58%) by 5 years, and 54% (CI 41%-67%) by 10 years. Neonatal seizures increased the risk of a remote seizure (hazard ratio 2.8, CI 1.3-5.8). Children with neonatal seizures had a 69% (CI 48%-87%) cumulative incidence of remote seizure by age 10 years. Among the 24 children with active epilepsy at last follow-up, 8 (33%) were having monthly seizures despite an anticonvulsant and 7 (29%) were on more than one anticonvulsant.Conclusions: Remote seizures and epilepsy, including medically refractory epilepsy, are common after perinatal stroke. Neonatal seizures are associated with nearly 3-fold increased remote seizure risk. Neurology ® 2016;86:2179-2186 GLOSSARY AIS 5 arterial ischemic stroke; CI 5 confidence interval; HR 5 hazard ratio; ICD-9 5 International Classification of Diseases-9; IQR 5 interquartile range; KPNC 5 Kaiser Permanente Northern California; PPIS 5 presumed perinatal ischemic stroke.Perinatal arterial ischemic stroke (AIS) occurs in 1 in 4,000 term births and is an important cause of childhood epilepsy.1 In some newborns, an ischemic brain injury is initially unrecognized and only diagnosed later during development when a hemiparesis becomes clinically apparent or a remote symptomatic seizure occurs. This subset often receives a diagnosis of presumed perinatal ischemic stroke (PPIS), which refers to a stroke presumed to have occurred in the perinatal period because of a chronic focal infarction on neuroimaging.2 Stroke that is clinically apparent in the neonatal period may differ from PPIS. Seizures during the neonatal period are perhaps the most notable factor differentiating these groups, and are reported in about 75%-90% of infants diagnosed with stroke during the perinatal period.3-5 Neonatal seizures of any cause may confer a long-term risk of postnatal epilepsy. An estimated 10%-20% of neonates with seizures from any cause will go on to have further seizures in childhood. 6 Our objective was to measure the incidence rate and risk factors for a first remote seizure after perinatal AIS utilizing a previo...