Current concepts on microscopic colitis: evidence-based statements and recommendations of the Spanish Microscopic Colitis Group

DIAGNOSIS AND TREATMENT OF MICROSCOPIC COLITIS: POSITION PAPER ON BEHALF OF THE BRAZILIAN FEDERATION OF GASTROENTEROLOGY

BACKGROUND

Microscopic colitis (MC) is a chronic inflammatory condition of the colon, primarily characterized by watery diarrhea, with normal or near-normal endoscopic findings. It encompasses two main subtypes: lymphocytic colitis and collagenous colitis.

OBJECTIVE

This position paper from the Brazilian Federation of Gastroenterology aims to review current evidence on the diagnosis and management of MC in Brazil, emphasizing the need for standardization across the country's healthcare systems.

METHODS

A comprehensive review of the latest scientific literature, clinical guidelines, and consensus statements was performed, focusing on randomized clinical trials, meta-analyses, and cohort studies. The evidence was analyzed by a panel of gastroenterologists and pathologists specializing in MC. The recommendations were based on the consensus of the group, approved by the majority of the panel members.

RESULTS

Histological examination with biopsies from multiple segments of the colon remains essential for the accurate diagnosis of MC, as endoscopic findings are often non-specific. Budesonide is the first-line treatment for inducing remission in most patients. However, alternatives such as immunosuppressants and biologics are available for those who are refractory to or intolerant of budesonide. Non-pharmacological interventions, including dietary and lifestyle modifications, can complement medical treatment. The need for long-term follow-up is highlighted due to the high recurrence rates and the impact of MC on the quality of life.

CONCLUSION

Standardizing the diagnosis and treatment of MC in Brazil is crucial, given the significant regional disparities in healthcare access. This position paper provides evidence-based recommendations to optimize care and improve patient outcomes across diverse clinical settings in Brazil. Further research is needed to address the gaps in understanding the epidemiology and management of MC in underserved regions.

Microscopic Colitis and Celiac Disease: Sharing More than a Diagnostic Overlap

Microscopic colitis (MC) is an emergent group of chronic inflammatory diseases of the colon, and celiac disease (CD) is a chronic gluten-induced immune-mediated enteropathy affecting the small bowel. We performed a narrative review to provide an overview regarding the relationship between both disorders, analyzing the most recent studies published at the epidemiological, clinical and pathophysiological levels. In fact, MC and CD are concomitantly prevalent in approximately 6% of the cases, mainly in the subset of refractory patients. Thus, physicians should screen refractory patients with CD against MC and vice versa. Both disorders share more than a simple epidemiological association, being multifactorial diseases involving innate and adaptive immune responses to known or unknown luminal factors based on a rather common genetic ground. Moreover, autoimmunity is a shared characteristic between the patients with MC and those with CD, with autoimmunity in the latter being quite well-established. Furthermore, CD and MC share some common clinical symptoms and risk factors and overlap with other gastrointestinal diseases, but some differences exist between both disorders. More studies are therefore needed to better understand the complex mechanisms involving the common pathogenetic ground contributing to the CD and MC epidemiological association.

Lymphocytic colitis can be transcriptionally divided into channelopathic and inflammatory lymphocytic colitis

BACKGROUND

The pathobiology of the non-destructive inflammatory bowel disease (IBD) lymphocytic colitis (LC) is poorly understood. We aimed to define an LC-specific mucosal transcriptome to gain insight into LC pathology, identify unique genomic signatures, and uncover potentially druggable disease pathways.

METHODS

We performed bulk RNA-sequencing of LC and collagenous colitis (CC) colonic mucosa from patients with active disease, and healthy controls (n = 4-10 per cohort). Differential gene expression was analyzed by gene-set enrichment and deconvolution analyses to identify pathologically relevant pathways and cells, respectively, altered in LC. Key findings were validated using reverse transcription quantitative PCR and/or immunohistochemistry. Finally, we compared our data with a previous cohort of ulcerative colitis and Crohn's disease patients (n = 4 per group) to distinguish non-destructive from classic IBD.

RESULTS

LC can be subdivided into channelopathic LC, which is governed by organic acid and ion transport dysregulation, and inflammatory LC, which is driven by microbial immune responses. Inflammatory LC displays an innate and adaptive immunity that is limited compared to CC and classic IBD. Conversely, we noted a distinct induction of regulatory non-coding RNA species in inflammatory LC samples. Moreover, compared with CC, water channel and cell adhesion molecule gene expression decreased in channelopathic LC, whereas it was accentuated in inflammatory LC and associated with reduced intestinal epithelial cell proliferation.

CONCLUSIONS

We conclude that LC can be subdivided into channelopathic LC and inflammatory LC that could be pathomechanistically distinct subtypes despite their shared clinical presentation. Inflammatory LC exhibits a dampened immune response compared to CC and classic IBDs. Our results point to regulatory micro-RNAs as a potential disease-specific feature that may be amenable to therapeutic intervention.

Histology of IBD and related colitides in the elderly

Inflammatory bowel disease (IBD) are chronic relapsing diseases, affecting both children and adults with a life-long duration. An increased co-morbidity gives raise to fragility in the elderly. In this regard it should consider that several non-IBD colitides may mimic both ulcerative colitis and Crohn's disease. Moreover, chronic diseases represent a clinical challenge, mostly about treatment effectiveness. Finally, it is worth noting that patients with long-standing diseases - and elderly patients among them - have an increased malignancy risk when compared to general (non-IBD) population. Our paper aims to review the three main histological topics that play a role in the clinical management of IBD in the elderly, namely differential diagnosis, mucosal healing and IBD-associated dysplasia.

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.

Medically Refractory Lymphocytic Colitis Successfully Treated With Upadacitinib

Lymphocytic colitis is a microscopic colitis characterized endoscopically by nearly normal-appearing colonic mucosa and histology demonstrating intraepithelial lymphocytosis. Microscopic colitis that is refractory to conventional therapies, including budesonide, is rare but challenging and with scarce evidence. Upadacitinib is a novel Janus kinase 1 selective inhibitor approved by the US Food and Drug Administration for atopic dermatitis, rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, and moderately to severely active ulcerative colitis. We present the first case of lymphocytic colitis refractory to conventional and immunosuppressive therapies, which responded promptly to upadacitinib.

