Post-traumatic seizures, their prevention and management

The College had asked about this in Question 28from the second paper of 2011.
Specifically, they wanted the risk factors for post-traumatic seizures.

The best resource for such things is the Brain Trauma Organisation Guidelines for Management Traumatic Brain Injury. In fact, the College examiners pillage their guidelines liberally, cutting and pasting whole blocks of text into the model answers.

Risk factors for post-traumatic seizures

• Glasgow Coma Scale (GCS) Score < 10
• Cortical contusion
• Depressed skull fracture
• Subdural hematoma
• Epidural hematoma
• Intracerebral hematoma
• Penetrating head wound
• Seizure within 24 h of injury

The below-linked review article on post-traumatic seizure prophylaxis presents an even more extensive table, which is perhaps more than is expected of a 2-mark SAQ answer.

It is reproduced below, more for completeness than educational value.

Rationale for antiepileptic prophylaxis

A good 2013 review article is available for the time-rich exam candidate to scrutinise.

For the rest of us, here are the salient points:

• Approximately 5-7% of TBI patients experience post-traumatic seizures.
• Neurotoxicity from such seizures represents a preventable morbidity
• Seizure activity (even when non-convulsive, and in the context of a protected airway) is a cause for increased cereberal metabolic demand, and may cause secondary brain injury.
• Antiepileptic therapy is not without its risks, but uncontrolled seizures in TBI represent an even greater risk
• However, there does not seem to be any evidence that reduction in post-traumatic seizures within the first week decreases long term mortality in any way.

Choice of agents and duration of therapy

• The 2003 AAN guidelines recommend a one-week course of therapy.
• There is no evidence to support prophylaxis for longer than seven days after TBI, even if risk factors are present.
• Phenytoin has been the drug of choice. BTF were unable to find any evidence to recommend levitiracetam over phenytoin.
  • Advantages include:
    • Its cheap.
    • Its safe.
    • Its effective (at least in preventing early post-TBI seizures)
  • Disadvantages include:
    • It requires monitoring
    • The exact therapeutic level to aim for in TBI is not well established
    • It has extensive interactions
    • It has unusual nonlinear elimination kinetics
    • It may have a negative effect on long-term cognitive function

• Levitiracetam is becoming the drug of choice.
  • Advantages include:
    • Its as safe and at least as effective as phenytoin
    • It has a more benign pharmacokinetic profile
    • It does not require monitoring (but only because levels do not correlate with effect)
  • Disadvantages include:
    • Its expensive
    • There are no studies to convincingly demonstrate its superiority over phenytoin. A survey of epilepsy specialists conducted in 2015 has demonstrated that there is genuine equipoise among senior medical experts, to the point where one major neurotrauma center might use exclusively phenytoin, and the other might use only levitiracetam.