The statements and recommendations on the management of microscopic colitis (MC) were released by United European Gastroenterology (UEG) and the European Microscopic Colitis Group (EMCG) in August 2020. The two main MC histologic subtypes are collagenous colitis (CC) and lymphocytic colitis (LC); however, incomplete forms exist (incomplete MC [MCi]).
Pathogenesis and Risk Factors
The pathogenesis of MC is complex and multifactorial, potentially including luminal factors, immune dysregulation, and genetic predisposition. Risk factors include the following:
Former and, particularly, current smoking is associated with an increased risk of CC and LC. Insufficient evidence exists to assess the influence of smoking cessation on the disease course.
Women have a higher risk of developing CC or LC than men.
Chronic or frequent use of proton pump inhibitors (PPIs), nonsteroidal anti-inflammatory drugs (NSAIDs), or selective serotonin reuptake inhibitors (SSRIs) is associated with a greater risk of MC, but a causal relationship is not implied.
UEG/EMCG suggests considering withdrawing any drugs that are suspected of having a chronologic relationship between introduction of the agent(s) and the diarrheal onset.
MC does not raise the risk of colorectal cancer or adenoma. A special surveillance colonoscopy program is not recommended.
The most common MC symptom is chronic watery, nonbloody diarrhea that is often associated with other symptoms, including fecal urgency/incontinence and nocturnal stools.
Rule out MC in those who fulfill the criteria for functional bowel disease, especially in the presence of MC risk factors and/or in the absence of response to therapy for irritable bowel syndrome (IBS).
Patients with MC have impaired health-related quality of life, depending on the activity, disease severity, and associated comorbidities.
In the absence of a formally validated metric of disease activity, disease activity and clinical remission in MC should be assessed by the Hjortswang criteria (clinical remission: mean of <3 stools per day and a mean <1 watery stool per day during a 1-week registration).
Although endoscopic findings are increasingly recognized in patients with MC, they are nonspecific.
For CC, the histopathologic criteria (on hematoxylin–eosin [H&E]-stained slides) are a thickened subepithelial collagenous band of 10 µm or greater, combined with an increased inflammatory infiltrate in the lamina propria.
For LC, the histopathologic criteria (on H&E-stained slides) are an increased number of intraepithelial lymphocytes (IELs) of at least 20 per 100 surface epithelial cells combined with an increased inflammatory infiltrate in the lamina propria and a not significantly thickened collagenous band (<10 µm).
Incomplete MC comprises incomplete CC (defined by a thickened subepithelial collagenous band >5 µm but <10 µm) and incomplete LC (defined by >10 IELs but <20 IELs and a normal collagenous band). Both types show a mild inflammatory infiltrate in the lamina propria. The criteria apply to H&E-stained slides.
UEG/EMCG recommends the following:
Ileocolonoscopy, with biopsies from at least the right and left colon
Not histologically monitoring patients with MC
Fecal calprotectin is not useful for excluding or monitoring MC
Screening for celiac disease in patients with MC
Considering testing for bile acid diarrhea in those experiencing nonresponse to budesonide treatment
UEG/EMCG recommends the following for treatment:
For induction of remission in CC or LC: Oral budesonide
Oral budesonide is effective for maintaining remission in patients with CC
Oral budesonide is suggested for maintaining remission in patients with LC
Budesonide in MC is not associated with an increased risk of serious adverse events
The risk of osteoporotic bone fractures does not appear to be increased in MC patients treated with budesonide; however, there may be an associated reduction in bone mineral density with prolonged use
Mesalazine therapy is not recommended for induction of remission in MC patients. No studies exist for maintenance
Not enough evidence exists for recommending bismuth subsalicylate, loperamide, nor antibiotics in MC patients. However, given loperamide’s documented effects in chronic diarrhea, the expert opinion favors using loperamide in mild MC disease
For MC and bile acid diarrhea, suggested treatment is with bile acid binders
Probiotics, prednisolone or other corticosteroids than budesonide, as well as methotrexate are not recommended as treatment of MC
Recommended treatment includes thiopurines, anti-tumor necrosis factor (anti-TNF) drugs, or vedolizumab in patients with MC whose condition fails to respond to budesonide to induce and maintain clinical remission
Consider surgery as the last option in selected patients with MC if all medical therapy fails
For more information, please go to Collagenous and Lymphocytic Colitis.
For more Clinical Practice Guidelines, please go to Guidelines.
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Any views expressed above are the author's own and do not necessarily reflect the views of WebMD or Medscape.
Cite this: Colitis Clinical Practice Guidelines (UEG/EMCG, 2020) - Medscape - Sep 02, 2020.