Efficacy and safety of biologic therapy in microscopic colitis: systematic review and meta-analysis

BACKGROUND

This systematic review and meta-analysis sought to evaluate the effectiveness and safety of biologic therapy in the treatment of steroid-refractory microscopic colitis (MC).

METHODS

We searched MEDLINE, Embase, Web of Science, and Cochrane Central to identify articles and abstracts reporting efficacy or safety data on biologic use (infliximab, adalimumab, certolizumab, golimumab, vedolizumab, ustekinumab, and tofacitinib) for induction and maintenance of remission in MC. We assessed clinical remission and response rates and all reported adverse events (AEs).

RESULTS

A total of 376 studies were screened yielding 13 articles (including four abstracts) with a combined information on 78 patients for efficacy and safety outcomes. Most studies were case series. Vedolizumab was used in five studies, adalimumab in three, and a combination of infliximab and adalimumab in five studies. The rates of remission were 66.08% (95% CI, 36.79-95.37%; I2 , 71%) at weeks 3-6 and 54.20% (95% CI, 39.39-69.01%; I2 , 0%) at weeks 12-16. Clinical response rates were 100% (95% CI, 88.04-100%; I2 , 0%) at weeks 3-6 and 67.20% (95% CI, 47.72-86.69%; I2 , 52%) at weeks 12-16. Most frequent AE was medication discontinuation with a pooled incidence of 16.1% (95% CI, 5.9-37.5%). No deaths attributable to biologic use were reported. The overall quality of evidence was very low due to the high risk of biases.

CONCLUSION

Low-quality evidence supports the short-term efficacy of biologics in budesonide refractory MC. While our findings represent the most comprehensive evaluation of biologic therapy in severe MC, further research including randomized clinical trials is needed to better define the role of specific agents and long-term therapy.

Rheumatologic Associations of Microscopic Colitis: A Narrative Review

Extra-intestinal manifestations are frequent complications of the classical inflammatory bowel diseases, Crohn's disease and ulcerative colitis. However, in addition to the classical diseases, there is a spectrum of conditions, often termed "microscopic colitis", in which extra-intestinal manifestations are less well described. Our objective was to review the literature regarding the extra-intestinal manifestations complicating microscopic colitis and describe the association with systemic autoimmune rheumatic diseases. A comprehensive search and review of peer-reviewed English-language and international journals and reports was completed based on key terms, including "microscopic colitis", "lymphocytic colitis", "collagenous colitis", "inflammatory bowel disease", "extraintestinal manifestations", and the specific disease associations utilizing the PubMed Central database and MEDLINE. A broad spectrum of rheumatologic manifestations has been reported in patients with microscopic colitis. The identification of rheumatoid arthritis and limited scleroderma as co-morbidities with microscopic colitis was noteworthy. Inflammatory arthropathy was frequently seen in microscopic colitis, usually preceding or occurring in conjunction with the onset of gastrointestinal symptoms. A variety of presentations of associated arthritis were reported: migratory, symmetric or asymmetric, peripheral or axial, oligoarticular or polyarticular, erosive or non-erosive. There was a high incidence of autoantibodies in these patients, supporting a potential autoimmune association. On the basis of these anecdotal reports, we would suggest development of a clinical registry to help define the incidence of extra-intestinal manifestations and systemic autoimmune rheumatic diseases among microscopic colitis patients to help elucidate shared predispositions, pathogenic mechanisms and therapeutic opportunities.

Pathogenesis of Microscopic Colitis: A Systematic Review

BACKGROUND

Whereas the exact aetiology of microscopic colitis [MC] remains unknown, a dysregulated immune response to luminal factors or medications is the most accepted pathogenesis hypothesis.

METHODS

We conducted a systematic review of the pathogenesis of MC. We applied the Joanna Briggs Institute methodologies and the PRISMA statement for the reporting of systematic reviews [PROSPERO Trial Identifier: CRD42020145008]. Populations, Exposure of interest, and Outcome [PEO] questions were used to explore the following topics in MC: 1] intestinal luminal factors; 2] autoimmunity; 3] innate immunity; 4] adaptive immunity; 5] extracellular matrix; 6] genetic risk factors; and 7] mechanism of diarrhoea. A search was done in PubMed, Embase, and Web of Science up to February 2020. A narrative description was performed explaining the findings for each aspect of MC aetiopathogenesis.

RESULTS

Thirty-eight documents provided evidence for PEO1, 100 for PEO2, 72 for PEO3 and 4, 38 for PEO5, 20 for PEO6, and 23 for PEO7. The majority of documents were cohorts, case reports, and case series, with a few case-control and some experimental studies. Consistency among data provided by different studies was considered to support pathogenetic hypotheses. MC is a multifactorial disease believed to involve innate and adaptive immune responses to luminal factors, genetic risk, autoimmunity, and extracellular matrix alterations, all contributing by varied mechanisms to watery diarrhoea.

CONCLUSIONS

This is the first systematic review on the aetiology of MC supporting the notion that MC is a multifactorial disease. However, high-profile studies are lacking, and most evidence derives from small heterogeneous studies.

Irritable bowel syndrome

Irritable bowel syndrome is one of the most common functional bowel disorders, and has a substantial impact on patients' daily lives, as well as a big economic impact on society. It is characterised by abdominal pain, bloating and abdominal distention and altered bowel movements, with a predominance of diarrhoea, constipation, or alternation of these signs, which cannot be explained by a structural or biochemical abnormality. Its aetiopathogenesis and pathophysiological mechanism are unknown. The disease affects 5%-10% of healthy individuals at any given time and, in most people, has a relapsing-remitting course. This article reviews some of the main and most current evidence on its epidemiology, risk factors, pathophysiology, clinical manifestations, diagnostic approach, and therapeutic options, both dietary, pharmacological and psychotherapeutic.

