A new case study published in the Journal of Neurosurgery: Pediatrics finds that a rare "second-impact syndrome" (or SIS) can occur when an athlete suffers a jolt to the head too soon after an earlier concussion -- even if a CT scan taken after the first concussion comes back clean.
Experts say that if the brain doesn’t have enough time to recover from the initial concussion, a second one can have a devastating, often fatal, effect -- even when the second jolt is no more than a light bump.
The second hit causes the brain to swell catastrophically, but it’s the first injury, experts say, that makes the player a walking time bomb.
“The thing that pushed us to publish this case report was the imaging we had,” says Dr. Michael Turner, a neurosurgeon at Goodman Campbell Brain and Spine, a center at the Indiana School of Medicine.
“The most important thing here is that a normal CT scan does not clear you for contact," added Turner, who worked on the study. He hopes the paper will draw the public’s attention once again to the dangers of returning to play too soon.
Experts estimate that more than a million and a half boys play football in U.S. secondary schools and three million play in organized youth leagues each year. Many players get concussions, but nobody knows the true number because players often dismiss head injuries as "dings" and "bell-ringers."
Second-impact syndrome appears to be relatively rare. The Centers for Disease Control and Prevention documented 17 deaths from the condition between 1992 and 1995 in a report that cautioned that those figures could be an underestimate.
Although SIS is rare, it is always devastating. Victims who don’t die are left with life-altering brain injuries.