Prevalence and incidence of microscopic colitis in patients with diarrhoea of unknown aetiology in a region in central Spain

Number of intraepithelial lymphocytes and presence of a subepithelial band in normal colonic mucosa differs according to stainings and evaluation method

Chronic watery diarrhea is a frequent symptom. In approximately 10% of the patients, a diagnosis of microscopic colitis (MC) is established. The diagnosis relies on specific, but sometimes subtle, histopathological findings. As the histology of normal intestinal mucosa vary, discriminating subtle features of MC from normal tissue can be challenging and therefore auxiliary stainings are increasingly used. The aim of this study was to determine the variance in number of intraepithelial lymphocytes (IELs) and presence of a subepithelial band in normal ileum and colonic mucosa, according to different stains and digital assessment. Sixty-one patients without diarrhea referred to screening colonoscopy due to a positive feacal blood test and presenting with endoscopically normal mucosa were included. Basic histological features, number of IELs, and thickness of a subepithelial band was manually evaluated and a deep learning-based algorithm was developed to digitally determine the number of IELs in each of the two compartments; surface epithelium and cryptal epithelium, and the density of lymphocytes in the lamina propria compartment. The number of IELs was significantly higher on CD3-stained slides compared with slides stained with Hematoxylin-and-Eosin (HE) (p<0.001), and even higher numbers were reached using digital analysis. No significant difference between right and left colon in IELs or density of CD3-positive lymphocytes in lamina propria was found. No subepithelial band was present in HE-stained slides while a thin band was visualized on special stains. Conclusively, in this cohort of prospectively collected ileum and colonic biopsies from asymptomatic patients, the range of IELs and detection of a subepithelial collagenous band varied depending on the stain and method used for assessment. As assessment of biopsies from patients with diarrhea constitute a considerable workload in the pathology departments digital image analysis is highly desired. Knowledge provided by the present study highlight important differences that should be considered before introducing this method in the clinic.

Diagnostic yield of colonoscopy for organic disease in irritable bowel syndrome and its risk factors: A meta-analysis

BACKGROUND

Colonoscopy is commonly performed in patients with irritable bowel syndrome (IBS) to rule out organic disease. We performed a meta-analysis to assess the prevalence of organic disease detected at colonoscopy in IBS and its potential risk factors.

METHODS

Medline, Embase, and Web of Science were searched through January 2022. Observational studies that reported diagnostic yield of colonoscopy for organic disease including colorectal cancer (CRC), inflammatory bowel disease (IBD), or microscopic colitis (MC) in adult IBS patients were eligible. Pooled prevalence and risk difference (RD) with 95% confidence intervals (CIs) were calculated.

RESULTS

Of 2490 citations identified, 12 studies were eligible containing 28,630 patients with IBS undergoing colonoscopy. Pooled prevalence of CRC, IBD, and MC in IBS was 0.78%, 4.48%, and 2.35%, respectively. No difference in the yield for CRC, IBD, and MC was seen between IBS and non-IBS patients. CRC was rare in IBS patients without alarm symptoms or younger than 40 years (<0.1%). Pooled Prevalence of CRC (2.47% vs. 0.11%; RD 2.57%, 95% CI 0.37%-4.78%) and IBD (8.86% vs. 4.25%; RD 10.75%, 95% CI 4.81%-16.68%) was significantly higher in IBS patients with alarm symptoms compared with those without. IBD and MC were more likely to be detected at colonoscopy in IBS-D compared with IBS-C. The prevalence of CRC and MC was higher in IBS patients with older age than younger age.

CONCLUSION

We provide the first pooled estimate of yield of colonoscopy in IBS and its risk factors, which may be used to inform clinical decision and support guidelines.

The Epidemiology of Microscopic Colitis in Olmsted County, Minnesota: Population-Based Study From 2011 to 2019

BACKGROUND & AIMS

Epidemiologic studies from Europe and North America have reported an increasing incidence of microscopic colitis (MC) in the late 20th century, followed by a plateau. This population-based study assessed recent incidence trends and the overall prevalence of MC over the past decade.

METHODS

Residents of Olmsted County, MN, diagnosed with collagenous colitis (CC) or lymphocytic colitis (LC) between January 1, 2011, and December 31, 2019 were identified using the Rochester Epidemiology Project. Clinical variables were abstracted by chart review. Incidence rates were age- and sex-adjusted to the 2010 US population. Associations between incidence and age, sex, and calendar periods were evaluated using Poisson regression analyses.

RESULTS

A total of 268 incident cases of MC were identified with a median age at diagnosis of 64 years (range, 19-90 y); 207 (77%) were women. The age- and sex-adjusted incidence of MC was 25.8 (95% CI, 22.7-28.9) cases per 100,000 person-years. The incidence of LC was 15.8 (95% CI, 13.4-18.2) and CC was 9.9 (95% CI, 8.1-11.9) per 100,000 person-years. A higher MC incidence was associated with increasing age and female sex (P < .01). There was no significant trend in age- and sex-adjusted incidence rate over the study period (P = .92). On December 31, 2019, the prevalence of MC, LC, and CC (including cases diagnosed before 2011) was 246.2, 146.1, and 100.1 per 100,000 persons, respectively.

CONCLUSIONS

The incidence of MC and its subtypes was stable between 2011 and 2019, but its prevalence was higher than in previous periods. The incidence of MC continues to be associated with increasing age and female sex.

Microscopic Colitis in Denmark: Regional Variations in Risk Factors and Frequency of Endoscopic Procedures

OBJECTIVE

Microscopic colitis [MC], encompassing collagenous colitis [CC] and lymphocytic colitis [LC], is an increasingly prevalent gastrointestinal disease with an unknown aetiology. Previous research has reported significant differences in the incidence of MC within Denmark, with the lowest incidence found in the most populated region [Capital Region of Denmark]. Our aim was to elucidate the causes of these regional differences.

