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Microscopic colitis is generally identified on random colon biopsies performed for chronic diarrhea, but rarely incidental polyps have histologic features of microscopic colitis. We compared patients with polypoid microscopic colitis to control patients with conventional polyps to determine the implications of polypoid microscopic colitis., Medical records were searched for patients without prior or concurrent microscopic colitis who were found to have polypoid microscopic colitis. For each patient with polypoid microscopic colitis, one patient with conventional polyps was selected as a control. We reviewed the histologic features of each polypoid microscopic colitis specimen, and evaluated endoscopic and clinical findings for polypoid microscopic colitis patients and controls., Twenty-six patients with polypoid microscopic colitis were identified with histologic features of collagenous colitis in 8 patients (31%) and lymphocytic colitis in 18 patients (69%). Polypoid microscopic colitis was unifocal in 14 patients (54%) and multifocal in 12 patients (46%). Patients with polypoid microscopic colitis were older than control patients (median age = 60 years vs 66 years, P  = .04). On follow-up 7 patients with polypoid microscopic colitis (33%) developed chronic diarrhea compared to 3 (12%) controls ( P  = .16). Of patients with follow-up biopsies, 1 patient with polypoid microscopic colitis (13%) and no control patients developed microscopic colitis ( P  = 1)., Polypoid microscopic colitis may be identified in asymptomatic patients and most patients do not develop chronic diarrhea, but some patients with polypoid microscopic colitis develop diarrhea (33% vs 12% in controls) or conventional microscopic colitis on follow-up. Thus pathologists should distinguish polypoid microscopic colitis from conventional microscopic colitis but may inform clinicians of the uncertain association with chronic diarrhea to guide decisions regarding follow-up., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Background: Lymphocytic colitis (LC) in the pediatric population has been associated with immune dysregulation., Methods: Single-center retrospective study of pediatric LC., Results: 50 patients (35 female, 70%) with a median age of 12 years at diagnosis (interquartile range: 5.7-15.8) of LC were identified. At presentation, 11 patients (22%) had malnutrition, 16 (32%) had a known underlying immune dysregulation, 4 (8%) had celiac disease (CD), and none had a diagnosis of inflammatory bowel disease. The most common medications prior to diagnosis were non-steroidal anti-inflammatory drugs, proton pump inhibitor, and selective serotonin reuptake inhibitors (10% each). Colonic biopsies showed a median number of intraepithelial lymphocytes (IELs)/100 epithelial cells of 48 (range: 25-85), and only 10% of cases had neutrophilic cryptitis. Upper gastrointestinal tract findings included lymphocytic esophagitis (4%), and duodenal IELs without and with villous blunting (9% each) (n: 47). Ten patients (23%) had increased IELs in the terminal ileum (n: 43). Treatments including 5-ASA, budesonide, prednisone, and gluten-free diet improved symptoms in <50% of patients (n: 42), and all follow-up colonoscopies showed persistent LC (n: 13)., Conclusion: Our study supports the association of LC with immune-mediated conditions, most commonly celiac disease. Symptomatic improvement was seen in <50% of patients with none of the patients with repeat colonoscopy showing histologic improvement., Competing Interests: Declaration of Conflicting InterestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Microscopic colitis is a chronic inflammatory disorder of the colon characterized by microscopic changes in the intestinal lining. Turmeric, a commonly used spice, is generally regarded as beneficial for digestive and articular health thanks to its anti-inflammatory properties. No cases of microscopic colitis under a food supplement containing turmeric has been previously described in the literature. This article highlights 3 cases where the consumption of a specific turmeric-based supplement caused microscopic colitis. Each of them complained about profuse watery diarrhea shortly after initiating the food supplement containing turmeric. Ileo-colonoscopies with biopsies confirmed the diagnosis of microscopic colitis, with two cases classified as lymphocytic colitis and the third as collagenous colitis. Following the discontinuation of the supplement, all patients experienced a resolution of their symptoms within a few days. Subsequent control biopsies for the three patients confirmed the resolution of microscopic colitis., (© Acta Gastro-Enterologica Belgica.)

A 69-year-old patient with no personal or family history of ichthyosis consulted our dermatology department for diffused cutaneous xerosis with intense pruritus evolving for 3 weeks. Physical examination revealed diffused ichthyosis of large polygonal fine scales on the skin without erythema (Figure 1). The lesions spared the face. Examination of the mucous membranes, hair, and nails revealed no abnormalities. There was no fever or adenomegaly. A skin biopsy revealed an orthokeratotic hyperkeratosis with thinning of granular layer (Figure 2). The initial diagnosis of acquired ichthyosis was maintained. The patient also reported a change in bowel habits since 2 weeks with watery, non-bloody diarrhea and mild steatorrhea. His laboratory investigations presented low serum vitamin B12 level, mild anemia, hypoalbuminemia, and fecal leukocytes; however, antinuclear antibodies, perinuclear anti-neutrophil cytoplasmic antibodies (pANCA), rheumatoid factor, and complement components C3 and C4 were normal. A colonoscopy performed was also normal without any abnormalities. Colon biopsies revealed histologic aspects of lymphocytic colitis with more than 20% increase in lymphocytes in the surface epithelium of colorectal mucosa. Laboratory investigations excluded neoplasia, hemopathies, or autoimmune-associated diseases. The patient was treated with salazopyrin with a remarkable lessening of diarrhea and cutaneous manifestations within 4 weeks (Figure 3).

