Jake banged his head hard when he was tackled, and he felt kind of weird afterward. He thought it was just another hit that he could shake off — and he wanted to stay on the field. After the game, though, he felt pretty sick. Should Jake have kept on playing?

Definitely not. Jake may have had a concussion, and it was actually a bad idea for him to stay in the game.

What Is a Concussion and What Causes It?

The brain is made of soft tissue and is cushioned by spinal fluid. It is encased in the hard, protective skull. When a person gets a head injury, the brain can move around inside the skull and even bang against it. This can lead to bruising of the brain, tearing of blood vessels, and injury to the nerves. When this happens, a person can get a concussion — a temporary loss of normal brain function.

Most people with concussions recover just fine with appropriate treatment. But it's important to take proper steps if you suspect a concussion because it can be serious.

Concussions and other brain injuries are fairly common. About every 21 seconds, someone in the United States has a serious brain injury. One of the most common reasons people get concussions is through a sports injury. High-contact sports such as football, boxing, and hockey pose a higher risk of head injury, even with the use of protective headgear.

People can also get concussions from falls, car accidents, bike and blading mishaps, and physical violence, such as fighting. Guys are more likely to get concussions than girls. However, in certain sports, like soccer, girls have a higher potential for concussion.

What Are the Signs and Symptoms?

The signs of concussion are not always well recognized. And because of that, teens may put themselves at risk for another injury. For example, players may return to a game before they should, or a skateboarder may get back on the board and continue skating, thinking nothing's wrong. That's a problem, because if the brain hasn't healed properly from a concussion and someone gets another brain injury (even if it's with less force), it can be serious.

Repeated injury to the brain can lead to swelling, and sometimes people develop long-term disabilities, or even die, as a result of serious head injuries. So it's really important to recognize and understand the signals of a concussion.

Although we may think of a concussion as someone passing out, a person can have a concussion and never lose consciousness.

Symptoms of a concussion may include:

• "seeing stars" and feeling dazed, dizzy, or lightheaded
• memory loss, such as trouble remembering things that happened right before and after the injury
• nausea or vomiting
• headaches
• blurred vision and sensitivity to light
• slurred speech or saying things that don't make sense
• difficulty concentrating, thinking, or making decisions
• difficulty with coordination or balance (such as being unable to catch a ball or other easy tasks
• feeling anxious or irritable for no apparent reason
• feeling overly tired

Different Grades of Concussion

The severity of concussion is determined after all of the symptoms have resolved, the neurologic exam is normal, and brain function has returned to normal. There are different types of concussion:

• Simple concussion. Someone with a simple concussion experiences symptoms that get better in 7-10 days.
• Complex concussion. Someone with a complex concussion experiences persistent symptoms that last longer than 7-10 days. Doctors also consider it a complex concussion if a person loses consciousness (passes out) for more than 1 minute or has a seizure at the time of the injury. It's also a complex concussion if someone has had a concussion before, no matter how long ago.

A player should not return to sports practice or a game on the day that they are injured and they should not return to sports activities until they are no longer experiencing symptoms. In many teens the physical symptoms get better before the symptoms related to thinking.

During the first few days following a concussion, a player should rest. Both physical and cognitive rest are important. Activities that require concentration and attention may make the symptoms worse and delay recovery.

After a player's symptoms have resolved, he or she may begin a supervised gradual return to play. The player should advance from one step to the next only if there are no symptoms. The steps to return to play are:

• no activity
• light aerobic exercise, such as walking or stationary cycling (no resistance training)
• sports-specific exercise (for example, running in soccer, skating in hockey)
• non-contact training drills
• full contact training after medical clearance

It's important for anyone who sustains a complex concussion to see a concussion or brain injury specialist.

What should you do if a friend or teammate has a concussion? Tell an adult or coach immediately. Even if the concussion seems mild, the player should sit out for the rest of the game.

