title: Postinfectious and chronic fatigue syndromes: clinical experience from a tertiary-referral centre in Norway.
abstract: BACKGROUND
  We aimed to compare patients reporting acute infection with those reporting no infection at onset of chronic fatigue syndrome (CFS).
  
  
  METHODS
  This study includes 873 patients with CFS referred to a tertiary centre on average 4.8 years after symptom onset. Assessment was by both observer query and self-reports. Antibody analyses against infectious agents including Epstein-Barr virus and enterovirus were performed in a majority of patients.
  
  
  RESULTS
  Females comprised 75.3% of the patient group, and the mean age was 33 years. Initial infection was reported by 77%. There was no difference as to antibody analyses. Logistic regression showed that initial infection was independently associated with acute onset of fatigue, improvement of fatigue at referral, and the following symptoms at referral: fever, tender lymph nodes, and myalgia.
  
  
  CONCLUSIONS
  CFS patients with initial infection as a precipitating factor more often report acute onset of fatigue, more frequent accompanying symptoms, and more frequent improvement on referral than do patients without initial infection.
authors.affiliation: Department of Neurology, Haukeland University Hospital, University of Bergen, Bergen, Norway. halvor.naess@haukeland.no
authors.forename: Halvor
authors.initials: H
authors.lastname: Naess
authors.forename: Endre
authors.initials: E
authors.lastname: Sundal
authors.forename: Kjell-Morten
authors.initials: KM
authors.lastname: Myhr
authors.forename: Harald Inge
authors.initials: HI
authors.lastname: Nyland
mesh_terms: D000328:Adult; D015673:Fatigue Syndrome, Chronic / Q000453:epidemiology* / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007239:Infections / Q000453:epidemiology* / Q000503:physiopathology*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009664:Norway / Q000453:epidemiology; D010044:Outpatient Clinics, Hospital / Q000706:statistics & numerical data; D015995:Prevalence; D012017:Referral and Consultation / Q000706:statistics & numerical data; D055815:Young Adult