Background: Microscopic colitis (MC) is one of the most underdiagnosed conditions leading to chronic watery diarrhoea in patients worldwide. This is the first study of this kind in Pakistan and we aimed to calculate the frequency as well as study the risk factors behind the disease., Methods: This was a prospective cross-sectional study in a tertiary care hospital in Pakistan. A total of 58 participants with chronic watery diarrhoea who had normal colonoscopy were recruited for the study and biopsies were obtained for diagnosing MC., Results: 2 participants out of 58 (3.4%) had biopsy proven microscopic colitis; one patient had a lymphocytic colitis variant and the other had a collagenous colitis variant. The average score based on the MC scoring system was 7.53 in the entire study group. The patient with lymphocytic colitis had a score of 06 while the patient with collagenous colitis had a score of 8., Conclusions: The frequency of microscopic colitis was found to be 3.4% of all cases of chronic watery diarrhoea. A link between MC and autoimmune diseases was also observed. However, we had a limited sample size and encouraged future studies to employ a larger sample size to get a multifaceted look at the disease process.

Microscopic colitis is part of the differential diagnosis of chronic watery diarrhea. Colonoscopy discloses a normal looking mucosa, therefore its diagnosis is based on histology of colonic biopsies. Two main phenotypes are distinguished: collagenous colitis and lymphocytic colitis. A third entity, incomplete microscopic colitis or unspecified microscopic colitis has been reported in the literature. It affects preferentially women over 60 years of age and its association with certain drugs is increasingly established. In case of suspected drug-induced microscopic colitis, identification of the responsible drug is a key to management. After discontinuation of the suspected drug, the gold standard of treatment is budesonide both for induction and for maintenance in case of clinical relapse, as is often the case after discontinuation. Therapy with immunomodulators, biologics, or surgery is reserved for refractory forms of microscopic colitis after multidisciplinary consultation. Through the clinical case of colitis on olmesartan, we will review the latest recommendations on drug-induced microscopic colitis., Competing Interests: The authors declare that they have no conflict of interest, (© Acta Gastro-Enterologica Belgica.)

Background and Aims: Microscopic colitis (MC) is a colonic inflammatory condition associated with autoimmune dysfunction. Type 1 diabetes (T1D) is a chronic disease induced by autoimmune destruction of pancreatic β-cells. We aimed to examine the association between T1D and MC., Methods: A matched case-control study was conducted using the nationwide ESPRESSO cohort as study base. All biopsy-confirmed MC patients born after 1940 were identified and compared to biopsy-free individuals matched from the general population for T1D diagnosis using the Swedish National Patient Register. The T1D-MC association was estimated as odds ratios (ORs) and 95% confidence intervals (CIs) by conditional logistic models, considering differences by sex and MC subtype. Full sibling comparison and adjustment for MC-associated medications were also performed., Results: We identified 352 (3.7%) and 945 (2.0%) T1D diagnoses from 9,600 MC cases and 47,870 matched population controls, respectively, which corresponded to an overall OR of 1.79 (95% CI: 1.56-2.05). The association was stronger for collagenous colitis (OR, 2.15; 95% CI: 1.70-2.71) than lymphocytic colitis (OR, 1.62; 95% CI: 1.37-1.92) and remained statistically significant in full sibling comparison (OR, 1.46; 95%: 1.18-1.81). Medication adjustment attenuated the association to null among females (OR: 1.02; 95% CI: 0.82-1.27) but not among males (OR: 1.45; 95% CI: 1.11-1.90)., Conclusion: T1D diagnosis was almost 80% more prevalent in MC patients compared to general population. This positive association did not seem to be spurious due to residual confounding shared by full siblings but may relate to consumption of medications associated with MC onset., (© 2023 The Authors. Alimentary Pharmacology & Therapeutics published by John Wiley & Sons Ltd.)

The clinical case of a patient in the fifth decade of life with a diagnosis of lymphocytic colitis is presented, who comes for chronic diarrhea, which receives treatment with Budesonide with partial response.

