What is the proper management of a neonatal seizure?

Management of Neonatal Seizures: A Case Scenario and Treatment Algorithm

In neonatal seizures, immediate neuroimaging with MRI is essential for diagnosis, while phenobarbital should be the first-line antiseizure medication regardless of etiology, followed by phenytoin, levetiracetam, midazolam, or lidocaine as second-line options if seizures persist. 1

Case Scenario

Presentation

• 3-day-old term male infant, born via uncomplicated vaginal delivery
• Presents with repetitive, subtle movements including lip smacking, eye deviation, and cycling movements of the limbs 2
• Mother notes the episodes last 1-2 minutes and have occurred 3 times in the past 6 hours
• No fever or other signs of infection
• No significant family history of seizures or neurological disorders

Initial Assessment and Stabilization

• Ensure patent airway, adequate breathing, and circulation 2
• Monitor vital signs including heart rate, blood pressure, temperature, and oxygen saturation 2
• Place on continuous cardiorespiratory monitoring
• Establish IV access for medication administration and blood sampling 2

Diagnostic Workup

• Immediate EEG monitoring to confirm seizure activity, as clinical diagnosis alone is insufficient (many neonatal seizures are subclinical) 1, 3

• Urgent neuroimaging 2:

  • Head ultrasound as initial bedside imaging if infant is unstable or MRI is not immediately available 2
  • MRI with diffusion-weighted imaging as the gold standard to identify etiology, especially for hypoxic-ischemic injury (most common cause) 2

• Laboratory investigations:

  • Complete blood count, electrolytes, glucose, calcium, magnesium 2
  • Blood culture if infection suspected
  • Lumbar puncture if meningitis is suspected
  • Consider metabolic screening and genetic testing if no clear etiology is found 2

Treatment Algorithm

First-Line Treatment

• Phenobarbital 20 mg/kg IV loading dose 1, 4
  • Administer slowly at 1 mg/kg/min
  • Monitor respiratory status during administration
  • Assess response after 15-20 minutes 4

If Seizures Continue After First-Line Treatment

• Additional phenobarbital 10 mg/kg IV (up to total of 40 mg/kg) 4
• If seizures persist, proceed to second-line therapy

Second-Line Treatment Options (based on clinical scenario) 1, 4

• Phenytoin/Fosphenytoin: 20 mg/kg IV loading dose

  • Administer at maximum rate of 1 mg/kg/min
  • Monitor cardiac rhythm and blood pressure during infusion
  • Avoid in cardiac disorders

• OR Levetiracetam: 40-60 mg/kg IV loading dose

  • Preferred in cardiac disorders
  • Can be administered more rapidly than phenytoin
  • Fewer drug interactions and side effects 1, 5

For Refractory Seizures (Third-Line)

• Midazolam: 0.15 mg/kg IV bolus, followed by continuous infusion at 0.1-0.4 mg/kg/hour 4
• OR Lidocaine: 2 mg/kg IV loading dose followed by continuous infusion at 4-6 mg/kg/hour 4, 3
  • Avoid if cardiac conduction abnormalities present
  • Monitor ECG during administration

Special Considerations

• For seizures associated with hypoxic-ischemic encephalopathy, therapeutic hypothermia may reduce seizure burden 1
• For drug withdrawal-associated seizures, the specific treatment may vary based on the drug of exposure 2
• For seizures not responding to second-line treatment, consider pyridoxine trial (100 mg IV) to rule out pyridoxine-dependent epilepsy 1

Monitoring and Follow-up

During Acute Management

• Continuous EEG monitoring to assess treatment response 1, 3
• Frequent neurological assessments
• Monitor vital signs, especially respiratory status with antiseizure medications 6
• Equipment for airway management should be immediately available 6

Duration of Treatment

• For acute provoked seizures without evidence of neonatal-onset epilepsy, discontinue antiseizure medications before discharge 1
• Withdrawal-associated seizures typically respond to opiates and carry no increased long-term risk of poor outcomes 2

Prognosis

• Prognosis depends primarily on underlying etiology 2
• Absence of major cerebral lesions on MRI is highly predictive of normal neurological outcome 2
• EEG background activity is an important prognostic indicator 7
• Seizures that respond to first-line treatment generally have better outcomes than those requiring second-line treatments 7

Common Pitfalls and Caveats

• Not all abnormal movements in neonates are seizures; EEG confirmation is essential 3
• Many neonatal seizures are subclinical and can only be detected by EEG 1, 3
• Respiratory depression is the most important risk with antiseizure medications; maintain airway patency and monitor respiration closely 6
• Delayed recognition and treatment of underlying causes (especially correctable ones like hypoglycemia or electrolyte disturbances) can worsen outcomes 6
• Prophylactic use of antiseizure medications in neonates without confirmed seizures is not recommended 2