A recent article published in Frontline Gastroenterology informed that microscopic colitis (MC) is a treatable cause of chronic, non-bloody, watery diarrhea. However, primary care physicians seem to be less familiar with MC.

The authors stated that the colon in patients with MC is macroscopically normal; this condition 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. Owing to the current practice of minimal colonoscopy referrals and non-adherence to guidelines on biopsies, the diagnosis of MC is often missed.

This article reported a higher incidence of MC compared to ulcerative colitis and Crohns disease and its symptomatic overlap with irritable bowel syndrome (IBS). Usually, colonoscopy referrals are based on a fecal calprotectin level of ≥100 µg/g, but fecal calprotectin is <100 µg/g in over half of individuals with active MC. Hence, the propensity to misdiagnose MC as IBS. This article highlighted the importance of identifying MC and treating these patients more effectively.

Source: Frontline Gastroenterology. 2019 Jul 5;11(3):228-234. doi: 10.1136/flgastro-2019-101227.