Seizures in newborns are sudden, abnormal bursts of electrical activity in the brain that differ significantly from those in older children or adults. These events occur during the neonatal period, the first 28 days of a full-term infant’s life, with most instances happening within the first week. Prompt medical attention is necessary, as newborn seizures often signal an underlying medical condition. Understanding their causes is crucial for proper diagnosis and management.
Identifying Seizures in Newborns
Recognizing seizures in newborns can be challenging for parents due to their subtle and varied manifestations, which often differ from typical seizure presentations in older individuals. Common subtle signs include unusual eye movements, such as persistent eye deviation, rapid eye fluttering, or rolling of the eyes. Infants might also exhibit repetitive oral movements like lip smacking, sucking, or chewing motions.
Motor manifestations can involve rhythmic, sustained jerking movements, known as clonic jerks, affecting the face, tongue, limbs, or fingers. Tonic posturing is observed as a stiffening of muscles, where the infant holds their head to one side. Myoclonic jerks are brief, sudden muscle spasms, similar to clonic seizures but occurring in shorter, isolated bursts. Some newborns may also experience apneic episodes, which are long pauses in breathing. These varied presentations underscore the need for careful observation and medical evaluation.
Leading Medical Causes
A common cause of newborn seizures is hypoxic-ischemic encephalopathy (HIE), a brain injury from a lack of oxygen and blood flow to the brain, often occurring during labor or delivery. This oxygen deprivation can lead to permanent brain damage if sustained. Brain injuries like HIE are frequently identified as underlying reasons for neonatal seizures.
Intracranial hemorrhage, or bleeding within the brain, is another significant cause of seizures in newborns. This can include intraventricular hemorrhage (bleeding into the fluid-filled spaces of the brain) or subdural hemorrhage (bleeding beneath the outermost membrane covering the brain). Central Nervous System (CNS) infections, such as meningitis (inflammation of the membranes surrounding the brain and spinal cord) or encephalitis (inflammation of the brain itself), can also trigger seizures. These infections can be acquired before or after birth, with common bacterial causes including Group B streptococci.
Cerebral stroke, involving a blood clot or bleeding in the brain leading to tissue damage, can also result in newborn seizures. Seizures caused by stroke tend to be focal, affecting a specific area of the brain, and may sometimes manifest as apnea. These serious conditions necessitate immediate medical attention.
Other Underlying Conditions
Beyond the more common causes, several other medical conditions can lead to newborn seizures. Metabolic disorders are conditions where the body’s chemical processes are disrupted. These include hypoglycemia (low blood sugar), hypocalcemia (low calcium), and hyponatremia (low sodium). Inborn errors of metabolism, rare genetic conditions affecting nutrient processing, can also cause seizures.
Genetic conditions, involving specific mutations or syndromes, can predispose newborns to seizure activity. Seizures in infancy may also stem from genetic disorders or abnormal brain development that occurred in the womb. Structural brain abnormalities, such as congenital malformations like cortical dysplasia, represent another category of causes. These malformations involve abnormal development of the brain’s outer layer.
Drug withdrawal, resulting from maternal substance use during pregnancy, can also induce seizures in newborns. A less common cause is vitamin B6 (pyridoxine) deficiency. This deficiency is treatable, and diagnosis can be established by observing if seizures improve after administering vitamin B6.
Diagnosing the Cause
Determining the specific cause of seizures in a newborn involves a thorough diagnostic process. A clinical evaluation is the initial step, including a detailed medical history (such as maternal health and birth complications) and a comprehensive physical examination of the infant. Specialized doctors, often pediatric neurologists, work to identify the cause.
An electroencephalogram (EEG) is an important tool for diagnosis and management, confirming seizure activity by recording the electrical patterns in the baby’s brain. This non-invasive test places electrodes on the baby’s head to detect abnormal electrical discharges. Neuroimaging techniques, such as Magnetic Resonance Imaging (MRI) or Computed Tomography (CT) scans, are frequently used to identify structural issues, bleeding, or evidence of a stroke.
Blood tests check for metabolic imbalances like low blood sugar or electrolyte abnormalities, and screen for infections or genetic markers. A lumbar puncture, also known as a spinal tap, may be performed to collect cerebrospinal fluid, which is then analyzed for central nervous system infections like meningitis or encephalitis. These diagnostic procedures are urgent for effective management and improving outcomes for the newborn.