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.

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.

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.

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

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.

The olmesartan is a selective antagonist of angiotensin II indicated for the treatment of essential hypertension. We report the case of a gastrointestinal involvement with duodenal villous atrophy and lymphocytic infiltrate duodenal epithelial and colonic secondary to the olmesartan taking with test of positive reintroduction. The patient had chronic diarrhea with weight loss of 10kg occurring one month after the passage of 20 to 40mg/day olmesartan took three years. A rectosigmoidoscopy highlighted some puncture slightly erythematous areas. The responsibility of olmesartan was suspected and the drug was stopped. The evolution was rapidly favorable with disappearance of diarrhea 48hours later. Two days after the patient took the drug on its own initiative. Sigmoid biopsies showed an inflammatory infiltrate rich in lymphocytes. Gastroscopy showed erosive esophagitis and duodenal biopsies showed chronic duodenitis with epithelial lymphocytosis and subtotal villous atrophy. The reintroduction has led to the immediate resumption of diarrhea. Olmesartan was finalized. Diarrhea has not returned since. A colonoscopy performed six weeks after discharge was normal. Knowledge of the bowel olmesartan is recent and based almost solely on the description of 22 cases observed at the Mayo Clinic with patients, as in our case, have similar symptoms and lesions. We stress, about a publication of an isolated case, the possibility of less severe cases with histological abnormalities without clinical translation.

The olmesartan is a selective antagonist of angiotensin II indicated for the treatment of essential hypertension. We report the case of a gastrointestinal involvement with duodenal villous atrophy and lymphocytic infiltrate duodenal epithelial and colonic secondary to the olmesartan taking with test of positive reintroduction. The patient had chronic diarrhea with weight loss of 10kg occurred 1 month after the passage of 20 to 40mg/day olmesartan took 3 years. A rectosigmoidoscopy highlighted some puncture slightly erythematous areas. The responsibility of olmesartan was suspected and the drug was stopped. The evolution was rapidly favorable with disappearance of diarrhea 4 8hours later. Two days after the patient took the drug on its own initiative. Sigmoid biopsies showed an inflammatory infiltrate rich in lymphocytes. Gastroscopy showed erosive esophagitis and duodenal biopsies showed chronic duodenitis with epithelial lymphocytosis and subtotal villous atrophy. The reintroduction has led to the immediate resumption of diarrhea. olmetec was finalized. Diarrhea has not returned since. A colonoscopy performed 6 weeks after discharge was normal. Knowledge of the bowel olmesartan is recent and based almost solely on the description of 22 cases observed at the Mayo Clinic with patients, as in our case, have similar symptoms and lesions. We stress about a publication an isolated case the possibility of less severe cases with histological abnormalities without clinical translation.

Microscopic colitis (MC) is the common denominator for lymphocytic and collagenous colitis (CC). It is now recognized as a relatively frequent cause of diarrhea that equals the prevalence of inflammatory bowel disease. Patients are typically middle-aged women, but disease may occur at every age. Patients with MC report watery, non-bloody diarrhea in the absence of endoscopic and radiologic abnormalities. Lymphocytic colitis is characterized by an increased number of intraepithelial lymphocytes, and CC by a thickened subepithelial collagen band, whereas in both an increased mononuclear infiltration of the lamina propria is found. The pathogenesis of MC is largely unknown, but may relate to autoimmunity, adverse reactions to drugs or (bacterial) toxins, and abnormal collagen metabolism in the case of CC. Budesonide is so far the only drug that has proven efficacy in randomized controlled trials both for the induction and maintenance of remission. Patients who are nonresponsive, dependent or who experience side effects on budesonide may benefit from thiopurine or anti-TNF treatment, but these options are still experimental. The long-term prognosis of MC is good; it does not appear to predispose to malignancies and can in some cases be self-limiting. Further research and randomized clinical trials are required to expand our understanding of the natural course and the pathogenesis of MC.

