Neonatal Seizures

Background

A seizure is caused by sudden, abnormal and excessive electrical activity in the brain. By definition, neonatal seizures occur during the newborn period — for a full-term infant, the first 28 days of life and for a preterm infant, until 28 days after the due date. Most occur in the first one to two days to the first week of a baby's life. The newborn period is the highest risk time for seizures during the entire lifespan. About 1-4/1,000 live born children experience seizures during the newborn period.

Right central seizure in a neonate with hypoxic-ischemic encephalopathy
Figure: Right central EEG seizure in a neonate with hypoxic-ischemic encephalopathy.

A newborn with seizures may have visible signs (rhythmic twitching of a body part, posturing, or subtle movements like eye deviation or bicycling). However, healthy newborns can have similar movements and at the same time, a seizure may not have visible signs. For this reason, testing is usually required to confirm the diagnosis. The gold standard test for neonatal seizures is an electroencephalogram (EEG) to capture the events of concern or at least 24 hours of recording in high risk newborns. These recommendations are outlined by the American Clinical Neurophysiology Society; all members of the Neonatal Seizure Registry follow these guidelines.

Causes

Neonatal seizures have a variety of causes. 

  • Most seizures in newborns are due to brain injury (acute symptomatic seizures)
    • Lack of oxygen before or during birth due to placental abruption (premature detachment of the placenta from the uterus), a difficult or prolonged labor, or compression of the umbilical cord (neonatal encephalopathy or hypoxic-ischemic encephalopathy, HIE)
    • Stroke before or after birth
    • Bleeding into the brain or fluid filled spaces around the brain (intracranial hemorrhage, intraventricular hemorrhage, IVH)
    • Infection acquired before or after birth, such as bacterial meningitis, viral encephalitis, toxoplasmosis, syphilis or rubella
  • Rarely, seizures may be caused by early onset epilepsy
    • Brain birth defects (malformations)
    • Genetic epilepsy (familial and non familial forms)
  • Other causes include
    • Blood sugar or salt imbalances
    • Inborn errors of metabolism 
    • Drug withdrawal

Treatment

Seizures in neonates are usually treated with one or more anti-seizure medications (examples include phenobarbital, lorazepam, phenytoin, levetiracetam). Some seizures may resolve after correction of blood sugar or salt correction. Genetic epilepsies may respond to specific treatments. 

Outcome

The outcomes for babies who have neonatal seizures depend on the type of seizure and the underlying cause. Some neonatal seizures are mild and short-lived and therefore do not cause any lasting health problems. However, seizures can be a sign of serious underlying brain conditions. For this reason, babies experiencing neonatal seizures should receive rapid, specialized care.

Why Study Neonatal Seizures?

Our experience at the bedside and working with parents of children with neonatal seizures made us aware of many unanswered questions related to neonatal seizures. Questions that are important to clinicians and parents alike: What is the best medicine? How long should they be treated? What is the long term impact of seizures and their treatment? Can we determine who will develop epilepsy after acute seizures? How can we best support parents and caregivers of children with seizures and epilepsy?

Select References by Our Investigators

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Chang T, Tsuchida TN. Conventional (continuous) EEG monitoring in the NICU.
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Glass HC, Grinspan ZM, Shellhaas RA. Outcomes after acute symptomatic
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