title: Motility response to colonic distention is increased in postinfectious irritable bowel syndrome (PI-IBS).
abstract: BACKGROUND
  Acute intestinal infection leads to persistent intestinal smooth muscle hypercontractility and pain hypersensitivity after resolution of the infection in animal models. We investigated whether postinfectious irritable bowel syndrome (PI-IBS) is associated with abnormalities in phasic contractions of the colon, smooth muscle tone, and pain sensitivity compared to non-PI-IBS (NI-IBS) or healthy controls (HC).
  
  
  METHODS
  Two hundred and eighteen Rome III-positive IBS patients and 43 HC participated. IBS patients were designated PI-IBS, if their IBS symptoms began following an episode of gastroenteritis characterized by two or more of: fever, vomiting, or diarrhea. Pain threshold to phasic distentions of the descending colon was assessed using a barostat. Colonic motility was assessed with the barostat bag minimally inflated to the individual operating pressure (IOP), at 20 mmHg above the IOP, and following a test meal. IBS symptom severity and psychological symptoms were assessed by the IBS Severity Scale (IBS-SS) and the Brief Symptom Inventory-18 (BSI-18).
  
  
  RESULTS
  Twenty two (10.1%) met criteria for PI-IBS. Both IBS and HC groups showed a significant increase in motility index during intraluminal distention and following meals. The magnitude of the response to distention above (orad to) the balloon was significantly greater in PI-IBS compared with NI-IBS (p < 0.05) or HC (p < 0.01). Differences between PI-IBS and NI-IBS were not significant for IBS symptom severity, pain threshold, barostat bag volumes, or any psychological score on the BSI-18.
  
  
  CONCLUSIONS
  Patients with PI-IBS have greater colonic hypercontractility than NI-IBS. We speculate that sustained mild mucosal inflammation may cause this colonic irritability.
authors.affiliation: Center for Functional GI and Motility Disorders, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Department of Behavioral Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Kanazawa
authors.forename: O S
authors.initials: OS
authors.lastname: Palsson
authors.forename: M A L
authors.initials: MA
authors.lastname: van Tilburg
authors.forename: L M
authors.initials: LM
authors.lastname: Gangarosa
authors.forename: S
authors.initials: S
authors.lastname: Fukudo
authors.forename: W E
authors.initials: WE
authors.lastname: Whitehead
mesh_terms: D015746:Abdominal Pain / Q000503:physiopathology*; D000328:Adult; D003106:Colon / Q000503:physiopathology*; D005260:Female; D005769:Gastrointestinal Motility / Q000502:physiology*; D006801:Humans; D043183:Irritable Bowel Syndrome / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D017288:Pain Threshold / Q000502:physiology*; D010812:Physical Stimulation; D055815:Young Adult
keywords: colonic motility; gut inflammation; irritable bowel syndrome (IBS); visceral sensitivity