Microscopic Colitis: A Concise Review for Clinicians

Leflunomide-induced collagenous colitis: a case report and literature review

We describe a patient with rheumatoid arthritis and Hashimoto's thyroiditis who developed chronic diarrhea and subsequently diagnosed with collagenous colitis (CC) 5 years after leflunomide initiation. Cessation of leflunomide resulted in complete resolution of diarrhea within 2 months. Although rare, leflunomide-induced colitis should be considered in patients with otherwise unexplained chronic diarrhea. Diagnosis is challenging as symptom onset can occur many years after leflunomide initiation, but diarrheal symptoms typically resolve within weeks to months of stopping the instigating drug.

Concomitant Lymphocytic Colitis With Recurrent Clostridium difficile Infection

Microscopic colitis is a clinicopathological diagnosis that is characterized by chronic microscopic inflammation of the colon and presents with chronic watery diarrhea. There are following two subtypes of microscopic colitis: lymphocytic colitis and collagenous colitis. This is a case of a 70-year-old female with a history of Clostridium difficile infections who presented with persistent watery diarrhea and was diagnosed with lymphocytic colitis in the setting of a concomitant C. difficile infection. Given her clinical presentation, the patient was initiated on empiric treatment for C. difficile infection and showed a lack of clinical improvement with persistent watery diarrhea and elevated white blood cell count. The patient's symptoms resolved upon the confirmatory diagnosis and treatment of lymphocytic colitis. This study illustrates the importance of assessing for, diagnosing, and treating lymphocytic colitis in patients with chronic non-resolving watery diarrhea, especially in the setting of concomitant or recurrent C. difficile infections. Additionally, it emphasizes the need for further characterization of the relationship between C. difficile infection and microscopic colitis.

The colitis may be microscopic, but the diarrhea is not: update on the treatment of microscopic colitis and immune checkpoint inhibitor colitis

PURPOSE OF REVIEW

Microscopic colitis is an inflammatory disease of the colon that presents as watery diarrhea with minimal to normal endoscopic changes on colonoscopy. It encompasses two common subtypes, lymphocytic colitis and collagenous colitis, which are both treated similarly.Immune checkpoint inhibitor colitis is among the most common immune-related adverse events. Endoscopic and histological findings range from normal colonic mucosa to inflammatory bowel like changes. This review article provides update in treatment and management of microscopic colitis and immune checkpoint inhibitor colitis (ICPi colitis).

RECENT FINDINGS

Recent studies on microscopic colitis have focused on the successful use of immunomodulators such as biologics for treatment of budesonide refractory microscopic colitis cases. Microscopic colitis does not confer an added risk for colorectal cancer.With the increasing usage of immunotherapy agents, immune checkpoint inhibitor colitis is becoming more common. ICPi colitis can be successfully managed with steroids, with treatment stepped up to biologics for moderate to severe cases or for mild cases that do not respond to steroids. Immunotherapy agents can be carefully re-introduced in mild cases, after treatment of ICPi colitis.

SUMMARY

Biologics can be used to treat budesonide refractory microscopic colitis. ICPi colitis can be managed with steroids and biologics in moderate to severe cases.

A Literature Review of Microscopic Colitis

Although the clinical importance of microscopic colitis (MC) is highly increasing, however, the disease is still mysterious due to several challenges. Recent MC data depend mainly on doubts and uncertainties leading to misclassification. This review discussed the current knowledge gaps about MC and various controversies regarding its subtypes, pathogenesis, and management. The diagnosis of MC is based mainly on histology and immunohistopathology which can discriminate two subtypes. However, transitional forms are often associated with misclassification. The site and number of the colon biopsies have been agreed upon as at least three from each side of the colon (right and left) with a total of six. There is no credible, clear explanation for the increased incidence. The etiopathogenesis is possibly multifactorial with a high impact on the immunological background. It is proposed that MC would be the initiative of irritable bowel disease, which needs further data clarification. Although budesonide is an effective treatment in most cases, budesonide-refractory MC represents a significant clinical challenge. Therefore, immunomodulators and biologics are now well-thought to be the second-line choice for treatment.

Efficacy and Safety of Vedolizumab and Tumor Necrosis Factor Inhibitors in the Treatment of Steroid-refractory Microscopic Colitis: A Systematic Review and Meta-analysis

BACKGROUND

Tumor necrosis factor (TNF-α) inhibitors and the α4β7 integrin antagonist, vedolizumab, have been investigated as treatment options for patients with steroid-refractory microscopic colitis.

AIMS

To evaluate the benefit of vedolizumab and TNF-α inhibitors in patients with steroid-refractory microscopic colitis.

