A brain concussion is a traumatic brain injury that is caused by a blow to the head, a fall or shaking of the brain, as explained by WebMD. There may be no signs of brain injury when the incident occurs.
Some people develop symptoms of a concussion that are obvious, according to WebMD. These symptoms include losing memory or passing out following the trauma. Most people who have a concussion should contact a doctor, and then recover by resting. It can take weeks for a full recovery to occur. The brain is more susceptible to damage following a concussion, so doctors advise patients to take it easy following any brain injury, even a mild bump on the head.