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Gordon Mao

, MD, Johns Hopkins University

Last full review/revision Jun 2021| Content last modified Jun 2021

A concussion is an alteration in mental function or level of awareness caused by a head injury. A concussion may involve a loss of consciousness, can occur without obvious damage to brain structures, and lasts less than 6 hours.

(See also Sports-Related Concussion and Overview of Head Injuries.)

In concussion, no brain damage can be detected on imaging tests, such as computed tomography (CT) or magnetic resonance imaging (MRI). Yet brain cells are temporarily damaged or dysfunctional. The person has temporary symptoms of brain dysfunction.

Symptoms of a concussion include one or more of the following:

  • Temporary confusion: Appearing dazed or stunned and/or answers slowly
  • Memory loss: Being unable to recall events just before the injury or just afterward
  • Double vision
  • Sensitivity to light
  • Dizziness, clumsy movements, and problems with balance
  • Headache
  • Nausea and vomiting
  • Ringing in the ears (tinnitus)
  • Loss of smell or taste

Consciousness may be lost for a brief time, rarely for more than 15 minutes. Some people may not realize they have had a concussion.

Postconcussion syndrome refers to certain symptoms that sometimes occur for up to a few weeks after a concussion. These symptoms include one or more of the following:

  • Headaches
  • Difficulty sleeping
  • Fatigue
  • Problems with short-term memory
  • Difficulty concentrating
  • Sensitivity to light or noise
  • Personality changes, such as irritability or mood swings

Postconcussion syndrome symptoms are common during the week after concussion and commonly resolve during the second week. However, sometimes, symptoms persist for months or, rarely, years. People who have had a concussion also seem to be more susceptible to another one, particularly if the new injury occurs before symptoms from the previous concussion have completely gone away.

To diagnose a concussion, doctors need to make sure brain structures are not damaged. The use of CT, MRI, or both may be needed. If there is no structural brain damage, only the symptoms need be treated.

For concussion, acetaminophen is given for pain. Aspirin or another nonsteroidal anti-inflammatory drug (NSAID) should not be taken because they interfere with blood clotting and may contribute to bleeding from damaged blood vessels. Rest of both the body and the brain is the best treatment for a concussion.

Treatment for postconcussion syndrome is based on the severity of the symptoms. Rest and close observation are important. If symptoms worsen, people who have had a concussion should be taken to the doctor or hospital for evaluation.

People who experience emotional difficulties may need psychotherapy.

People should not return to contact sports after a concussion until all ill effects have resolved and medical evaluation has been completed.

Repeated concussions may increase a person’s risk of dementia, Parkinson disease, and depression in later life.

More Information

The following English-language resource may be useful. Please note that THE MANUAL is not responsible for the content of this resource.

  • Brain Injury Association of America: Information regarding prevention, diagnosis, and treatment of brain injuries in children and adults

Drugs Mentioned In This Article

Generic Name Select Brand Names
acetaminophen TYLENOL
Aspirin No US brand name

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