DESIGN

All incident MC patients [n = 14 302] with a recorded diagnosis of CC [n = 8437] or LC [n = 5865] entered in The Danish Pathology Register between 2001 and 2016 were matched to 10 reference individuals [n = 142 481]. Information regarding drug exposure, including proton pump inhibitors [PPIs], selective serotonin reuptake inhibitors [SSRIs], statins, and nonsteroidal anti-inflammatory drugs [NSAIDs], were retrieved from The Danish National Prescription Registry. Information regarding endoscopy rate, smoking-related diseases, and immune-mediated inflammatory diseases were acquired from The Danish National Patient Registry.

RESULTS

Smoking, immune-mediated inflammatory diseases, exposure to PPIs, SSRIs, statins, and NSAIDs were significantly associated with MC in all Danish regions. The association between drug exposure and MC was weakest in the Capital Region of Denmark with an odds ratio of 1.8 (95% confidence interval [CI]: 1.61-2.01). The relative risk of undergoing a colonoscopy with biopsy was significantly increased in sex- and age-matched controls in all regions compared with controls from the Capital Region of Denmark, with the greatest risk found in the Region of Southern Denmark, 1.37 [95% CI: 1.26-1.50].

CONCLUSIONS

The cause of the regional differences in MC incidence in Denmark seems to be multifactorial, including variations in disease awareness and distribution of risk factors.

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.

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.

Pain Severity Correlates With Biopsy-Mediated Colonic Afferent Activation But Not Psychological Scores in Patients With IBS-D

INTRODUCTION

Despite heterogeneity, an increased prevalence of psychological comorbidity and an altered pronociceptive gut microenvironment have repeatedly emerged as causative pathophysiology in patients with irritable bowel syndrome (IBS). Our aim was to study these phenomena by comparing gut-related symptoms, psychological scores, and biopsy samples generated from a detailed diarrhea-predominant IBS patient (IBS-D) cohort before their entry into a previously reported clinical trial.

METHODS

Data were generated from 42 patients with IBS-D who completed a daily 2-week bowel symptom diary, the Hospital Anxiety and Depression score, and the Patient Health Questionnaire-12 Somatic Symptom score and underwent unprepared flexible sigmoidoscopy. Sigmoid mucosal biopsies were separately evaluated using immunohistochemistry and culture supernatants to determine cellularity, mediator levels, and ability to stimulate colonic afferent activity.

RESULTS

Pain severity scores significantly correlated with the daily duration of pain (r = 0.67, P < 0.00001), urgency (r = 0.57, P < 0.0005), and bloating (r = 0.39, P < 0.05), but not with psychological symptom scores for anxiety, depression, or somatization. Furthermore, pain severity scores from individual patients with IBS-D were significantly correlated (r = 0.40, P < 0.008) with stimulation of colonic afferent activation mediated by their biopsy supernatant, but not with biopsy cell counts nor measured mediator levels.

DISCUSSION

Peripheral pronociceptive changes in the bowel seem more important than psychological factors in determining pain severity within a tightly phenotyped cohort of patients with IBS-D. No individual mediator was identified as the cause of this pronociceptive change, suggesting that nerve targeting therapeutic approaches may be more successful than mediator-driven approaches for the treatment of pain in IBS-D.

Microscopic colitis and its associations with complications observed in classic inflammatory bowel disease: a systematic review

Objectives: Crohn's disease and ulcerative colitis are associated with an increased risk to develop anemia, cutaneous diseases, liver diseases, malignancy, osteoporosis, rheumatic diseases, thromboembolism and uveitis. The association between these diseases and microscopic colitis (MC) is not known. The aim of the present systematic review was to examine associations between MC and diseases observed in association with Crohn's disease and ulcerative colitis.Material and methods: According to the review protocol, original articles which described the prevalence of abovementioned diseases in relation to MC, were searched for in PubMed, Embase and Web of Science.Results: After exclusion of duplicates, 928 articles remained. Based on relevancy of their title, abstract or type of article, 16 articles were ordered in full text and after assessment, nine articles could be included in the review. A second research strategy with individual diseases rendered further two articles. Seven articles covered malignancy/neoplasia, where four showed no association with malignancy and three a reduced association compared with controls. Four articles covering rheumatic diseases showed an association between these diseases and MC. One study showed an association between MC and osteoporosis, whereas one did not. One study showed an association between MC and cutaneous diseases, whereas anemia, eye diseases and thromboembolism showed no associations.Conclusions: Due to short follow-up time in small studies, with selection bias due to exclusion of former or prevalent malignancy in an older population, no conclusions can be drawn concerning the true association between MC and malignancy. Rheumatic diseases seem to be associated with MC.

Over 90% of cases of Microscopic Colitis can be diagnosed by performing a short colonoscopy

AIMS

To determinate the topographical distribution of key diagnostic histological features of lymphocytic colitis (LC) and collagenous colitis (CC) and to establish what correlations may exist between the histological findings and the causes and severity of MC.

PATIENTS AND METHODS

Patients with MC were included in a prospective multicentre French study from September 2010 to October 2012. MC was diagnosed by performing total colonoscopy with multiple biopsies of the rectum and colon collected in separate jars and analyzed separately for each site (descending and sigmoid colon, transverse colon, ascending colon). CC was defined as a subepithelial collagen layer>10μm thick and LC as an intraepithelial lymphocyte (IEL) count>20 lymphocytes per 100 epithelial cells without any associated thickening of the subepithelial collagen.

RESULTS

Ninety-five patients, 69 with LC 26 and with CC, were included in the analysis. The sensitivity of the biopsies for diagnosing MC was maximum in the transverse colon and minimum in the rectum. Rectal and left colonic biopsies resulted in the diagnosis of CC and CL in 93% and 94% of cases, respectively. All the remaining cases of MC were diagnosed by performing additional biopsies beyond the splenic flexure. In patients with LC, a higher rate of IELs was associated with the absence of abdominal pain (P=0.01) and a shorter duration of diarrhea (P=0.001). In patients with CC, a lower level of collagen thickness in the basement membrane was associated with the presence of an autoimmune disease (P=0.02).

