Management of Chronic Diarrhea with Elevated Inflammatory Markers and Intestinal Permeability

Diagnostic Approach

The European Crohn’s and Colitis Organisation (ECCO) recommends measuring fecal calprotectin to assess for ongoing intestinal inflammation, as this is the only biomarker approved for distinguishing organic from functional disease 1
The American Gastroenterological Association suggests performing colonoscopy with biopsies to evaluate for IBD, microscopic colitis, or other mucosal pathology, as endoscopic assessment with histopathology remains the gold standard 1, 2
Cross-sectional imaging (CT or MRI enterography) is recommended to assess for structural complications, small bowel involvement, or anatomic abnormalities 1

The American College of Gastroenterology recommends initiating proton pump inhibitor therapy for symptomatic acid reflux, as this is standard first-line treatment and particularly important if gastroduodenal Crohn's disease is identified 3
The European Society for Clinical Nutrition and Metabolism suggests that increased intestinal permeability may normalize with treatment of underlying inflammation, although it is not yet an established therapeutic target 4, 5

The British Society of Gastroenterology recommends performing glucose or lactulose hydrogen breath testing to evaluate for small intestinal bacterial overgrowth (SIBO), particularly given the intestinal yeast finding suggesting dysbiosis 4, 5
The American Gastroenterological Association suggests considering SeHCAT scan or empiric trial of bile acid sequestrants (cholestyramine 4g with meals) to evaluate for bile acid diarrhea, especially if diarrhea is postprandial 2, 1
The European Crohn’s and Colitis Organisation (ECCO) recommends breath testing for lactose and fructose intolerance, as these are more frequent in IBD and can persist even in remission 4, 5
The American College of Gastroenterology recommends serological testing with tissue transglutaminase IgA and total IgA to evaluate for celiac disease 2

The American Gastroenterological Association recommends aminosalicylates (mesalazine ≥2g/day) for mild-moderate ulcerative colitis, and immunomodulators (azathioprine 1.5-2.5 mg/kg/day or mercaptopurine 0.75-1.5 mg/kg/day) for moderate-severe or steroid-dependent disease 1, 3
The European Crohn’s and Colitis Organisation (ECCO) recommends biologic therapy after discussion of risks/benefits and surgical options for refractory disease 3
The American College of Gastroenterology suggests a trial of low FODMAP diet with nutritional monitoring for dietary modification, as this addresses carbohydrate malabsorption and has evidence in IBD-related functional symptoms 5, 1

The British Society of Gastroenterology warns against attributing symptoms to IBS or functional disease without objective exclusion of inflammation, as nocturnal diarrhea is an alarm feature suggesting organic pathology 2
The World Gastroenterology Organisation recommends avoiding escalation of immunosuppression if C. difficile infection is identified, as this can worsen outcomes 6
The American Gastroenterological Association suggests monitoring for complications, such as dehydration from chronic diarrhea, and IBD-associated dermatologic manifestations requiring specific management 7