title: The diagnostic credibility of second impact syndrome: A systematic literature review.
abstract: OBJECTIVE
  The purpose of this review was to examine current literature to determine whether or not enough evidence exists to support a World Health Organization (WHO) recognized ICD-10 case definition for Second Impact Syndrome (SIS).
  
  
  METHODS
  Systematic literature review.
  
  
  METHODS
  A sensitive search strategy was developed in order to include all relevant literature. Data were extracted and placed into a diagnostic framework constructed based upon previously accepted ICD-10 diagnoses. The quality of included studies was assessed using a checklist developed specifically for case reports.
  
  
  RESULTS
  The literature search yielded 338 articles. After duplicates were removed, the remaining 222 articles were screened. Seventy-five articles were assessed for full-text eligibility, which resulted in eight case studies appropriate for this review. Significant information regarding imaging and confirmed signs and symptoms is mixed or absent. Information exists to support possible at-risk populations, signs and symptoms.
  
  
  CONCLUSIONS
  At present, there lacks a unique presentation scheme of SIS to support a standardized WHO case definition. Furthermore, future studies are needed to better understand and define at risk populations, diagnostic signs and symptoms, and the multisystem consequences of Second Impact Syndrome.
authors.affiliation: Doctor of Physical Therapy Division, Duke University, United States.
authors.forename: Olivia
authors.initials: O
authors.lastname: Hebert
authors.affiliation: Doctor of Physical Therapy Division, Duke University, United States.
authors.forename: Kaitlyn
authors.initials: K
authors.lastname: Schlueter
authors.affiliation: Doctor of Physical Therapy Division, Duke University, United States.
authors.forename: Meg
authors.initials: M
authors.lastname: Hornsby
authors.affiliation: Doctor of Physical Therapy Division, Duke University, United States.
authors.forename: Samantha
authors.initials: S
authors.lastname: Van Gorder
authors.affiliation: School of Health Sciences, The University of Newcastle, Australia.
authors.forename: Suzanne
authors.initials: S
authors.lastname: Snodgrass
authors.affiliation: Doctor of Physical Therapy Division, Department of Orthopaedics, Duke University, United States. Electronic address: chad.cook@duke.edu.
authors.forename: Chad
authors.initials: C
authors.lastname: Cook
mesh_terms: D000293:Adolescent; D006801:Humans; D038801:International Classification of Diseases; D008297:Male; D010808:Physical Examination / Q000379:methods*; D038223:Post-Concussion Syndrome / Q000175:diagnosis* / Q000503:physiopathology*; D012307:Risk Factors; D014944:World Health Organization; D055815:Young Adult
keywords: Concussion; International Classification of Diseases; Physical examination; Reference standards; SIS; World Health Organization