The literature review gives the present-day views of the definition, etiology, pathogenesis, diagnosis, and treatment of microscopic colitis (MC). In the present view, MC is an inflammatory bowel disease of unknown etiology, which is characterized by chronic watery diarrhea, no macroscopic signs of large bowel involvement in the presence of specific pathomorphological changes. There are two major forms of MC, which are similar in its clinical picture, yet, heterogeneous in histological criteria: collagenous colitis (CC) and lymphocytic colitis (LC). As of now, the prevalence of MC is about 100 cases per 100,000 population, which is similar with that in other inflammatory bowel diseases, such as ulcerative colitis and Crohn's disease. MC generally prevails in women aged over 50 years. The etiology and pathogenesis of MC have not fully investigated. Watery diarrhea is as a predominant pathognomonic symptom in all the patients with MC. The major histological criterion for the diagnosis of CC is subepithelial collagen lining thickening (more than 10 pm) and that for LC is higher intraepithelial lymphocyte counts (more than 20 intraepithelial lymphocytes/100 epitheliocytes). The topical glucocorticosteroid budesonide is currently the only agent, the efficacy of which has been proven in both inducing and maintaining remission in patients with MC in many clinical trials.

There have been several reported cases of lansoprazole-associated collagenous colitis (CC) reported in the literature but only 1 reported case of lansoprazole-associated lymphocytic colitis (LC) in the literature. Both CC and LC are considered inflammatory bowel diseases, but they are distinctly classified based on the condition of the colon, which is typically confirmed through biopsy.

A 52-year-old white male (Patient 1), with a height of 178 cm and weight of 75 kg, presented to Gazi University Hospital, Ankara, Turkey, with a 3-month history of abdominal pain and nonbloody, watery diarrhea. The patient reported receiving PO lansoprazole 30 mg/d to treat heartburn ~1 week prior to the onset of diarrhea. The patient's medical history revealed that he did not have any preexisting conditions, other than gastroesophageal reflux disease (GERD) for which lansoprazole was prescribed. The medical history report also revealed that the patient was not receiving any concomitant medications or treatments at the time. A colon biopsy confirmed LC. Additionally, a 43-year-old white female (Patient 2), with a height of 168 cm and weight of 61 kg, presented to the same facility with a 6-month history of nonbloody, watery diarrhea and mild lower abdominal cramping. The patient reported that initial onset began ~2 months after receiving a 10-day Helicobacter pylori eradication combination treatment regimen that included lansoprazole, amoxicillin, and clarithromycin, followed by lansoprazole monotherapy to treat GERD. The patient's medical history revealed no other concomitant medications were being adminstered at the time. A colon biopsy confirmed LC.

A search of the literature using the MEDLINE database and all relevant English-language articles with key words lansoprazole and lymphocytic colitis, found that there were several cases of lansoprazole-associated CC reported and 1 reported case of lansoprazole-associated LC. Histologic findings from laboratory tests and colon biopsies confirmed diagnoses of LC in both patients in this case report. Patient 1 presented with diarrhea and cramping, which the patient reported had been ongoing for ~3 months, following lansoprazole administration. However, after lansoprazole was discontinued, the symptoms completely resolved within 7 days. Patient 2 presented with diarrhea and cramping, which had been occurring for ~6 months. That patient reported that initial onset commenced ~2 months after a 10-day H pylori eradication combination treatment regimen that included lansoprazole, amoxicillin, and clarithromycin, followed by lansoprazole monotherapy to treat GERD. However, after sulfasalazine (3 g/d) was prescribed for 2 months immediately upon diagnosis of LC, there was little improvement in the effort to control the diarrhea in this patient. After omeprazole 20 mg/d was substituted for lansoprazole, the patient's diarrhea ceased. Follow-up sigmoidoscopy 2 months later revealed normal mucosa and complete normalization of histologic findings. The patient remains diarrhea-free while on omeprazole. A causality assessment using the Naranjo adverse reaction algorithm produced scores of 6 for both patients, suggesting that LC was probably associated with lansoprazole treatment.

Here we report 2 cases of LC in patients probably associated with the administration of lansoprazole treatment. Complete remission occurred after lansoprazole was discontinued.

The relationship between the thickness of subepithelial collagen bands (CB) and the development of linear ulcerations (LU) in collagenous colitis (CC) remains unclear. The aim of the present study was to compare the clinical and pathological features, including the thickness of CB, in CC patients with and without LU.

