What is Neonatal Seizure?
Neonatal seizures refer to sudden and irregular changes in brain activity in newborn babies. They occur from the time of birth until the end of the newborn period. During this time, a newborn’s brain is still growing and developing. As a result, neonatal seizures are different due to this unique growth stage and may be harder to recognize compared to seizures in older babies and children.
If a baby has a neonatal seizure, it could be the first sign of a serious brain disorder. That’s why quick identification and assessment are crucial to uncover and treat the root cause, avoid more brain damage, and stop the seizures. This summary gives an overview of the causes, symptoms, evaluation, and management of neonatal seizures.
What Causes Neonatal Seizure?
When a newborn baby experiences seizures, it can sometimes be traced back to a cause that can be fixed. There are several medical conditions that need to be checked for immediately and treated as soon as possible:
Firstly, there can be issues with the baby’s metabolism. This could be low blood sugar (hypoglycemia), low calcium (hypocalcemia), low magnesium (hypomagnesemia), or problems with sodium levels, either too low (hyponatremia) or too high (hypernatremia).
Secondly, there could be conditions related to lack of enough oxygen (hypoxic conditions). This could include things like damage to the brain due to lack of oxygen (hypoxic-ischemic encephalopathy) or not getting enough oxygen during birth (perinatal asphyxia).
Thirdly, there might be bleeding inside the brain (intracranial hemorrhage) which can happen in various parts of the brain.
Infections are another potential cause. The most common types include bacterial meningitis (caused by bacteria like Group B Streptococcus, Escherichia coli, and Listeria), viral brain infections (such as Herpes or Enteroviruses), or infections contracted before birth (like Cytomegalovirus, Toxoplasmosis, Varicella, Zika virus).
Additionally, there might be inborn defects in the baby’s metabolism. This could include specific enzyme deficiencies, such as a problem with the urea cycle, which is a series of reactions that break down waste products in the body. Peroxisomal disorders, where parts of the cells don’t work properly, and organic acidemias, which are a group of genetic disorders, might also appear. Deficiencies of certain vitamins, like Pyroxidine, or cofactors, like molybdenum, also need to be considered.
Thromboembolic conditions, such as arterial ischemic stroke, which is a blockage of blood flow to the brain, or sinus venous thrombosis (blood clots that form in veins of the brain) may also be possible causes.
Additionally, other conditions that should be explored include several neonatal epilepsy syndromes, which are genetic disorders that can cause seizures. Some congenital brain malformations, or problems in the baby’s brain that were present at birth, such as Schizencephaly (where a baby has clefts or divisions in the brain tissue), Lissencephaly (brain’s surface has less folds and grooves), Holoprosencephaly (the brain doesn’t properly split into right and left hemispheres) and Hydranencephaly (parts of the brain are replaced by sacs filled with fluid) should be considered too.
Risk Factors and Frequency for Neonatal Seizure
Neonatal seizures, or seizures in newborn babies, are a common neurological emergency. They occur in approximately 1 to 5.5 out of every 1000 live births in babies born on time. The rate of occurrence is even higher in babies born early, or preterm. In the United States, it’s estimated that there are between 80 and 120 cases per 100,000 newborns each year.
Signs and Symptoms of Neonatal Seizure
When a newborn baby starts having seizures, it’s essential to first get a thorough history and conduct a physical examination. It’s common that some underlying issue is actually causing the seizures. The goal of gathering this history is to identify risk factors and figure out the cause. This approach helps decide the best treatment strategies and predict the likely outcome of that treatment.
The historical information required for this should include when the seizures started, the mother’s health background, details of the birth, and family history. If seizures occur within the first day after birth, it usually indicates a condition called hypoxic-ischemic encephalopathy. Seizures that start after this period might be due to infection, bleeding, or stroke. Examining the mother’s health history can reveal genetic and other conditions that could cause the baby to have seizures.
This investigation might require information about previous miscarriages, which could point to a genetic syndrome, gestational diabetes, which could suggest a complicated birth, or a history of infections. Additionally, it’s important to know if the baby was exposed to prescription or illegal drugs, or if there was a withdrawal from such substances. It’s also crucial to find out if there’s a background of inherited clotting or bleeding disorders.
The birth history should be checked to rule out the possibility of brain injury due to lack of oxygen and brain bleeding. Relevant information includes whether the baby showed signs of distress, was born with low APGAR scores, or if the birth was planned to happen at home. Family history helps to confirm if there were any early deaths among the siblings that might indicate the presence of a genetic syndrome or epilepsy.
The physical examination should focus on signs that may reveal an underlying cause. This includes evaluating the general appearance, vital signs, head size, mental status, and the soft spot on the baby’s head. This helps to determine if the patient has bacterial meningitis or a form of brain bleeding. If the newborn is stable, a complete neurological examination should be carried out focusing on the cranial nerves, motor exam, tone, and presence of facial abnormalities.