If the symptoms are severe (such as seizures or a long period of unconsciousness) or the person seems to be getting worse, that's an indication of a serious head injury. Get medical help right away.

What Do Doctors Do?

If a doctor suspects that someone may have a concussion, he or she will ask about the head injury (such as how it happened and when) and the symptoms. The doctor may ask what seem like silly questions — things like "Who are you?" or "Where are you?" or "What day is it?" and "Who is the President?" Doctors ask these questions to check the person's level of consciousness and memory and concentration abilities.

The doctor will perform a thorough examination of the nervous system, including testing balance, coordination of movement, and reflexes. He or she may test memory, thinking, concentration, and reaction time — all of which might be impaired after a concussion. Sometimes a doctor will order a CT scan (a special brain X-ray) or an MRI (a special non-X-ray brain image) to rule out bleeding or other serious injury involving the brain.

If a person's symptoms last longer than a week, the doctor will likely recommend further testing of thinking, memory, reaction time, and other brain functions.

If the concussion isn't serious enough to require hospitalization, the doctor will give instructions on what to do at home, like having someone wake the person up at least once during the night. If a person with a concussion cannot be easily awakened, becomes increasingly confused, or has other symptoms such as vomiting, it may mean there is a more severe problem that requires contacting the doctor again.

The doctor will recommend rest. It is important to get physical rest and avoid physical exertion and playing sports. It is also important to avoid loud, bright, busy environments. People who are getting over a concussion should also avoid activities that require lots of thinking and concentration, so a doctor may recommend that the person stay home from school or work.

The doctor will probably recommend that someone with a concussion take acetaminophen or other aspirin-free medications for headaches. If the symptoms last longer than a week, the doctor will likely recommend further testing of the person's thinking, memory, reaction time, and processing speed. This is done by performing a neuropsychological evaluation.

After a Concussion

After a concussion, the brain needs time to heal. It's really important to wait until all symptoms of a concussion have cleared up before returning to normal activities. The amount of time someone needs to recover depends on how long the symptoms last. Healthy teens can usually resume their normal activities within a few weeks, but each situation is different. A doctor will monitor the person closely to make sure everything's OK. Once the symptoms of a concussion have resolved, an athlete may begin a supervised gradual return to play.

Someone who has had a concussion and has not recovered within a few months is said to have post-concussion syndrome. The person may have the same problems described earlier — such as poor memory, headaches, dizziness, and irritability — but these will last for longer periods of time and may even be permanent.

Someone who has continuing problems after a concussion might be referred by the doctor to a rehabilitation specialist for additional help.

Can Concussions Be Prevented?

Some accidents can't be avoided. But you can do a lot to prevent a concussion by taking simple precautions:

• Always wear a seat belt in a car. If you drive, be attentive at all times, and obey speed limits, signs, and safe-driving laws to reduce the chances of having an accident. Driving rules and regulations were created to protect everyone. Never use alcohol or other drugs when you're behind the wheel. There's a reason it's illegal: Alcohol and drugs make your reaction time slower and impair your judgment, making you much more likely to have an accident. Never text while driving.
• Wear appropriate headgear and safety equipment. Wearing appropriate headgear and safety equipment when biking, blading, skateboarding, snowboarding or skiing, and playing contact sports can significantly reduce your chances of having a concussion. By wearing a bike helmet, for instance, you can reduce your risk of having a concussion by about 85%.

It's vital to take good care of yourself after a concussion. If you injure your brain during the time it is still healing, it will take even more time to completely heal. Each time a person has a concussion, it does additional damage — and since it's damage no one can see on the outside, there's no way of knowing how serious it might be. If someone has multiple concussions over a period of time, it can affect the person's brain as much as being knocked unconscious for several hours.

"When in Doubt, Sit Out!"

Preventing concussions is mostly common sense. The best thing you can do to protect your head is to use it.

Reviewed by: Rochelle Haas, MD
Date reviewed: January 2011