Background: An association has been reported between celiac disease (CD) and microscopic colitis (MC). However, large, population-based cohort studies are rare., Objective: To systematically examine the association between CD and MC in a large, nationwide cohort., Methods: We conducted a nationwide population-based matched cohort study in Sweden of 45,138 patients with biopsy-verified CD (diagnosed in 1990-2016), 223,149 reference individuals, and 51,449 siblings of CD patients. Data on CD and MC were obtained from all (n = 28) pathology departments in Sweden. Adjusted hazard ratios (aHRs) were calculated using Cox regression., Results: During follow-up, 452 CD patients and 197 reference individuals received an MC diagnosis (86.1 vs. 7.5 per 100,000 person-years). This difference corresponded to an aHR of 11.6 (95% confidence interval [CI] = 9.8-13.8) or eight extra MC cases in 1000 CD patients followed up for 10 years. Although the risk of MC was highest during the first year of follow-up (aHR 35.2; 95% CI = 20.1-61.6), it remained elevated even after 10 years (aHR 8.1; 95% CI = 6.0-10.9). Examining MC subtypes lymphocytic colitis (LC) and collagenous colitis (CC) separately, the aHR was 12.4 (95% CI = 10.0-15.3) for LC and 10.2 (95% CI = 7.7-13.6) for CC. MC was also more common before CD (adjusted odds ratio [aOR] = 52.7; 95% CI = 31.4-88.4). Compared to siblings, risk estimates decreased but remained elevated (CD and later MC: HR = 6.2; CD and earlier MC: aOR = 7.9)., Conclusion: Our study demonstrated a very strong association of MC with CD with an increased risk of future and previous MC in CD patients. The magnitude of the associations underscores the need to consider the concomitance of these diagnoses in cases in which gastrointestinal symptoms persist or recur despite a gluten-free diet or conventional MC treatment. The comparatively lower risk estimates in sibling comparisons suggest that shared genetic and early environmental factors may contribute to the association between CD and MC., (© 2023 The Authors. United European Gastroenterology Journal published by Wiley Periodicals LLC on behalf of United European Gastroenterology.)

Aim: We previously reported the first population-based study of the epidemiology of microscopic colitis in Northern Ireland. The aim of the current study is to provide updated data on incidence, diagnostic methods and clinicopathological associations, following dissemination of the previous report. A further aim was to compare the findings against relevant recommendations from the 2020 European guidelines., Method: Study cases were identified via the Belfast Health and Social Care Trust pathology laboratory system for new cases of collagenous colitis or lymphocytic colitis diagnosed from 2017 to 2020 inclusive. Demographic and clinical information was collated from electronic healthcare records., Results: Two hundred and seventeen new diagnoses of microscopic colitis were made between 2017 and 2020, comprising 89 (41%) collagenous colitis and 128 (59%) lymphocytic colitis. The overall incidence of microscopic colitis, expressed per 100,000 adult population, ranged from 7.6 to 11.5 (5.9 to 9.0 per 100,000 total population). The 2019 peak of 11.5 cases per 100,000 adult population represents a 71.6% increase in incidence compared with the mean incidence of 6.7 per 100,000 adult population from previous data for 2008-2016. There has also been a significant increase in number of cases diagnosed on separate sampling from the right and left colon (85% in 2019-2020 compared with 30% in 2008-2016; p < 0.001). Overall compliance with coeliac serology testing has improved, with 89% tested in 2017-2018 compared with 75% in 2008-2016., Conclusion: Clinicopathological communication has contributed to an increased incidence of microscopic colitis in Northern Ireland through better endoscopic diagnostic sampling and pathology coding practices. Coeliac serology testing has also improved, although continued clinical awareness is required of the need for coeliac serology testing in all patients diagnosed with microscopic colitis., (© 2022 The Authors. Colorectal Disease published by John Wiley & Sons Ltd on behalf of Association of Coloproctology of Great Britain and Ireland.)

Competing Interests: Competing interests: None declared.

Microscopic colitis is an inflammatory bowel disease divided into two subtypes: collagenous colitis and lymphocytic colitis. With an increasing incidence of microscopic colitis exceeding those of ulcerative and Crohn's disease among elderly people in some countries, microscopic colitis is a debilitating life experience. Therefore, physicians should be familiar with its clinical features and management strategies because the disease deserves the same attention as the classical inflammatory bowel diseases. Here, state-of-the-art knowledge of microscopic colitis is provided from a global perspective with reference to etiopathology and how to establish the diagnosis with the overall aim to create awareness and improve rational management in clinical practice. The immune system and a dysregulated immune response seem to play a key role combined with risk factors (e.g. cigarette smoking) in genetically predisposed individuals. The symptoms are characterized by recurrent or chronic nonbloody, watery diarrhea, urgency, weight loss, and a female preponderance. As biomarkers are absent, the diagnosis relies on colonoscopy with a histological assessment of biopsy specimens from all parts of the colon. Although the disease is not associated with a risk of colorectal cancer, a recent nationwide, population-based cohort study found an increased risk of lymphoma and lung cancer. Budesonide is the first-line therapy for management, whereas immunomodulatory drugs (including biologics) and drugs with antidiarrheal properties may be indicated in those failing, dependent, or intolerant to budesonide. In microscopic colitis induced by checkpoint inhibitors, a drug class used increasingly for a wide range of malignancies, a more aggressive therapeutic approach with biologics introduced early seems reasonable. However, particular attention needs to be drawn to the existence of incomplete forms of microscopic colitis with the risk of being overlooked in routine clinical settings., Competing Interests: ON, TS No competing interests declared, FF Research grant from Falk Pharma; Consulting fee from Tillotts and Biomedal; Lectures for General Electrics and Termo Fisher, and travel support from Tillotts, Ferring, and Janssen as listed in the ICMJE form, DP Grants from Atlantic, Finch, Salix, Janssen, Pfizer, Seres, Applied Molecular Transport, and Takeda; Consulting fees from Abbvie, Vedanta, Seres, Immunic, Merck, Otsuka, Ferring, Rise Therapeutics, Boehringer Ingelheim, and Summit Therapeutics as listed in the ICMJE form, (© 2022, Nielsen et al.)