CONCLUSION

More than 90% of cases of microscopic colitis were diagnosed in this study by performing rectal and left colonic biopsies.

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.

Chronic Diarrhea: Diagnosis and Management

Chronic diarrhea is a common problem affecting up to 5% of the population at a given time. Patients vary in their definition of diarrhea, citing loose stool consistency, increased frequency, urgency of bowel movements, or incontinence as key symptoms. Physicians have used increased frequency of defecation or increased stool weight as major criteria and distinguish acute diarrhea, often due to self-limited, acute infections, from chronic diarrhea, which has a broader differential diagnosis, by duration of symptoms; 4 weeks is a frequently used cutoff. Symptom clusters and settings can be used to assess the likelihood of particular causes of diarrhea. Irritable bowel syndrome can be distinguished from some other causes of chronic diarrhea by the presence of pain that peaks before defecation, is relieved by defecation, and is associated with changes in stool form or frequency (Rome criteria). Patients with chronic diarrhea usually need some evaluation, but history and physical examination may be sufficient to direct therapy in some. For example, diet, medications, and surgery or radiation therapy can be important causes of chronic diarrhea that can be suspected on the basis of history alone. Testing is indicated when alarm features are present, when there is no obvious cause evident, or the differential diagnosis needs further delineation. Testing of blood and stool, endoscopy, imaging studies, histology, and physiological testing all have roles to play but are not all needed in every patient. Categorizing patients after limited testing may allow more directed testing and more rapid diagnosis. Empiric antidiarrheal therapy can be used to mitigate symptoms in most patients for whom a specific treatment is not available.

Intestinal anti-inflammatory effect of the rhizome extracts of Menispermum dauricum DC. on trinitrobenzene sulfonic acid induced ulcerative colitis in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Menispermum dauricum DC., commonly known as "Bei Dou Gen" (BDG) in China, has been used extensively in folk medicine to treat inflammatory diseases, especially intestinal inflammations such as enteritis and dysentery, and in pharyngitis, tonsillitis, rheumatism and bronchitis. Although previous studies showed that BDG has anti-inflammatory activities, its effects on ulcerative colitis (UC) have not yet been explored.

AIM OF THE STUDY

To investigate the intestinal anti-inflammatory effect of the rhizome extracts of Menispermum dauricum DC. on UC model induced by 2,4,6-trinitrobenzene sulfonic acid (TNBS) in mice.

MATERIALS AND METHODS

UC in mice was induced by colonic administration with TNBS. BDG (100, 200 and 400mg/kg/day) and sulfasalazine (500mg/kg/day) were administered orally for 7 consecutive days. The inflammatory degree was assessed by gross appearance, macroscopic and histological analysis, and accumulation of myeloperoxidase (MPO) activity. Pro-inflammatory mediators, including tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6, were determined by enzyme-linked immunoassay. The expression of cyclooxygenase (COX)-2 was assessed by immunohistochemical analysis.

RESULTS

Treatment with different doses of BDG significantly ameliorated macroscopic damage and histological changes, reduced the accumulation of MPO activity, depressed serum and colonic tissue levels of TNF-α, IL-1β and IL-6 in a dose-dependent manner. In addition, administration of BDG effectively reduced COX-2 overexpression in colon.

CONCLUSION

We demonstrated for the first time that BDG possessed marked intestinal anti-inflammatory effect in TNBS induced colitis in mice, which might be related to the reduction of up-regulated productions and expressions of pro-inflammatory mediators, suggesting that it may have beneficial use for the treatment of inflammatory bowel disease.

Prevalence and Natural History of Microscopic Colitis: A Population-Based Study With Long-term Clinical Follow-up in Terrassa, Spain

BACKGROUND AND AIMS

Few studies have assessed the prevalence of microscopic colitis (MC) and the natural history of this disease is not well known. The aim of this study was to evaluate the prevalence rate of MC, the burden of disease in terms of loss of health and the long-term natural history of MC in a population-based cohort study.

METHODS

Cases were obtained from the pathology department registry Hospital Universitari Mutua Terrassa. Belonging to the catchment area, maintaining residence in that area, and being alive on August 31, 2014 were confirmed for each case. Adjusted prevalence rates were calculated. Current active drugs for MC and diarrhoea persistence in every patient were recorded.

RESULTS

The prevalence rate of MC was 107 per 10(5) inhabitants. The rate of patients with active disease, i.e. those representing the true burden of the disease in terms of loss of health, was 31 per 10(5) inhabitants. After a follow-up of 7.8±0.38 years from diagnosis, 75% of the patients experienced prolonged disease remission, defined as clinical remission without requiring drugs for 1 year or more. The only variable associated with prolonged MC remission was how clinical remission was achieved (spontaneous 93.3%, drug-induced, 60.5%; odds ratio 8.4, 95% confidence interval 2.7-26).

CONCLUSIONS

The rate of patients with MC and active disease, which represents the true disease burden in terms of loss of health, is low. Most patients with MC experience prolonged disease remission, with key differences between spontaneous and drug-induced clinical remission.

Irritable Bowel Syndrome and Microscopic Colitis: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

Patients with microscopic colitis and patients with irritable bowel syndrome (IBS) present with similar symptoms. We examined the association between IBS and microscopic colitis in a systematic review and meta-analysis.

METHODS

We searched the medical literature to identify cross-sectional surveys or case-control studies reporting the association between microscopic colitis and IBS in 50 or more unselected adult patients. We recorded the prevalence of IBS symptoms in patients with histologically confirmed microscopic colitis, or the prevalence of histologically confirmed microscopic colitis in patients with IBS. Data were pooled using a random-effects model; the association between microscopic colitis and IBS was summarized using an odds ratio (OR) with a 95% confidence interval (CI).

