A seizure is caused by sudden, abnormal, and excessive electrical activity in the brain. Most neonatal seizures occur in the first one to two days to the first week of a baby’s life.
Causes of Neonatal Seizures
Neonatal seizures have a variety of causes. These include:
- Lack of oxygen before or during birth which can be due to placental abruptio (premature detachment of the placenta from the uterus), a difficult or prolonged labor, or compression of the umbilical cord.
- Infection such as bacterial meningitis, viral encephalitis, toxoplasmosis, syphilis or rubella.
- Stroke before or after birth
- Hemorrhage or Blood clot in the neonate’s brain
- Bleeding in the brain
- Brain birth defects
- Blood sugar or electrolyte imbalances (e.g. hypoglycemia, hypocalcemia and hypomagnesemia)
- Drug withdrawal, which may affect babies born to mothers addicted to barbiturates, alcohol, heroin, cocaine or methadone.
Signs and Symptoms of Neonatal Seizures
Neonatal seizures can be difficult to diagnose because symptoms of neonatal seizures may mimic normal movements and behaviors seen in healthy babies.
Symptoms depend on the type of seizure which is explained below:
- Subtle Seizures: This type is common in the newborn period. Subtle seizure signs may resemble usual newborn movements and may be difficult to diagnose. Symptoms of subtle seizures include:
- Random or roving eye movements, eyelid blinking or fluttering, eyes rolling up, eye opening, staring
- Sucking, smacking, chewing and protruding tongue
- Unusual bicycling movements of the legs
- Struggling movements
- Long pauses in breathing (apnea).
2. Clonic Seizures: This is characterized by rhythmic jerking movements that may involve the muscles of the face, tongue, arms, legs, or other regions of the body.
3. Tonic Seizures: This is the stiffness of muscles. Symptoms may include:
- Stiffening or tightening of the muscles
- Turning the head or eyes to one side, or bending or stretching one or more arms or legs
- Moaning or crying out involuntarily
- Bending or holding their arms or legs in awkward positions.
4. Tonic-Clonic Seizures: a type of seizure that involves loss of consciousness and violent muscle contractions. Here, the seizure starts with stiffening (tonic phase), followed by jerking (clonic phase).
Diagnosis of Neonatal Seizures
Electroencephalogram (EEG): This is a test that measures electrical activity in the brain. It is essential for diagnosing and managing neonatal seizures. Other neonatal conditions that induce seizures may also produce healthy EEG readings. An imaging test, such as Magnetic Resonance Imaging (MRI) and Computed Tomography (CT) scan may be done to see if any structural changes are causing seizures.
Treatment of Neonatal Seizures
Once a seizure has been diagnosed, treatment of the underlying cause or disease needs to be initiated. For example, electrolyte imbalances should be corrected through a central venous site. Hypocalcaemia should be treated with calcium. Once the underlying cause has been addressed, antiepileptic drug e.g. Phenobarbital should be considered.
Anticonvulsant or Antiseizure therapy includes the following:
- Phenobarbital is the drug of first choice to treat neonatal seizures. It is relatively effective, the side effects are well appreciated, and the pharmacokinetics is reasonably well understood for term and preterm infants. The intravenous route is preferred because of the more rapid onset of action.
- Dilantin (Phenytoin) is often the second drug of choice to be added when seizures are not controlled by phenobarbital alone. It is useful for the prevention of tonic-clonic seizures.
- Benzodiazepine such as Lorazepam is useful for infants with “uncontrolled” seizures in spite of therapy with phenobarbital and Dilantin. Due to the possibility of respiratory depression especially with phenobarbital on board, the safest use of these drugs is when ventilatory support has been initiated.
Prevention of Seizures
Prevention depends on the causes of the seizure.
- Avoid sepsis and metabolic derangements
- Improved delivery methods and oxygenation can help to reduce neonatal seizures.
- Early diagnosis, detection and treatment of seizures and subclinical seizures can decrease complication
- Specific diets may help prevent seizures if they are caused by metabolic disturbances.
- Genetic counseling for neonates with disorders such as benign familial neonatal seizures will help to prevent seizure.
- Pyridoxine deficiency/dependent seizures and metabolic disorders with a known mutation can help some couples avoid these disorders in future pregnancies.
Complication of Seizures
Complications from prolonged or frequent neonatal seizures include:
- Developmental delay
- Cerebral palsy with possible contractures
- Epilepsy later in life
- Feeding issues or swallowing issues
- Permanent brain damage