Background: Microscopic colitis (MC) primarily affects older adults; thus, data in younger patients are scarce., Aims: To compare clinical characteristics and treatment response by age at diagnosis., Methods: This retrospective cohort study was performed at Mayo Clinic and Massachusetts General Hospital. Patients were chosen consecutively using established databases. Patients were 'younger' if age at diagnosis was ≤ 50 years and 'older' if age > 50 years. Treatment outcomes were captured for induction (12 ± 4 weeks), based on the total number of daily stools, and defined as remission (complete resolution), response (≥ 50% improvement), non-response (< 50% improvement), and intolerance. Patients were considered 'responders' if they had remission or response and 'non-responders' if they had non-response or intolerance., Results: We included 295 patients (52 younger, 243 older). There were no differences in sex, race, MC subtype, and diarrhea severity between groups (all P > 0.05). Younger patients were more likely to have celiac disease (17.3% vs. 5.8%, P = 0.01), while older patients had higher BMI (mean 25.0 vs. 23.8 kg/m 2 , P = 0.04) were more likely smokers (53.9% vs. 34.6%, P = 0.01) and use NSAIDs (48.6% vs. 15.4%, P < 0.01) and statins (22.6% vs. 3.8%, P < 0.01). Overall treatment response was highest for budesonide (88.3%) and did not differ when comparing older to younger patients (90.6% vs. 77.8%, P = 0.12) or by MC subtype (LC, 81.5% vs. CC, 92.9%, P = 0.07)., Conclusions: There are no significant differences in MC treatment response based on age or disease subtype. These findings support treating patients with MC based on symptom severity rather than age., (© 2021. The Author(s).)

Microscopic colitis (MC) is an inflammatory disease of the colon characterized by persistent watery, nonbloody diarrhea. Subtypes of MC include collagenous and lymphocytic MC. Microscopic examination of colon tissue is crucial to confirming the diagnosis because the colonic mucosa often appears normal during flexible sigmoidoscopy or colonoscopy. We aim to determine the optimal sites and minimum number of colon biopsies required to diagnose MC from published studies. We systematically searched PubMed, Web of Science, Scopus, and Cochrane databases from inception until October 2020 using the following keywords: microscopic, lymphocytic, collagenous, colitis, biopsy, and biopsies. We screened the search results for eligibility and extracted data from the included studies. We pooled the numbers of biopsies provided by each study to calculate the mean number of biopsies, SD, and SEM. We included three retrospective cohort studies with 356 patients (148 collagenous, 192 lymphocytic, and 16 mixed), and the total number of biopsies were 1854. The mean number of biopsies that were recommended by the included studies are 4, 4, and 9, respectively. The pooled mean ± SD is 5.67 ± 2.89. The included studies reported that biopsies from the ascending colon (AC) and descending colon (DC) had the highest diagnostic rates. To ensure a high level of certainty in diagnosing MC, a total of six biopsies should be taken from the AC and DC (3 AC and 3 DC). However, special care should be directed toward differentiating MC from other forms of colitis. In addition, detailed and comparative studies are needed to provide stronger recommendations to diagnose MC., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

This is the first scientific report describing lymphocytic colitis after administration of the Pfizer severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) messenger RNA (mRNA) vaccine. The patient developed liquid stools, abdominal pain, and nausea within 24 hours of receiving the second dose. Symptoms were persistent for 3 months but improved 113 days after onset. Laboratory profiles and gastrointestinal polymerase chain reaction were normal. Esophagogastroduodenoscopy and colonoscopy performed 98 days after onset revealed patchy erythema in the descending colon and rectosigmoid. Mucosal evaluation revealed lymphocytic colitis. Review of the Vaccine Adverse Event Reporting System revealed 5 cases of microscopic colitis after the second mRNA dose. This report and Vaccine Adverse Event Reporting System cases suggest providers should consider microscopic colitis in the differential diagnosis of patients with severe, persistent diarrhea after the SARS-CoV2 mRNA vaccine., (Copyright © 2022 by The American College of Gastroenterology.)

A 49-year-old woman was referred to our hospital for further evaluation and treatment of diarrhea. Colonoscopic findings revealed indistinct vascular patterns and extensive edema in a colon segment, and white granular mucosa and crack-like appearance in the sigmoid colon and rectum. She was diagnosed with lymphocytic colitis (LC) based on lymphocytic infiltration into the epithelium on histopathological examination. Diarrhea symptoms resolved after long-term medication withdrawal. This medicine's composition was changed 4 years ago and this modification possibly triggered LC.

