Simply put it is;
When an athlete, who has already sustained a head injury, sustains a second head injury before symptoms and pathophysiology from the first injury have resolved. Many times this occurs because the athlete has returned to play too soon either due to not being truthful with care givers/coaches or those individuals missed something.
2nd Impact Syndrome is a problem isolated to the adolescent demographic, primarily due to the developing brain. The second impact can result in a loss of auto-regulation of the brain’s blood supply, causing massive swelling. This happens in a very rapid time frame and can be due to the most minor of “bumps”.
2nd Impact Syndrome has been reported to have a 95% morbidity rate (life long effect compromising brain function) and a WHOPPING 65-70% mortality rate (meaning death as a result).
Again this is a problem that only occurs in the developing brain, meaning high school and younger aged kids!!!