Advances in classification, causes, treatment and outcome of perinatal ischemic stroke are reviewed by researchers at Alberta Children's Hospital, Calgary; and the Hospital for Sick Children, Toronto, Canada. Four perinatal stroke syndromes are described in order of decreasing incidence: 1) neonatal arterial ischemic stroke (accounts for two-thirds); 2) neonatal cerebral sinovenous thrombosis; 3) presumed perinatal ischemic stroke; and 4) periventricular venous infarction. MRI of the head and neck is the investigation of choice in perinatal stroke. Diffusion-weighted MRI provides information on timing for acute, focal infarction. MR angiography defines arterial occlusion or arteriopathy. MR venography defines location and extent of venous thrombosis, and diffusion weighted MRI confirms or excludes venous edema or infarction.
Maternal, prenatal, and placental risk factors include chorioamnionitis, prolonged rupture of membranes, preeclampsia, placental thrombi and intrauterine growth retardation. Intrapartum factors include neonatal encephalopathy with asphyxia that may co-occur with perinatal stroke. Prothrombotic and hematological factors occur in 20-68% of neonates with ischemic stroke. Cardiac evaluation is recommended in all cases of perinatal stroke, and complex congenital heart disease predisposes neonates to cerebral thromboembolism, especially during diagnostic and surgical procedures. Infection and inflammation are common in perinatal stroke, and the association with bacterial meningitis and chorioamnionitis requires further study.
Treatment involves maternal prevention approaches (counseling regarding smoking, weight control), rescue at risk brain tissue (anticoagulation, maintain normal blood sugar, temperature, oxygenation, blood pressure), and optimize outcome (study of hypothermia, treatment of seizures). Congenital hemiplegia and epilepsy are the most common neurological deficits, and disorders of language, vision and cognition occur in 20-60% of perinatal stroke cases. Neuroimaging lesion size and location are helpful in prediction of outcome. Basal ganglia involvement correlates with poor prognosis. 
COMMENT. The distinction between specific causative factors and coincidental associations is a challenge, particularly with prenatal factors in the etiology of perinatal ischemic stroke. Advances in neuroimaging (functional MRI, diffusion tensor imaging, and transcranial magnetic stimulation) have improved prediction of outcome and should increase understanding of brain reorganization and plasticity.
Risk of epilepsy after perinatal stroke was studied by retrospective review of 64 children followed after 6 months of age at Indiana University School of Medicine (Ped Neur Briefs Oct 2007;21:79) . Neonatal seizures were recorded in the NICU in 75% of cases. Epilepsy had developed in 67% between age 6 months and follow-up at a mean age of 43 months. Infarct on prenatal ultrasound and family history of seizures were significantly associated with development of epilepsy following perinatal stroke.