RESULTS

The search strategy identified 3926 citations, of which 10 were eligible for our analysis. The pooled prevalence of IBS in patients with microscopic colitis was 33.4% (95% CI, 31.5%-40.6%), but was not significantly higher in patients with microscopic colitis than in patients with diarrhea (OR, 1.39; 95% CI, 0.43-4.47). In 3 cross-sectional surveys, the pooled OR for microscopic colitis in participants with IBS, compared with other patients with diarrhea, was 0.68 (95% CI, 0.44-1.04). In 4 case-control studies the prevalence of IBS in patients with microscopic colitis was significantly higher than in asymptomatic controls (OR, 5.16; 95% CI, 1.32-20.2).

CONCLUSIONS

Based on a meta-analysis, one third of patients with microscopic colitis reported symptoms compatible with IBS, but the prevalence of IBS was no higher than in other patients with diarrhea. The odds of microscopic colitis were no higher in patients with IBS compared with other patients with diarrhea. The value of routine colonoscopy and biopsy to exclude microscopic colitis in patients with typical IBS symptoms, unless other risk factors or alarm symptoms are present, remains uncertain.

Fecal calprotectin: a marker for clinical differentiation of microscopic colitis and irritable bowel syndrome

Background

The aim of this study is to compare two methods for measuring fecal calprotectin (FC) concentration and to evaluate the possibility of differentiation between microscopic colitis (MC) and irritable bowel syndrome (IBS).

Methods

Twenty-three patients with MC (six patients with active disease and 17 patients retested in remission) and 20 patients with IBS were prospectively included in this study. Active disease state of MC was determined by clinical symptoms of >3 bowel movements per day and histological correlate. All patients underwent ileocolonoscopy, including segmental biopsy samples for histology. FC levels in stool samples were analyzed using a rapid test system (Quantum Blue^®) and an enzyme-linked immunosorbent assay (ELISA).

Results

FC levels were significantly higher in patients with active MC (median 48 μg/g [23–106]) compared to patients with IBS (median 2 μg/g [1–111.83]), P=0.0001 using an ELISA. FC level of patients with MC in remission was 22 μg/g (1–106.4), which is similar to those identified in patients with IBS. The difference of FC levels between active MC and IBS was not detected by the FC rapid test (P=0.635).

Discussion

FC levels might serve as parameter for differentiation between patients with active MC and IBS. Since there is no surrogate marker available at present for MC, FC appears to be a candidate for differentiating MC from IBS.

Conclusion

High FC levels, which were analyzed by ELISA, are a potential marker for patients with active MC compared to those with IBS. The FC rapid test was less suitable for this purpose.

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.

Advances for improved diagnosis of microscopic colitis in patients with chronic diarrhoea

Microscopic colitis is a generic term that includes 2 main forms, collagenous colitis and lymphocytic colitis, and describes a form of inflammatory bowel disease with a chronic and relapsing course. The incidence of microscopic colitis is between 2 and 8 times higher in women than in men, although age, more than sex, increases the risk of collagenous colitis (odds ratio [OR] 8.3 for age ≥65 vs. <65 and OR 2.8 for women). The main symptom is chronic non-bloody watery diarrhoea. Other common symptoms include abdominal pain (50%-70%), with the result that many patients with microscopic colitis meet criteria for irritable bowel syndrome. Colonoscopy with multiple colonic biopsies is currently recommended, as histological changes are the main characteristic feature. The colonic mucosa is macroscopically normal, although certain minimal endoscopic abnormalities have been described.

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

BACKGROUND

Microscopic colitis (MC) is an underdiagnosed inflammatory bowel disease.

AIM

To develop an evidence-based clinical practice guide on MC current concepts.

METHODS

Literature search was done on the Cochrane Library, EMBASE and MEDLINE electronic databases, which were consulted covering the period up until March 2015. Work groups were selected for each of the reviewed topics, with the purpose of drafting the initial statements and recommendations. They subsequently underwent a voting process based on the Delphi method. Each statement/recommendation was accompanied by the result of the vote the level of evidence, and discussion of the corresponding evidence. The grade of recommendation (GR) using the GRADE approach was established for diagnosis and treatment recommendations.

RESULTS

Some key statements and recommendations are: advancing age increases the risk of developing MC, mainly in females. The symptoms of MC and IBS-D may be similar. If MC is suspected, colonoscopy taking biopsies is mandatory. Treatment with oral budesonide is recommended to induce clinical remission in patients with MC. Oral mesalazine is not recommended in patients with collagenous colitis for the induction of clinical remission. The use of anti-TNF-alpha drugs (infliximab, adalimumab) is recommended for the induction of remission in severe cases of MC that fail to respond to corticosteroids or immunomodulators, as an alternative to colectomy.

CONCLUSIONS

This is the first consensus paper on MC based on GRADE methodology. This initiative may help physicians involved in care of these patients in taking decisions based on evidence.

Ethnic Distribution of Microscopic Colitis in the United States

BACKGROUND

A large electronic database of histopathology reports was used to study the ethnic distribution of microscopic colitis in the United States.

METHODS

Miraca Life Sciences is a nation-wide pathology laboratory that receives biopsy specimens submitted by 1500 gastroenterologists distributed throughout the United States. In a case-control study, the prevalence of microscopic colitis in 4 ethnic groups (East Asians, Indians, Hispanics, and Jews) was compared with that of all other ethnic groups (composed of American Caucasians and African Americans), serving as reference group.

