Contemporary methods for the diagnosis and treatment of microscopic colitis

Abstract

Microscopic colitis is a common cause of chronic diarrhea. It is characterized by non-bloody watery diarrhea with macroscopically normal colonic mucosa. Its specific histological characteristics confirm the diagnosis. Two distinct histological forms can be identified, namely, collagenous colitis and lymphocytic colitis. In collagenous colitis, a thick colonic subepithelial collagenous deposit can be observed, whereas in lymphocytic colitis, a pronounced intraepithelial lymphocytic inflammation in the absence of a thickened collagen band can be identified. Microscopic colitis occurs more frequently in elderly females and its etiology is believed to be multifactorial, although smoking and consumption of several drugs have been identified as risks factors for the development of the disease. The treatment is based on avoiding the risks factors and administration of oral budesonide.

KEYWORDS:

• chronic diarrhea
• collagenous colitis
• histology
• lymphocytic colitis
• microscopic colitis

Financial & competing interests disclosure

This paper was supported by funding from the Department of Gastroenterology and the Department of Pathology at KULeuven. S Vermeire has received research support from Abbvie, MSD and Takeda and has provided consultancy for Abbvie, MSD, Pfizer, Genentech/Roche, Takeda, Mundipharma, Hospira and Ferring. The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Key issues

• Microscopic colitis (MC) is characterized by chronic watery diarrhea with no endoscopic abnormalities, but specific histopathologic changes can be observed at microscopic examination.

• MC is considered a subgroup of inflammatory bowel diseases and it is divided into two histopathologic entities: collagenous colitis, characterized by a subepithelial collagen layer reaching or exceeding 10 µm thickness, and lymphocytic colitis, defined by an increased intraepithelial lymphocyte count reaching or exceeding 20 lymphocytes per 100 epithelial cells.

• MC is associated with elderly females; its incidence has risen over the last decades and has stabilized over the past years.

• Its etiology remains unclear, although it is believed to be multifactorial, with genetic factors and environmental factors being involved.

• Smoking and drug consumption (NSAIDs, proton-pump inhibitors, selective serotonin reuptake inhibitors, statins and β-blockers) have been identified as the risk factors for the development of MC.

• MC is often associated with other immune-mediated diseases, mainly with celiac disease, thyroid disease, rheumatoid arthritis, diabetes mellitus, Crohn’s disease and ulcerative colitis. Bile acid malabsorption is commonly present in patients with MC.

• Oral budesonide is the only drug that has shown efficacy in randomized controlled trials for the induction and maintenance of clinical remission of MC.

• Clinical relapse is frequently observed after budesonide withdrawal, but re-introduction of budesonide is effective.

• In budesonide-refractory cases with mild symptoms, cholestyramine, bismuth or loperamide, even in combination, may be given. In more severe cases, immunomodulators or anti-TNF drugs could be administered.

Notes