Objective: Microscopic colitis is a chronic inflammatory disorder characterized by a triad of chronic diarrhea, endoscopy without significant abnormality, and distinct histopathological features. Histopathologically, microscopic colitis is divided into 3 subtypes; collagenous colitis, lymphocytic colitis, incomplete microscopic colitis. The main purpose of this study was to analyze the detailed clinicopathological parameters of microscopic colitis cases in the Turkish population., Material and Method: The clinicopathological parameters were evaluated in 53 microscopic colitis cases (37 collagenous colitis, 7 lymphocytic colitis, 9 incomplete microscopic colitis) diagnosed between 2010 and 2019., Results: All cases had lymphoplasmacytosis. The presence of ≥20 eosinophils/high power field in the lamina propria was remarkable in 75.7%, 57.1%, and 11.1% of collagenous colitis, lymphocytic colitis, and incomplete microscopic colitis cases, respectively. One of the striking findings was the presence of concomitant Celiac disease in 29% of the lymphocytic colitis cases. In terms of drug use, proton pump inhibitors and nonsteroidal anti-inflammatory drugs were the most commonly used drugs., Conclusion: The mean age in our series is lower than the literature and a distinct male predominance was observed in lymphocytic colitis and incomplete microscopic colitis, contrary to the literature. These suggest that susceptibility to microscopic colitis may differ between ethnic groups. The presence of overt lymphoplasmacytosis, eosinophilic infiltration and epithelial damage are the microscopic features which should alert the pathologist for the diagnosis of complete microscopic colitis. Given that microscopic colitis is a common treatable cause of chronic diarrhea, awareness of the aforementioned histopathological features is of utmost importance for accurate diagnosis and not to miss incomplete cases.

The ability of SARS-CoV-2 to infect the gastrointestinal tract is well described. Inflammatory bowel diseases (IBD) are believed to represent a disorganised immune response in genetically predisposed individuals, which are triggered by various environmental factors, notably infections. Here we report a case of chronic watery diarrhoea that was triggered by a SARS-CoV-2 infection. The work-up confirmed a new diagnosis of lymphocytic colitis, and the patient responded favourably to a course of oral budesonide. Clinicians should become vigilant to the possibility of triggered IBD in patients with persistent diarrhoea following a SARS-CoV-2 infection., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2021. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Microscopic colitis (MC) is a common cause of chronic watery diarrhea. Biopsies with characteristic histological features are crucial for establishing the diagnosis. The two main subtypes are collagenous colitis (CC) and lymphocytic colitis (LC) but incomplete forms exist. The disease course remains unpredictable varying from spontaneous remission to a relapsing course., Aim: To identify possible histological predictors of course of disease., Methods: Sixty patients from the European prospective MC registry (PRO-MC Collaboration) were included. Digitised histological slides stained with CD3 and Van Gieson were available for all patients. Total cell density and proportion of CD3 positive lymphocytes in lamina propria and surface epithelium were estimated by automated image analysis, and measurement of the subepithelial collagenous band was performed. Histopathological features were correlated to the number of daily stools and daily watery stools at time of endoscopy and at baseline as well as the clinical disease course (quiescent, achieved remission after treatment, relapsing or chronic active) at 1-year follow-up., Results: Neither total cell density in lamina propria, proportion of CD3 positive lymphocytes in lamina propria or surface epithelium, or thickness of collagenous band showed significant correlation to the number of daily stools or daily watery stools at any point of time. None of the assessed histological parameters at initial diagnosis were able to predict clinical disease course at 1-year follow-up., Conclusions: Our data indicate that the evaluated histological parameters were neither markers of disease activity at the time of diagnosis nor predictors of disease course., (© 2021 John Wiley & Sons Ltd.)

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)., (Copyright © 2021 AGA Institute. Published by Elsevier Inc. All rights reserved.)

Background/introduction: Lymphocytic colitis (LC) and the incomplete form (LCi) are common causes of chronic watery diarrhea. Endoscopy is often inconspicuous, and the diagnosis relies on histopathological assessment of colonic biopsies. Digital Image Analysis (DIA) eliminates interobserver variation. The aim of this study was to establish digital cutoff values for LC and LCi on CD3 stained slides., Material and Methods: One hundred and six patients with a hematoxylin and eosin (HE) diagnosis of normal colonic mucosa (N = 19), non-specific reactive changes (N = 24), LCi (N = 23) and LC (N = 40) were eligible for analysis. The number of intraepithelial lymphocytes (IELs) reached by DIA in the total surface epithelium and in hot spots of the biopsies was compared with the diagnostic category assigned by the pathologists based on HE stained slides. The digitalized slides were analyzed for number of IELs using Visiopharm Quantitative Digital Pathology software. All digitalized slides were examined manually to identify differences in the approach to the evaluation of the biopsies by the pathologists and DIA., Results: The median IEL counts and interquartile range in the total surface epithelium were 3.6 (3.2-4.3), 4.4 (3.4-5.3), 19.8 (16.6-30.0) and 41.3 (37.0-47.8) in normal colon mucosa, mucosa with non-specific reactive changes, LCi and LC, respectively. Discrimination between normal mucosa and non-specific reactive changes was not possible. Digital cutoff values with the best separation between non-LC, LCi and LC were > 13 IELs/100 epithelial cells for LCi and > 36 IELs/100 epithelial cells for LC. These cutoff values resulted in an agreement between the pathologist's and DIA that was very good with a kappa value of 0.90., Conclusion: Despite differences among the approach of DIA and the pathologist's assessment of IELs in colonic mucosa DIA is able discriminate between the HE based diagnoses of the three subgroups non-LC, LCi and LC with high accuracy., (Copyright © 2019 Elsevier GmbH. All rights reserved.)

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.