Twenty-five patients with CC diagnosed by pathological examination of biopsy specimens were analyzed. Eleven patients with LU (LU group) and 14 patients without LU (non-LU group) were compared.

Ten patients in the LU group and seven in the non-LU group were taking lansoprazole (P = 0.038). Seven patients in the LU group and one in the non-LU group were taking non-steroidal anti-inflammatory drugs (NSAIDs) (P = 0.004). All LU were locatedin the transverse or left colon. Patients in the LU group were older than those in the non-LU group (P = 0.015). CB were significantly thicker in the LU group than in the non-LU group (mean ± SD, 40 ± 21 μm vs 20 ± 11 μm, P = 0.004). Multivariate analysis showed that NSAIDs use (odds ratio, 19.236; 95% confidence interval, 1.341-275.869) and CB thickness (odds ratio, 0.893; 95% confidence interval, 0.804-0.999) were independently associated with the development of LU.

Use of lansoprazole and NSAIDs, thick CB, and advanced age are associated with the development of LU in CC patients.

Microscopic colitis (MC) is an inflammatory bowel disease presenting with chronic, non-bloody watery diarrhoea and few or no endoscopic abnormalities. The histological examination reveals mainly two subtypes of MC, lymphocytic or collagenous colitis. Despite the fact that the incidence in MC has been rising over the last decades, research has been sparse and our knowledge about MC remains limited. Specialists in the field have initiated the European Microscopic Colitis Group (EMCG) with the primary goal to create awareness on MC. The EMCG is furthermore a forum with the intention to promote clinical and basic research. In this article statements and comments are given that all members of the EMCG have considered being of importance for a better understanding of MC. The paper focuses on the newest updates in epidemiology, symptoms and diagnostic criteria, pathophysiology and highlights some unsolved problems. Moreover, a new treatment algorithm is proposed on the basis of new evidence from well-designed, randomized control trials.

Lymphocytic colitis (LC) and collagenous colitis (CC), 2 histologic forms of microscopic colitis, were recognized as rare disease entities 4 decades ago. An increasing body of evidence accumulated in the past 40 years reveals increasing incidence and prevalence rates, a wide spectrum of clinical presentations, and several histologic variants. Although several recent randomized clinical trials confirmed the efficacy of oral budesonide in treating LC and CC, disease relapse after a short-duration treatment is common. Despite their common clinical presentations and well-defined histologic diagnostic criteria, there are only few studies on the immunologic abnormalities in colonic tissue. The aim of this review is to (1) familiarize the pathologists in general practice with histomorphology of LC and CC, including the rare histologic variants and the clinical implication associated with these 2 diagnoses, (2) summarize the data from recent randomized clinical trials of oral budesonide, and (3) review immunological studies on colonic tissue. Overall, immunologic abnormalities of colonic tissue seem to explain for the histomorphologic features and the clinical symptomatology of LC and CC. Advances in the understanding of the underlying immunologic abnormalities in the colonic tissue may help develop novel and effective therapies for these 2 diseases.

Microscopic colitis is a common cause of chronic watery diarrhea, especially among older persons. Diagnosis requires histologic analysis of colon biopsy samples in the appropriate clinical setting. Recent studies have shown an increase in the incidence of microscopic colitis, and several have addressed potential mechanisms. We review recent findings about the clinical features, diagnosis, epidemiology, pathophysiology, and treatment of microscopic colitis.

There has been an ample interest in delivery of therapeutic molecules using live cells. Oral delivery has been stipulated as best way to deliver live cells to humans for therapy. Colon, in particular, is a part of gastrointestinal (GI) tract that has been proposed to be an oral targeted site. The main objective of these oral therapy procedures is to deliver live cells not only to treat diseases like colorectal cancer, inflammatory bowel disease, and other GI tract diseases like intestinal obstruction and gastritis, but also to deliver therapeutic molecules for overall therapy in various diseases such as renal failure, coronary heart disease, hypertension, and others. This review provides a comprehensive summary of recent advancement in colon targeted live bacterial cell biotherapeutics. Current status of bacterial cell therapy, principles of artificial cells and its potentials in oral delivery of live bacterial cell biotherapeutics for clinical applications as well as biotherapeutic future perspectives are also discussed in our review.

