Post Traumatic Seizures (PTS) may contribute to secondary injury following head injury through the increase of metabolic demands and elevation of ICP (Chung & O'Brien 2016). The incidence of early PTS (onset <1 week post-injury) in children has been reported at 12-18% (Liesemer et al. 2011; Thapa et al. 2010), but can be upwards of 42.5% with continuous electroencephalography monitoring (Arndt et al. 2013). Risk factors of PTS include severe TBI, abusive head trauma, and younger age (<2 years) (Arndt et al. 2013; Liesemer et al. 2011; O'Neill et al. 2015). Children are different from adults in terms of mechanism of injury and likely the pathophysiology leading to the development of PTS. Children have been reported to react differently to a brain injury than adults, particularly with an increased amount of significant edema (Aldrich et al. 1992). This may affect the development of PTS as intracerebral heme deposition has been postulated to be an important mediator in the pathogenesis of both early and late PTS (Willmore 1990). Prophylactic anticonvulsants have proved effective in reducing early PTS in adults and thus it is important to investigate their efficacy in the pediatric population.
Phenytoin prophylaxis was ineffective at preventing both early PTS (<1wk of injury) (Young et al. 2004) and late PTS (>1wk of injury) (Young et al. 1983) compared to controls. However, there was an overall low occurrence of PTS (6%) that is not reported consistently with previous studies, according to the authors, which may have confounded the results (Young et al. 2004). There was also no difference in survival outcomes between phenytoin and placebo groups (Young et al. 2004).
PTS occurred at a rate of 17.6-25% under levetiracetam prophylaxis (Chung & O'Brien 2016; Vaewpanich & Reuter-Rice 2016). Children that developed early PTS after levetiracetam prophylaxis were younger and had experienced abusive head trauma, compared to those that did not develop PTS (Chung & O'Brien 2016; Vaewpanich & Reuter-Rice 2016). Although lacking a comparison group Chung and O’Brien (2016) report the prevalence of PTS (17.6%) post-levetiracetam administration is similar to prior studies without any seizure prophylaxis. Future RCTs are needed.
There is Level 1b evidence that phenytoin does not reduce the occurrence of early seizures in children.
There is Level 1b evidence from a second study that phenytoin is ineffective in reducing late seizures in children.
There is Level 4 evidence that children that develop early post-traumatic seizure under levetiracetam prophylaxis are younger and have experienced abusive head trauma, compared to those that did not develop post-traumatic seizure.
Phenytoin does not reduce early or late seizures in children post ABI.