What is a concussion?

Sometimes called a mild traumatic brain injury, a concussion is caused by a blow or a jolt to the head. The injury keeps the brain from working normally. Symptoms of a concussion may last less than a day or may linger for months or longer.


Millions of mild traumatic brain injuries occur in the U.S. each year, but most don't require a visit to the hospital.

What are the causes of concussions?

Many of the cases of concussion that require emergency treatment are because of falls, motor vehicle accidents, assaults, and sports injuries. Children, young adults, and older adults are at especially high risk for concussions and may take longer to recover after a concussion. People who have had concussions before are more likely to have them again.

What are the symptoms of a concussion?

These are symptoms of a possible concussion:

  • Headache
  • Vomiting or nausea
  • Trouble thinking normally
  • Memory problems
  • Trouble walking
  • Dizziness
  • Vision problems
  • Fatigue
  • Mood changes
  • Changes in sleep patterns

These symptoms may occur right away. But some may not start for weeks or even months after the injury.

How are concussions diagnosed?

To diagnose a concussion, your doctor will probably ask you a variety of questions. Be sure to say if you lost consciousness and report any other symptoms. The doctor will also want to know how the injury occurred and where you hit your head.

You may also be asked questions to test your memory and asked to do certain tasks to show how well your brain is functioning. Your doctor may also ask your friends or family questions about your symptoms and the injury.

Images of your brain using CT or MRI scans may be taken and evaluated.                                                     

How are concussions treated?

An important part of treatment for a concussion is getting plenty of rest, both sleep at night and naps or rest breaks during the day if needed. Your doctor will probably tell you to avoid certain physical activities and sports while you recover and may suggest medicine to take if you have a headache.

If your symptoms don't go away in a few days or if they get worse, you may need to see a doctor who specializes in concussions.

Can concussions be prevented?

You can take a number of steps to help reduce your risk for a concussion or prevent it in your children:

  • Wear a seat belt every time you're in a motor vehicle.
  • Make sure your children use the proper safety seat, booster seat, or seat belt.
  • Never drive under the influence of drugs or alcohol. 
  • Wear a helmet for activities such as riding a bicycle or motorcycle, playing contact sports, skiing, horseback riding, and snowboarding.
  • Reduce your risk for falls by eliminating clutter in your home, removing slippery area rugs, and installing grab bars in the bathroom if needed, especially for older adults.
  • Never work on a ladder if you feel dizzy or lightheaded. Alcohol can make you dizzy. Some medicines also can make you dizzy or affect your balance.
  • Have your vision checked at least once a year. Poor vision can increase your risk for falls and other types of accidents.

Managing a concussion

After a concussion, your health care provider may decide to monitor you in the emergency room. When you’re released, the provider will want someone to stay with you at home for a day or two to keep track of your condition. Follow your health care provider’s directions about avoiding sports, physical education classes, and activities such as running and bicycling while you are recovering.

You should also limit activities that require you to concentrate heavily. This includes taking tests if you are in school or doing tasks at work that require intense focus. You may also need to take rest breaks during the day. As your symptoms go away, you may be able to go back to your normal activities.

If you have symptoms or problems that last more than three months, you may have a problem called postconcussion syndrome. Discuss this possibility with your doctor.

When should I call a health care provider?

Call your health care provider right away or go to the emergency room if someone loses consciousness after a blow to the head or if he or she has any of the following symptoms:

  • Headache that gets worse and does not go away
  • Weakness, numbness or decreased coordination
  • Nausea or vomiting
  • Slurred speech
  • Feeling very confused
  • Feeling very drowsy
  • Convulsions or seizures

These could be signs of a serious condition that needs treatment right away.

Key points

  • Concussions are caused by a blow or a jolt to the head.
  • Symptoms such as headache, nausea, vomiting, dizziness, or trouble thinking can happen right away, or they may come on gradually over time.
  • Call a health care provider right away or go to the emergency room if a person loses consciousness after a blow to the head.
  • Getting plenty of rest is an important part of treating concussions.

Next steps

Tips to help you get the most from a visit to your health care provider:

  • Before your visit, write down questions you want answered.
  • Bring someone with you to help you ask questions and remember what your provider tells you.
  • At the visit, write down the names of new medicines, treatments, or tests, and any new instructions your provider gives you.
  • If you have a follow-up appointment, write down the date, time, and purpose for that visit.
  • Know how you can contact your provider if you have questions