Second Impact Syndrome in Children
With children and mild concussion, we also have another thing that's very controversial in the literature, and that's a disorder referred to as second-impact syndrome. This apparently only happens in younger people. There are two recorded cases of people over the age of 21 who have had this injury, and all of the rest are below 21. Now it's not a great deal of cases. These are about 30 or 35 cases. And they are case studies, so there hasn't been a controlled study on this issue. So there is some controversy as to whether it actually exists or not, but these are the people that have a mild head injury and then within hours or a few days have a second mild head injury on top of it. And this is characteristic of violent sports or contact sports, where you see it the most. This would be in football players, for example, is where we find many of these injuries. And we believe it's due to the fact that once you have a mild head injury, it takes you time to recover, to get back to normal glucose utilization and so on, this 5- to 10-day curve. And the person is getting their injury before their brain has had a full chance to recover. Why it may be happening in children more than adults it that their brain may in fact be more vulnerable based on the model I just talked about with mice, that it takes longer for the brain to get back to normal. And this makes sense on another practical level with regard to sports injuries. That is, for example, if you strain your knee, the ACL, you know that coaches on the sidelines or at basketball games when they get a sprained knee, they take players out of the game. They don't let them play through that injury, which is kind of typical of athletes--they like to play through things and play through that pain. They pull them out of the game, because they know if they have a strained knee they are vulnerable to that knee, in fact, having a much more severe injury associated with the second injury on top of it. And I think we're dealing with similar types of dynamics here.
If your brain doesn't get to recover properly from one concussion before sustaining another concussion -- even a seemingly mild one -- the damage can be far worse, long-lasting, even fatal.
Posted on BrainLine July 23, 2010. Reviewed December 20, 2017.
Produced by Victoria Tilney McDonough and Brian King, BrainLine.