Neonatal seizures

Neonatal seizures are abnormal electrical discharges in the brain of a newborn, typically occurring within the first 28 days of life, often with an acute brain injury or insult.

Neonatal seizures arise when normal asynchronous cortical activity becomes synchronous, detected on electroencephalography as spike-and-slow-wave patterns. This aberrant firing often reflects a combination of enhanced neuronal connectivity, heightened excitatory transmission, and failed inhibitory mechanisms, all of which are influenced by developmental factors such as transient overexpression of glutamate receptors and the immature expression of GABA receptors. Most common causes of neonatal seizures are hypoxic-ischemic encephalopathy, stroke, infections, and intraventricular hemorrhage. Other causes may include hypoglycemia, CNS infections, subarachnoid hemorrhage, brain malformations, metabolic disorders, genetic causes (such as mutations in KCNQ2, STXBP1, SCN2A, PNKP, ARX genes), and drug withdrawal syndrome.

The incidence of neonatal seizures is estimated at 1-5 per 1,000 live births in full-term neonates and 14 per 1,000 in preterm neonates.

Risk factors for neonatal seizures include smoking during pregnancy, nulliparity, advanced maternal age, increased maternal BMI, diabetes mellitus during pregnancy, hypertensive disorders of pregnancy, maternal fever, chorioamnionitis, shoulder dystocia, placental abruption, assisted vaginal delivery, induced labor, and occiput posterior position at birth.

Seizures may present clinically or be detectable only on electroencephalography (subclinical). Seizure activity often begins focally but may generalize and involve the entire body. The clinical presentation varies widely depending on gestational age, underlying etiology, and concurrent medical conditions. Clinical seizures can include automatisms, clonic, myoclonic, or tonic seizures, epileptic spasms, autonomic seizures, behavioral arrest, sequential seizures, and other unclassified seizure types.

Neonatal seizures are associated with a 20% mortality rate and poor neurodevelopmental outcomes, including worsened motor and cognitive function compared with neonates without seizures, as well as an increased risk of remote seizures and epilepsy.