Concussive convulsions. Incidence in sport and treatment recommendations.
Concussive convulsions (CC) are nonepileptic phenomena which are an immediate sequelae of concussive brain injury. Although uncommon, occurring with an approximate incidence of 1 case per 70 concussions, these episodes are often confused with post-traumatic epilepsy which may occur with more severe structural brain injury. The pathophysiological mechanism of CC remains speculative, but may involve a transient traumatic functional decerebration with loss of cortical inhibition and release of brainstem activity. The phenomenology of the CC is somewhat akin to convulsive syncope, with an initial tonic phase occurring within 2 seconds of impact, followed by a clonic or myoclonic phase which may last several minutes. Lateralising features are common during the convulsions. There is no evidence of structural or permanent brain injury on clinical assessment, neuropsychological testing or neuroimaging studies. Long term outcome is universally good with no evidence of long term epilepsy and athletes are usually able to return to sport within 2 weeks. The correct management of these episodes centres on the appropriate management of the associated concussive injury and the exclusion of other cerebral injury by medical assessment. The CC requires no specific management beyond immediate onfield first aid measures such as protection of the airway. Antiepileptic therapy is not indicated and prolonged absence from sport is unwarranted. These episodes, although dramatic, are relatively straightforward to manage and all team physicians and those involved in athlete care need to be aware of this condition.