Microscopic colitis: lymphocytic colitis, collagenous colitis, and beyond

Update on the Epidemiology and Management of Microscopic Colitis

Microscopic colitis is an inflammatory bowel disease that commonly presents with debilitating chronic watery diarrhea. Recent epidemiologic studies and randomized trials of therapeutics have improved the understanding of the disease. Medications, such as nonsteroidal anti-inflammatories, proton pump inhibitors, and antidepressants, have traditionally been considered as the main risk factors for microscopic colitis. However, recent studies have challenged this observation. Additionally, several epidemiologic studies have identified other risk factors for the disease including older age, female sex, smoking, alcohol use, immune-mediated diseases, and select gastrointestinal infections. The diagnosis of microscopic colitis requires histologic assessment of colon biopsies with findings including increased in intraepithelial lymphocytes with or without expansion of the subepithelial collagen band. The pathophysiology is poorly understood but is thought to be related to an aberrant immune response to the luminal microenvironment in genetically susceptible individuals. Antidiarrheal medications, such as loperamide or bismuth subsalicylate, may be sufficient in patients with mild symptoms. In patients with more severe symptoms, treatment with budesonide is recommended. Maintenance therapy is often necessary and several potential treatment strategies are available. Biologic and small molecule treatments seem to be effective in patients who have failed budesonide. There is an unmet need to further define the pathophysiology of microscopic colitis. Additionally, trials with novel therapies, particularly in patients with budesonide-refractory disease, are needed.

The Association Between Primary Sclerosing Cholangitis and Microscopic Colitis: A Systematic Review

The association between primary sclerosing cholangitis (PSC) and microscopic colitis (MC) has been explored in limited studies, suggesting potential shared pathophysiological mechanisms. This systematic review aimed to investigate this relationship by analyzing studies identified through comprehensive searches in PubMed, Embase, and the Cochrane Library. Two studies met the inclusion criteria: a case series of 12 patients and a case report, collectively analyzing 13 cases. The case series revealed that 75% of MC diagnoses occurred after PSC, with many cases being asymptomatic, suggesting potential underdiagnosis. The case report described a patient with collagenous colitis who developed severe PSC complications, underscoring the bidirectional relationship and clinical impact of these conditions. Both studies highlighted immune dysregulation, genetic predisposition (HLA-DR3, HLA-DRw52a), and alterations in gut flora as shared mechanisms. These findings emphasize the importance of increased clinical vigilance, early diagnosis, and management of MC in PSC patients. Further research is needed to validate these associations, evaluate routine screening, and explore therapeutic approaches.

Microscopic colitis found together with celiac disease in a female population is associated with one episode of lymphocytic colitis

BACKGROUND

Microscopic colitis (MC) is considered a chronic disease associated with autoimmune disease, smoking, and drugs. The aim was to examine the association between MC and celiac disease, adjusted for smoking, considering subtypes and clinical course of the disease in a retrospectively collected female cohort.

METHODS

Women (n = 240), ≤ 73 years, diagnosed as MC in medical records or pathological registers were invited. One hundred and fifty-eight women accepted to be included. Participants completed a study questionnaire about sociodemographic factors, lifestyle habits, and medical history; the Rome III questionnaire; and the visual analog scale for irritable bowel syndrome (VAS-IBS). Participants were categorized into collagenous colitis (CC) (n = 92) and lymphocytic colitis (LC) (n = 66) or MC with one episode of the disease (n = 70) and refractory MC (n = 88). Presence of IBS-like symptoms were noted. Blood samples were collected and analyzed for anti-transglutaminase antibodies. Differences between groups were calculated and logistic regression was adjusted for smoking habits.

RESULTS

MC and celiac disease debuted simultaneously in half of the cases. Celiac disease was most prevalent in LC (12.1% vs. 3.3%; p = 0.05) and MC with one episode (12.9% vs. 2.3%; p = 0.01). Anti-transglutaminase antibodies were found in one patient with one episode of MC. Corticosteroid use was most often found in CC (37.0% vs. 21.2%; p = 0.037) and refractory MC (38.6% vs. 20.0%; p = 0.015). Past smokers were most prevalent in patients with one episode of MC (54.3 vs. 29.5%; p = 0.007). Current smoking was the smoking habit with highest prevalence of IBS-like symptoms. When adjusted for smoking habits, celiac disease was associated with LC (OR: 4.222; 95% CI: 1.020-17.469; p = 0.047) and tended to be inversely associated with refractory MC (OR: 0.210; 95% CI: 0.042-1.506; p = 0.058).

CONCLUSION

Celiac disease is most common in patients with one episode of LC. The question remains whether LC in combination with celiac disease should be classified as celiac disease or two different entities.