METHODS

Retrospective studies and case series involving patients with steroid-refractory MC who either received vedolizumab, adalimumab, or infliximab were eligible for inclusion. Pooled proportional meta-analyses were used to calculate the rate of clinical remission at induction, clinical response, maintenance of remission, histologic remission, and overall medication related adverse effects. Statistical analysis was performed in R using the metafor and meta packages.

RESULTS

A total of 14 studies involving 164 patients were included. Pooled analysis showed a clinical remission rate of 63.5% [95% CI (0.483; 0.776), I2=43% P=0.08], 57.8% [95% CI (0.3895; 0.7571), I2=0%, P=0.7541], and 39.3% [95% CI (0.0814; 0.7492), I2=66%, P=0.02] for vedolizumab, infliximab, and adalimumab, respectively. The maintenance of remission rates were 65.9% [95% CI (0.389; 0.889), I2=67%, P=0.02], 45.3% [95% CI (0.1479; 0.7747), I2=0%, P=0.36] and 32.5% [95% CI (0.000; 0.8508), I2=53%, P=0.14] in patients who received vedolizumab, infliximab, and adalimumab, respectively. Rate of biological-related adverse events warranting discontinuation of therapy was 12.2%, 32.9%, and 23.0% for the vedolizumab, infliximab, and adalimumab groups, respectively.

CONCLUSION

Vedolizumab and anti-TNF-α agents demonstrated a clinical benefit in the treatment of steroid-refractory microscopic colitis and with a tolerable safety profile. Future randomized controlled trials are needed to compare vedolizumab with TNF-α inhibitors and examine treatment effect on patients' quality of life.

MICROSCOPIC COLITIS: CONSIDERATIONS FOR GASTROENTEROLOGISTS, ENDOSCOPISTS, AND PATHOLOGISTS

•Diagnosis of microscopic colitis necessitates effective communication among gastroenterologists, endoscopists, and pathologists. •The gastroenterologist should refer every patient with chronic watery diarrhea to perform a colonoscopy in spite of the benign course of the disease and the absence of alarm symptoms. •The endoscopist should take 2 or 3 biopsy samples of the colonic mucosa from the right and left colon, put in separate recipients, despite that the mucosa looked macroscopically normal. •The pathologist should be encouraged to use objective histological criteria to make the diagnosis. Microscopic colitis is a chronic inflammatory bowel disease characterized by non-bloody diarrhea that can range from mild to severe. It is difficult to attribute up to 10-20% of chronic diarrhea to microscopic colitis. The three determinants factors of the diagnosis are characteristic clinical symptoms, normal endoscopic picture of the colon, and pathognomonic histological picture. This manuscript aimed to update considerations and recommendations for professionals involved (gastroenterologist, endoscopists and pathologist) in the diagnosis of MC. In addition, a short recommendation about treatment.

Microscopic colitis in older adults: impact, diagnosis, and management

Microscopic colitis (comprising lymphocytic and collagenous colitis, albeit an incomplete variant is gaining recognition as well) is a chronic, immune-mediated inflammatory state of the lower gastrointestinal tract (colon). The diagnosis requires diagnostic colonoscopy with characteristic histopathological findings. They have a propensity to present in senior populations (above 60 years of age), particularly women – who are approximately 2.5–3 times more likely to develop microscopic colitis. Preexisting other immune-inflammatory diseases are also shown to predispose patients for the development of microscopic colitis. The classic presentation is profuse watery diarrhea, often during the night or early morning hours. Fecal incontinence and abdominal pain are frequent as well. Thus, the disease impacts patients’ quality of life and well-being. The first described cases date back to the seventies and eighties of the twentieth century, thereby they can be considered fairly recently discovered disease states. Our understanding of the disease and its pathophysiology is still incomplete. Although there is a lack of unified recommendation for treatment, most clinicians prefer the use of budesonide, and most published guidelines regard this locally acting glucocorticoid as the therapy of choice. In our article, we aimed for a brief, noncomprehensive overview of the clinical significance, diagnosis, and management of microscopic colitis.

OUP accepted manuscript

Microscopic colitis (MC) is a chronic inflammatory disease of the large intestine and as a relatively late recognized condition, its relationship with other disorders of the gastrointestinal tract is gradually being understood and investigated. As a multifactorial disease, MC interacts with inflammatory bowel disease, celiac disease, and irritable bowel syndrome through genetic overlap, immunological factors, and gut microflora. The risk of colorectal cancer was significantly lower in MC, gastrointestinal infections increased the risk of developing MC, and there was an inverse association between Helicobacter pylori infection and MC. A variety of associations are found between MC and other gastrointestinal disorders, where aspects such as genetic effects, resemblance of immunological profiles, and intestinal microecology are potential mechanisms behind the relationships. Clinicians should be aware of these connections to achieve a better understanding and management of MC.