Although some cases of collagenous colitis have been induced by lansoprazole (LPZ), the clinicopathologic features of LPZ-associated collagenous colitis have not been elucidated.

To elucidate the clinical, endoscopic, and histopathologic features of LPZ-associated collagenous colitis.

Retrospective case study.

The subjects were 13 patients with collagenous colitis diagnosed during a period from 2002 to 2007.

The colonoscopic and histopathologic findings were compared retrospectively between 9 cases of LPZ use (LPZ group) and 4 cases without the use of LPZ (non-LPZ group).

A colonoscopy revealed a linear mucosal defect more frequently in the LPZ group (7 of 9 cases [78%]) than in the non-LPZ group (0 of 4 cases [0%], P = .02). Friable mucosa was also noted in 4 patients (44%) in the LPZ group but none in the non-LPZ group. The colonoscopic finding in the non-LPZ group was either normal mucosa or nonspecific minimal abnormalities, whereas patients in the LPZ group had either a linear mucosal defect, mucosal bleeding, or both (P = .001). On histologic examination, the subepithelial collagen band was thicker in patients in the LPZ group than in those in the non-LPZ group (median 45 vs 26.3 mum). All patients in the LPZ group recovered from diarrhea after discontinuance of LPZ.

A small number of patients.

Linear mucosal defects and friable mucosa may be characteristic colonoscopic findings in cases of LPZ-associated collagenous colitis.

Collagenous colitis is a cause of chronic diarrhea. Treatment has been based mainly on anecdotal evidence. This review was performed to identify therapies for collagenous colitis that have been proven in randomized trials.

To determine effective treatments for patients with collagenous colitis.

Relevant papers published between 1970 and December 2007 were identified via the MEDLINE and PUBMED databases. Manual searches from the references of identified papers, as well as review papers on collagenous or microscopic colitis were performed to identify additional studies. Abstracts from major gastroenterological meetings were searched to identify research submitted in abstract form only. Finally, the Cochrane Controlled Trials Register and the Cochrane Inflammatory Bowel Disease and Functional Bowel Disorders Group Specialized Trials Register were searched for other studies.

Ten randomized trials were identified. Seven of these compared active treatment to placebo for treating active disease. Of these, 1 trial studied bismuth subsalicylate, 1 trial studied Boswellia serrata extract, 3 trials studies budesonide, 1 trial studied prednisolone, and 1 trial studied probiotics. One trial compared mesalamine to mesalamine + cholestyramine for treating active disease. Two trials compared budesonide to placebo in maintaining response induced by budesonide.

Data were extracted independently by each author onto 2x2 tables (treatment versus comparator and response versus no response). For therapies assessed in one trial only, P-values were derived using the chi-square test. For therapies assessed in more than one trial, summary test statistics were derived using the Peto odds ratio and 95% confidence intervals. Data were combined for analysis only if the outcomes were sufficiently similar in definition.

