What Is It?

A concussion is a short-lived disturbance in brain function caused by a mild Head injury that causes:

  • Typical symptoms such as confusion, headache or dizziness
  • Loss of consciousness lasting less than 30 minutes or no loss of consciousness at all
  • Amnesia lasting less than 24 hours
  • A normal or near-normal neurological exam

About 8 million people suffer head injuries in the United States each year. Less than 10 percent require hospitalization, and most of these people have only minor injuries. About half of all head injuries result from motor vehicle accidents. The rest are caused by falls, sports and assaults. Alcohol and drug use are major contributing factors.

Most head injuries result from direct trauma (for example, the head hitting the ground or 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. In fact, injury to the neck commonly accompanies head injuries. magnetic resonance imaging or computed tomography (CT) scans of people who have a concussion rarely show obvious signs of brain injury, although it is believed the symptoms are caused by swelling and damage to nerve fibers in the brain. 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).


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 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 has occurred. However, in some cases, a person will feel fine at first then will develop 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.


All head injuries should be evaluated promptly by a physician, especially if there has been any loss of consciousness or 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 are taking
  • 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 then do a thorough physical and neurological exam. He or she will check your blood pressure and pulse, your vision and the way your eyes respond to light, your reflexes and balance, and your ability to answer questions and remember things. If you are seen immediately after a Head injury, the examination may be repeated over several hours to make sure that 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 for a period of time without doing any more tests. This can be done in the hospital or, if you have had a very minor injury, at home. If you are sent home, it is important that someone stay with you all the time for the first 24 to 48 hours. If your symptoms are more serious or your neurological examination is abnormal, you probably will have a CT scan of the brain to look for the type of bruising or bleeding that requires emergency treatment.

Expected Duration

Young people and athletes may recover from a Head injury over minutes or hours. Some people may 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 once believed that these symptoms, called post-concussion syndrome, were mainly psychological, but we now understand that they are caused by subtle damage to the brain. Most people with minor head injuries recover completely over a period of 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 types of injuries. If you have had a Head injury, speak to your doctor about when it is safe to return to usual activities, including contact sports.


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

To help prevent head injuries:

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

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

  • If you play sports, wear appropriate 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 accidental 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, because 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, make sure to 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.


Most minor head injuries improve on their own and are treated just 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. This person should be given specific instructions about watching for danger signs.

Headache and neck pains can be treated with over-the-counter analgesics. Acetaminophen (Tylenol and other brand names) usually is preferred over an anti-inflammatory such as ibuprofen (Advil, Motrin and other brand names) or naproxen (Aleve) because it is less likely to cause bleeding. If you have more severe pain, your doctor may give you a prescription pain reliever.

In a small percentage of cases, minor head trauma results in serious injury such as bruising or bleeding within the brain. This sometimes requires emergency surgery or medications given intravenously (into a vein) to prevent swelling of the brain. Severe injuries almost always produce symptoms such as coma, seizures or paralysis.

When To Call A Professional

Call for emergency assistance if you find someone unconscious at an accident scene. Also 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


Most people with minor head injuries will recover without any lingering problems. Keep in mind, however, that some symptoms (headaches, dizziness, difficulty concentrating) may improve slowly over six to 12 weeks. Recovery is expected to 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 “persistent post-concussive syndrome.” This may include ongoing headaches, dizziness and difficulty concentrating. Consult your physician if you are still experiencing 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.

Johns Hopkins patient information

Last revised:

Diseases and Conditions Center

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All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.