When a cartoon character gets bonked on the head, stars appear and float in a silly circle. It may be funny to see in a cartoon, but it's not so funny when it happens for real. Seeing stars, feeling goofy or dazed for a little while, or being knocked out after getting hit in the head are all symptoms of a type of brain injury called a concussion.

What's a Concussion?

The brain is made up of soft tissue and it's cushioned by blood and spinal fluid. When someone gets a blow to the head or hits something very hard, the brain suddenly shifts inside the skull and can knock against the skull's bony surface. Sometimes this can happen with a lot of force. A concussion (say: kun-kuh-shun) is a temporary change in the way the brain works when it is suddenly moved or jarred in this way.

Sometimes, concussions last for a short time. Other times, a person can have symptoms of a concussion that last for days or weeks. But even concussions that seem to be short can be serious.

Every year, more than 400,000 kids are sent to the emergency department for serious brain injuries. Injuries from car crashes, playgrounds, or sports are the most common ways that kids get concussions.

Most of the time, after a mild head injury, people return to normal even if the injury caused a concussion. But getting more than one concussion can lead to more serious problems. You may have heard of football players and boxers who have medical problems because of repeated concussions.

Severe concussions can happen after a bad blow to the head, like from a bad bike accident or a car crash. A severe concussion is a medical emergency. The person will need to go to the hospital right away. If the brain is seriously injured, someone could have long-lasting problems with movement, learning, or speaking.

What Happens When Someone Gets a Concussion?

How someone acts after a concussion depends upon how forcefully the brain was jarred inside of the head. Sometimes a person loses consciousness, or is knocked out, for a few seconds or minutes.

A person may have a milder head injury and not be knocked out but still have a concussion. Despite being awake, some people might be unable to remember what happened right before or after the head injury. This is called amnesia (say: am-nee-zhuh).

Most people who have a concussion will feel groggy and dazed for at least a little while. They may feel like they are in a fog. They may be shaky or dizzy if they try to walk or do normal activities right away. Some feel nauseated (sick to their stomachs) or may even throw up right after a concussion. Many people will have a mild headache that lasts for a few days or longer.

Sometimes, with a severe head injury, there may be bleeding inside of the head or bruising of the delicate brain. Often people with a bad head injury will be knocked out for longer than a few minutes, act very confused (unable to remember the names of people or places, and sometimes even their own name), vomit repeatedly, or have a bad headache.

What Will the Doctor Do?

Anyone with a head injury — especially kids — should get checked by a doctor. Someone who is knocked unconscious should get care in the emergency room as soon as possible.

Doctors get many clues about a possible concussion just by talking to someone who has had a head injury. If that person was knocked unconscious, can't remember the injury, or has amnesia, then a concussion is very likely.

If a concussion is suspected, the doctor will perform a complete examination. The doctor may ask some questions that seem silly, like "what is your name?" or "where are you?" or "what day of the week is it?" or even "who is the current president of the United States?" — but these questions are important because they check someone's memory and ability to concentrate.

The doctor will examine someone who may have a concussion by looking into the eyes and also checking reflexes and balance. Sometimes the person who had the injury may even be asked to do an activity such as moving around or running in place for a few minutes to see how well the brain functions after a physical workout.

A CAT scan (a special three-dimensional brain X-ray) is sometimes ordered to make sure there is no bleeding or bruising inside someone's head after a head injury, especially if the person lost consciousness or is feeling very sick in the emergency department.

When a kid is released from the hospital soon after a concussion, the doctor will give the parent a list of instructions to follow. Parents may be asked to wake the child once or twice during the night to check on how he or she is doing.

Playing Sports Again

A kid with a concussion should never go right back to playing in a game or other activity after the injury. Kids who have concussions will need extra rest during the next few days or weeks, and also may need to take it easy at school or stay out of school for a few days or more.

The doctor will tell the kid to wait a certain amount of time before returning to sports and other activities. This is because if the kid gets another concussion, it could harm the brain more seriously. Then the kid would have to wait even longer to get back to sports and other activities.

Healthy kids can usually go back to their normal activities within a few weeks or months, but each kid and situation is different. The doctor will want to do a checkup before letting a kid return to soccer, hockey, or football.

Can Concussions Be Prevented?

Injuries happen. But the best way to prevent a concussion is by taking care of your head.

Here's how:

• Always wear a seatbelt in a car. Depending on your height, you might need a booster seat. Booster seats help the car's seat belt hold you properly in case of an accident and they help you see out the front window better. Kids need a booster seat until they are 4'9" in height and usually 8 to 12 years old. Each state has its own laws for booster seat requirements.
• When you are walking on the street, always look both ways before you cross, and obey all streetlights and traffic signs. Always use a crosswalk.
• To avoid a head injury, always wear helmets or headgear and other safety equipment when biking, riding motorized bikes or vehicles, skateboarding, riding your scooter, playing contact sports like football, skiing, and doing other activities.

See what we're saying? If you use your head, you can protect your head!

Reviewed by: Kate M. Cronan, MD
Date reviewed: January 2011