Regarding the types of neonatal seizures, they are classified and characterized as follows:
- Focal clonic seizures: These are repetitive rhythmic contractions that could involve the face, arms or legs, neck, or trunk. The seizure might spread to other body parts, and if generalized, it affects the whole body.
- Focal tonic seizures: These seizures manifest as continuous, brief posturing of an arm or leg, or asymmetrical posturing of the trunk or neck. If it’s generalized, it may imitate extreme rigid posturing (like that seen in severe brain injuries), with limb flexion or extension
- Myoclonic seizures: These involve random contractions, affecting the muscles that pull limbs toward the body, mainly in the arms or upper body. If generalized, the seizures may appear as twitching of the arms and legs.
Rarely, seizures in healthy newborns can cause sudden changes in vital signs. However, in newborns at risk for seizures, these sudden changes are often associated with seizure activity that doesn’t show obvious physical signs.
Testing for Neonatal Seizure
When a newborn baby is showing signs of seizures, doctors need to figure out the cause to provide the right treatment. Right away, they would need to rule out conditions such as low blood glucose, abnormal electrolyte levels, and infections that could affect the brain like sepsis, meningitis or encephalitis. These are checked through blood glucose tests, an electrolyte panel, and various other blood tests.
Doctors might also use imaging techniques like a CT scan, ultrasound, or MRI to look at the brain. These scans can help determine if the baby had a stroke, bleeding in the brain, or any physical abnormalities in the brain. A test may also be carried out to check the baby’s first stool (meconium) to check for exposure to illegal substances.
An Electroencephalography (EEG), which records the electrical activity of the brain, can also be used to confirm if the baby is having seizures. This is especially useful as seizures can be difficult to identify just by observing the baby.
In cases where seizures are hard to manage or if the baby has other symptoms, doctors may test for inborn defect of metabolism. These are rare genetic disorders that affect metabolism. Blood tests would be performed to check the levels of pyruvate and lactic acid (substances involved in the body’s energy production process), as well as the amino acids and organic acids in the urine. This can give insights into the baby’s metabolic state.
Lastly, if doctors suspect the seizures may be due to an underlying genetic or epilepsy syndrome, they may conduct specific blood tests to confirm this.
Through performing these tests, doctors can identify the root of the problem and provide the right treatment to help the baby.
Treatment Options for Neonatal Seizure
When a patient is faced with a health crisis, doctors first make sure the patient can breathe properly, stabilize their blood pressure and heart rate, and establish a way to give them medication and fluids through an IV. The doctor will then focus on treating the cause of the patient’s illness, like cooling the body down to treat brain injury from lack of oxygen, using antibiotics to treat infections, providing sugar-rich fluids if the patient’s blood sugar is too low, correcting any imbalance of minerals in the body, or referring to a brain surgeon if the patient has bleeding inside their brain. If the patient is suspected of having a genetic disorder that affects their metabolism, doctors may stop giving them food, correct any metabolic imbalances, and start treatment with vitamins and other necessary substances.
If the patient is having a long-lasting, apparent seizure, the most common initial medication given is phenobarbital. If seizures do not stop after the first dose, additional doses may be given. Another drug often used is fosphenytoin. Other possible medications include levetiracetam and lidocaine, depending on the situation. If there is a delay in giving these medicines, short-acting drugs like midazolam can be used to control seizures.
After starting immediate treatment for neonatal seizures, a child neurologist should be contacted right away to help manage the treatment. A child neurologist can monitor the brain activity using a method called electroencephalography, or EEG, to confirm the presence of seizures, identify seizures that are not obvious from patient behavior, and help manage seizures that are hard to control. They can also help manage long-term seizure treatment in both hospital and outpatient settings. The length of treatment depends on the cause of the seizures.
What else can Neonatal Seizure be?
It is critical to differentiate between behaviors in newborns that are non-epileptic and those that indicate neonatal seizures. It can be very tricky to tell the difference just by observing the infant’s behavior. This is why monitoring with an electroencephalogram (EEG), a machine that records brain activity, is often advised.
Typical infant behaviors that can be mistaken for seizures are:
- Sucking motions
- Hiccups
- Benign neonatal sleep myoclonus, which can be understood as normal muscle jerking during sleep
Contemporary with certain illnesses, some infants may exhibit behaviors like:
- Startling easily (hyperekplexia)
- Not breathing temporarily (apnea)
- Jitteriness
- Infantile spasms
- Clonus (muscular spasm involving repeated, often rhythmic, contractions)
- Tremors
All these could be mistaken for seizures. There are also other repetitive motor behaviors like continuous eye opening, eye movements, mouth and tongue movements, and movements that resemble biking or certain postures; these can seem like signs of a seizure. However, you can usually cause these movements by touch, and stop them by repositioning the affected limb. They are not caused by epilepsy but could still be a sign of a neurological condition. Therefore, if these signs are observed alongside additional symptoms, a detailed neurological examination might be needed.
