Gastroenterology and hepatology
Diarrhoea, acute and chronic
Infective causes and when to test or treat acute diarrhoea, Clostridioides difficile under the 2025 ASID guideline, and a structured work-up of chronic diarrhoea including bile acid diarrhoea, microscopic colitis, coeliac disease and pancreatic insufficiency.
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Written with AI assistance and fact-checked against the sources below. For exam study, not clinical decisions. How notes are made
At a glance
- Diarrhoea is 3 or more loose or watery stools a day (Bristol 6 or 7). Acute under 14 days, persistent 14 to 30 days, chronic over 4 weeks.
- Acute diarrhoea is mostly infective and self-limiting. Rehydrate first. Test and treat only selected patients.
- Chronic diarrhoea is classified as watery, fatty or inflammatory, which directs the work-up. Common causes are IBS-D, bile acid diarrhoea, microscopic colitis, coeliac disease, drugs and IBD.
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Sources
- Therapeutic Guidelines: Gastrointestinal and Antibiotic (eTG complete), acute gastroenteritis and chronic diarrhoeaAU/NZTherapeutic Guidelines Limited
- Australasian Society of Infectious Diseases updated guidelines for the management of Clostridioides difficile infection in adults and children in Australia and New Zealand. Intern Med J 2025AU/NZAustralasian Society for Infectious Diseases (Internal Medicine Journal), 2025
- Arasaradnam RP et al. Guidelines for the investigation of chronic diarrhoea in adults: British Society of Gastroenterology, 3rd edition. Gut 2018;67:1380-99British Society of Gastroenterology, 2018
- Smalley W et al. AGA Clinical Practice Guidelines on the Laboratory Evaluation of Functional Diarrhea and Diarrhea-Predominant Irritable Bowel Syndrome in Adults. Gastroenterology 2019;157:851-4American Gastroenterological Association, 2019
- Fischer M, Vaughn BP, Peery AF, Kelly CR. AGA Clinical Practice Update on Management of Clostridioides difficile Infection in Adults: Expert Review. Clin Gastroenterol Hepatol 2026;24:2359-69American Gastroenterological Association, 2026
- Riddle MS et al. ACG Clinical Guideline: Diagnosis, Treatment, and Prevention of Acute Diarrheal Infections in Adults. Am J Gastroenterol 2016;111:602-22American College of Gastroenterology, 2016
- Last updated
- 14 November 2026
What changed
- 14 November 2026 Turnstile bot check on sign-in and signed-out feedback