RESULTS

A total of 11,706 patients with microscopic colitis were included in the analysis. In all ethnic groups alike, microscopic colitis was more common in women than men (78% versus 22%, odds ratio = 3.40, 95% confidence interval = 3.26-3.55). In all ethnic groups, the prevalence of microscopic colitis showed a continuous age-dependent rise. Hispanic patients with microscopic colitis were on average younger than the reference group (59.4 ± 16.2 years versus 64.2 ± 13.8 years, P < 0.001). Jewish patients with microscopic colitis were slightly older than the reference group (65.6 ± 13.4 years, P = 0.015). Compared with the reference group (prevalence = 1.20%), microscopic colitis was significantly less common among patients of Indian (prevalence = 0.28%, odds ratio = 0.32, 95% confidence interval = 0.13-0.65), East Asian (0.22%, 0.19, 0.14-0.26), or Hispanic decent (0.48%, 0.40, 0.36-0.45) and significantly more common among Jewish patients (1.30%, 1.10, 1.01-1.21).

CONCLUSIONS

Microscopic colitis shows striking variations of its occurrence among different ethnic groups. Such variations could point at differences in the exposure to environmental risk factors.

Incidence, prevalence, and temporal trends of microscopic colitis: a systematic review and meta-analysis

OBJECTIVES

A systematic review and meta-analysis was conducted to provide an accurate estimate of the incidence rate of microscopic colitis (MC) and to assess the association between medication use and the risk of MC.

METHODS

We searched Medline, Embase, and Institute for Scientific Information (ISI) Web of Science up to 26 September 2014 to identify published epidemiological studies of MC. The pooled incidence rate, female-to-male incidence rate ratio, age at diagnosis, prevalence, as well as odds ratios (ORs) of MC in association with medication use were calculated using a fixed-effects model or a random-effects model.

RESULTS

Of the 1,972 citations retrieved, 25 studies were included. Pooled incidence rate of collagenous colitis (CC) was 4.14 (95% confidence interval (CI) 2.89-5.40) per 100,000 person-years and 4.85 (95% CI, 3.45-6.25) for lymphocytic colitis (LC). The female-to-male incidence rate ratios were 3.05 (95% CI 2.92-3.19) for CC and 1.92 (95% CI 1.53-2.31) for LC. The median age at diagnosis for CC was 64.9 (range, 57.03-72.78) years, similar to LC (median 62.18, range 53.99-70.38). Furthermore, the incidence rate of MC increased with rising age. A steadily increasing trend of incidence rate for both CC and LC was observed before 2000; however, the incidence rate since then has become stable in the United States, Sweden, and Spain. An increased risk of MC was associated with the use of proton pump inhibitors (PPIs) and selective serotonin reuptake inhibitors (SSRIs) (OR 2.68, 95% CI 1.73-4.17 and OR 2.41, 95% CI 1.64-3.53, respectively).

CONCLUSIONS

MC is a common disease process. Female gender, increased age, and the use of PPIs and SSRIs are associated with a significantly increased risk of developing MC. Further work is needed to evaluate reported data from developing countries and to elucidate the biologic mechanisms behind the risk factors for MC.

Incidence of microscopic colitis in the Netherlands. A nationwide population-based study from 2000 to 2012

BACKGROUND

Incidence rates of microscopic colitis are mainly based on regional data from a limited number of countries. To evaluate geographical differences and changes over time, more nationwide incidence rates are needed.

AIMS

The aim of this retrospective study was to assess the incidence rate of microscopic colitis in the Netherlands in a nationwide cohort.

METHODS

A search was performed in the Dutch pathology registry, covering records of all approximately 16.5 million inhabitants. Incident cases were defined as a first diagnosis of microscopic colitis (collagenous or lymphocytic colitis) between 2000 and 2012.

RESULTS

In total, 7228 incident cases were identified with a mean annual incidence rate of 3.4 per 100,000 person years. Collagenous colitis was present in 3741 cases and lymphocytic colitis in 2718 cases, with a mean annual incidence rate of 1.8 and 1.3 per 100,000 person years, respectively. Remaining 769 cases were described as undefined microscopic colitis. Collagenous and lymphocytic colitis incidence rates increased significantly over time (p<0.001) with a male:female ratio of 1:3 and 1:2, respectively.

CONCLUSION

The Dutch mean annual incidence rates of collagenous and lymphocytic colitis were considerably lower than previously reported by other countries. However, incidence rates increased gradually over time, with a clear female predominance.

Microscopic colitis: a review

AIM

In recent years, microscopic colitis has been increasingly diagnosed. This review was carried out to evaluate demographic factors for microscopic colitis and to perform a systematic assessment of available treatment options.

METHOD

Relevant publications up to December 2013 were identified following searches of PubMed and Google Scholar using the key words 'microscopic colitis', 'collagenous colitis' and 'lymphocytic colitis'. Two-hundred and forty-eight articles were identified.

RESULTS

The term microscopic colitis includes lymphocytic colitis and collagenous colitis. Both have common clinical symptoms but are well defined histopathologically. The clinical course is usually benign, but serious complications, including death, may occur. A peak incidence from 60 to 70 years of age with a female preponderance is observed. Although most cases are idiopathic, associations with autoimmune disorders, such as coeliac disease and hypothyroidism, as well as with exposure to nonsteroidal anti-inflammatory drugs and proton-pump inhibitors, have been observed. The incidence and prevalence of microscopic colitis is rising and good-quality epidemiological research is needed. Treatment is currently largely based on anecdotal evidence and on results from limited clinical trials of budesonide. Long-term follow-up of these patients is not well established.

CONCLUSION

The review synthesizes work on the definition of microscopic colitis and the relationship between collagenous and lymphocytic colitis. It reviews the international epidemiology and work on aetiology. In addition, it critically considers the efficacy of a range of treatments.

Microscopic colitis or functional bowel disease with diarrhea: a French prospective multicenter study

OBJECTIVES

To describe the characteristics of a cohort of patients with microscopic colitis (MC; lymphocytic (LC) or collagenous (CC) colitis) and to compare them with patients with functional bowel disorder with diarrhea (FBD-D).