Low prevalence of colorectal neoplasia in microscopic colitis: A large prospective multi-center study

BACKGROUND AND AIMS

Microscopic colitis (MC) is the most frequent condition in subjects undergoing ileocolonoscopy for chronic non-bloody diarrhea (CNBD) in Western countries. Emerging evidence has shown a negative association between MC and colorectal cancer. Within this prospective multi-center study we have evaluated the risk of colorectal neoplasia in MC and non-MC patients with CNBD receiving ileocolonoscopy with high-definition plus virtual chromoendoscopic imaging and histopathological assessment.

METHODS

Patients with CNBD of unknown origin were prospectively enrolled in 5 referral centers in Northern Italy for ileocolonoscopy with high-definition and digital/optical chromoendoscopy plus multiple biopsies in each segment. The prevalence of colorectal neoplasia (cancer, adenoma, serrated lesion) in MC was compared to that observed in a control group including CNBD patients negative for MC, inflammatory bowel disease or eosinophilic colitis.

RESULTS

From 2014 and 2017, 546 consecutive CNBD patients were recruited. Among the 492 patients (mean age 53±18 years) fulfilling the inclusion criteria against the exclusion critieria, MC was the predominant diagnosis at histopathological assessment (8.7%: N=43, 28 CC, 15 LC). The regression model adjusted for age and gender showed a significant negative association between the diagnosis of CM and colorectal neoplasia (OR=0.39; 95% CI 0.22-0.67, p <0.001) with a 60% decreased risk of adenomatous and neoplastic serrated polyps as compared to the control group (n=412).

CONCLUSION

This multi-center study confirms MC as a low-risk condition for colorectal neoplasia. No surveillance colonoscopy program is to be performed for MC diagnosis.

Microscopic colitis

Microscopic colitis (MC) is an inflammatory disease of the large intestine associated with urgent watery diarrhoea. MC may occur in people of all ages, although the disease primarily affects older women. Once believed to be rare, MC is now known to be a common cause of chronic watery diarrhoea in high-income countries, affecting 1 in 115 women and 1 in 286 men during their lifetime in Swedish population-based estimates. An inappropriate immune response to disturbances in the gut microenvironment is implicated in the pathogenesis of MC. Evidence also supports an underlying genetic basis for disease. The diagnosis of MC relies on clinical symptoms and microscopic assessment of colonic biopsy samples. MC is categorized histologically into collagenous colitis, lymphocytic colitis and their incomplete forms. The mainstay of treatment includes the use of budesonide, with or without adjunctive therapies, and withdrawal of offending drugs. Emerging studies suggest a role for biologicals and immunosuppressive therapies for the management of budesonide-refractory or budesonide-dependent disease. MC can have a substantial negative effect on patient quality of life. The outlook for MC includes a better understanding of the immune response, genetics and the microbiome in disease pathogenesis along with progress in disease management through robust clinical trials.

Gastrointestinal Infection and Risk of Microscopic Colitis: A Nationwide Case-Control Study in Sweden

BACKGROUND AND AIMS

Gastrointestinal infections have been linked to changes in the composition and function of gut microbiome and development of inflammatory bowel diseases. We therefore sought to examine the relationship between gastroenteritis and risk of microscopic colitis (MC).

METHODS

We conducted a case-control study of all adult patients with MC diagnosed between 1990 and 2016 in Sweden matched to up to 5 general population controls according to age, sex, calendar year, and county. Cases of MC were identified using Systematized Nomenclature of Medicine codes from the ESPRESSO (Epidemiology Strengthened by histoPathology Reports in Sweden) study, a cohort of gastrointestinal pathology reports from all 28 pathology centers in Sweden. We used logistic regression modeling to estimate adjusted odds ratios (aORs) and 95% confidence intervals (CIs).

RESULTS

Through December of 2016, we matched 13,468 MC cases to 64,479 controls. The prevalence of previous diagnosed gastrointestinal infection was 7.5% among patients with MC, which was significantly higher than in controls (3.0%, P_comparison < .001). After adjustment, gastroenteritis was associated with an increased risk of MC (aOR 2.63; 95% CI 2.42-2.85). Among specific pathogens, Clostridioides difficile (aOR 4.39; 95% CI 3.42-5.63), Norovirus (aOR 2.87; 95% CI 1.66-4.87), and Escherichia species (aOR 3.82; 95% CI 1.22-11.58), but not Salmonella species, were associated with an increased risk of MC. The association between gastrointestinal infections and risk of MC was stronger for collagenous subtype (aOR 3.23; 95% CI 2.81-3.70) as compared with lymphocytic colitis (aOR 2.51; 95% CI 2.28-2.76; P_{heterogeneity} = .005). The associations remained significant after adjustment for immune-mediated conditions and polypharmacy and when compared with unaffected siblings.

CONCLUSION

In a nationwide study, we found that gastrointestinal infection, particularly Clostridioides difficile, is associated with an increased risk of subsequent MC. This study was approved by the Regional Ethics Committee, Stockholm, Sweden (Protocol no. 2014/1287-31/4).

European guidelines on microscopic colitis: United European Gastroenterology and European Microscopic Colitis Group statements and recommendations

INTRODUCTION

Microscopic colitis is a chronic inflammatory bowel disease characterised by normal or almost normal endoscopic appearance of the colon, chronic watery, nonbloody diarrhoea and distinct histological abnormalities, which identify three histological subtypes, the collagenous colitis, the lymphocytic colitis and the incomplete microscopic colitis. With ongoing uncertainties and new developments in the clinical management of microscopic colitis, there is a need for evidence-based guidelines to improve the medical care of patients suffering from this disorder.

METHODS

Guidelines were developed by members from the European Microscopic Colitis Group and United European Gastroenterology in accordance with the Appraisal of Guidelines for Research and Evaluation II instrument. Following a systematic literature review, the Grading of Recommendations Assessment, Development and Evaluation methodology was used to assess the certainty of the evidence. Statements and recommendations were developed by working groups consisting of gastroenterologists, pathologists and basic scientists, and voted upon using the Delphi method.

