A seizure is when there is an unusual and excessive amount of electrical activity in the brain. Neonatal seizures occur within the first 28 days of life and are more common in premature or low birth weight babies. While some of the physical symptoms of neonatal seizures are similar to those of healthy newborns, a diagnosis usually requires testing. The outcome for babies with neonatal seizures depends on the type and underlying cause, with mild seizures not causing lasting harm, but untreated seizures causing permanent brain damage. Neonatal seizures often indicate a more severe underlying condition, such as brain injury, and therefore, require prompt and specialized medical attention.
Neonatal Seizures Causes
An abnormal discharge of electrical activity in the central nervous system (CNS) can occur due to various reasons such as primary intracranial problems like meningitis, encephalitis, tumor, ischemic stroke, intracranial hemorrhage or malformation, or systemic issues like hypoxia-ischemia, hypoglycemia, hypocalcemia, hyponatremia, or other metabolic disorders. It is difficult to distinguish between seizures caused by intracranial problems and those caused by systemic issues based on their clinical features, such as whether they are focal or generalized.
There are several reasons why newborns may experience seizures. These include a lack of oxygen before or during birth due to placental abruption, a difficult or prolonged labor, or compression of the umbilical cord. Infections acquired before or after birth, such as bacterial meningitis, viral encephalitis, toxoplasmosis, syphilis, or rubella, can also cause seizures. Additionally, strokes, blood clots or bleeding in the brain, brain birth defects, blood sugar or electrolyte imbalances, metabolic disorders like maple syrup urine disease, pyridoxine dependency, or phenylketonuria (PKU), and drug withdrawal can all be underlying causes of neonatal seizures.
Mothers addicted to drugs such as methadone or cocaine, heroin, barbiturates and alcohol can make their babies susceptible to seizures.
Neonatal seizures Signs and Symptoms
Neonatal seizures are often localized and can be difficult to distinguish from regular neonatal behavior because such seizures show up as normal chewing or cycling movements of neonates. Some typical symptoms include involuntary muscle jerks, alternating seizures on one side of the body, and primitive subcortical seizures which can lead to respiratory arrest, persistent eye deviations or nystagmus, and changes in muscle tone. Generalized tonic-clonic seizures are not very common.
After a hypoxic-ischemic event like perinatal asphyxia or stroke, or in cases of CNS infections, it’s common to see electrical seizure activity without any visible clinical symptoms. Even when initial antiseizure medication treatment is given, it may not stop the electrical seizure activity.
Characteristic features of Seizures in Infants
seizures in infants typically happen within a few days, and less than half of the babies who experience them develop seizures later in life. These seizures are considered acute reactive or symptomatic and are not classified as neonatal epilepsy.
Seizures in newborns are relatively common and can present with various symptoms. They often indicate neurological dysfunction and can lead to cognitive and developmental problems in the long term. Focal seizures are more common than generalized seizures in neonates, although the latter can occur in rare cases.
Subtle seizures are more frequently observed in full-term infants compared to premature babies. Studies using video electroencephalograms have revealed that most subtle seizures are not associated with abnormal brain activity. Examples of subtle seizures include chewing, pedaling, and eye movements, which are not necessarily epileptic and may be an associated phenomenon of severe encephalopathy.
… Read Part 2 of Neonatal Seizures