METHODS

Between September 2010 and June 2012, patients fulfilling the following inclusion criteria were prospectively included in 26 centers in France: (i) having at least three bowel movements daily with change in stool consistency; (ii) duration of abnormal bowel habit >4 weeks; and (iii) normal or near-normal colonoscopy. Each patient underwent a colonoscopy and colonic biopsies. We compared the demographic, clinical, biological, and etiological characteristic of patients with MC (CC and LC) with those of control patients with FBD-D.

RESULTS

A total of 433 patients were included: 129 with MC (87 LC and 42 CC), 23 with another organic disease, and 278 with FDB-D, including patients with diarrhea and abdominal pain who met the criteria of Rome III (irritable bowel syndrome with diarrhea) and patients with functional diarrhea without abdominal pain. Logistic regression analysis identified the following independent predictors of MC: age >50 years (odds ratio (OR)=3.1, 95% confidence interval (CI)=1.6-5.9), presence of nocturnal stools (OR=2, 95% CI=1.1-3.9), weight loss (OR=2.5, 95% CI=1.3-4.7), duration of diarrhea <12 months (OR=2.0, 95% CI=1.1-3.5), recent introduction of new drugs (OR=3.7, 95% CI=2.1-6.6; P<0.0001), and the presence of a known autoimmune disorder (OR=5.5, 95% CI=2.5-12).

CONCLUSIONS

Age >50 years, the presence of nocturnal stools, weight loss, the introduction of a new drug, and the presence of a known autoimmune disease increase the probability of MC and thus the indication for colonoscopy with biopsies.

Diagnosis and management of microscopic colitis: current perspectives

Collagenous colitis and lymphocytic colitis, together constituting microscopic colitis, are common causes of chronic diarrhea. They are characterized clinically by chronic nonbloody diarrhea and a macroscopically normal colonic mucosa where characteristic histopathological findings are seen. Previously considered rare, they now have emerged as common disorders that need to be considered in the investigation of the patient with chronic diarrhea. The annual incidence of each disorder is five to ten per 100,000 inhabitants, with a peak incidence in 60- to 70-year-old individuals and a predominance of female patients in collagenous colitis. The etiology and pathophysiology are not well understood, and the current view suggests an uncontrolled mucosal immune reaction to various luminal agents in predisposed individuals. Clinical symptoms comprise chronic diarrhea, abdominal pain, fatigue, weight loss, and fecal incontinence that may impair the patient's health-related quality of life. An association is reported with other autoimmune disorders, such as celiac disease, thyroid disorders, diabetes mellitus, and arthritis. The best-documented treatment, both short-term and long-term, is budesonide, which induces clinical remission in up to 80% of patients after 8 weeks' treatment. However, after successful budesonide therapy is ended, recurrence of clinical symptoms is common, and the best possible long-term management deserves further study. The long-term prognosis is good, and the risk of complications, including colonic cancer, is low. We present an update of the epidemiology, pathogenesis, diagnosis, and management of microscopic colitis.

The epidemiology of microscopic colitis in Olmsted County from 2002 to 2010: a population-based study

BACKGROUND & AIMS

The increasing incidence of microscopic colitis has been partly attributed to detection bias. We aimed to ascertain recent incidence trends and the overall prevalence of microscopic colitis in a population-based study.

METHODS

Using data from the Rochester Epidemiology Project, we identified residents of Olmsted County, Minnesota, who were diagnosed with collagenous colitis or lymphocytic colitis from January 1, 2002, through December 31, 2010, based on biopsy results and the presence of diarrhea (N = 182; mean age at diagnosis, 65.8 years; 76.4% women). Poisson regression analyses were performed to evaluate associations between incidence and age, sex, and calendar period.

RESULTS

The age- and sex-adjusted incidence of microscopic colitis was 21.0 cases per 100,000 person-years (95% confidence interval [CI], 18.0-24.1 cases per 100,000 person-years). The incidence of lymphocytic colitis was 12.0 per 100,000 person-years (95% CI, 9.6-14.3 per 100,000 person-years) and collagenous colitis was 9.1 per 100,000 person-years (95% CI, 7.0-11.1 per 100,000 person-years). The incidence of microscopic colitis and its subtypes remained stable over the study period (P = .63). Increasing age (P < .001) and female sex (P < .001) were associated with increasing incidence. On December 31, 2010, the prevalence of microscopic colitis was 219 cases per 100,000 persons (90.4 per 100,000 persons for collagenous colitis and 128.6 per 100,000 persons for lymphocytic colitis).

CONCLUSION

The incidence of microscopic colitis in Olmsted County residents has stabilized and remains associated with female sex and increasing age.

Microscopic colitis and colorectal neoplastic lesion rate in chronic nonbloody diarrhea: a prospective, multicenter study

BACKGROUND

Lymphocytic and collagenous colitis are emerging as common findings in subjects undergoing colonoscopy for chronic non-bloody diarrhea (CNBD). Data concerning microscopic colitis (MC) are still limited and affected by controversial epidemiological evidences. Recent converging lines of evidence suggest that MC correlates a lower risk of colorectal neoplasia. Accordingly, we prospectively assessed MC prevalence in a multicenter cohort of subjects submitted to colonoscopy for CNBD, thereby defining whether MC influences the risk of colorectal neoplasia.

METHODS

Consecutive patients with CNBD of unknown origin underwent pan-colonoscopy with multiple biopsies. The prevalence of neoplastic patients in MC was compared with that observed in negative CNBD subjects.