In treating active disease, there were 9 patients with collagenous colitis in the trial studying bismuth subsalicylate (nine 262 mg tablets daily for 8 weeks). Clinical response occurred in 100% of patients who received bismuth subsalicylate compared to 0% of patients who received placebo (P = 0.03). Thirty-one patients were enrolled in the trial studying Boswellia serrata extract (three 400 mg capsules daily for 8 weeks). Clinical response occurred in 44% of patients who received Boswellia serrata extract compared to 27% of patients who received placebo (P = 0.32). A total of 94 patients were enrolled in 3 trials studying budesonide (9 mg daily or in a tapering schedule for 6 to 8 weeks). Clinical response occurred in 81% of patients who received budesonide compared to 17% of patients who received placebo (P < 0.00001). The pooled odds ratio for clinical response to treatment with budesonide was 12.32 (95% CI 5.53 to 27.46), with a number needed to treat of 2 patients. Statistically significant histological response occurred with treatment in all 3 trials studying budesonide therapy. Eleven patients were enrolled in the trial studying prednisolone (50 mg daily for 2 weeks). Clinical response occurred in 63% of patients who received prednisolone compared to 0% who received placebo (P = 0.15). Twenty-nine patients were enrolled in the trial studying probiotics (2 capsules containing 0.5 x 10(10) CFU each of L. acidophilus LA-5 and B. animalis subsp. lactis strain BB-12 twice daily for 12 weeks). Clinical response occurred in 29% of patients who received probiotics compared to 13% of patients who received placebo (P = 0.38). Twenty-three patients were enrolled in the trial studying mesalamine (800 mg three times daily) with or without cholestyramine (4 g daily) for 6 months. Clinical response occurred in 73% of patients who received mesalamine alone compared to 100% of patients who received mesalamine + cholestyramine (P = 0.14). In maintaining response, 80 patients who had responded to open-label budesonide were enrolled in 2 trials studying budesonide (6 mg daily for 6 months). Clinical response was maintained in 83% of patients who received budesonide compared to 28% of patients who received placebo (P = 0.0002). The pooled odds ratio for maintenance of clinical response to treatment with budesonide was 8.40 (95% CI 2.73 to 25.81), with a number needed to treat of 2 patients. Histological response was maintained in 48% of patients who received budesonide compared to 15% of patients who received placebo (P = 0.002).

Budesonide is effective for inducing and maintaining clinical and histological response in patients with collagenous colitis. The evidence for benefit with bismuth subsalicylate and for mesalamine with or without cholestyramine is weak. There is no evidence for the effectiveness of Boswellia serrata extract, prednisolone, or probiotics. These agents and other therapies require further study.

Both diarrhea and colitis associated with clozapine have been reported. In this article, the authors present a case of clozapine-induced microscopic colitis (MC)-the first reported in the literature. The definitive diagnosis was suggested on colon biopsy, which showed an intraepithelial lymphocytosis (with >20 lymphocytes for every 100 epithelial cells) more striking in the surface epithelium than in the crypts. In addition, there were a mixed inflammatory infiltrate in the lamina propria (with lymphocytes predominating over eosinophils and neutrophils), an architecturally preserved colonic mucosa (particularly in the crypts), and a subepithelial collagen band normally thickened (<10 microm). Clozapine was thought to be the culprit and discontinued. After some days, the patient gradually improved. Diarrhea and spiking fever disappeared within 72 hours. Multiple colon biopsies taken after 7 days from the discontinuation of the clozapine revealed no abnormal histological findings. It is important to clarify the issue of clozapine-induced MC because MC may require the use of expensive or potentially toxic treatments and can occasionally be life-threatening (eg, hypokalemia). Thus, any case of MC that can be cured by withdrawal of the clozapine must be investigated and identified.

Approximately 10% of patients with chronic diarrhea carry a diagnosis of microscopic colitis. The endoscopic appearance of both collagenous colitis and lymphocytic colitis may be normal; however, biopsies confirm the diagnosis. Available treatments include antidiarrheals, bismuth salicylate, and budesonide. Although most patients with fecal diversion may have endoscopic evidence of colitis, a much smaller percentage of patients are symptomatic. Some cases of diversion colitis respond to treatment with short-chain fatty acid enemas; however, return of the fecal stream is the most successful therapy. A variety of oral, intravenous, and per rectum chemicals may cause colitis; symptoms usually abate when chemical exposure is discontinued.

Collagenous colitis is a disorder that is recognized as a cause of chronic diarrhea. Treatment has been based mainly on anecdotal evidence. This review was performed to identify therapies for collagenous colitis that have been proven in randomized trials.

To determine effective treatments for patients with clinically active collagenous colitis.

Relevant papers published between 1970 and June 2006 were identified via the MEDLINE and PUBMED databases. Manual searches from the references of identified papers, as well as review papers on collagenous or microscopic colitis were performed to identify additional studies. Abstracts from major gastroenterological meetings were searched to identify research submitted in abstract form only. Finally, the Cochrane Controlled Trials Register and the Cochrane Inflammatory Bowel Disease and Functional Bowel Disorders Group Specialized Trials Register were searched for other studies.

