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The Injury Clinic - The Concussion

Continuing our series of posts on sports injuries. - Paragon

The Concussion Injury
This one of the most misunderstood injuries in sports, concussions can be mild or severe depending on the mechanism of injury and you done have to lose consciousness to get a concussion. Any blow to the head can cause a concussion and results in a temporary disruption of normal brain function. The injury may involve subtle pulling, tugging or shearing of brain cells without causing any obvious structural damage. Falls and traffic accidents often involve concussions, with or without other injuries. And anyone who has had a concussion in the past is at higher risk of having concussions in the future.

It is thought that there may be microscopic shearing of nerve fibers in the brain from the sudden acceleration or deceleration resulting from the injury to the head.

The length of unconsciousness may relate to the severity of the concussion. Often victims have no memory of events preceding the injury or immediately after regaining consciousness with worse injuries causing longer periods of amnesia.

Often the maximal memory loss occurs immediately after the injury with regaining of some memory function as time passes. Complete memory recovery for the event may not occur.

Bleeding into or around the brain can occur with any blow to the head, whether or not unconsciousness occurs. If someone has received a blow to the head, observe closely for signs indicating possible brain damage.

Things to watch for include repetitive vomiting, unequal pupils, confused mental state or varying levels of consciousness, seizure-like activity, weakness on one side of the body or the inability to wake up (coma). If any of these signs are present, contact your health care provider promptly. (more on symptoms below)

The Anatomy
Image: The Hughston Clinic
The Anatomy (from The Hughston Clinic)

The brain is composed of soft tissues encased within the hard bone of the skull. A concussion occurs when your head is hit or jolted and your brain's soft tissue moves in reaction to the sudden force. At impact with the skull, the brain can become bruised, tissues can be torn, and minor swelling can occur. An injury to the brain can cause neurons (nerve cells) and nerve tracts (neurological pathways) to change or not function properly. The changes in brain function can change the way you think, act, or feel.

Three membranes, collectively called the meninges, provide protection by separating the brain's soft tissue from the rigid wall of the skull. Three layers cover the brain; the dura, a tough, leathery outer covering; the arachnoid, a thin inner layer with threadlike strands that attach it to the pia mater; and the pia mater, which is a thin, delicate layer tightly attached to the surface of the brain. In addition to the protection of the layers, cerebrospinal fluid surrounds the brain and cushions it as well. Even with these protections, the meninges and deeper tissues within the brain can become bruised when there is a blow or jolt to the head or when the head is severely jarred or shaken.

The brain is more delicate than some realize which is why there has been such an increase in the study of brain injuries.

From The Mayo Clinic:

Signs and Symptoms

The signs and symptoms of a concussion can be subtle and may not appear immediately. Symptoms can last for days, weeks or longer.

The two most common concussion symptoms are confusion and amnesia. The amnesia, which may or may not be preceded by a loss of consciousness, almost always involves the loss of memory of the impact that caused the concussion.

Other immediate signs and symptoms of a concussion may include:

  • Headache
  • Dizziness
  • Ringing in the ears
  • Nausea or vomiting
  • Slurred speech
Some symptoms of concussions don't appear until hours or days later. They include:
  • Mood and cognitive disturbances
  • Sensitivity to light and noise
  • Sleep disturbances
Head trauma is very common in young children. But concussions can be difficult to recognize in infants and toddlers because they can't readily communicate how they feel. Nonverbal clues of a concussion may include:
  • Listlessness, tiring easily
  • Irritability, crankiness
  • Change in eating or sleeping patterns
  • Lack of interest in favorite toys
  • Loss of balance, unsteady walking

I am sure that anyone who has played sports has seen someone get this injury and have seen the symptoms listed above. The brain does not like to be violently shaken disturbed. I am often amazed that boxers don't get concussions more than they do as they can take some pretty violent shots to the head.

These are the grades of concussions:

Grade 1 (mild): confusion without amnesia; no loss of consciousness--forces a player out of the game for at least 20 minutes, pending further evaluation.

Grade 2 (moderate): confusion with amnesia; no loss of consciousness--keeps a player out of the game and practice for at least a week

Grade 3 (severe): loss of consciousness--benches the player for at least a month.

This is serious business as it is sometimes hard to tell early on what grade of concussion the player has.

The Neurological Damage
Screening and Diagnosis

Diagnosing a concussion is usually straightforward. If a blow to your head has knocked you out or left you dazed, you've had a concussion. It's more difficult, however, to determine whether the blow has caused potentially serious bleeding or swelling in your skull. Signs and symptoms of these injuries may not appear until hours or days after the injury.

Your doctor may start your evaluation with questions about the accident, then proceed to a neurological exam. This exam includes checking your memory and concentration, vision, hearing, balance, coordination and reflexes.

The standard test to assess post-concussion damage is a computerized tomography (CT) scan. A CT scanner takes multiple cross-sectional X-rays and combines all the resulting images to produce detailed, two-dimensional images of your skull and brain. During the procedure, you lie still on a table that slides through a large, doughnut-shaped X-ray machine. The scan is painless and generally takes less than 10 minutes.

Not every concussion requires a CT scan, but the test is usually done as a precaution if there's a chance your injury is more severe than your immediate condition suggests.

You may need to be hospitalized overnight for observation after a concussion. If your doctor says it's OK for you to be observed at home, someone should check on you periodically for at least 24 hours. You may need to be awakened every two hours to make sure you can be roused to normal consciousness. Post-concussion syndrome, a poorly understood complication, as it causes concussion symptoms to last for weeks or months.

The bigger problem is when players have multiple concussions, they double their risk of developing epilepsy within the first five years after the injury.

There also is evidence that people who have had multiple concussions over the course of their lives suffer cumulative neurological damage. Chronic encephalopathy is an example of the cumulative damage that can occur as the result of multiple concussions or less severe blows to the head. The condition called dementia pugilistica, or "punch drunk" syndrome, which is associated with boxers, can result in cognitive and physical deficits such as parkinsonism, speech and memory problems, slowed mental processing, tremor, and inappropriate behavior. It shares features with Alzheimer's disease, a link between concussions and the eventual development of Alzheimer's disease also has been suggested.

A "baseline" neurological evaluation by a physician determines appropriate treatment for an uncomplicated concussion. The best treatment for a concussion is rest.