Do patients with subdural (subdural hematoma) hematomas require seizure prophylaxis?

Seizure Prophylaxis in Subdural Hematomas

Routine seizure prophylaxis is not recommended for patients with subdural hematomas who have not experienced seizures. 1

Evidence-Based Recommendations

The management of seizure risk in patients with subdural hematomas should be guided by the following principles:

Risk Assessment

• No Prophylaxis for Most Patients: The American College of Anaesthesia strongly recommends against routine use of antiepileptic drugs (AEDs) for primary prevention of post-traumatic seizures in patients with subdural hematomas (Grade 2-, Strong Agreement) 1

• Risk Factors for Seizures: Consider the following risk factors when evaluating seizure risk:

  • Acute subdural hematoma with thickness >5mm and midline shift >5mm 1
  • Brain contusion 1
  • Skull fracture 1
  • Loss of consciousness or amnesia >24 hours 1
  • Age >65 years 1
  • Craniectomy 1
  • Alcohol abuse (OR 14.3) 2
  • Change in mental status (OR 7.2) 2
  • Previous stroke (OR 5.3) 2

Management Algorithm

1. For patients who have already experienced seizures:

   • Initiate standard antiepileptic treatment
   • Limit treatment to ≤7 days in the perioperative period 1
   • Treatment beyond 7 days is not effective for reducing future seizure risk 1

2. For patients without seizures:

   • Without high-risk features: No prophylactic AEDs (Class III recommendation) 1
   • With high-risk features: Prophylactic AEDs may be considered only in the immediate post-hemorrhagic period 3, but evidence for benefit is limited

3. If prophylaxis is deemed necessary (based on multiple risk factors):

   • Choose levetiracetam over phenytoin due to better side effect profile 1, 3
   • Limit use to 7-14 days in the acute phase 3
   • Discontinue if no seizures occur during this period

Important Considerations

• Potential Harm: Prophylactic AEDs, especially phenytoin, are associated with:

  • Worse cognitive outcomes at 3 months 3
  • Dampening of neural plasticity mechanisms that contribute to recovery after brain injury 1
  • Significant risk of side effects 1

• Medication Selection: If prophylaxis is used, levetiracetam is preferred over phenytoin due to:

  • Similar efficacy (OR 1.3) 2
  • Significantly lower adverse effects (OR 0.1) 2
  • Fewer drug interactions 3

• Caution with Levetiracetam: May be associated with higher risk of electrographic seizures during hospitalization in patients with midline shift compared to phenytoin 4

Monitoring

• Consider EEG monitoring in patients with:
  • Fluctuating neurological examination 1
  • Depressed mental state 1
  • High-grade subdural hematoma with mass effect 1
  • Hydrocephalus 1
  • Cortical infarction 1

Incidence of Seizures

• Acute/subacute subdural hematomas: 6-26% risk of seizures 3
• Chronic subdural hematomas: Lower risk (early seizures 5.3%, late seizures 10%) 2
• Overall incidence of early post-traumatic seizures in traumatic brain injury: 2.2-3.7% 1, 5

Conclusion

The evidence does not support routine prophylactic use of antiepileptic drugs in patients with subdural hematomas. The risks of adverse effects, including potential negative impact on recovery, outweigh the unproven benefits in patients without seizures. Reserve prophylaxis only for patients with multiple high-risk features, and if used, prefer levetiracetam over phenytoin for a limited duration.