People who have concussions caused by sports activities are at risk of serious consequences, including repeated concussions and possibly permanent brain damage.
A concussion (see Concussion) is a 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 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.
Unlike with other causes of concussion, such as car crashes and falls, sports participants are continually at risk for concussion. Thus, repeat injury is more likely. Athletes are particularly susceptible if another head injury occurs before they have fully recovered from a previous concussion. And even after recovery, athletes who continue participating are 2 to 4 times more likely to have another concussion than if they had never had one. Also, repeat concussions can be caused by an impact less severe than the impact that caused the first one.
Although people eventually recover fully from a single concussion, about 3% of those who had multiple (even apparently minor) concussions develop long-term brain damage. This damage is termed chronic traumatic encephalopathy (CTE) and was first described in boxers (and termed dementia pugilistica). However, CTE can happen in anyone who had multiple concussions. People with CTE have evidence of brain damage on CT or MRI and have symptoms that are similar to those of dementia. Such symptoms include memory problems, impaired judgment and decision making, personality changes (such as becoming easily angered and violent), depression, and parkinsonism. Several prominent retired athletes who had multiple concussions have committed suicide, possibly caused, at least partly, by CTE.
People may or may not lose consciousness, but they have symptoms of brain dysfunction. Symptoms include
Certain symptoms may be present for a few days to weeks after a concussion. People may have
In teenagers, many postconcussion symptoms, particularly irritability, fatigue, and inability to concentrate, may mistakenly be attributed to normal adolescence.
Athletes with symptoms of a concussion should be evaluated by a doctor experienced in evaluation and treatment of this type of injury. Sometimes such doctors are on site at high-level athletic events. When they are not, sideline staff should be prepared by obtaining training in how to recognize concussion, how to evaluate affected athletes, and when to refer them for further evaluation. Tools such as Sports Concussion Assessment Tool 2 (SCAT2) or 3 (SCAT 3) can help coaching staff, trainers, and others evaluate athletes on site. SCAT2 and 3 are available free online (SCAT2) and can also be downloaded to handheld devices. The Centers for Disease Control and Prevention (CDC) has tools and training information for sideline staff (CDC "Heads Up" programs).
In some programs, all athletes undergo neurocognitive testing (testing of certain brain functions) before sports participation. Then, if a concussion is suspected, doctors can retest the athlete and determine whether brain function has deteriorated.
Treatment is similar to that of other people who have concussion. People should rest and take acetaminophen as needed for headache. School and work activities, driving, alcohol, and excessive brain stimulation (for example, using computers, television, video games) should be avoided. Family members should take the athlete to a hospital if symptoms worsen.
Returning to sports activities is not recommended until several steps have been completed. Once symptoms of concussion have resolved, people may begin light aerobic exercise and then advance through sport-specific training, non-contact drills, full-contact drills, and finally competitive play. Athletes should not move to the next stage until all symptoms at the prior stage have resolved. Even if symptoms improve quickly, athletes should probably not return to full competitive play until all symptoms have resolved for at least a week. A person who had a severe concussion (for example, being unconscious for more than 5 minutes or losing memory of events that occurred more than 24 hours before or after the injury) should wait at least a month before resuming full competitive play. A person who has had multiple concussions in one season needs to understand the risks of continued participation. The person (or the parents if the person is a child) should discuss these risks with a doctor who has experience with brain injuries.