1. Incidence

  • Challenges in Estimation:
    • Clinical overestimation due to non-seizure abnormal movements.
    • Underestimation due to electrographic seizures without clinical manifestations.
  • Statistics:
    • Term infants: 1-3 per 1000 live births.
    • Preterm/low birth weight (<1500g): 57.5–132 per 1000 live births.
  • Recognition Tools:
    • Increased identification using continuous EEG monitoring.

2. Pathophysiology

  • General Mechanism:
    • Seizures result from disturbed brain electrical activity.
  • Immature Brain Susceptibility:
    • Characteristics of neurons, neurotransmitters, synapses, myelination, and circuitry contribute to increased seizure susceptibility.
    • Imbalance: Increased excitation and reduced inhibition (e.g., GABA is excitatory in neonates, becoming inhibitory with maturity).

3. Aetiology

  • Underlying Cause Identified: 75–90% of cases.
  • Common Causes:
    • Term infants: Hypoxic-ischemic encephalopathy (HIE).
    • Preterm infants (<30 weeks): Intraventricular hemorrhage.
    • Other: Intracranial infections, developmental defects.
  • ILAE Classification:
    • Organizes causes for uniform classification (genetic, metabolic, structural, infectious, etc.).

4. Clinical Presentation

  • Types of Neonatal Seizures:
    • Clonic: Repetitive jerking.
    • Myoclonic: Sudden, brief muscle contractions.
    • Tonic: Sustained muscle contraction.
    • Autonomic: Alteration in autonomic functions (e.g., apneas).
    • Behavioural Arrest: Pauses in activity, freezing.

5. History and Examination

  • History:
    • Maternal: Diseases, drug use, consanguinity.
    • Pregnancy: Fetal movements, infections, complications.
    • Birth: Apgar scores, resuscitation details.
    • Seizures: Age of onset, frequency, associated symptoms.
  • Examination:
    • Monitor vital signs (HR, RR, BP, oxygen saturation).
    • Assess general features (e.g., jaundice, dysmorphism).
    • Neurological assessment (consciousness, tone, reflexes).

6. Investigations

  • First Line:
    • Plasma: Glucose, electrolytes, LFTs, FBC.
    • CSF: Culture, virology, glucose, protein.
    • Imaging: Cranial ultrasound.
  • Second Line:
    • Genetic testing (e.g., epilepsy panels).
    • Metabolic testing (e.g., plasma amino acids, urine organic acids).
  • Advanced Imaging:
    • MRI: Gold standard for brain pathology.
  • Neurophysiology:
    • EEG: Full lead and video EEG for detailed analysis.
    • aEEG: Bedside tool for monitoring electrographic activity.

See Investigations in Neonatal Seizures

7. Treatment

  • Initial Management:
    • Stabilize airway, breathing, circulation, and glucose levels.
    • Initiate cardiovascular and respiratory monitoring.
    • Evaluate underlying cause (e.g., metabolic disturbance, sepsis).
  • When to Treat:
    • Prolonged seizures (>3 min), frequent seizures (≥3/hour), or associated cardiovascular disturbance.
  • Anti-Epileptic Drugs (AEDs):
    • Phenobarbital (First Line):
      • Mechanism: Potentiates GABA action.
      • Loading dose; monitor therapeutic levels (15–40 mg/L).
    • Levetiracetam (Second Line):
      • Fewer side effects, preferred in renal/hepatic impairment.
    • Phenytoin Sodium (Second Line):
      • Sodium channel blocker; requires cardiac monitoring.
    • Midazolam (Third Line):
      • Used if refractory to phenobarbital and phenytoin.
  • Vitamin-responsive Therapy:
    • Pyridoxine (B6) trial for intractable seizures.
  • Withdrawal Seizures:
    • Morphine for opiate withdrawal-related seizures.

8. Prognosis

  • Dependent Factors:
    • Cause of seizures: Poor outcomes with inborn errors of metabolism, HIE, malformations.
    • Seizure characteristics: Frequent/severe seizures lead to poorer outcomes.
    • EEG Findings: Normal interictal EEG suggests better prognosis.
  • Long-term Risks:
    • 10–20% risk of childhood seizures or epilepsy.

9. Follow-Up

  • All infants with neonatal seizures require neurodevelopmental assessments.
  • Follow-up plans depend on the underlying cause and response to treatment (e.g., HIE cases followed for up to 2 years).

10. Differential Diagnosis

  • Differentiating Seizures from Non-epileptic Events:
    • Jitteriness: Stops with restraint.
    • Benign Neonatal Myoclonus: Occurs during sleep, ceases on arousal.
    • Automatisms: Stereotyped movements not associated with EEG changes.

Key Takeaways

  • Neonatal seizures are a critical clinical entity requiring prompt identification, evaluation, and management.
  • Use EEG for accurate diagnosis and differentiate from non-epileptic movements.
  • Tailored treatment and follow-up based on etiology, seizure type, and response to interventions.