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Harvard Health Publications

Concussion

What Is It?

A concussion is a short-term disturbance in brain function caused by a head injury. A concussion causes:

  • Confusion, headache or dizziness

  • Loss of consciousness lasting less than 30 minutes or no loss of consciousness at all

  • Loss of memory (amnesia) lasting less than 24 hours

About half of all head injuries happen during motor vehicle accidents. Falls, sports and assaults cause the rest. Alcohol and drug use are major contributing factors.

Most head injuries result from direct trauma (for example, the head hitting the ground or the windshield of a car). In the elderly, serious head injuries can result from even minor falls. Injuries also can occur from rapid acceleration or deceleration, as may happen in a whiplash injury. People who injure their heads often injure their necks, too.

Magnetic resonance imaging or computed tomography (CT) scans of someone with a concussion rarely show obvious signs of brain injury. .

Occasionally, minor head trauma can trigger a more serious problem such as bruising of the brain tissue (brain contusion) or bleeding within the head (subdural hematoma or subarachnoid hemorrhage). Bleeding and other complications of minor head injuries appear to be more common in the elderly and in people taking blood thinners such as warfarin (Coumadin).

Symptoms

A concussion can cause any or all of the following symptoms:

  • Headache

  • Neck pain

  • Nausea or vomiting

  • Dizziness or vertigo

  • Hearing loss

  • Blurred or double vision

  • Changes in the ability to smell or taste

  • Fatigue

  • Irritability, anxiety or change in personality

  • Loss of memory (amnesia)

  • Confusion, difficulty concentrating or slowing of reaction time

  • Brief loss of consciousness

Symptoms most often appear immediately after the injury. However, in some cases, a person will feel fine at first and have the symptoms minutes to hours later.

Symptoms such as coma (unresponsiveness), seizures or paralysis or weakness of an arm or leg suggest a more serious form of head injury.

Diagnosis

A doctor should check anyone who has a head injury, especially if the person lost consciousness or showed a change in thinking, such as confusion or memory loss. A doctor usually will want to know:

  • How your injury occurred

  • What symptoms developed after the injury

  • Whether you have had head injuries in the past (repeat injuries are more likely to cause serious damage)

  • Whether you have other medical problems

  • What medications you take

  • Whether you have been drinking alcohol or using drugs

  • Whether you have symptoms of other injuries (neck pain, shortness of breath, etc.)

The doctor will do a thorough physical and neurological exam. The doctor will check your blood pressure, pulse, vision, the way your eyes respond to light, reflexes and balance, and your ability to answer questions and remember things. If a doctor sees you immediately after a head injury, the examination may be repeated over several hours to make sure you are not getting worse.

If you have mild symptoms, are awake and alert, and have a normal examination, your doctor may just monitor you without doing any more tests. This monitoring can be done at home if you have had a very minor injury. If your symptoms are serious or your neurological exam is abnormal, you will likely need a CT scan of your brain to look for signs of a more serious head injury.

If you are sent home, have someone stay with you for the first 24 to 48 hours because symptoms can become worse quickly or you could lose consciousness if your injury is more serious than your doctor suspected.

Expected Duration

Young people and athletes may recover from a head injury in minutes or hours. Some people experience lingering symptoms such as headache, dizziness, disrupted sleep, irritability and poor concentration for weeks or even months. In general, the more severe the concussion, the longer the recovery period. Doctors often use the term post concussion syndrome for these lingering symptoms. The duration of a post concussion syndrome varies, Most people recover completely within three months.

Repeated minor injuries over a short period greatly increase the risk of serious or permanent brain damage. Young people who play contact sports are at particular risk of these injuries. If you have had a head injury, talk to your doctor about when it is safe to return to your usual activities, including contact sports.

Prevention

Accidents, including head injuries, are the leading cause of death in young people. Many of these accidents are related to drug and alcohol use. Many accidents can be prevented by avoiding dangerous activities or wearing safety equipment.

To help prevent head injuries:

  • If you drink alcohol, drink in moderation. Never drink or use drugs and drive.

  • Protect yourself from vehicle-related head trauma by wearing a seat belt, motorcycle helmet and bicycle helmet.

  • If you play sports, wear the right kind of protective headgear. If you suffer a blow to the head while playing, leave the game immediately and seek medical attention.

  • If your job involves working high above the ground, use approved safety equipment to prevent falls. Never work in a high place if you feel lightheaded or unsteady, if you have been drinking alcohol, or if you are taking medication that can make you dizzy or affect your balance.

  • Have your vision checked regularly. Poor vision can increase your risk of falls and other types of accidents. This is especially true if you are elderly or if you work in high places.

  • If you are elderly, clear your home or apartment of hazards such as throw rugs and extension cords, which can cause you to trip and fall. If you feel unsteady on your feet, consider using a cane or walker.

Treatment

Most minor head injuries improve with rest and observation. Your doctor may choose to observe you in the hospital or may send you home under the care of a responsible adult. The doctor will give this person specific instructions about watching for danger signs.

Headache and neck pains can be treated with over-the-counter pain relievers, such as acetaminophen (Tylenol and other brand names). If you have more severe pain, your doctor may give you a prescription pain reliever.

When To Call a Professional

Call for emergency help if you find someone unconscious at an accident scene. Seek immediate attention if someone with a head injury experiences any of the following symptoms:

  • Drowsiness or a decrease in alertness

  • Nausea or vomiting

  • Confusion or amnesia

  • Difficulty walking or poor coordination

  • Slurred speech

  • Double vision

  • Irrational or aggressive behavior

  • Seizures

  • Numbness or paralysis in any part of the body

Even if a head injury appears minor, and the symptoms are mild, certain people are at high risk of serious complications. Call a doctor or go to an emergency room immediately if an injured person:

  • Is elderly

  • Takes medications to thin the blood

  • Has a bleeding disorder

  • Has a history of heavy alcohol or drug use

Prognosis

Most people with minor head injuries recover without any problems. Keep in mind, however, that some symptoms (headaches, dizziness, difficulty concentrating) may improve slowly over 6 to 12 weeks. Recovery will probably be slower in people whose injuries resulted in long periods of unconsciousness or amnesia. Recovery is also slower in the elderly, in those with previous head trauma, and in people with psychiatric or substance abuse problems.

A small percentage of people who suffer minor head injury may develop permanent disabilities or a condition called persistent post-concussive syndrome. This may include headaches, dizziness and difficulty concentrating. Consult your doctor if you still experience any symptoms three months after your head injury. Although there is no known cure for this condition, treatment is available for many of the symptoms.

External resources

National Institute of Neurological Disorders and Stroke
P.O. Box 5801
Bethesda, MD 20824
Phone: 301-496-5751
Toll-Free: 1-800-352-9424
TTY: 301-468-5981
http://www.ninds.nih.gov/

American Academy of Neurology (AAN)
1080 Montreal Ave.
St. Paul, MN 55116
Phone: 651-695-2717
Toll-Free: 1-800-879-1960
Fax: 651-695-2791
http://www.thebrainmatters.org/

Brain Injury Association of America
1608 Spring Hill Road
Suite 110
Vienna, VA 22182
Phone: 703-761-0750
Toll-Free: 1-800-444-6443
http://www.biausa.org/

Brain Trauma Foundation
708 Third Ave.
New York, NY 10017
Phone: 212-772-0608
http://www.braintrauma.org/


Disclaimer: This content should not be considered complete and should not be used in place of a call or visit to a health professional. Use of this content is subject to specific Terms of Use & Medical Disclaimers.

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