Here are a few other conditions that may reveal similar signs as neonatal seizures:
- lack of Oxygen (Anoxia) causing muscle jerks (Myoclonus)
- Benign epilepsy syndromes
- Conditions causing muscle, nerve, and brain problems (Mitochondrial cytopathies)
- Myoclonic epilepsy (jerking movements)
- Metabolic disorders (Organic acidurias)
- Pyridoxine-dependent epilepsy (seizures that respond to vitamin B6)
- Blood accumulation beneath the covering of the brain (Subdural hematoma)
- Subarachnoid hemorrhage (bleeding in the area between the brain and the thin tissues that cover it)
- Tuberous sclerosis (a genetic disorder that causes noncancerous tumors to grow in many parts of the body)
- Viral encephalitis (inflammation of the brain)
- Viral meningitis (inflammation of the protective membranes covering the brain and spinal cord)
- Malformation of the vein of Galen (a blood vessel in the brain)
- Benign neonatal convulsions
- Bleeding in part of the brain (Cerebellar hemorrhage)
- Herpes simplex encephalitis
- Stockholm syndrome (Myoclonic epilepsy)
- Child abuse
- Neonatal meningitis (inflammation of the protective membranes covering the brain and spinal cord)
- Shuddering attacks
What to expect with Neonatal Seizure
The outcome for newborn babies with seizures largely depends on the cause. If an electroencephalogram (EEG, a test used to detect electrical activity in the brain) is normal, then the baby has a great chance of recovery. However, if the EEG shows many irregularities, these babies have a higher chance of developing cerebral palsy and epilepsy, both of which can impact their brain function.
If the EEG shows spikes, which are sudden bursts of electrical activity in the brain, there is a 30% risk that the baby will develop epilepsy in the future. The mortality rate, or the rate of death, for newborn seizures can be as high as 20%. For the babies that do survive, neurological impairment (damage to the brain, spinal cord, or nerves), disability, developmental delay, and epilepsy are common issues.
Possible Complications When Diagnosed with Neonatal Seizure
Most complications from neonatal seizures, which are seizures in newborns, are linked to the side effects from the medication used to treat these seizures. These medications can cause serious issues like blocked airways, low oxygen levels, or high carbon dioxide levels. This is particularly the case when administering benzodiazepines or phenobarbital – two types of drugs commonly used in seizure treatment.
Notably, low oxygen levels are a cause for concern as they often lead to cardiac arrest in children. Two other drugs – phenobarbital and phenytoin – have their own issues. Phenytoin can cause irregular heart rhythms and phenobarbital can cause depression of the heart muscles leading to instability in normal heart function. In these cases, doctors must be ready to administer drugs that support heart function. They might opt for using fosphenytoin to avoid the side effects typically seen with phenytoin.
There are other side effects associated with these seizure medications, too. They can lead to liver and kidney dysfunction which is why it’s important to closely monitor drug levels during the critical phase of treatment and during ongoing medication use. Other complications can include cerebral palsy, cerebral atrophy, Hydrocephalus ex-vacuo (a brain condition), epilepsy (a neurological disorder), and feeding difficulties.
- Blocked airways
- Low oxygen levels
- High carbon dioxide levels
- Cardiac arrest in children
- Irregular heart rhythms
- Depression of heart muscles
- Liver and kidney dysfunction
- Cerebral Palsy
- Cerebral atrophy
- Hydrocephalus ex-vacuo
- Epilepsy
- Feeding difficulties
Preventing Neonatal Seizure
If a person experiences a seizure lasting more than 5 minutes, or has several seizures in a short time span, it is crucial to call for emergency help. If prescribed, parents may need to give their child an emergency seizure medicine, like rectal diazepam. Parents will be taught how to use this medicine properly.
Parents should also be aware of the long-term effects of seizures in newborns, which can include problems with brain function in those who survive. Early rehabilitative care is important and beneficial for these patients.
If the child develops chronic epilepsy, parents need to be particularly careful in situations where a seizure could be particularly dangerous, such as when the child is scuba diving. In these situations, having someone watch over the child closely is essential.
Regular visits to a children’s brain specialist (a pediatric neurologist) are important for a child with seizures. It is also crucial for parents to ensure that their child is receiving their medication as advised. Adherence to medication helps manage seizures and promotes a better quality of life.