Microscopic Colitis: Clinical and Pathologic Perspectives

Andreas Münch; Cord Langner


Clin Gastroenterol Hepatol. 2015;13(2):228-236. 

In This Article

Abstract and Introduction


Microscopic colitis is a chronic inflammatory bowel disease characterized by chronic nonbloody diarrhea and specific histopathology features. Active disease, defined as 3 or more stools or 1 or more watery stools per day, significantly reduces quality of life. Epidemiologic studies have found the incidence and prevalence of microscopic colitis to be comparable with those of Crohn's disease and ulcerative colitis. Nevertheless, microscopic colitis is still under-recognized in clinical practice—most health care workers know little about its etiology and pathophysiology. Furthermore, there are many challenges to the diagnosis and treatment of patients. We review the epidemiologic and clinical features of this disorder and discuss its pathogenesis. We also outline the criteria for histopathologic evaluation of microscopic colitis, recently published by the European Consensus on Inflammatory Bowel Disease, and discuss a treatment algorithm created by the European Microscopic Colitis Group. Treatment options for patients with budesonide-refractory disease are discussed.


During the past decade, microscopic colitis (MC) has emerged as a common cause of chronic nonbloody diarrhea, especially in the elderly population.[1] Up to 10% to 20% of patients with chronic diarrhea are diagnosed with MC.[2] A normal or nearly normal endoscopic picture is typically seen and only histology can confirm the diagnosis, differentiating between its major subtypes: collagenous colitis (CC) or lymphocytic colitis (LC). Affected individuals present with frequent loose or watery stools, leading to urgency and, ultimately, fecal incontinence. Abdominal pain and weight loss are common. Hence, patients with active MC have a severely deteriorated quality of life (QoL).[3] The only drug that has been tested in multiple randomized controlled trials (RCT) and that fulfills the criteria of evidence-based medicine is budesonide.[4] This drug is highly effective and achieves clinical remission in approximately 80% of patients. However, symptom relapse occurs in 60% to 80% of patients after withdrawal of treatment,[5] necessitating a discussion regarding maintenance therapy in patients with an active chronic course.

The cause of MC is unknown, but it is believed that a luminal agent triggers an uncontrolled immunologic response in the mucosa of genetically predisposed individuals. On a scientific level, MC has not received the same attention as other inflammatory bowel diseases (IBDs) (ie, ulcerative colitis and Crohn's disease). Therefore, knowledge of MC among physicians as well as pathologists is limited.