Concussion Health Article

Definition

Concussion is a trauma-induced change in mental status, associated with confusion and amnesia, that may or may not be accompanied by a brief loss of consciousness.

Description

A concussion occurs when the head hits or is hit by an object, or when the brain is jarred against the skull with sufficient force to cause temporary loss of function in the higher centers of the brain. The injured person may remain conscious or briefly lose consciousness and become disoriented for some minutes after the blow. According to the Centers for Disease Control and Prevention, approximately 300,000 people sustain mild to moderate sports-related brain injuries each year, most of them young men between the ages of 16 and 25.

While a concussion usually resolves on its own without lasting effect, it can set the stage for a much more serious condition. "Second impact syndrome" occurs when a person with a concussion, even a very mild one, suffers a second blow before fully recovering from the first. The brain swelling and increased intracranial pressure that can result is potentially fatal. More than 20 such cases have been reported since the syndrome was first described in 1984.

Causes

Most concussions are caused by motor vehicle accidents and sports injuries. In motor vehicle accidents, concussion can occur without an actual blow to the head. Instead, concussion occurs because the skull suddenly decelerates or stops, which causes the brain to be jarred against the skull. Contact sports, especially football, hockey, and boxing, are among those most likely to lead to concussion. Other significant causes include falls, collisions, or blows due to bicycling, horseback riding, skiing, and soccer.

The risk of concussion from football is extremely high, especially at high school level. Studies show that approximately one out of every five players suffers a concussion or more serious brain injury during their brief high-school careers. The rate at the collegiate level is approximately one person in 20. Rates for hockey play- ers are not known with certainty but are believed to be similar.

A concussion is usually accompanied by another area of brain injury on the opposite side of the head from the initial blow. This is called a contrecoup injury. It is caused by to the impact of the brain on the opposite side of the skull after the initial blow.

Concussion and lasting brain damage is an especially significant risk for boxers, since the goal of the sport is, in fact, to deliver a concussion to the opponent. For this reason, the American Academy of Neurology has called for a ban on boxing. Repeated concussions over months or years can cause cumulative head injury. The cumulative brain injuries suffered by most boxers can lead to permanent brain damage. Multiple blows to the head can cause "punch-drunk" syndrome or dementia pugilistica, as evidenced by Muhammed Ali, whose Parkinson's disease is a result of his career in the ring.

Young children are likely to suffer concussions from falls or collisions on the playground or around the home. Child abuse is, unfortunately, another common cause of concussion.

Symptoms

Symptoms of concussion include:

• headache
• disorientation relative to time, date, or place
• amnesia for the events immediately preceding the blow
• confusion
• dizziness
• vacant stare or confused expression
• incoherent or incomprehensible speech
• incoordination or weakness
• nausea or vomiting
• double vision
• ringing in the ears (tinnitus)

These symptoms may last from several minutes to several hours. More severe or longer-lasting symptoms may indicate more severe brain injury. A person with a concussion may or may not lose consciousness from the blow. If consciousness is lost, the duration is usually brief, for several minutes at most. More prolonged unconsciousness indicates more severe brain injury.

The severity of concussion is graded on a three-point scale. This is used as a basis for treatment decisions.

• Grade 1: no loss of consciousness, transient confusion, and other symptoms that resolve within 15 minutes.
• Grade 2: no loss of consciousness, transient confusion, and other symptoms that require more than 15 minutes to resolve.
• Grade 3: loss of consciousness for any period of time.
• Days or weeks after the accident, a person may show signs of:
• headache
• poor attention and concentration
• memory difficulties
• anxiety
• depression
• sleep disturbances
• light and noise intolerance

The occurrence of such symptoms is called "post- concussion syndrome."