Recurrent athletic head injury: risks and when to retire.

This article focuses on the issues related to recurrent athletic head injuries; specifically, when cumulative exponential injury or the second impact syndrome may be anticipated. Case histories and research studies are used to illustrate the salient points. A signs-and-symptoms checklist for use in concussion evaluation and management is included. Finally, the topic of when to retire after repeated athletic head injuries is discussed and illustrated with a case study.