What is the recommended prophylactic use of Keppra (levetiracetam) for patients with subdural hematoma (SDH) at high risk of seizures?

Prophylactic Levetiracetam for Subdural Hematoma

Prophylactic levetiracetam is recommended for patients with subdural hematoma who have high-seizure-risk features, but should be limited to 7 days in the perioperative period unless seizures occur.

Risk Assessment for Seizures in SDH Patients

Seizures are a known complication of subdural hematoma, but not all patients require prophylaxis. The decision to use prophylactic antiepileptic drugs should be based on risk factors:

High-Risk Features (Consider Prophylaxis):

• Thick subdural hematoma (thickness correlates with seizure risk) 1
• Midline shift
• Cortical involvement
• Acute hemorrhage component
• Need for surgical intervention

Low-Risk Features (Prophylaxis May Not Be Beneficial):

• Thin subdural hematoma
• Preserved consciousness (GCS ≥13)
• Chronic subdural hematoma without other risk factors

Evidence for Prophylactic Antiepileptic Use

The overall seizure risk in SDH varies considerably:

• In patients with isolated SDH and preserved consciousness, in-hospital seizures are rare (approximately 2.2%) regardless of prophylactic medication use 2
• For chronic subdural hematoma, systematic reviews have not found significant reduction in seizure incidence with prophylactic antiepileptic drugs 3, 4

Medication Selection

When prophylaxis is indicated:

• Levetiracetam is preferred over phenytoin due to:

  • Similar efficacy in preventing clinical/electrographic seizures
  • Significantly lower risk of adverse drug effects 1
  • No enzyme induction (important for patients on multiple medications) 5
  • Better tolerability profile 5

• Dosing recommendations:

  • Starting dose: 500 mg twice daily
  • Maintenance dose: 1000-3000 mg/day divided into two doses 5
  • Duration: Limited to ≤7 days in the perioperative period unless seizures occur 6

Duration of Prophylaxis

• Short-term use (≤7 days) is reasonable to reduce seizure-related complications in the perioperative period 6
• Extended use beyond 7 days is not effective for reducing future seizure risk in patients without prior epilepsy 6
• Prophylactic antiepileptic drugs should be discontinued after the perioperative period in patients who have not experienced seizures 6

Monitoring Recommendations

• For patients with altered mental status out of proportion to their imaging findings, consider continuous EEG monitoring for at least 24-48 hours 6
• If seizures occur, treatment with antiseizure medications should be continued
• Monitor for adverse effects, particularly psychiatric side effects with levetiracetam 5

Special Considerations

• Patients with midline shift >0 mm may have a higher risk of electrographic seizures on levetiracetam compared to phenytoin, but levetiracetam still has a lower risk of adverse effects 1
• In patients with no history of seizures who are not undergoing surgery, antiepileptic medication may be omitted 6
• Risk scores can be used to estimate the risk of late seizures (>7 days after hemorrhage), but should not be used to guide continuation of antiepileptic drugs 6

Key Pitfalls to Avoid

• Continuing prophylactic antiepileptic drugs beyond 7 days without evidence of seizures
• Using phenytoin for prophylaxis (associated with excess morbidity and mortality) 6
• Failing to monitor for adverse effects of antiepileptic medications
• Overlooking the need for EEG monitoring in patients with disproportionate mental status changes

In summary, while prophylactic levetiracetam is reasonable for high-risk SDH patients, it should be limited to the perioperative period (≤7 days) unless seizures occur, with phenytoin specifically avoided due to its adverse effect profile.