Sports-related concussion

[Tariq Zaki]

People who have concussions caused by sports activities are at risk of serious consequences, including repeated concussions and possibly permanent brain damage.
A concussion is a temporary change in brain function after a head injury without any signs of brain damage visible on imaging tests, such as computed tomography (CT) or magnetic resonance imaging (MRI).
Sports that involve high-speed collisions (for example, football, rugby, ice hockey, and lacrosse) have the highest rates of concussion, but few sports, including cheerleading, are free of risk. Almost 20% of contact sports participants have a concussion over the course of a season. Estimates of the number of sports-related concussions vary from 200,000 per year to 3.8 million per year. Estimates vary so much because getting an accurate count is difficult when people are not evaluated in a hospital.
Concussions probably do not occur more often in athletes than they have in the past, but they are being recognized more often. The increased recognition is because people are more aware that repeated concussions can have serious consequences.

[Renato]

Sports activities are a common cause of concussion, a form of mild traumatic brain injury. Symptoms include loss of consciousness, confusion, memory difficulties, and other signs of brain dysfunction. Diagnosis is clinical with neuroimaging done as needed. Neuroimaging is not mandatory because there is rarely any evidence of structural brain injury. Early return to competition can be harmful; once symptoms are resolved, athletes can gradually resume athletic activity.
Concussion is a transient disturbance in brain function caused by head injury, usually a blow. By definition, there are no structural brain abnormalities visible directly or on imaging studies, in contrast to more serious brain injuries (traumatic brain injuries [TBIs]).
Pathophysiology is still being clarified, but brain dysfunction is thought to involve excitotoxicity, which is neuronal damage caused by excessive release of excitatory neurotransmitters, particularly glutamate. For additional information, see Concussions: What a neurosurgeon should know about current scientific evidence and management strategies.
Estimates of the incidence of sports-related concussion in the US vary from 200,000 a year up to 3.8 million a year; the highest numbers include rough estimates of injuries that are not evaluated in a hospital or otherwise reported. The awareness and thus reporting of concussions has risen significantly in the past decade—the incidence of serious and fatal sports-related TBI has not increased similarly. Sports that routinely involve high-speed collision (eg, football, rugby, ice hockey, lacrosse) have the highest rates of concussion, but no sport, including cheerleading, is free of risk. An estimated 19% of participants in contact sports have a concussive injury over the course of a season.