RESULTS

These guidelines provide information on epidemiology and risk factors of microscopic colitis, as well as evidence-based statements and recommendations on diagnostic criteria and treatment options, including oral budesonide, bile acid binders, immunomodulators and biologics. Recommendations on the clinical management of microscopic colitis are provided based on evidence, expert opinion and best clinical practice.

CONCLUSION

These guidelines may support clinicians worldwide to improve the clinical management of patients with microscopic colitis.

Treatment of microscopic colitis: the role of budesonide and new alternatives for refractory patients

Microscopic colitis is a common cause of chronic watery diarrhea with a great impact on patient quality of life. Microscopic colitis includes two histological subtypes: collagenous colitis and lymphocytic colitis. Due to the increasing incidence and awareness of this disease over the last decades, several international guidelines have been recently published. However, there is still significant heterogeneity in the management of these patients, and treatments without solid scientific evidence support are often used in clinical practice. This article reviews the therapeutic role of budesonide in microscopic colitis and summarizes the current evidence regarding other treatments available for this disease, especially for the management of refractory patients. Finally, an updated treatment algorithm is proposed.

Distribution of histopathological features along the colon in microscopic colitis

PURPOSE

The diagnosis microscopic colitis (MC) consisting of collagenous colitis (CC) and lymphocytic colitis (LC) relies on histological assessment of mucosal biopsies from the colon. The optimal biopsy strategy for reliable diagnosis of MC is controversial. The aim of this study was to evaluate the distribution of histopathological features of MC throughout the colon.

METHODS

Mucosal biopsies from multiple colonic segments of patients with MC who participated in one of the three prospective European multicenter trials were analyzed. Histological slides were stained with hematoxylin-and-eosin, a connective tissue stain, and CD3 in selected cases.

RESULTS

In total, 255 patients were included, 199 and 56 patients with CC and LC, respectively. Both groups exhibited a gradient with more pronounced inflammation in the lamina propria in the proximal colon compared with the distal colon. Similarly, the thickness of the subepithelial collagenous band in CC showed a gradient with higher values in the proximal colon. The mean number of intraepithelial lymphocytes was > 20 in all colonic segments in patients within both subgroups. Biopsies from 86 to 94% of individual segments were diagnostic, rectum excluded. Biopsies from non-diagnostic segments often showed features of another subgroup of MC.

CONCLUSION

Conclusively, although the severity of the histological changes in MC differed in the colonic mucosa, the minimum criteria required for the diagnosis were present in the random biopsies from the majority of segments. Thus, our findings show MC to be a pancolitis, rectum excluded, questioning previously proclaimed patchiness throughout the colon.

Epidemiological and clinical characteristics, and response to treatment in 113 patients with microscopic colitis

OBJECTIVE

To study the epidemiological and clinical characteristics, and response to treatment in patients with microscopic colitis.

PATIENTS AND METHOD

Epidemiological, clinical, blood test and endoscopic data were retrospectively collected from 113 patients with microscopic colitis. Response to treatment was analyzed in 104 of them. Efficacy and relapse after treatment with budesonide were assessed using survival curves (Kaplan-Meier).

RESULTS

78% of the patients were women, with a mean age of 65 ± 16 years. In smokers, the mean age was 10 years younger. 48% of them had some concomitant autoimmune disease; 60% suffered a single outbreak of the disease. The clinical presentation was similar in both subtypes, although patients with collagenous colitis had a chronic course more frequently (48% vs. 29%, p = 0.047). The remission rate with budesonide was 93% (95% CI 82-98). The cumulative incidence of relapse, after a median follow-up of 21 months, was 39% (95% CI 26-54%): 19% at one year, 32% at two years, and 46% at three years of follow-up. There were no differences in clinical response to budesonide based on smoking habit or microscopic colitis subtype.

CONCLUSIONS

Microscopic colitis is more frequent in elderly women. Smoking was associated with earlier onset of the disease, although it did not influence the clinical course or response to treatment. The majority (> 90%) of patients treated with budesonide achieved remission, although nearly half subsequently relapsed.

Non-neoplastic colorectal disease biopsies: evaluation and differential diagnosis

A wide variety of non-neoplastic conditions may be encountered on colorectal biopsy encompassing idiopathic, infectious, vascular and immune-mediated aetiologies. Although interpretation of such biopsies may be challenging, appreciation of the dominant pattern of injury and subsequent host response may allow for a more focused histological diagnosis in the correct clinical and endoscopic setting. This article aims to provide a systematic, methodical approach to the assessment of such biopsies, concentrating mainly on diagnoses other than inflammatory bowel disease.

Les colites microscopiques

Microscopic colitis is frequently found as a cause of chronic watery diarrhea in women after menopause. The disease can be associated with a medication side effect in half of the patients (non-steroidal anti-inflammatory drugs or proton pump inhibitors for instance). Colonic biopsies are mandatory for the diagnosis of microscopic colitis and should be performed in several locations of the colon. Management of microscopic colitis is first based on avoiding iatrogenic factors and smoking together with symptomatic treatment of diarrhea (loperamide, cholestyramine). In case of failure or severe symptoms, budesonide is the key treatment. The aim of the treatment is to achieve clinical remission, defined as less than 3 liquid stools per day, to improve quality of life. After a first course of budesonide, recurrence of diarrhea is frequent and a maintenance therapy can be prescribed for several months. In case of intolerance or refractoriness, second-line therapy (immunosuppressants, biological therapy, surgery) should be discussed in multidisciplinary team meeting.

