What is the role of prophylactic anti-epileptic drugs (AEDs) in patients with subdural hematoma (SDH)?

Prophylactic Antiepileptic Drugs in Subdural Hematoma

Prophylactic antiepileptic drugs (AEDs) are not routinely recommended for patients with subdural hematoma (SDH) who have not experienced seizures. 1, 2

Evidence-Based Recommendations

General Approach

• Routine prophylactic AEDs are not recommended for patients with SDH who have not had seizures 1
• Short-term prophylactic AEDs may be considered only in the immediate post-hemorrhagic period (first 7 days) in high-risk patients 1
• Clinical seizures or electrographic seizures in patients with altered mental status should be treated with AEDs 1

Risk Factors That May Warrant Consideration of Short-Term Prophylaxis

• Cortical involvement of the hematoma 1
• Acute-on-chronic subdural hematoma (which has a 72.4% incidence of acute symptomatic seizures) 3
• Middle cerebral artery territory involvement 1, 4
• Intracerebral hematoma 1, 4
• Prior seizure history 1, 4
• Intractable hypertension 1, 4
• Cerebral infarction 1, 4

Medication Selection and Monitoring

Preferred Medication

• If prophylactic AEDs are considered, levetiracetam is preferred over older AEDs due to:
  • Better tolerability profile 2, 5
  • No significant drug interactions with steroids or other medications commonly used in neurocritical care 2
  • No requirement for serum level monitoring 2

Medications to Avoid

• Phenytoin should be avoided as it is associated with:
  • Worse cognitive outcomes 1
  • Higher risk of adverse drug effects (reported in 23% of patients) 1
  • Potential for increased morbidity and mortality 5

Duration of Therapy

• If prophylactic AEDs are initiated, they should be limited to the immediate post-hemorrhagic period (7 days) 1, 5
• Long-term prophylactic AED use is not recommended 1
• For patients who have had a seizure, AED treatment should be continued until local control of the hemorrhage has been achieved 2

Special Considerations

Monitoring

• Continuous EEG monitoring should be considered in SDH patients with depressed mental status disproportionate to the degree of brain injury 1, 5
• Patients should be monitored for psychiatric side effects of AEDs, particularly with levetiracetam 2

Conflicting Evidence

• Older retrospective studies suggested benefit from prophylactic AEDs in chronic SDH, with one study showing seizures in 2.4% of patients receiving prophylaxis versus 32% without 6
• However, more recent systematic reviews and meta-analyses have found no significant reduction in seizure incidence with prophylactic AEDs in chronic SDH 7
• A 2020 cohort study even suggested a potential increase in seizure risk with prophylaxis (OR 5.92 in univariate analysis), though this was not significant in multivariate analysis 8

Conclusion

The current best evidence does not support routine prophylactic AED use in patients with SDH. Short-term prophylaxis may be considered only in patients with specific risk factors, with levetiracetam being the preferred agent if prophylaxis is deemed necessary.