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Undiagnosed microscopic colitis: A hidden cause of chronic diarrhoea and a frequently missed treatment opportunity

Lookup NU author(s): Emeritus Professor Amritpal Hungin



This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License (CC BY-NC 4.0).


© Author(s) (or their employer(s)) 2019. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.Microscopic colitis (MC) is a treatable cause of chronic, non-bloody, watery diarrhoea, but physicians (particularly in primary care) are less familiar with MC than with other causes of chronic diarrhoea. The colon in patients with MC is usually macroscopically normal. MC can only be diagnosed by histological examination of colonic biopsies (subepithelial collagen band >10 μm (collagenous colitis) or >20 intraepithelial lymphocytes per 100 epithelial cells (lymphocytic colitis), both with lamina propria inflammation). The UK National Health Service exerts downward pressure to minimise colonoscopy referrals. Furthermore, biopsies are often not taken according to guidelines. These factors work against MC diagnosis. In this review, we note the high incidence of MC (comparable to ulcerative colitis and Crohn's disease) and its symptomatic overlap with irritable bowel syndrome. We also highlight problems with the recommendation by National Health Service/National Institute for Health and Care Excellence guidelines for inflammatory bowel diseases that colonoscopy referrals should be based on a faecal calprotectin level of ≥100 μg/g. Faecal calprotectin is <100 μg/g in over half of individuals with active MC, building into the system a propensity to misdiagnose MC as irritable bowel syndrome. This raises important questions - how many patients with MC have already been misdiagnosed, and how do we address this silent burden? Clarity is needed around pathways for MC management; MC is poorly acknowledged by the UK healthcare system and it is unlikely that best practices are being followed adequately. There is an opportunity to identify and treat patients with MC more effectively.

Publication metadata

Author(s): Munch A, Sanders DS, Molloy-Bland M, Hungin APS

Publication type: Review

Publication status: Published

Journal: Frontline Gastroenterology

Year: 2019

Volume: 11

Issue: 3

Pages: 228-234

Print publication date: 03/04/2020

Online publication date: 05/07/2019

Acceptance date: 20/06/2019

ISSN (print): 2041-4137

ISSN (electronic): 2041-4145

Publisher: BMJ Publishing Group


DOI: 10.1136/flgastro-2019-101227