Topographical distribution of microscopic colitis and the importance of orientation of paraffin-embedded biopsies

The diagnosis of microscopic colitis (MC) relies on specific histopathological findings in colon biopsies. The number of biopsies needed to diagnose MC remains disputed. The aim of the study was to determine the number and site of biopsies necessary for the diagnosis and the effect of perpendicular orientation when embedding the biopsies. This retrospective multicenter European study included 42 patients with a consensus diagnosis of collagenous colitis (CC), 51 patients with lymphocytic colitis (LC), and three patients with incomplete LC (LCi). The number of individual diagnostic biopsies from each patient was determined. The diagnostic rate of 744 individual biopsies from 96 patients with MC was 69.5% for the specific MC subgroup, 79.4% for MC and 93.4% for MC plus incomplete MC (MCi). The risk of missing a diagnosis of the specific subgroup of MC when analyzing four biopsies was 0.87%, decreasing to 0.18% for MC and 0.0019% for MC plus MCi. More biopsies from the right colon were diagnostic of the specific MC subgroup (76.3% vs. 64.0%, p = 0.0014). Perpendicular orientation of biopsies increased the diagnostic rate of the specific MC subgroup (73.1% vs. 65.0%, p = 0.0201). Histological changes diagnostic of MC were present in almost all biopsies from the right colon, with orientated biopsies more often being diagnostic of the specific MC subgroup. The results of this study indicate that four biopsies from the colon, rectum excluded, are sufficient to diagnose MC.

Microscopic colitis: pathophysiology and clinical management

Microscopic colitis is a chronic inflammatory disease of the colon that frequently causes chronic watery diarrhoea that might be accompanied by abdominal pain, nocturnal diarrhoea, urgency, and faecal incontinence. These symptoms lead to poor quality of life and increased health-care costs. Diagnosis relies on histological examination of multiple biopsy samples from the colonic mucosa, which often show no or only few abnormalities on endoscopy. Two major histological subtypes can be distinguished-collagenous colitis and lymphocytic colitis-but incomplete and variant forms with fewer characteristic features have been reported. Here we summarise the latest evidence on epidemiology, pathogenesis, and risk factors, and discuss established and novel therapeutic options for clinical remission. Finally, we propose an updated treatment algorithm. Further prospective studies are needed to clarify the natural history of microscopic colitis, supported by validated criteria for the assessment of disease activity.

Faecal Calprotectin and 7-α Cholestenone Levels in Microscopic Colitis: Experience from Edinburgh

Introduction

Microscopic colitis (MC) is an important cause of chronic, watery diarrhoea. Currently, there is no specific biomarker available to guide diagnosis. The use of faecal calprotectin (FCP) as a potential marker has been addressed in only a few studies. Further, bile acid malabsorption (BAM) often accompanies MC. Current practice recommends the selenium-labelled homocholic acid-taurine (SeHCAT) test, but at our centre, 7 alpha-hydroxy-4-cholesten-3-one (7αC) is used as a simpler and less expensive alternative to SeHCAT, with values over 22ng/mL indicating BAM. This study aims to evaluate the use of FCP as a biomarker in the diagnosis of MC and the role of 7αC in detecting concomitant BAM with MC.

Methods

Pathology records were retrospectively reviewed for patients diagnosed with collagenous colitis (CC) between 2000 and 2018 and lymphocytic colitis (LC) between 1995 and 2011. FCP and 7αc results, if measured within 6 months of pathological diagnosis, were extracted for analysis.

Results

Between 2000 and 2018, 646 CC cases were confirmed on histology. Of 646 patients, 147 had FCP measured; in 111 (75.5%) FCP was elevated with mean levels 238.1μg/g (SD±273.0); 140/646 had 7αC measured; 16 (11.4%) indicated BAM. Mean levels were 10.2ng/mL (SD±9.4). During a 21-year period (1995–2011), 204 LC diagnoses were made: 14/204 had FCP measured; 8 (57.1%) were elevated. Mean levels were 128.4μg/g (SD±107.7). Of 204 LC patients, 20 had 7αC measured, 5 (25%) indicating BAM. Mean levels were 13.95ng/mL (SD±9.4).

Discussion

Both CC and LC were associated with raised FCP during the diagnostic phase, supporting the potential role of its use in clinical practice. Furthermore, we present results of using 7αC in identifying BAM amongst patients with MC. In our cohort, low levels of 7αC suggest relatively low concordance of BAM with MC.

Microscopic Colitis and Risk of Inflammatory Bowel Disease in a Nationwide Cohort Study

BACKGROUND & AIMS

Microscopic colitis shares pathogenetic mechanisms with inflammatory bowel disease (IBD). We studied the association between microscopic colitis and risk of incident IBD using data from a nationwide cohort study.

METHODS

We conducted a prospective cohort study of all adults who received a diagnosis of microscopic colitis from 1990 through 2017 in Sweden and risk of incident IBD. Cases of microscopic colitis (n= 13,957) were identified through Systematized Nomenclature of Medicine codes from the ESPRESSO (Epidemiology Strengthened by histoPathology Reports in Sweden) study, which included gastrointestinal pathology reports from all of Sweden's 28 centers. Individuals with microscopic colitis were matched to 5 general population controls (n = 66,820) and to unaffected siblings (n =13,943). Cox regression was used to estimate adjusted hazard ratio (aHRs) and 95% confidence intervals (CIs).

RESULTS

Through December of 2017, we identified 323 incident cases of ulcerative colitis (UC) and 108 incident cases of Crohn's disease (CD) in patients with microscopic colitis compared with 94 UC and 42 CD cases in population comparators. Mean times from diagnosis of microscopic colitis to diagnosis of CD was 3.3 ± 3.2 years and to diagnosis of UC was 3.2 ± 3.5 years. In multivariable models, microscopic colitis was associated with an aHR of 12.6 (95% CI 8.8-18.1) for CD, 17.3 (95% CI 13.7-21.8) for UC, and 16.8 (95% CI 13.9-20.3) for IBD. The 10-year absolute excess risks of CD and UC were 0.9 (95% CI 0.7-1.1) and 2.6 (95% CI 2.2-2.9) percentage points, respectively. In sensitivity analyses, comparing patients with microscopic colitis with their unaffected siblings, the aHRs of CD and UC were 5.4 (95% CI 3.2-9.2) and 9.4 (95% CI 6.4-13.8), respectively.

