What are the Neurocritical Care Society guidelines for seizure prophylaxis in high-risk patients, such as those with traumatic brain injury (TBI) or subarachnoid hemorrhage (SAH)?

Neurocritical Care Society Guidelines for Seizure Prophylaxis

Key Recommendations for Seizure Prophylaxis in High-Risk Patients

In high-risk patients with aneurysmal subarachnoid hemorrhage (aSAH), short-term prophylactic antiseizure medication for ≤7 days may be reasonable, while routine prophylaxis in low-risk patients is not beneficial and phenytoin specifically should be avoided due to associated harm. 1

Seizure Prophylaxis in Aneurysmal Subarachnoid Hemorrhage (aSAH)

Risk Stratification

• High-risk features requiring consideration for prophylaxis:
  • Ruptured MCA aneurysm
  • High-grade SAH
  • Intracerebral hemorrhage (ICH)
  • Hydrocephalus
  • Cortical infarction 1

Recommendations for aSAH

1. Continuous EEG monitoring is reasonable in patients with:

   • Fluctuating neurological examination
   • Depressed mental state
   • High-risk features (Class 2a, Level B-NR) 1

2. Prophylactic antiseizure medications:

   • May be reasonable in high-risk patients (Class 2b, Level B-NR)
   • Not beneficial in patients without high-risk features (Class 3: No benefit, Level B-R)
   • Should be limited to ≤7 days in the perioperative period
   • Should not be continued beyond 7 days in patients without prior epilepsy (Class 3: No benefit) 1

3. Avoid phenytoin:

   • Associated with excess morbidity and mortality (Class 3: Harm, Level B-NR)
   • Consider newer antiseizure medications like levetiracetam 1

Seizure Prophylaxis in Traumatic Brain Injury (TBI)

• Short-term use of AEDs for seizure prophylaxis may be beneficial 2
• Levetiracetam is preferred over phenytoin due to better side effect profile 3
• Patients with brain contusion, acute subdural hematoma, skull fracture, prolonged loss of consciousness, age >65 years, and craniectomy are at increased risk 3

Optimal Medication and Dosing

• Preferred medication: Levetiracetam over phenytoin due to:

  • Better side effect profile
  • Fewer drug interactions
  • Lower risk of adverse effects 3

• Optimal dosing:

  • Higher doses (750-1000 mg twice daily) are more than twice as likely to achieve target serum levels compared to 500 mg twice daily 4
  • Higher doses reduce seizure odds by 68% compared to low-dose regimens 4
  • Critically ill patients eliminate levetiracetam more rapidly than healthy individuals 4

Duration of Prophylaxis

• Limit prophylaxis to ≤7 days in the perioperative period for aSAH 1
• Discontinue if no seizures occur during the acute period 3
• Extended prophylaxis beyond 7 days is not effective for reducing future seizure risk in patients without prior epilepsy 1

Monitoring Recommendations

• Use continuous EEG monitoring in patients with:
  • Fluctuating neurological examination
  • Depressed mental state
  • High-risk features 1
  • Monitor for behavioral side effects with levetiracetam 3

Common Pitfalls and Caveats

1. Overuse of prophylaxis: Routine prophylactic antiseizure medication in low-risk patients is not beneficial and may cause harm 1

2. Continued use beyond acute phase: Extended prophylaxis beyond 7 days is not effective for reducing future seizure risk in patients without prior epilepsy 1

3. Underdosing: Only 54% of patients achieve target serum levels with common dosing practices; consider higher doses (750-1000 mg twice daily) 4

4. Inappropriate medication selection: Phenytoin is associated with excess morbidity and mortality, poorer cognitive outcomes, and potential drug interactions 1, 3

5. Failure to monitor: Lack of appropriate EEG monitoring may miss subclinical seizures in high-risk patients 1

By following these evidence-based guidelines, clinicians can optimize seizure prophylaxis in neurocritical care patients, improving outcomes while minimizing unnecessary medication exposure and adverse effects.