Second Impact Syndrome (SIS), also called recurrent traumatic brain injury, refers to when an individual suffers a second traumatic brain injury before the symptoms of an earlier traumatic brain injury have completely healed. Second Impact Syndrome is quite rare, but extremely dangerous. The second impact may occur several weeks after the first and may not initially appear to be serious; it need not involve loss of consciousness.
The second impact, even though minor, can be fatal, though the reason is not fully understood. It is believed that the second blow to the head can impede the body’s ability to autoregulate blood flow to the brain. Consequently, the brain swells, increasing intracranial pressure (ICP) and displacing the brain (herniation). The time from the second impact to complete brainstem failure is extremely rapid, usually occurring in fewer than five minutes. If this occurs there is very little hope for recovery. In non-fatal cases of second impact syndrome, long-term effects include muscle spasms, emotional instability, cognitive impairment, and hallucinations.
Second impact syndrome in athletes is common and can affect those participating in baseball, football and hockey. Second impact syndrome can result with a few days or weeks, or it can develop in the same game if the athlete isn’t taken out of the game and treated properly. Symptoms of second impact syndrome develop rapidly after the second impact and typically include:
- Loss of eye movement
- Dilated pupils
- Respiratory failure
Because second impact syndrome can be fatal, athletes should not return to their sport until the symptoms of the first brain injury are no longer present.
If you or a loved one suffered second impact syndrome, you may be eligible for compensation. Fill out our free case review form on the right to speak with a brain injury attorney today.