CONCLUSIONS

In a population-based study in Sweden, we found a significant increase in risk of incident IBD among patients with microscopic colitis. Future studies should focus on potential mechanisms underlying these observed associations.

Usefulness of fecal calprotectin as a biomarker of microscopic colitis in a cohort of patients with chronic watery diarrhoea of functional characteristics

BACKGROUND

Information on the use of fecal markers in microscopic colitis screening is limited.

AIM

To evaluate the risk variables associated with a diagnosis of microscopic colitis including fecal calprotectin.

METHODS

Patients submitted for a colonoscopy due to chronic watery diarrhea fulfilling criteria of functional disease were evaluated. Colonic mucosa was normal but mild erythema and edema was allowed. Fecal calprotectin was analyzed. A logistic regression was used to evaluate variables associated with both raised fecal calprotectin and a diagnosis of microscopic colitis.

RESULTS

94 patients were included, 30 were diagnosed with microscopic colitis and 64 made up the control group. Median calprotectin levels were 175 (IQR, 59-325) for the microscopic colitis and 28 (IQR, 16-111) for the control group (p < 0.001). The optimal cut-off for fecal calprotectin was >100 μg/g (AUC, 0.73), with 67% sensitivity and 75% specificity. The number of drugs used ≥3 (OR, 3.9; CI, 1.4-10.4) and microscopic colitis diagnosis (OR, 6; CI, 2.2-16.3) were associated with raised calprotectin levels. Age >60 years (OR, 3.8; CI, 1.4-10.1) and calprotectin levels (OR, 5.3; CI, 2-14.1) were associated with a risk of microscopic colitis.

CONCLUSIONS

Elevated fecal calprotectin concentrations are often seen in microscopic colitis, and may be helpful in the diagnosis of women over 60 with chronic watery diarrhea.

Effects of subspecialty signout and group consensus on the diagnosis of microscopic colitis

Microscopic colitis (MC) includes lymphocytic colitis (LC) and collagenous colitis (CC). Microscopic changes are required to establish these diagnoses. While criteria exist, interobserver variability has been reported previously. This has not been evaluated in the context of subspecialty signout (SSSO) or a consensus conference. We identified 133 colon biopsies diagnosed as LC, CC, MC, or normal but with mild changes insufficient for MC. All predated the introduction of SSSO at our institution. They were independently reviewed by three gastrointestinal (GI) pathologists. Cases lacking independent consensus were reviewed by the same pathologists in consensus conference to establish a final diagnosis. Individual diagnoses were compared with the consensus diagnoses, and consensus diagnoses were compared with original diagnoses made by GI and non-GI pathologists. Consensus diagnoses were normal (n = 34), LC (n = 57), and CC (n = 42). "Normal" was the diagnosis most commonly agreed upon independently (27/34 cases, P = 0.0073 versus LC, P = 0.0172 versus CC). The reviewing pathologists independently agreed with 80%, 80%, and 94% of consensus diagnoses (κ = 0.70, 0.69, and 0.91). The group consensus agreed with the diagnoses in 49 of 58 (84%) cases originally signed out by non-GI pathologists (κ = 0.77) and in 44 of 57 (77%) cases originally signed out by GI pathologists (κ = 0.63). Good interobserver agreement exists for MC, though whether GI subspecialty training improves agreement remains unclear. Group consensus may aid in diagnosis of difficult/borderline MC cases.

Management of microscopic colitis: challenges and solutions

Microscopic colitis (MC) is a chronic inflammatory bowel disease characterized by nonbloody diarrhea in the setting of normal appearing colonic mucosa. MC has two main subtypes based on histopathologic features, collagenous colitis and lymphocytic colitis. Management of both subtypes is the same, with treatment goal of reducing the number of bowel movements and improving consistency. First-line treatment involves counseling the patient about decreasing their risk factors, like discontinuing smoking and avoiding medications with suspected association such as NSAIDs, proton pump inhibitor, ranitidine, and sertraline. Starting loperamide for immediate symptomatic relief is used as an adjunct to therapy with glucocorticoids. Budesonide is considered first-line treatment for MC given its favorable side effect profile and good efficacy, though relapse rates are high. Systemic glucocorticoids should be reserved to patients unable to take budesonide. In glucocorticoid refractory disease, medications that have been tried include cholestyramine, bismuth salicylate, antibiotics, probiotics, aminosalicylates, immunomodulators, and anti-tumor necrosis factor-alpha inhibitors. More research is needed for the creation of a systematic stepwise approach for relapsing and refractory disease.

Microscopic colitis: a population-based case series over a 9-year period in Northern Ireland

AIM

We report clinicopathological experience of microscopic colitis (MC) in a population-based case series in Northern Ireland over a 9-year period.

METHOD

The pathology laboratory information system within a large teaching centre serving two healthcare trusts was interrogated for cases coded between 2008 and 2016 as collagenous colitis (CC) or lymphocytic colitis (LC). Demographic, clinical and follow-up information was collected from healthcare records.

RESULTS

A total of 326 new diagnoses of MC were identified, an average annual incidence of 6.7 per 100 000 population. The average annual incidence of CC and LC was 5.0 and 1.7 per 100 000 population, respectively. For coding reasons it is likely that LC data are incomplete. Of 191 cases diagnosed by specialist gastrointestinal pathologists, 141 patients had CC and 50 patients had LC. Both CC and LC predominantly involved women aged 60-79. Some 15% demonstrated endoscopic abnormalities. Endoscopic sampling protocols varied widely: 30% of individuals with CC and 32% of those with LC had the right and left colon sampled separately, with histology concordant in 95% of cases. Of the 191 cases, only one case (of LC) was refractory to treatment; the rest exhibited a clinical response. Only 35 patients had follow-up endoscopy and biopsies, and three of each diagnosis showed persistent disease on histology.

CONCLUSION

Overall, CC and LC are benign conditions with similar demographics, clinical associations, management and outcomes. Separate sampling of the right and left colon is advised at colonoscopy if this diagnosis is being considered, but left colonic sampling, which can be performed at flexible sigmoidoscopy, will diagnose the vast majority of cases.

