title: Prevalence and incidence of microscopic colitis in patients with diarrhoea of unknown aetiology in a region in central Spain.
abstract: BACKGROUND
  Often previously overlooked, microscopic colitis, including collagenous colitis and lymphocytic colitis, has now emerged as a common cause of chronic diarrhoea.
  
  
  OBJECTIVE
  To evaluate the prevalence and incidence of microscopic colitis in patients with diarrhoea of unknown aetiology.
  
  
  METHODS
  271 consecutive patients who were referred to the General Hospital of Tomelloso from April 2008 to December 2010 for diarrhoea of unknown aetiology underwent a full colonoscopy to obtain biopsy samples to diagnose microscopic colitis on the basis of commonly accepted histological criteria. All patients were classified according to the Roma III criteria for diarrhoea-dominant irritable bowel syndrome.
  
  
  RESULTS
  In 234/271 consecutive patients with normal endoscopic appearance we observed 32/234 patients with microscopic colitis (30 lymphocytic colitis and 2 collagenous colitis) with a prevalence of microscopic colitis of 48 cases/100,000 inhabitants (95%CI: 30-65) and mean annual standardised incidence of 18 cases/100,000 inhabitants (95%CI: 16.0-20.0). Analysing only the patients that met the Roma III criteria (84/271), we observed 10.7% microscopic colitis diagnosis, with higher risk in the presence of autoimmune disease, seronegative celiac disease and intake of non-steroidal anti-inflammatory drugs.
  
  
  CONCLUSIONS
  Microscopic colitis was found in 13.7% of patients with chronic diarrhoea. Microscopic colitis is present in a relevant proportion of symptomatic patients meeting diagnostic criteria for irritable bowel syndrome (10.7%).
authors.affiliation: Department of Gastroenterology, Hospital General de Tomelloso, Tomelloso, Spain. danila_g@libero.it
authors.forename: Danila
authors.initials: D
authors.lastname: Guagnozzi
authors.forename: Alfredo J
authors.initials: AJ
authors.lastname: Lucendo
authors.forename: Teresa
authors.initials: T
authors.lastname: Angueira-Lapeña
authors.forename: Sonia
authors.initials: S
authors.lastname: González-Castillo
authors.forename: José Maria
authors.initials: JM
authors.lastname: Tenias Burillo
mesh_terms: D015746:Abdominal Pain / Q000453:epidemiology / Q000209:etiology; D018798:Anemia, Iron-Deficiency / Q000453:epidemiology; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000627:therapeutic use; D001706:Biopsy; D002446:Celiac Disease / Q000453:epidemiology; D046728:Colitis, Microscopic / Q000175:diagnosis / Q000453:epidemiology*; D003106:Colon / Q000473:pathology; D003113:Colonoscopy; D003967:Diarrhea / Q000453:epidemiology / Q000209:etiology*; D005260:Female; D006801:Humans; D015994:Incidence; D043183:Irritable Bowel Syndrome / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011565:Psoriasis / Q000453:epidemiology; D013030:Spain / Q000453:epidemiology; D013966:Thyroiditis / Q000453:epidemiology; D015431:Weight Loss
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal