Does Second Impact Syndrome Exist?McCrory, Paul MBBS, PhDClinical Journal of Sport Medicine: July 2001 - Volume 11 - Issue 3 - pp 144-149 Thematic Articles Abstract Author Information Abstract Second impact syndrome (SIS) is a widely feared complication of traumatic brain injury. Although postulated to occur after repeated concussion, the evidence for such a premise is not compelling. This paper reviews the published evidence for and against the existence of this controversial entity. Rather than SIS being a complication of recurrent concussion, it is far more likely that the clinical condition represents “diffuse cerebral swelling,” a well-recognized complication of traumatic brain injury. This condition is more common in children and adolescents, which reflects the known demographics of so-called “second impact syndrome.” We propose that clinicians abandon the misleading term second impact syndrome and refer to the syndrome as diffuse cerebral swelling. Author Information Centre for Sports Medicine Research & Education, and Brain Research Institute, University of Melbourne, Melbourne, Australia Address correspondence to Paul McCrory, MBBS, PhD, 31 Grosvenor Parade, Balwyn, Victoria 3101, Australia. E-mail: pmccrory@ compuserve.com © 2001 Lippincott Williams & Wilkins, Inc.