Introduction
According to the CDC, more than 300,000 sport-related concussions are reported every year (1). However, due to lack of recognition of the signs and symptoms of concussion, upwards of an estimated 3.8 million sport-related concussions occur every year (2). The largest burden of injury falls upon adolescents and children. Continuing neurological development predisposes this age group to a greater risk of traumatic brain injury. Sports is second only to motor vehicle crashes as the most common cause of traumatic brain injury in individuals ages 15-24 (3).
The Neurological Surgeons of America define a concussion as “a clinical syndrome characterized by immediate and transient post-traumatic impairment of neural functions, such as alteration of consciousness, disturbance of vision or equilibrium due to brain stem involvement” (1). Concussions occur in varying degrees and may differ in noticeable symptoms. The brain floats in protective cerebrospinal fluid. Under normal conditions, this fluid protects the brain from colliding with the skull. However, a sudden, forceful impact can cause the brain to make contact with the skull, possibly leading to bleeding in or around the brain or nerve fiber damage (4).
Image: MD Consult
It is difficult to identify trends in concussion rates because this injury often goes unnoticed and unrecognized. The number of concussions reported today is probably far greater than a decade ago because of education programs that have increased awareness and, thus, reporting of concussions. On rare occasions, fatalities can occur as the result of second impact syndrome (SIS). SIS occurs when a concussion goes unnoticed, and the individual suffers “a second head injury before symptoms associated with the first have fully cleared” (5). Brain herniation and coma or death can follow. Like concussion, SIS is associated with adolescent age. However, few cases have been reviewed in the literature, and data on fatality trends is unavailable.
Image: USA Hockey Magazine