When a baby experiences a seizure, the event signals abnormal electrical activity in the developing brain. While serious, modern medical interventions have significantly lowered the associated risks. The prognosis largely depends on the underlying cause and how quickly effective treatment begins. Understanding the specific risks and how seizures manifest in this age group is crucial for management.
Recognizing Seizures in Infants
Identifying a seizure in a newborn or young infant is challenging because their developing nervous system often prevents the generalized convulsions seen in older children. Seizures in this population are frequently “subtle,” meaning they can be easily missed or mistaken for normal behaviors like the startle reflex. The neonatal period (the first 28 days of life) is particularly prone to these inconspicuous presentations.
Subtle seizures often involve small, repetitive movements in the face or limbs. Parents might observe rhythmic eye movements, such as sustained staring, eye rolling, or eyelid fluttering, that do not stop when the baby is gently stimulated. Other signs include repetitive oral movements (tongue protrusion, lip smacking, or sucking motions) or bicycling movements of the legs. Seizures can also manifest as abrupt, unexplained pauses in breathing, known as apnea.
Infantile seizures, occurring after the neonatal period, can also be challenging to recognize, often involving only one side of the body or a specific limb. A distinct type, known as infantile spasms, involves a sudden, brief stiffening or crunching forward of the body, often occurring in clusters when the baby is waking up. These spasms can be confused with the Moro reflex, but unlike a reflex, they occur repetitively without external stimulation. Prompt identification, often confirmed with an electroencephalogram (EEG), is necessary because prolonged or untreated seizures can interrupt normal brain development.
Factors That Determine Mortality Risk
While a single, brief seizure rarely causes direct death, mortality risk increases significantly when specific factors are present. The most serious immediate risk is status epilepticus, defined as a seizure lasting longer than five minutes or a series of seizures without a return to baseline consciousness. Status epilepticus is a medical emergency because extended activity can lead to complications such as respiratory failure, brain injury from excessive neuronal firing, and hemodynamic instability.
In infants, death is more frequently a consequence of the severe underlying medical condition that caused the seizure, rather than the seizure itself. For example, a baby experiencing seizures due to a massive intracranial hemorrhage or a systemic infection like meningitis faces a high mortality risk primarily from the underlying disease. The prognosis is tied directly to the severity of the brain injury or illness that triggered the event. Mortality rates are highest in infants with seizures caused by conditions such as hypoxic-ischemic encephalopathy (HIE), which involves brain injury from a lack of oxygen or blood flow.
Another factor in mortality risk, particularly for infants who develop long-term epilepsy, is Sudden Unexpected Death in Epilepsy (SUDEP). SUDEP is the sudden, unexplained death of a person with epilepsy, typically occurring during sleep, and is considered the leading cause of epilepsy-related death. SUDEP is thought to result from a cascade of events, including post-seizure heart rhythm abnormalities or breathing difficulties. The risk is strongly linked to the occurrence of generalized tonic-clonic seizures, though the increased risk in otherwise neurologically normal children usually begins later in adolescence.
Underlying Causes of Infant Seizures
The origin of the seizure activity (etiology) is the main determinant of a baby’s long-term health and mortality risk. Causes of infant seizures reflect the diverse vulnerabilities of the developing brain. Many cases are related to structural or acquired brain injuries that occur before, during, or shortly after birth.
Primary Etiologies
Infant seizures stem from various causes:
- Hypoxic-ischemic encephalopathy (HIE): Resulting from oxygen deprivation, this is one of the most common causes of seizures in full-term infants.
- Structural issues: These include intracranial hemorrhage (bleeding in the brain), common in premature babies, or congenital brain malformations.
- Metabolic disturbances: These involve the body’s inability to regulate necessary chemicals, such as low blood sugar (hypoglycemia) or imbalances in electrolytes like calcium and magnesium, which are often correctable.
- Infectious causes: Serious triggers like bacterial meningitis or viral encephalitis cause inflammation within the brain.
- Genetic factors: Some forms of epilepsy result from inherited disorders or spontaneous gene mutations.
Identifying infections quickly is crucial, as they require immediate and specialized treatment to reduce seizure activity and mortality risk. However, some neonatal seizures, such as benign familial neonatal seizures, are benign and self-limited, carrying an excellent prognosis.
Emergency Response and Medical Management
An immediate and informed response is important for any caregiver witnessing a baby’s seizure. The first step is to ensure the infant is safe by placing them on a soft surface and turning them onto their side to keep the airway clear and prevent choking. Caregivers should remove any nearby objects that could cause injury and time the seizure accurately from start to finish. Never attempt to place anything inside the baby’s mouth.
Caregivers should call for emergency medical services if a seizure lasts five minutes or longer, or if the baby stops breathing. Once in a medical setting, initial management focuses on stopping the seizure and identifying its cause. Doctors use first-line anti-seizure medications, typically a benzodiazepine such as lorazepam or midazolam, to rapidly halt the excessive electrical activity. If the seizure continues, second-line drugs like phenobarbital or levetiracetam are administered.
A comprehensive diagnostic workup is initiated simultaneously. This often includes blood tests to check for metabolic issues like low glucose or electrolyte imbalances, which are corrected immediately. Diagnostic imaging, such as a brain MRI, and an EEG are necessary to pinpoint the underlying cause and determine the long-term treatment plan. For infants with an acute, reversible cause, anti-seizure medication may be discontinued after several months if they remain seizure-free.