Concussion (Commotio cerebri)

Definition and causes of Concussion

Concussion is a minor injury to the brain, which causes temporary disruption to the brain function. Concussion can occur when the head is exposed to external physical impact. The brain is well protected in the skull, but because the brain is slightly smaller than the skull, it can move a little bit inside the skull. If someone suffers a blow to the head the brain shakes inside the skull. In the process the nerve cells become stretched which might result in minor bleeding from the surface of the brain.

Symptoms of concussion

The following symptoms indicate a concussion but need not all be present:

The short-term unconsciousness (seconds to minutes).
Memory loss for a few minutes covering the period before and after the blow to the head.
Confusion.
Headache.
Nausea and vomiting.

Complications

The outer veins of the brain might have been torn resulting in bleeding which will result in compression of the underlying brain tissue. See Bleeding under the hard meninges, Bleeding between the hard meninges and skull and Bleeding in the middle meninges (subaraknoidea bleeding).

Bleeding in the brain, is a potentially life-threatening condition, which should be treated immediately by discharging the blood accumulation or relieving the built up pressure in the brain.

This is normally done by making a small burr hole in the skull.

Often, it takes several hours before the first symptoms appear and it is very important to observe closely a person who has taken a knock to the head. Children, elderly people and alcoholics all have an increased risk of complications and special attention it important for these types of patients.

Precautions and diagnosis

A person having sustained a blow to the head should never be left alone as the signs of serious complications in some cases show up hours or even days after the incidence. Since the patient at this point might not be able to react, for example if unconscious, it is important that others can take charge and immediately arrange medical attention if any of the below symptoms are present:

Unconscious following the blow to the head lasting for more than a few minutes.
The person is drowsy and difficult to contact.
The person continues to be very confused.
The person, after being awake again, becomes drowsy or unconscious.
Persistent violent nausea and vomiting.
Suddenly worsening headaches.
Difference in the size of the pupils.
Seizures.

Medical examination will determine whether there are any signs of damage to the brain (difference in pupil size, paralysis, sensory disturbances and changes in reflexes). If the person has not been unconscious for more than a few minutes, there are no signs of injury, and the person is fully awake, it is probably a concussion.

If more serious damage to the brain cannot be ruled out a CT or MRI scan of the brain should be made, or the person should hospitalized for observation. If the physician deems that there is no need for scanning or hospitalization, the person can go home contingent upon the presence of a responsible adult in the home. If there is not someone responsible to properly observe the person at home, observation for at least 12 hours in a hospital is recommended.

Treatment of brain concussion

There is no treatment for a brain concussion. Symptoms normally disappear spontaneously within a few days.

However, the brain needs peace and quiet to recover and the patient should rest, preferably in bed. It is important to avoid the following until the symptoms have disappeared.

Noise.
Bright light.
Reading
Watching television for longer spells.
Physical work.
Alcohol.

Outlook

The symptoms usually disappear after a few days, but particularly if the patient has not observed the above precautions the symptoms may last for weeks to months. Some may have problems long after the concussion such as headaches and dizziness, fatigue, having trouble remembering and concentrating and may no longer tolerate noise or alcohol as well as in the past. This is called post commotio syndrome.