What is microcystic colitis (inflammatory bowel disease)?

From the Guidelines

Microscopic colitis is a chronic inflammatory bowel disease characterized by chronic watery diarrhea caused by inflammation in the colon, diagnosed by colonic biopsy, and comprising two subtypes: lymphocytic colitis and collagenous colitis. The goal of medical therapy is to relieve symptoms and improve quality of life while minimizing drug-related adverse effects 1.

Key Characteristics

• Microscopic colitis is not associated with increased mortality, although symptoms can lead to impaired quality of life 1.
• The reported prevalence of microscopic colitis ranges from 48 to 219 per 100,000 1.
• It has a predilection for those 60 years of age or older, with a female predominance in collagenous colitis 1.

Diagnosis and Treatment

• Diagnosis is made by colonic biopsy, and it would be prudent to perform colonoscopy with biopsies of multiple segments of the colon when assessing patients with chronic diarrhea 1.
• The medical treatment of microscopic colitis focuses on relieving symptoms and improving quality of life, with the first-line treatment typically involving medications such as budesonide 1.
• For patients with refractory symptoms, coexisting causes of chronic diarrhea such as celiac disease should be considered, and potential medication triggers like nonsteroidal anti-inflammatory drugs, proton pump inhibitors, and selective serotonin reuptake inhibitors should be avoided 1.

Management Approach

• The management approach should prioritize minimizing drug-related adverse effects while effectively managing symptoms 1.
• The guideline developed by the American Gastroenterological Association Institute provides recommendations for the medical management of microscopic colitis, including the use of the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach to assess the certainty of the evidence and grade the strength of the recommendations 1.

From the Research

Definition and Characteristics of Microcystic Colitis

• Microcystic colitis, also known as microscopic colitis (MC), is a chronic inflammatory bowel disease characterized by nonbloody diarrhea in the setting of normal appearing colonic mucosa 2, 3.
• It has two main subtypes based on histopathologic features: collagenous colitis and lymphocytic colitis 2, 3.
• The disease is a common cause of chronic watery diarrhea, predominantly in older patients, and its incidence is expected to increase due to the aging population 3.

Risk Factors and Clinical Presentation

• Risk factors for MC include increasing age, female sex, presence of other autoimmune diseases, and possibly the use of certain medications such as proton pump inhibitors, nonsteroidal anti-inflammatory drugs, selective serotonin reuptake inhibitors, and statins 3, 4.
• The clinical presentation of MC is nonspecific and includes watery nonbloody diarrhea, nocturnal stools, fecal urgency, abdominal pain, arthralgias, and weight loss 3.
• Smoking has been identified as a risk factor for MC, and exposure to certain medications may also play a role in the development of the disease 2, 4.

Treatment and Management

• The approach to treatment is similar for both lymphocytic colitis and collagenous colitis and should be guided by the severity of the patient's symptoms 2, 3.
• First-line treatment involves counseling the patient about decreasing their risk factors, and medications such as loperamide, budesonide, and cholestyramine may be used to reduce symptoms 2, 5.
• Budesonide is considered a first-line treatment for MC due to its favorable side effect profile and good efficacy, although relapse rates are high 2, 6.
• In cases of refractory disease, medications such as immunomodulators, anti-tumor necrosis factor-alpha inhibitors, and diverting ileostomy may be considered 6, 4.