Post-infectious irritable bowel syndrome

Abstract

Irritable bowel syndrome developing following an acute infectious illness accounts for 6-17% of all cases of irritable bowel syndrome. The features of post-infectious irritable bowel syndrome are abdominal pain relieved by defecation associated with loose urgent stools and bloating and fit best with the diarrhea-predominant subtype of irritable bowel syndrome. Risk factors include in order of increasing importance (Relative Risk), stressful life events (2.0), hypochondriasis (2.0), female sex (3.4), bacterial toxins (10.3) and initial illness lasting > 21 days (11.4). Accelerated whole gut transit and reduced threshold for discomfort on rectal distension are associated features seen most prominently in those who develop post-infectious irritable bowel syndrome. Although normal by conventional histological criteria, quantitative histology of rectal mucosal biopsies indicates increased chronic inflammatory and enteroendocrine cells. Furthermore, increased urinary mannitol/lactulose ratios indicates abnormalities of small bowel permeability. Increased postprandial release of serotonin has been reported in diarrhea-predominant irritable bowel syndrome but whether this correlates with increased serotonin-containing enteroendocrine cells remains to be determined. Bile acid malabsorption may account for some cases and around 50% of these respond to cholestyramine. Prognosis is variable and recovery may take some years.