Microscopic colitis-microbiome, barrier function and associated diseases

Microscopic colitis (MC) is a chronic inflammatory bowel disease (IBD) with little in terms of endoscopic abnormalities and is frequently associated with other autoimmune diseases. The peak incidence of the disease is in middle aged or older populations, mostly females. The pathogenesis of MC is complex, multifactorial and poorly understood. Current concepts revolve around innate immunity or microbiome alterations as well as gut barrier dysfunction, all of which lead to the development of subtle inflammatory lesions in gut mucosa. The results of numerous basic and clinical studies involving molecular techniques as well as advanced endoscopic imaging revealed the important role of both intrinsic (e.g., hormonal) as well as extrinsic (e.g., NSAIDs and PPIs) factors in the modulation of gastrointestinal microbiome and MC pathogenesis. Capsule endoscopy as well confocal endomicroscopy imaging, alongside standard endoscopic techniques offer new tools in the evaluation of MC patients and allow their better stratification for novel treatment protocols based on modulation of gut microbiome and barrier function.

Collagenous colitis: Requirement for high-dose budesonide as maintenance treatment

BACKGROUND

Controlled studies show high efficacy of budesonide in inducing short-term clinical remission in collagenous colitis (CC), but relapses are common after its withdrawal.

AIM

To evaluate the need for high-dose budesonide (≥6mg/d) to maintain clinical remission in CC.

METHODS

Analysis of a multicentre retrospective cohort of 75 patients with CC (62.3±1.5years; 85% women) treated with budesonide in a clinical practice setting between 2013 and 2015. Frequency of budesonide (9mg/d) refractoriness and safety, and the need for high-dose budesonide to maintain clinical remission, were evaluated. Drugs used as budesonide-sparing, including azathioprine and mercaptopurine, were recorded. Logistic regression analysis was performed to evaluate the risk factors associated with the need for high-dose budesonide (≥6mg/d) to maintain clinical remission.

RESULTS

Budesonide induced clinical remission in 92% of patients, with good tolerance. Fourteen of 68 patients (21%; 95% CI, 13-32%) needed high-dose budesonide to maintain remission. Only intake of NSAIDs at diagnosis (OR, 8.6; 95% CI, 1.6-44) was associated with the need for high-dose budesonide in the multivariate analysis.

TREATMENT

with thiopurines was effective in 5 out of 6 patients (83%; 95% CI, 44-97%), allowing for withdrawal from or a dose decrease of budesonide.

CONCLUSIONS

One fifth of CC patients, especially those with NSAID intake at diagnosis, require high-dose budesonide (≥6mg/d) to maintain clinical remission. In this setting, thiopurines might be effective as budesonide-sparing drugs.

Macroscopic findings, incidence and characteristics of microscopic colitis in a large cohort of patients from the United Kingdom

OBJECTIVE

Microscopic colitis (MC) is classically associated with normal or near-normal endoscopic appearances. However, non-specific macroscopic findings have been described, the importance of biopsy location for confirming a diagnosis of MC is unclear, and reported incidence data from the United Kingdom are limited. This study was designed to assess macroscopic features, incidence, demographics, and location and positivity of biopsy samples in MC.

MATERIALS AND METHODS

Retrospective, cross-sectional study of individuals with newly diagnosed MC.

RESULTS

From 2010 to 2015, 540 cases of MC were reported. Macroscopic findings occurred in 16.5% (n = 89) cases, with trends towards increased frequency of ulceration or linear scarring in collagenous colitis (CC). The mean incidence of MC was 11.3 per 100,000 population/year, including 291 (53.9%) with CC (incidence 6.1 per 100,000/year), 203 (37.6%) with lymphocytic colitis (incidence 4.2 per 100,000/year) and 46 (8.5%) with MC, not otherwise specified. Most individuals were female (70.2%). Common features in patients with MC included symptom duration <6 months, weight loss, abdominal pain and use of proton pump inhibitors, statins, or non-steroidal anti-inflammatory drugs. In individuals with right- and left-sided biopsies taken, 98.2% had diagnostic features in both. However, rectal biopsies were only positive in 88.7%.

CONCLUSIONS

One in six patients with MC demonstrated distinct macroscopic findings at colonoscopy. Our data confirm a female preponderance in MC, a relatively short symptom duration and use of certain drugs as common features. Both right- and left-sided biopsies were frequently positive, suggesting flexible sigmoidoscopy and biopsy could confirm a diagnosis in certain individuals.

Drug Exposure and the Risk of Microscopic Colitis: A Critical Update

A variety of luminal antigens, including a wide range of drugs, have been associated with the still little-known pathophysiology of microscopic colitis (MC), with variable evidence suggesting causality. This article aims to review the aspects related to drugs as potential triggers of MC; to discuss the most commonly identified associations between drugs and MC; and to analyze the limitations of the studies currently available. A literature search was performed in PubMed combining the search terms 'drug exposure', 'drug consumption', and 'risk factors' with 'microscopic colitis', 'lymphocytic colitis', and 'collagenous colitis', with no language restrictions. Reference lists of retrieved documents were also reviewed. A handful of case-control studies have demonstrated significant associations between some commonly used drugs and a higher risk of developing MC. No universally accepted criteria for establishing cause-effect relationships in adverse reactions to drugs are available, but several methods that can be applied to MC, can provide degrees of the likelihood of an association. A high probability imputation in the development of MC as a drug adverse effect has only been demonstrated for individual cases by applying chronological (challenge, de-challenge, and relapse with re-challenge) and semiological criteria. Several case-control studies have shown significant associations between exposure to drugs and MC, but the variability in their design, the reference populations used, and the definitions for drug exposure considered require specific analyses. It can be concluded that drug exposure and MC as a likely cause-effect relationship has only been described for a handful of drugs and in individual cases.