Lymphocytic colitis (LC) and LC incomplete (LCi) are common causes of chronic watery diarrhea. The diagnosis relies on clinical findings and histopathologic evaluation. The diagnostic criteria of LC are based on hematoxylin and eosin (HE) staining. However, supplementary immunohistochemical staining for highlighting the lymphocytes in borderline cases is now widely used. This change in diagnostics could lead to incorrectly diagnosing patients with LC and LCi if the present histologic criteria are used. The number of intraepithelial lymphocytes (IELs) was estimated and categorized in intervals based on HE- versus CD3-stained slides from patients with an HE diagnosis of normal colonic mucosa (n = 19), mucosa with nonspecific reactive changes (n = 24), LCi (n = 24), and LC (n = 40). The number of IELs was compared with clinical symptoms. Overall, the number of IELs was higher with CD3 stain compared with HE stain in 73% of cases, unchanged in 26% of cases, and lower in 1 case. The number of IELs detected was higher using the CD3 stain in 53%, 79%, 79%, and 75% of cases included as normal colonic mucosa, nonspecific reactive changes, LCi, and LC, respectively. Based on CD3 stain, 58% of the cases with nonspecific reactive changes fulfilled the HE criteria for LCi, and 79% of the cases with LCi fulfilled the HE criteria for LC. Automated image analysis of CD3-stained slides resulted in even higher numbers of IELs in all 4 diagnostic groups. Conclusively, our data support considering increased cutoff values for LCi and LC when assessed in CD3-stained specimens., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Aim: This study assessed the prevalence, clinical presentation and outcome of lymphocytic colitis (LC) and eosinophilic gastrointestinal disease (EGID) in children with severe, recurrent abdominal pain (RAP), by describing the predominant symptoms, diagnostic approaches and treatment options., Methods: We performed a retrospective follow-up study at a Danish regional hospital by reviewing the histology reports of the children who had undergone gastrointestinal endoscopy for RAP. Data were retrieved from the medical records of those who met the diagnostic criteria for LC and, or, EGID from 2011 to 2016. The study population comprised 381 patients who underwent a diagnostic process to clarify RAP., Results: A total of 74 patients (39 females) aged 2-17 years, with severe RAP as the most predominant symptom underwent gastrointestinal endoscopy. This identified 16/74 (21.6%) with LC (n = 6) and, or, EGID (n = 11), which equated to 4.2% with RAP. No biochemical patterns of abnormalities were found. Medical treatment and, or, diet generally induced and maintained clinical remission., Conclusion: We found 16 children with LC and, or, EGID. The predominant symptom was severe RAP. All patients had a macroscopically normal mucosa at endoscopy, a specific histopathological feature and no characteristic biochemical findings. Endoscopy should be considered in these cases., (©2018 Foundation Acta Paediatrica. Published by John Wiley & Sons Ltd.)

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., (Colorectal Disease © 2018 The Association of Coloproctology of Great Britain and Ireland.)

Microscopic colitis (MC) is still an underestimated cause of chronic, non-bloody watery diarrhea. It is typically manifested in elderly patients with a female predominance. The incidence of microscopic colitis has been increasing. The aetiology and pathophysiology remain unclear. Conditions associated with it include autoimmune diseases. There may be a genetic predisposition, as familial cases have been described. As implicated by the name microscopic colitis, the diagnosis is found by histological examination. There are mainly two subtypes, the lymphocytic colitis (LC) and the collagenous colitis (CC). Even if the condition's long-term course is benign, a chronic recurrent course of the symptoms is frequent. Due to the symptoms, there is an impairment of patient's health-related quality of life. A correct diagnosis and therapy is therefore mandatory. The aim of this paper is to create awareness for microscopic colitis.

Objectives: Data on heredity, risk factors and comorbidity in microscopic colitis, encompassing collagenous colitis (CC) and lymphocytic colitis (LC), are limited., Aim: The aim was to carry out a case-control study of family history, childhood circumstances, educational level, marital status, smoking and comorbidity in microscopic colitis., Methods: A postal questionnaire was sent in 2008-2009 to microscopic colitis patients resident in Sweden and three population-based controls per patient, matched for age, sex and municipality., Results: Some 212 patients and 627 controls participated in the study. There was an association with a family history of microscopic colitis in both CC [odds ratio (OR): 10.3; 95% confidence interval (CI): 2.1-50.4, P=0.004] and LC (OR not estimated, P=0.008). Current smoking was associated with CC [OR: 4.7; 95% CI: 2.4-9.2, P<0.001) and LC (OR: 3.2; 95% CI: 1.6-6.7, P=0.002). The median age at diagnosis was around 10 years earlier in ever-smokers compared with never-smokers.CC was associated with a history of ulcerative colitis (UC) (OR: 8.7, 95% CI: 2.2-33.7, P=0.002), thyroid disease (OR: 2.3; 95% CI: 1.1-4.5, P=0.02), coeliac disease (OR: 13.1; 95% CI: 2.7-62.7, P=0.001), rheumatic disease (OR 1.9; 95% CI: 1.0-3.5, P=0.042) and previous appendicectomy (OR: 2.2; 95% CI: 1.3-3.8, P=0.003), and LC with UC (OR: 6.8; 95% CI: 1.7-28.0, P=0.008), thyroid disease (OR: 2.4; 95% CI: 1.1-5.4, P=0.037) and coeliac disease (OR: 8.7; 95% CI: 2.8-26.7, P<0.001)., Conclusion: Association with a family history of microscopic colitis indicates that familial factors may be important. The association with a history of UC should be studied further as it may present new insights into the pathogenesis of microscopic colitis and UC.