RESULTS

Among 8006 colonoscopy, 305 subjects were enrolled for CNBD. Patients with CNBD were more likely to be women than men (odds ratio = 1.5; P = 0.001). Histopathology detected high prevalence of MC (16%) with a clear predominance of collagenous colitis (70%). A striking age-dependent rise in MC-associated risk was observed, depicting outstanding differences among varying age groups, as in the number needed to screen 1 new case. Gender distribution was balanced within MC patients (Female/Male = 1.5/1), especially among lymphocytic colitis (Female/Male = 1.2/1). MC patients were negatively associated with the risk of neoplastic polyps compared with negative CNBD subjects (odds ratio = 0.22; P = 0.035).

CONCLUSIONS

MC is the first cause of CNBD in subjects submitted to colonoscopy. Multiple biopsies are strongly recommended, even in the case of uneventful endoscopic inspection, especially for age ≥40 years. MC has a reduced risk of colorectal neoplasia, suggesting that this model of chronic inflammation plays a protective effect against colorectal carcinogenesis.

Chronic non-bloody diarrhoea: a prospective study in Malmö, Sweden, with focus on microscopic colitis

BACKGROUND

Chronic non-bloody diarrhoea affects up to 5% of the population. Microscopic colitis is one of the most common causes, encompassing the subtypes collagenous colitis and lymphocytic colitis. The diagnosis of microscopic colitis is made by histological examination of colonic mucosal biopsy specimens. The aim of this investigation was to determine whether laboratory parameters or questions about disease history or concomitant disease could be helpful in discriminating patients with MC from those with a histologically normal colonic mucosa.

FINDINGS

Patients admitted for colonoscopy because of chronic non-bloody diarrhoea (>2 loose stools for >3 weeks) at endoscopy units in Malmö during 2007 and 2009, were enrolled. A total number of 78 patients were included (60 women, 18 men, median age 59, IQR 45-69 years). Out of these 78, 15 patients (19%) had microscopic colitis (CC; n = 10, LC; n = 5). MC was especially prevalent in patients above the age of 50 (25%). No differences were found between those with normal histology and MC in laboratory analyses (inflammatory and liver parameters). Neither were differences shown in questions regarding symptoms, environmental factors or concomitant diseases except for an association with celiac disease (p = 0.019) and a trend maybe indicating an inverse association with appendectomy (p = 0.057).

CONCLUSIONS

Microscopic colitis is associated with female gender, celiac disease and consumption of NSAIDs. Trends were observed indicating that age above 50 years, acute onset and absence of appendectomy may be associated with MC. No associations were observed with other symptoms, calprotectin levels or liver parameters.

A cross-sectional study of subclinical and clinical thyroid disorders in women with microscopic colitis compared to controls

BACKGROUND AND AIMS. Microscopic colitis (MC), predominantly affecting women, is associated with thyroid disorders, although purely defined of which type, or compared with controls. Its association with subclinical thyroid disorders, and related increased risk of cardiovascular diseases, has never been examined. The aim was to examine the prevalence of autoantibodies and subclinical and clinical thyroid dysfunction in female patients with MC compared with controls. METHODS. Women younger than 73 years old with biopsy-verified MC from the Department of Gastroenterology in Skåne, during 2002-2010, were invited. Out of 240 identified, 133 were finally included. A questionnaire about medical history was completed and blood samples were collected. Serum was analyzed for free thyroxin and triiodothyronine, thyroid-stimulating hormone and anti-thyroid peroxidase (anti-TPO) antibodies. A population-based group of 737 women served as controls. RESULT. The prevalence of thyroid disorders in patients was higher compared to controls [odds ratio (OR) = 2.98, 95% confidence interval (CI) = 1.78-4.99], but the prevalence of subclinical disorders was not different (OR = 1.18, 95% CI = 0.48-2.85). Anti-TPO antibodies were present in 10.6% of MC patients and 18.6% of controls. Twenty-five MC patients had hypothyroidism: 15 with Hashimoto's hypothyroidism, 6 with completed treatment of thyrotoxicosis and 4 with completed surgery after nontoxic goiter. CONCLUSION. Thyroid disorders, autoimmune hypothyroidism being most frequent, are more prevalent in patients with MC than in controls, whereas the prevalence of subclinical thyroid disorders in MC patients does not differ significantly from controls.

Stable incidence of collagenous colitis and lymphocytic colitis in Örebro, Sweden, 1999-2008: a continuous epidemiologic study

BACKGROUND

The incidence of microscopic colitis (MC) has increased in several centers, but long-term epidemiologic data are missing. We report an epidemiologic study of collagenous colitis (CC) and lymphocytic colitis (LC) during 1999-2008, as a follow-up of our previous studies 1984-1998.

METHODS

Population-based study of residents of the catchment area of the hospital, with a new diagnosis of MC between 1999 and 2008. Patients were identified by diagnosis registers of the Departments of Medicine and Pathology. Medical files were reviewed, and colonic biopsies were reevaluated.

RESULTS

Collagenous colitis was diagnosed in 96 patients (75 females) and LC in 90 patients (74 females). The mean annual age-standardized incidence (per 100,000 inhabitants) was MC 10.2 (95% confidence interval: 8.7-11.7), CC 5.2 (4.2-6.3), and LC 5.0 (4.0-6.0). Age-specific incidence showed a peak in females older than 70 years. Prevalence (per 100,000 inhabitants) on December 31, 2008, was MC 123 (107.6-140.0), CC 67.7 (56.4-80.6), and LC 55.3 (45.2-67.1). A comparison of current study period with 1993-1998 showed unchanged mean incidence of MC, but a 2-fold increase in women older than 60 years with LC (standardized rate ratios 2.2, [1.2-3.7]) and increased female to male ratio (4.6:1 versus 2.1:1; P = 0.02) in LC.

CONCLUSIONS

After an initial rise during 1980s and early 1990s, annual incidence of CC and LC has been stable during the last 15 years around 5/100,000 inhabitants for each disorder. The increasing incidence in older women with LC may be related to an increasing proportion of older individuals in the background population and increased colonoscopy frequency in elderly.

