title: Non-sinonasal-related olfactory dysfunction: A cohort of 496 patients.
abstract: OBJECTIVE
  There is a high prevalence of olfactory dysfunction in the general population. Several causes of olfactory dysfunction have been reported and this disorder is classically divided into sinonasal and non-sinonasal-related olfactory dysfunction. The aims of this study were firstly, to evaluate the frequency of the various aetiologies of olfactory dysfunction in a population of patients with non-sinonasal-related olfactory dysfunction and secondly, to evaluate the degree of olfactory impairment associated with these various aetiologies.
  
  
  METHODS
  We retrospectively reviewed a cohort of 496 patients with non-sinonasal-related olfactory dysfunction. The aetiology of the olfactory dysfunction was recorded for each patient. The aetiology was determined by a complete clinical assessment, including medical history, complete otorhinolaryngological examination, psychophysical testing of olfactory function, recording of olfactory event-related potentials and brain magnetic resonance imaging. Six groups of patients were defined on the basis of the aetiology of the disease and orthonasal and retronasal psychophysical olfactory performances were evaluated in each group.
  
  
  RESULTS
  Post-infectious and post-traumatic aetiologies were the most common causes, representing 37.9% and 33.1% of patients, respectively, followed by idiopathic (16.3%), congenital (5.9%), toxic (3.4%) and neurological (3.4%) olfactory dysfunction. Anosmia was significantly more frequent in congenital (93.1%) and post-traumatic (62.8%) olfactory dysfunction, whereas hyposmia was more frequent in the post-infectious group (59.6%). Orthonasal and retronasal olfactory function tests were significantly correlated in all groups except for the congenital group.
  
  
  CONCLUSIONS
  The data of this study confirm that the most common causes of non-sinonasal-related olfactory dysfunction are post-infectious and post-traumatic. Post-infectious olfactory dysfunction is mainly observed in middle-aged women and is mainly associated with hyposmia, whereas post-traumatic olfactory dysfunction is mainly observed in young men and is associated with a high rate of anosmia.
authors.affiliation: Département d'oto-rhino-laryngologie, cliniques universitaires Saint-Luc, avenue Hippocrate, 10, 1200 Brussels, Belgium.
authors.forename: S
authors.initials: S
authors.lastname: Fonteyn
authors.affiliation: Département d'oto-rhino-laryngologie, cliniques universitaires Saint-Luc, avenue Hippocrate, 10, 1200 Brussels, Belgium; Institute of neuroscience, université catholique de Louvain, avenue Hippocrate, 54, 1200 Brussels, Belgium.
authors.forename: C
authors.initials: C
authors.lastname: Huart
authors.affiliation: Département d'oto-rhino-laryngologie, cliniques universitaires Saint-Luc, avenue Hippocrate, 10, 1200 Brussels, Belgium; Institute of neuroscience, université catholique de Louvain, avenue Hippocrate, 54, 1200 Brussels, Belgium.
authors.forename: N
authors.initials: N
authors.lastname: Deggouj
authors.affiliation: Département d'oto-rhino-laryngologie, CHU de Mont-Godinne, 1, rue Docteur Gaston Therasse, 5530 Yvoir, Belgium.
authors.forename: S
authors.initials: S
authors.lastname: Collet
authors.affiliation: Département d'oto-rhino-laryngologie, cliniques universitaires Saint-Luc, avenue Hippocrate, 10, 1200 Brussels, Belgium; Département d'oto-rhino-laryngologie, CHU de Mont-Godinne, 1, rue Docteur Gaston Therasse, 5530 Yvoir, Belgium.
authors.forename: P
authors.initials: P
authors.lastname: Eloy
authors.affiliation: Département d'oto-rhino-laryngologie, cliniques universitaires Saint-Luc, avenue Hippocrate, 10, 1200 Brussels, Belgium; Institute of neuroscience, université catholique de Louvain, avenue Hippocrate, 54, 1200 Brussels, Belgium. Electronic address: philippe.rombaux@uclouvain.be.
authors.forename: P
authors.initials: P
authors.lastname: Rombaux
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D000857:Olfaction Disorders / Q000453:epidemiology* / Q000209:etiology*; D012189:Retrospective Studies; D055815:Young Adult
keywords: Anosmia; Olfaction disorders; Smell