Microscopic colitis (MC) is a relatively common cause of chronic watery diarrhea, especially in older persons. Associated symptoms, including abdominal pain and arthralgias, are common. The diagnosis is based upon characteristic histological findings in the presence of diarrhea. The two types of MC, collagenous and lymphocytic colitis, share similar clinical features, with the main difference being the presence or absence of a thickened subepithelial collagen band. There are several treatment options for patients with MC, although only budesonide has been well studied in multiple controlled clinical trials. This review will describe the clinical features, epidemiology, pathophysiology, diagnostic criteria, and treatment of patients with MC.

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., Competing Interests: Conflict-of-interest statement: No potential conflicts of interest. No specific financial support.

Microscopic colitis (MC) designates two types of chronic diarrhea diseases, which are lymphocytic colitis and collagenous colitis. The prevalence of microscopic colitis is increasing in both Western and Eastern countries, possibly due to the high incidence of colonoscopic survey in chronic diarrhea patients. Although the overall prognosis of MC patients is mostly good, it should be noted that appropriate diagnosis and choice of treatment is required to assure a good clinical outcome for MC patients. Also, a certain population of MC patients may take a severe and refractory clinical course, and thus require advanced clinical care using medications supported by less evidence. In this review, we would like to feature the essential points regarding the diagnosis of MC, and also describe the current standard of treatments for MC patients. In addition, we would like to add some findings from the national survey and research carried out in Japan, to compare those data with the western countries.

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%; I 2 : 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%; I 2 : 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., (© 2016 John Wiley & Sons Ltd.)

Microscopic colitis (MC) is a common cause of chronic watery diarrhea. Traditionally, MC encompasses the 2 subgroups lymphocytic colitis (LC) and collagenous colitis, but recently, an additional subgroup, MC incomplete, has been introduced. Distinguishing between the subgroups relies exclusively on histopathologic evaluation. In the present study, 4 pathologists evaluated 156 archived biopsies originally diagnosed as LC or LC incomplete (LCi). Each pathologist assigned a diagnosis of LC, LCi, or nonspecific inflammation to all cases at 2 independent assessments. At the first assessment, hematoxylin and eosin (HE) stainings were available. At the second assessment, a supplementary CD3 immunohistochemical staining was also available. The aim was to evaluate whether a supplementary CD3 would increase the diagnostic agreement among pathologists, and whether a CD3 stain would change the diagnosis based on HE staining only. After the complete assessment, the cases were divided into 3 groups, that is, full agreement, partial agreement, and disagreement. The CD3 staining increased the number of cases with full agreement from 60 to 78. One hundred thirty-one cases with agreement or partial diagnostic agreement based on HE + CD3 were compared with the HE diagnoses. In 44 (34%) of 131 cases, CD3 changed the diagnosis. Cases assigned to the LCi category based on HE were often changed by a supplementary CD3. Conclusively, it is recommended to use a CD3 before giving the histopathologic diagnosis of LCi., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Objective: Microscopic colitis is a common cause of chronic diarrhoea in the Scandinavian countries. This report comprises demographic data, clinical and endoscopic features, and occurrence of coeliac and inflammatory bowel disease (IBD) in a large urban cohort of patients with lymphocytic colitis (LC) and collagenous colitis (CC)., Materials and Methods: A total of 795 patients with microscopic colitis from two hospitals in Stockholm were included. Medical records were reviewed and clinical data, including endoscopic and histological findings, were compiled., Results: Forty-three percent had CC (female:male ratio 3.7:1) and 57% had LC (female:male ratio 2.7:1). The mean age at diagnosis of CC was 63 years and of LC was 59 years (p = 0.005). Clinical features were similar in both entities, but the intensity of symptoms differed. Watery diarrhoea was reported in 55% in CC patients versus in 43% in LC patients (p = 0.0014), and nocturnal diarrhoea in 28% versus 18% (p = 0.002). Subtle endoscopic mucosal findings were reported in 37% of the CC patients and in 25% of the LC patients (p = 0.0011). Colorectal adenomatous polyps were found in 5.3% of all patients. Coeliac disease occurred in 6% and IBD occurred in 2.1% of all patients., Conclusions: Clinical features of LC and CC are similar but not identical. CC seems to be a more severe type of bowel inflammation and LC tends to occur earlier in life. Both forms might indeed feature endoscopic findings despite the designation 'microscopic'. Our study confirms the strong association with coeliac disease.