Biomarkers and Microscopic Colitis: An Unmet Need in Clinical Practice

One of the most common causes of chronic diarrhea is ascribed to microscopic colitis (MC). MC is classified in subtypes: collagenous colitis (CC) and lymphocytic colitis (LC). Patients with MC report watery, non-bloody diarrhea of chronic course, abdominal pain, weight loss, and fatigue that may impair patient's health-related quality of life. A greater awareness, and concomitantly an increasing number of diagnoses over the last years, has demonstrated that the incidence and prevalence of MC are on the rise. To date, colonoscopy with histological analysis on multiple biopsies collected along the colon represents the unique accepted procedure used to assess the diagnosis of active MC and to evaluate the response to medical therapy. Therefore, the emerging need for less-invasive procedures that are also rapid, convenient, standardized, and reproducible, has encouraged scientists to turn their attention to the identification of inflammatory markers and other molecules in blood or feces and within the colonic tissue that can confirm a MC diagnosis. This review gives an update on the biomarkers that are potentially available for the identification of inflammatory activity, related to CC and LC.

Towards a new paradigm of microscopic colitis: Incomplete and variant forms

Microscopic colitis (MC) is a chronic inflammatory bowel disease that has emerged in the last three decades as a leading cause of chronic watery diarrhoea. MC classically includes two main subtypes: lymphocytic colitis (LC) and collagenous colitis (CC). Other types of histopathological changes in the colonic mucosa have been described in patients with chronic diarrhoea, without fulfilling the conventional histopathological criteria for MC diagnosis. Whereas those unclassified alterations remained orphan for a long time, the use of the term incomplete MC (MCi) is nowadays universally accepted. However, it is still unresolved whether CC, LC and MCi should be considered as one clinical entity or if they represent three related conditions. In contrast to classical MC, the real epidemiological impact of MCi remains unknown, because only few epidemiological studies and case reports have been described. MCi presents clinical characteristics indistinguishable from complete MC with a good response to budesonide and cholestiramine. Although a number of medical treatments have been assayed in MC patients, currently, there is no causal treatment approach for MC and MCi, and only empirical strategies have been performed. Further studies are needed in order to identify their etiopathogenic mechanisms, and to better classify and treat MC.

Successful use of adalimumab in patient with treatment-refractory microscopic colitis

A 50-year-old woman with treatment-refractory lymphocytic colitis was diagnosed with ankylosing spondylitis. She was started on adalimumab injections which significantly improved her stool frequency and consistency and, consequently, her quality of life.

High risk of drug-induced microscopic colitis with concomitant use of NSAIDs and proton pump inhibitors

BACKGROUND

Microscopic colitis (MC) is a chronic bowel disorder characterised by watery diarrhoea. Nonsteroidal anti-inflammatory drugs (NSAIDs), proton pump inhibitors (PPIs), selective serotonin reuptake inhibitors (SSRIs) and statins have been associated with MC. However, underlying mechanisms remain unclear.

AIM

To study the association between exposure to these drugs and MC, with attention to time of exposure, duration, dosage and combined exposure, and to test hypotheses on underlying pharmacological mechanisms.

METHODS

A case-control study was conducted using the British Clinical Practice Research Datalink. MC cases (1992-2013) were matched to MC-naive controls on age, sex and GP practice. Drug exposure was stratified according to time of exposure, duration of exposure or dosage. Conditional logistic regression analysis was applied to calculate adjusted odds ratios (AORs).

RESULTS

In total, 1211 cases with MC were matched to 6041 controls. Mean age was 63.4 years, with 73.2% being female. Current use of NSAIDs (AOR 1.86, 95% CI 1.39-2.49), PPIs (AOR 3.37, 95% CI 2.77-4.09) or SSRIs (AOR 2.03, 95% CI 1.58-2.61) was associated with MC compared to never or past use. Continuous use for 4-12 months further increased the risk of MC. Strongest associations (fivefold increased risk) were observed for concomitant use of PPIs and NSAIDs. Statins were not associated with MC.

CONCLUSIONS

Current exposure to NSAIDs, PPIs or SSRIs and prolonged use for 4-12 months increased the risk of MC. Concomitant use of NSAIDs and PPIs showed the highest risk of MC. Acid suppression related dysbiosis may contribute to the PPI effect, which may be exacerbated by NSAID-related side-effects.

Systematic review with meta-analysis: diagnostic overlap of microscopic colitis and functional bowel disorders

BACKGROUND

Microscopic colitis shares certain common clinical manifestations with functional bowel disorders, especially diarrhoea-dominant irritable bowel syndrome (IBS) and functional diarrhoea. However, the exact relationship between microscopic colitis and functional bowel disorders has not been systematically assessed.

AIM

To conduct a systematic review and meta-analysis on the diagnostic overlap between functional bowel disorders and microscopic colitis.

METHODS

We searched MEDLINE, EMBASE and SCOPUS databases, as well as the abstract books of the major gastroenterology meetings, to investigate the prevalence of microscopic colitis among patients with functional bowel disorders (considering all subtypes of both disorders) and vice versa. Data were pooled with a random-effects model.

RESULTS

Of 227 references identified, data were collected from 26 studies and a total of 5,099 adult patients. The pooled prevalence any type of functional bowel disorders in patients who present diagnostic criteria of microscopic colitis was 39.1% (95% CI: 22.8-56.6%; I² : 97%) and was higher for lymphocytic colitis than for collagenous colitis (40.7% vs. 28.4%, respectively; P = 0.58). The prevalence of microscopic colitis in functional bowel disorders patients was 7% (95% CI: 3.6-11.4%), reaching 9.8% (95% CI: 4.4-17.1%; I² : 95%) in patients exhibiting diarrhoea-dominant IBS, nonsignificantly higher than microscopic colitis rates among patients with constipation-dominant IBS (1.3%) or mixed-dominant IBS (1.9%).

CONCLUSIONS

There is a significant overlap of symptoms between microscopic colitis and functional bowel disorders, especially in diarrhoeal subtypes. The high proportion of microscopic colitis among diarrhoea-dominant functional syndromes should serve as a call for more active diagnosis in selected patients.