title: The significance of post-traumatic amnesia as a risk factor in the development of olfactory dysfunction following head injury.
abstract: OBJECTIVE
  To test the following hypothesis in the assessment of head injury
  
  
  METHODS
  only patients with 5 min or more of post-traumatic amnesia (PTA) are at risk of acute olfactory dysfunction (OD).
  
  
  METHODS
  This was a retrospective comparative study of olfactory status in head injury patients seen at a head injury clinic at Glasgow Royal Infirmary from 1985 to 2003. Of 828 clinic attenders, 101 had acute OD. These subjects were compared with a randomly selected control group of 102 patients with head injury but normal olfactory function. The main outcome measure was a significant likelihood of patients with PTA lasting for 5 or more minutes having acute OD compared with those with PTA of less than 5 min.
  
  
  RESULTS
  The likelihood of patients with a PTA of 5 min or more having acute OD compared to those with PTA of less than 5 min is clinically significant with an odds ratio of 9.6 (p<0.01).
  
  
  CONCLUSIONS
  Examination of patients with 5 min or more of PTA should include a simple test of sense of smell. Patients with impaired smell sensation should be aware of their condition prior to discharge from hospital. In addition, the need for a CT brain scan and appropriate follow up should be considered.
authors.affiliation: Emergency Medicine Department, Glasgow Royal Infirmary, Glasgow, UK. Ian.Swann@northglasgow.scot.nhs.uk
authors.forename: I J
authors.initials: IJ
authors.lastname: Swann
authors.forename: B
authors.initials: B
authors.lastname: Bauza-Rodriguez
authors.forename: R
authors.initials: R
authors.lastname: Currans
authors.forename: J
authors.initials: J
authors.lastname: Riley
authors.forename: V
authors.initials: V
authors.lastname: Shukla
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000647:Amnesia / Q000150:complications* / Q000175:diagnosis; D006259:Craniocerebral Trauma / Q000150:complications*; D005260:Female; D015600:Glasgow Coma Scale; D006801:Humans; D008297:Male; D008875:Middle Aged; D000857:Olfaction Disorders / Q000453:epidemiology / Q000209:etiology*; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors