A concussion is a temporary change in brain function after a head injury without any signs of brain damage on imaging tests, such as computed tomography (CT) or magnetic resonance imaging (MRI). People who have concussions caused by sports activities are at risk of repeated concussions which may have serious consequences, including permanent brain damage.
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.
Repeat injury
Unlike with other causes of concussion, such as car crashes and falls, sports participants are continually at risk of 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 two to four 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 several (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 has had several 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 the following:
Dementia-like symptoms (for example, disturbances in memory, cognitive function, or behavior)
Impaired judgment and decision making
Personality changes (such as becoming easily angered and violent)
Several prominent retired athletes who had multiple concussions have committed suicide, possibly caused, at least partly, by CTE.
Second-impact syndrome
Second-impact syndrome is a rare but serious complication of concussion. In this syndrome, the brain rapidly swells after athletes have a second concussion before they recover completely from a previous concussion. Almost half of athletes with this syndrome die.
Symptoms of Sports-Related Concussion
People with a concussion may or may not lose consciousness, but they have symptoms of brain dysfunction. Symptoms include
Confusion: Appearing dazed or stunned, being unsure of opponent or score, and/or answering slowly
Memory loss: Not remembering plays or assignment and/or not recalling events just before the injury or just afterward
Vision disturbance: Double vision
Sensitivity to light
Dizziness, clumsy movements, and impaired balance
Headache
Nausea and vomiting
Ringing in the ears (tinnitus)
Loss of smell or taste
Postconcussion syndrome
Certain symptoms may be present for a few days to weeks after a concussion. People may have
Headaches
Problems with short-term memory
Difficulty concentrating
Fatigue
Difficulty sleeping
Personality changes (such as irritability and mood swings)
Sensitivity to light and noise
In teenagers, many postconcussion symptoms, particularly irritability, fatigue, and inability to concentrate, may mistakenly be attributed to normal adolescence.
Diagnosis of Sports-Related Concussion
A doctor's evaluation
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 trained in how to recognize concussion, how to evaluate affected athletes, and when to refer them for further evaluation.
Tools such as Sports Concussion Assessment Tools (SCAT2, SCAT3, or SCAT5) are available for free online and can be downloaded to handheld devices to help coaching staff, trainers, and others evaluate athletes on site. The Centers for Disease Control and Prevention (CDC) also has tools and training information for sideline staff (CDC "Heads Up" programs).
Doctors and sideline staff should be aware that athletes may deny or understate symptoms resulting from concussion so that they can continue playing.
Imaging tests such as computed tomography (CT) are done if doctors suspect a more serious injury, such as accumulation of blood within the brain or between the brain and skull (intracranial hematomas) or bruises (contusions) of the brain.
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 of Sports-Related Concussion
Rest
No return to play until symptoms are gone
Family members should take the athlete to a hospital if symptoms worsen.
Did You Know...
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Did You Know...
Return to play
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, then noncontact 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.
