ASGE Annual GI Advanced Practice Provider Course (On-demand) (Day Two) | March 2026-Clinical Vignettes: Approach to Acute and Chronic Diarrhea Including Celiac Sprue and SIBO

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This presentation reviews a practical approach to bloating, celiac disease, chronic diarrhea, and small-bowel disorders (especially small intestinal bacterial overgrowth, SIBO). It emphasizes building a differential for bloating that includes common dietary intolerances (lactose/fructose), celiac disease, SIBO, motility disorders (gastroparesis, delayed transit), pelvic floor dysfunction, prior foregut/bariatric surgery, obstruction, endocrine disease, ascites, central adiposity, and malignancy. It also highlights the role of abnormal viscerosomatic reflexes in visible abdominal distension.<br /><br />Celiac disease is presented as an autoimmune, gluten-mediated small-intestinal injury causing malabsorption and a wide symptom spectrum. Classical symptoms include diarrhea, weight loss, bloating/dyspepsia, growth failure, and dermatitis herpetiformis; nonclassical presentations include iron-deficiency anemia, osteoporosis, neurologic/psychiatric symptoms, and headaches. Testing is recommended in patients with chronic diarrhea, steatorrhea, weight loss, bloating, iron-deficiency anemia, elevated liver enzymes, dermatitis herpetiformis, and relevant family history. Preferred initial testing is tissue transglutaminase IgA with total IgA (IgG-based tests if IgA deficient), performed while the patient is consuming gluten; if already gluten-free, a gluten challenge is advised. Diagnosis is confirmed with upper endoscopy and duodenal biopsies (bulb and distal duodenum) showing increased intraepithelial lymphocytes and villous atrophy (Marsh criteria). Management centers on lifelong gluten-free diet, dietitian referral, correcting nutrient deficiencies, patient education (including hidden gluten), and follow-up with repeat serologies and, when indicated, repeat biopsy.<br /><br />For chronic diarrhea, the talk defines chronicity (≥4 weeks) and categorizes etiologies (malabsorptive, secretory, osmotic, inflammatory, motility-related). It outlines alarm features (e.g., onset >50, bleeding, nocturnal symptoms, weight loss, anemia, elevated inflammatory markers, family history) and a workup including labs, stool studies (including osmotic gap, calprotectin/lactoferrin), endoscopy with biopsies, and imaging. Case vignettes illustrate microscopic colitis despite normal colonoscopy and celiac disease after years of symptoms. SIBO is reviewed with symptoms, associated conditions, breath testing options, and treatment (rifaximin for hydrogen-predominant SIBO; rifaximin plus neomycin for methane-predominant overgrowth), often paired with dietary strategies and prokinetics when dysmotility is present.

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Jill Olmstead, DNP, ANP-BC, FAANP

Keywords

bloating differential diagnosis

celiac disease diagnosis

gluten-free diet management

tissue transglutaminase IgA (tTG-IgA)

duodenal biopsy Marsh criteria

chronic diarrhea evaluation

microscopic colitis

small intestinal bacterial overgrowth (SIBO)

breath testing hydrogen methane

rifaximin neomycin treatment