Clinical presentation, diagnosis, pathogenesis and treatment options for lymphocytic colitis (Review)

Lymphocytic colitis (LC) is characterized by chronic or relapsing non-bloody watery diarrhea and a macroscopically normal colon. However, histopathological examination of colonic biopsy samples reveals an increased intraepithelial infiltration of lymphocytes (≥20/100 enterocytes), and increased inflammatory cells within the lamina propria, but with a normal mucosal architecture. The reported prevalence of LC varies from 14.2 to 45 per 100,000 individuals, while its reported incidence is between 0.6 and 16 per 100,000 individuals. LC has a high rate of spontaneous symptomatic remission and is not associated with an increased risk of colon cancer or inflammatory bowel disease. The diagnosis is based on the histopathological findings. The density of colonic chromogranin A-positive cells provides an effective diagnostic tool with high sensitivity and specificity in both the right and left colon. Gastrointestinal infections, drugs, and/or autoimmunity may trigger chronic colonic low-grade inflammation. Colonic nitric oxide, serotonin and peptide YY (PYY) cell densities are markedly increased in patients with LC. It has been hypothesized that the low-grade inflammation in LC through the endocrine-immune axis causes this increase. It has been postulated further that these abnormalities in the neuroendocrine system of the colon are responsible for the diarrhea observed in patients with LC. The benign course and rate of spontaneous remission of LC denotes that drugs with severe side-effects should be avoided if possible. The drug cost and drug coverage may also be limiting factors for some patients. These aspects should be taken into account when making decisions regarding treatment options.

Microscopic colitis: epidemiology, pathophysiology, diagnosis and current management-an update 2013

Microscopic colitis is a common cause of chronic diarrhea. Over the last years the incidence and the prevalence of microscopic colitis are rising and this rise is largely attributed to a rising awareness, and concomitantly an increasing number of diagnoses are made. Patients with microscopic colitis report watery, nonbloody diarrhea of chronic, intermittent, or chronic recurrent course. Following an unremarkable physical examination the diagnosis of microscopic colitis is made by colonoscopy, which shows essentially a normal colonic mucosa. Biopsies taken during the colonoscopy procedure will then finally establish the correct diagnosis. Histological workup can then confirm a diagnosis of microscopic colitis and can distinguish the two distinct histological forms, namely, collagenous colitis and lymphocytic colitis. Presently both forms are diagnosed and treated in the same way; thus the description of the two forms is not of clinical value, though this may change in future. Depending on the patients age and gender 10-30% of patients investigated for chronic diarrhea will be diagnosed with microscopic colitis if biopsies are taken. Microscopic colitis is most common in older patients, especially in female patients and is frequently associated with autoimmune disorders and the consumption of several drugs. This review summarizes the present knowledge of the epidemiology, the pathophysiology, and the diagnosis of microscopic colitis and discusses the former and the present treatment options.

Update on idiopathic colitides

PURPOSE OF REVIEW

This article summarizes the latest developments for three types of idiopathic colitis: ulcerative colitis, Crohn's disease, and microscopic colitis.

RECENT FINDINGS

Crohn's disease and ulcerative colitis are highly related genetically. Colonoscopy remains the gold standard for making a diagnosis. The addition of chromoendoscopy can aid in identification and removal of colonic dysplasia in both disorders. The therapy for ulcerative colitis and Crohn's disease has been transformed with the introduction of anti-TNF treatment. For ulcerative colitis, recent data show that prolonged use of infliximab is effective, well tolerated and that early mucosal healing is associated with decreased risk of colectomy. There is no evidence of a significant increased risk for anti-TNF-induced malignancies. Combination therapy with azathioprine and infliximab for ulcerative colitis has now been shown to be superior to monotherapy. Natalizumab is effective in anti-TNF failures and patients can be risk stratified for progressive multifocal leukoencephalopathy by testing for John Cunningham virus antibodies. Microscopic colitis can often be related to medications, and symptoms may be worsened by coexisting celiac disease.

SUMMARY

Combination therapy with an anti-TNF and a thiopurine is currently the most effective treatment for moderate-to-severe Crohn's disease or ulcerative colitis. Stem cell therapy for perianal fistulas in patients with Crohn's disease is a promising new therapy approach.

Systematic review: are lymphocytic colitis and collagenous colitis two subtypes of the same disease - microscopic colitis?

BACKGROUND

Despite similar clinical symptoms, collagenous colitis (CC) and lymphocytic colitis (LC) are considered two distinct disease entities.

AIM

To compare pathoanatomical findings, clinical presentations, risk factors, course of diseases and response to treatment in CC and LC to establish whether they could be subtypes of the same disease, microscopic colitis (MC).

METHODS

The MEDLINE was searched for CC, LC and MC, and clinical studies of >20 patients were included. Pooled results with 95% confidence intervals were calculated based on the number of patients.

RESULTS

An abnormal number of intraepithelial lymphocytes are found in 45% (40-50%) with CC, and an abnormal subepithelial collagen band in 16% (13-20%) with LC suggesting a histological overlap. The incidence of CC and LC has increased in parallel. Mean age (CC 63 years; LC 60 years) and clinical presentation are indistinguishable, and females are predominant in CC (77%; 75-79%) as well as LC (68%; 66-70%). Risk factors such as nonsteroid anti-inflammatory drugs consumption CC 39% (36-42%); LC 32% (29-35%) are similar and prevalence of concomitant autoimmune diseases such as coeliac disease (CC 5%; CI: 4-6% and LC 7%; CI: 6-9%) do not differ. Bile acid diarrhoea is highly prevalent in CC (41%; 37-45%) and LC (29%; 24-34%). The effect of budesonide is identical.

CONCLUSIONS

CC and LC could be considered histological subtypes of the same disease, MC. To facilitate recruitment to clinical trials, all MC patients could be included in future trials and stratified for subtypes.