Seizure prophylaxis for patients with mild or moderate traumatic brain injury may be effective for preventing early post-traumatic seizures, a meta-analysis suggests.
However, the researchers warned the reduced risk was significant but small and should be weighed against the low prevalence of early seizures, the potential acute risks of antiseizure medications and the potential for inappropriate continuation of the drugs.
The systematic review and meta analysis included eight studies involving 5637 patients for the mild and moderate traumatic brain injury (TBI) analysis, and five studies involving 3803 patients for the secondary outcome measure of mild TBI.
They compared rates of early post-traumatic seizures among patients presenting to trauma centres in high-income countries with and without seizure prophylaxis.
Mild and moderate TBI were defined as Glasgow Coma Scale [GCS], 13-15 and 9-12, respectively, and early seizures were defined as within seven days of injury.
As for type of prophylaxis, most patients received levetiracetam, phenytoin, or valproic acid. The average ages of patients varied from 33-65 and most were male.
Findings published in JAMA Neurology [link here] showed prophylaxis was associated with a small but significant effect for preventing early post-traumatic seizures for mild to moderate TBI, with an absolute risk reduction of 0.6%.
The rates of early post-traumatic seizures ranged from 0-4% depending on study.
The number needed to treat to prevent one seizure was 167 patients.
Further, when only including mild TBI, the absolute risk reduction was also 0.6%.
The authors, led by US neurosurgeons and neurologists, noted that until now the effectiveness of seizure prophylaxis in mild or moderate TBI was unknown and no major guidelines existed for mild TBI, specifically, despite the large potential for clinical impact with one million mild cases occurring annually in North America.
They stressed the absolute risk reduction of 0.6% was small. By comparison, prophylaxis reduced the risk of early seizures by almost 11% after severe TBI.
“Although this meta-analysis did show a modest yet clear associated risk reduction of early seizures using prophylaxis with antiseizure medications in mild and moderate TBI, the relatively small absolute risk reduction coupled with the low incidence of post-traumatic seizures in these populations makes the decision to use seizure prophylaxis in non-severe TBI challenging,” the authors wrote.
“We encourage practitioners to carefully weigh the prevalence and risks of early seizures against potential adverse events from antiseizure medications.
“Older antiseizure medications are associated with increased risks of hyponatremia, memory problems, and fatigue. The depressive adverse effects of antiseizure medications on the central nervous system are felt more acutely by older adults, who make up the majority of those with mild TBI.”
However, they added, newer antiseizure medications might pose less risks.
The authors also noted that prolonged and unnecessary antiseizure medication use might inhibit recovery from TBI, with inappropriate prescribing not uncommon.