title: Does second impact syndrome exist?
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.
authors.affiliation: Centre for Sports Medicine Research & Education, and Brain Research Institute, University of Melbourne, Australia. pmccrory@compuserve.com
authors.forename: P
authors.initials: P
authors.lastname: McCrory
mesh_terms: D000293:Adolescent; D000328:Adult; D001265:Athletic Injuries / Q000150:complications*; D001929:Brain Edema / Q000453:epidemiology / Q000209:etiology* / Q000401:mortality; D001930:Brain Injuries / Q000150:complications*; D006801:Humans; D008297:Male; D012737:Sex Factors; D013577:Syndrome