What are the causes and signs of concussion?

This article has been slightly adapted. The full original, along with further information on concussion, can be found at www.theconcussionplace.com.

What causes a concussion?

Your brain is a soft organ, surrounded by spinal fluid and protected by your hard skull. Normally, that fluid acts like a cushion, keeping your brain from banging into the skull around it. But if your head or body is hit hard enough, your brain can crash into the skull, or be jolted enough to move around inside your head. That force can injure the brain, bruising it, damaging blood vessels, and injuring nerves. The result is a brain that doesn’t function normally. If you’ve had a concussion, your vision may be disturbed, you might lose your balance, or you may briefly lose consciousness. In short, the brain becomes confused.

There are plenty of ways to get a concussion. Fights, falls, playground accidents, car crashes and bike accidents among the most common. Concussions also happen regularly during sport and physical activity, including football, boxing, hockey, football (soccer), skiing and snowboarding.

Concussion doesn’t always involve losing consciousness. Most people who have one never pass out, instead, they might describe seeing white, black, or stars. It’s entirely possible to have a concussion without realising it.

Some people show obvious symptoms, like passing out or forgetting what happened right before the injury. Others won’t show anything so clear. With rest, most people recover fully from a concussion within 7 to 10 days, though some take a few weeks or months. In rare cases, concussion causes more serious problems. Repeated concussions, or a single severe one, can require surgery or lead to lasting difficulties with movement, learning or speech. Because of that small but real risk of lasting damage, it’s important to contact a concussion specialist if you, or someone you know, shows symptoms of concussion.

Research in basic neuroscience shows that a mild traumatic brain injury (concussion) sets off a complex chain of chemical, metabolic and physiological changes that can affect how the brain functions for anywhere from several days to several weeks. This begins with a sudden, indiscriminate release of excitatory amino acids and a rapid shift in the brain’s ion balance, followed by a short burst of increased glucose use, then a longer period of metabolic instability, including reduced blood flow to the brain, disrupted energy metabolism, and altered communication between nerve cells. Together, these changes can injure the brain’s nerve fibres and disrupt normal neuron function, which is what shows up clinically as the neurological, cognitive and physical symptoms of concussion.

The terms concussion, mild brain injury, mild traumatic brain injury (MTBI), mild head injury (MHI) and minor head trauma are all generally used to mean the same thing. So are head injury, closed head injury, head trauma, brain injury, diffuse axonal injury, “goose-egg,” bump on the head, post-concussive syndrome, “seeing stars,” and “getting your bell rung.”