Characterized by colonic mucosa intraepithelial lymphocytosis, lymphocytic colitis is primarily an entity presented in the middle-aged to elderly patient population. Very few large series of lymphocytic colitis of childhood occurrence are available in the medical literature. Ten cases each of lymphocytic colitis and of colonic lymphocytosis of other diagnosis, all with duodenal disaccharidases analysis data, were collected from the files of our institution. The electronic medical records were reviewed and multiple variables were analyzed. The ten patients with lymphocytic colitis presented with diarrhea. Of these, three had abdominal pain. The age range was 2-18 years. Nearly all patients were Caucasian (90%) and 70% were female. Endoscopically, most had normal appearing colonic mucosa. Significant past medical history, family medical history and associated comorbidities included celiac disease, Down syndrome, juvenile arthritis and other autoimmune diseases. Interestingly, the most revealing observation was that the majority of cases (80%) were associated with lactase deficiency and, for the most part, gastrointestinal symptoms improved simply by treatment with Lactaid or avoidance of dairy products. This association is statistically significant. Our clinicopathological study indicates that the typical pediatric patient is a female Caucasian. A large of portion of the patients had associated lactase deficiency and improved on Lactaid supplement alone., (Copyright © 2014 Elsevier GmbH. All rights reserved.)

Aim: To investigate Toll-like receptor (TLR) signaling regulators in microscopic and ulcerative colitis patients., Methods: Total RNA and microRNA were isolated from fresh frozen colonic biopsies of non-inflamed controls and patients with active or in-remission collagenous colitis (CC), lymphocytic colitis (LC), or ulcerative colitis (UC). We compared expressions of interleukin-1 receptor-associated kinase (IRAK)-2, IRAK-M, interleukin (IL)-37, microRNA (miR)-146a, miR-155, and miR-21 using quantitative real time reverse transcription polymerase chain reaction., Results: IRAK-M expression was increased in LC patients with active disease in histopathological remission (LC-HR; P = 0.02) and UC patients (P = 0.01), but no differences in IRAK-2 expression were detected compared to controls. miR-146a, -155 and -21 expressions were increased in LC-HR (P = 0.04, 0.07, and 0.004) and UC (P = 0.02, 0.04 and 0.03) patients. miR-146a and miR-21 expressions were significantly enhanced in UC patients compared to UC remission (UC-R; P = 0.01 and 0.04). Likewise, active CC patients showed significantly increased expression of miR-155 (P = 0.003) and miR-21 (P = 0.006). IL-37 expression was decreased in both CC (P = 0.03) and LC (P = 0.04) patients with a similar trend in UC patients but not statistically significant, whilst it was increased in UC-R patients compared to controls (P = 0.02) and active UC (P = 0.001)., Conclusion: The identification of differentially expressed miRNAs, IL-37, and IRAK-M suggests different pathophysiologic mechanisms in various disease stages in LC, CC, and UC.

Non-celiac gluten sensitivity (NCGS) is an emerging disorder characterized by intestinal and extra-intestinal symptoms related to the ingestion of gluten-containing food in non-celiac patients. Its prevalence has been estimated to be six to ten-times higher than that of celiac disease (CD). A gluten-free diet is the most widely recommended therapy, but the causative agent remains unknown and there are no consensus diagnostic criteria. Recent studies on NCGS have included patients with possibly overlooked minor CD and diarrhea-predominant irritable bowel syndrome without self-reported gluten intolerance, but showing a response to a gluten-free diet. Furthermore, FODMAPs (Fermentable Oligosaccharides, Disaccharides, Monosaccharides And Polyols) have recently been postulated as the culprit component for NCGS in wheat, instead of gluten. This review updates evidence on the pathophysiology of NCGS and the efficacy of different dietary interventions in its treatment, stressing the need for proper screening for CD before a diagnosis of NCGS is made., (Copyright © 2013 Elsevier España, S.L. and AEEH y AEG. All rights reserved.)

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.

Microscopic colitis is a frequent cause of chronic watery diarrhea, especially in older persons. Common associated symptoms include abdominal pain, arthralgias, and weight loss. The incidence of microscopic colitis had been increasing, although more recent studies have shown a stabilization of incidence rates. The diagnosis is based on characteristic histologic findings in a patient with diarrhea. Microscopic colitis can occur at any age, including in children, but it is primarily seen in the elderly. Several treatment options exist to treat the symptoms of microscopic colitis, although only budesonide has been well studied in randomized clinical trials., (Copyright © 2014 Elsevier Inc. All rights reserved.)

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.

Lymphocytic and collagenous colitis are forms of microscopic colitis which typically presents in elderly patients as chronic watery diarrhea. The association between microscopic colitis and inflammatory bowel disease is weak and unclear. Lymphocytic colitis progressing to ulcerative colitis has been previously reported; however there is limited data on ulcerative colitis evolving into microscopic (lymphocytic or collagenous) colitis. We report a series of six patients with documented ulcerative colitis who subsequently were diagnosed with collagenous colitis or lymphocytic colitis suggesting microscopic colitis could be a part of the spectrum of inflammatory bowel disease. The median duration of ulcerative colitis prior to being diagnosed with microscopic colitis was 15 years. We noted complete histological and/or symptomatic remission in three out of six cases while the other three patients reverted back into ulcerative colitis suggesting lymphocytic or collagenous colitis could present as a continuum of ulcerative colitis. The exact molecular mechanism of this histological transformation or the prognostic implications is still unclear. Till then it might be prudent to follow up these patients to assess for the relapse of inflammatory bowel disease as well as for dysplasia surveillance.