Practice Implications of Colonoscopic Investigation of Microscopic Colitis in Patients Above 50 Years of Age Presenting With Chronic Diarrhoea: A Multi-Centre Review

Background Patients with an unknown cause for chronic diarrhoea will usually undergo a colonoscopy as part of the investigative work-up, and it is acceptable practice for the patients to undergo random biopsies. The optimum number of biopsies has yet to be established. This study investigated the implications of routine random biopsies for diagnosing microscopic colitis in patients 50 years and older who presented with chronic diarrhoea. Methodology A retrospective cohort study of a prospectively maintained internal hospital database across three tertiary teaching hospitals in Perth, Western Australia, on participants >50 years old who presented for an elective colonoscopy to investigate chronic diarrhoea between January 2016 and June 2019. Data was captured from medical records, imaging, colonoscopy, and histopathology reports, and patient follow-up was analysed using SPSS v.29 (IBM Corp., Armonk, NY). Results There were 216 patients, with the majority female (67%) and a mean age of 64.6 (SD±9.9). Microscopic colitis was identified in 7.4% (95% CI = 3.9-10.9%). Most positive biopsies (81.3%) were from the left colon. The median number of biopsies per case was seven (IQR=5). The median procedure duration and scope withdrawal time were 23 and eight minutes, respectively. Most of the procedures were done by a consultant (77%). Bowel was adequately prepped in 76.9% of the cases. Univariate analysis demonstrated that the rate of identification of microcolitis was associated with the number of biopsies taken; microcolitis positivity had a higher mean number of biopsies, 10.8 vs 6.7 (p<0.001). Key complications were a 30-day readmission rate, seven-day re-presentation with acute colitis, post-procedure bleeding, requiring further imaging or angioembolisation and increased length of stay on readmission. Conclusion The prevalence of positive biopsies for microcolitis is low (7.4%). Biopsies during colonoscopy are associated with clinically significant morbidity and health care costs. Most positive biopsies were attained from the left colon. It may be time to standardise practice in investigating microscopic colitis as a cause of chronic diarrhoea in patients > 50 years old.

Diagnosis and Pharmacological Management of Microscopic Colitis in Geriatric Care

Microscopic colitis, a diagnosis under the umbrella term of inflammatory bowel disease, is a prevalent cause of watery diarrhea, often with symptoms of urgency and bloating, typically observed in older adults aged ≥ 60 years. Its incidence has been reported to exceed those of ulcerative colitis and Crohn's disease in some geographical areas. Although nonpathognomonic endoscopic abnormalities, including changes of the vascular mucosal pattern; mucosal erythema; edema; nodularity; or mucosal defects, e.g., "cat scratches" have been reported, a colonoscopy is typically macroscopically normal. As reliable biomarkers are unavailable, colonoscopy using random biopsies from various parts of the colon is compulsory. Based on the histological examination under a microscope, the disease is divided into collagenous (with a thickened subepithelial collagenous band) and lymphocytic (with intraepithelial lymphocytosis) colitis, although incomplete forms exist. In routine clinical settings, the disease has a high risk of being misdiagnosed as irritable bowel syndrome or even overlooked. Therefore, healthcare providers should be familiar with clinical features and rational management strategies. A 6-8-week oral budesonide treatment course (9 mg/day) is considered the first-line therapy, but patients often experience relapse when discontinued, or might become intolerant, dependent, or even fail to respond. Consequently, other therapeutic options (e.g., bismuth subsalicylate, biologics, loperamide, bile acid sequestrants, and thiopurines) recommended by available guidelines may be prescribed. Herein, clinically meaningful data is provided based on the latest evidence that may aid in reaching a diagnosis and establishing rational therapy in geriatric care to control symptoms and enhance the quality of life for those affected.

Getting the BS out of Irritable Bowel Syndrome with Diarrhea (IBS-D): Let's Make a Diagnosis

PURPOSE OF REVIEW

Irritable bowel syndrome with diarrhea (IBS-D) is diagnosed when chronic symptoms of abdominal pain accompany loose stools, and alarm features, such as fever, anemia, rectal bleeding, and weight loss are absent. This combination of symptoms makes structural disorders, such as inflammatory bowel disease or cancer, unlikely, but does not exclude other conditions that cause these symptoms. The question is whether making a "positive diagnosis" of IBS-D based on symptoms alone and instituting therapy based on that diagnosis still makes sense.

RECENT FINDINGS

Clinical observations suggest that at least two-thirds of cases of IBS-D can be explained by three mechanisms: a) food intolerances (~ 30-40%), b) bile acid diarrhea (~ 20-30%), and c) disturbed microbial flora (~ 15-20%). Other conditions that are less frequent but can cause IBS symptoms or be confused with IBS include: celiac disease, microscopic colitis, mastocytosis/mast cell activation, and drug side-effects. Many cases of IBS-D have a discoverable, underlying cause that can direct therapy more efficiently.