According to the U.S. Centers for Disease Control and Prevention (CDC), around 300,000 athletes suffer mild to moderate traumatic brain injuries (TBIs) each year.[1] Most of the injuries are diagnosed as concussions. How many of these result in second impact syndrome is not known. The CDC also reports that the likelihood of suffering a head injury is greater for those who have already had a previous head injury. When a repeated mild brain injury happens before the first can heal, the result can be fatal. This type of injury results in “second impact syndrome,” an illness first defined in 1984.
Because Second Impact Syndrome is so dangerous, it is vital that athletes and coaches recognize the initial traumatic brain injury and keep athletes from play until the first injury has healed. If coaches and players do not realize the extent of the danger, they may return to play before it is safe to do so.
Second Impact Chain Reaction
A second impact creates a chain reaction in the brain. Normally, the brain and other bodily organs keep a steady flow of blood by widening and narrowing blood vessels with changes in pressure. A second strike to the head, even a slight one, can interrupt this blood flow, leading to swelling in the brain. The swelling can cause increased pressure inside the skull and may even force the tissues to move from their regular locations in the brain.
A second impact can kill as quickly as in two minutes. Brain swelling and pressure push on the brain stem, where the body’s regulatory systems reside. When the brain stem fails, breathing stops and the body dies.
In the seconds or minutes after a second impact, an athlete may appear stunned. He or she may collapse and fall to the ground of experience a seizure. Pupils rapidly changing size, loss of eye movement and respiratory failure can all signal the deadly syndrome. Because victims die within minutes, there is rarely any way to treat the syndrome. Prevention is the only way to avoid second impact syndrome.
Prevention
Second impact syndrome can be prevented by keeping athletes from returning to play until the first brain injury has healed. The syndrome is rare in the overall population, but more common in male teenage athletes. For this reason, young adults and teens should be watched closely for signs of injury following any blow to the head, even a mild one. These athletes should stay off the field for at least ten days, possibly longer if symptoms persist.