Seven randomized trials were identified. One trial studied bismuth subsalicylate (published in abstract form only), one trial studied Boswellia serrata extract (published in abstract form only), one trial studied probiotics, one trial studied prednisolone, and 3 trials studied budesonide for the therapy of collagenous colitis.

Data were extracted independently by each author onto 2x2 tables (treatment versus placebo and response versus no response). For therapies assessed in one trial only, p-values were derived using the chi-square test. For therapies assessed in more than one trial, summary test statistics were derived using the Peto odds ratio and 95% confidence intervals. Data were combined for analysis only if the outcomes were sufficiently similar in definition.

There were 9 patients with collagenous colitis in the trial studying bismuth subsalicylate (nine 262 mg tablets daily for 8 weeks). Those randomized to active drug were more likely to have clinical (p = 0.003) and histological (p = 0.003) improvement than those assigned to placebo. Eleven patients were enrolled in the trial studying prednisolone (50 mg daily for 2 weeks). There was a trend towards clinical response in patients on active medication compared to placebo (p = 0.064). The effect of prednisolone on histologic improvement was not studied. Thirty-one patients were enrolled in the Boswellia serrata extract trial. Clinical improvement was noted in 44% of patients who received active treatment compared to 27% of patients who received placebo (p = 0.32). Twenty-nine patients were enrolled in the probiotics trial. Clinical improvement was noted in 29% of patients who received probiotics compared to 13% of patients who received placebo (p = 0.635). A total of 94 patients were enrolled in 3 trials studying budesonide (9 mg daily or in a tapering schedule for 6 to 8 weeks). The pooled odds ratio for clinical response to treatment with budesonide was 12.32 (95% CI 5.53-27.46), with a number needed to treat of 2 patients. There was significant histological improvement with treatment in all 3 trials studying budesonide therapy. Budesonide also appears to improve patients' quality of life.

Budesonide is effective for the treatment of collagenous colitis. The evidence for benefit with bismuth subsalicylate is weaker. The effectiveness of prednisolone, Boswellia serrata extract, probiotics and other therapies for induction or maintenance of remission of collagenous colitis is unknown and requires further study.

Collagenous colitis is characterised by watery diarrhoea, normal colonic mucosa on endoscopy, diffuse colitis with surface epithelial injury, and a distinctive thickening of the subepithelial collagen table on histology. Some patients can develop medically refractory collagenous colitis, in which case they may require surgical intervention. This is the first report of collagenous pouchitis in a collagenous colitis patient with proctocolectomy and ileal pouch-anal anastomosis. A patient with medically refractory collagenous colitis who underwent a total proctocolectomy and ileal pouch-anal anastomosis was sequentially evaluated with an endoscopy and histology of the colon, distal small intestine, and ileal pouch. A 58-year-old female had a 10-year history of collagenous colitis before having a total proctocolectomy and ileal pouch-anal anastomosis for medically refractory disease. The histologic features of collagenous colitis were present in all colon and rectum biopsy or resection specimens, but were absent in the distal ileum specimen. The post-operative course was complicated by persistent increase of stool frequency, abdominal cramps, and incontinence. A pouch endoscopy was performed 3 years after ileal pouch-anal anastomosis which showed the histologic features of collagenous colitis in the ileal pouch, collagenous pouchitis, while the pre-pouch neo-terminal ileum had no pathologic changes. After antibiotic therapy, the histologic changes of collagenous pouchitis resolved. This is the first reported case of collagenous pouchitis. Since the abnormal collagen table and its associated features were only present in the pouch and absent in the neo-terminal ileum, and the patient had histologic improvement after antibiotic therapy, it would suggest that faecal stasis and bacterial load may play a role in the pathogenesis.

The pathophysiology of microscopic colitis is unknown, although it is thought to be because of an abnormal immune reaction to luminal antigens in predisposed hosts. Specific antigens have not been proved, although various infectious triggers and drugs have been proposed. The responsibility of several drugs has been questioned, some with strong clinical and/or histological evidence suggesting causality. The issue of drug-induced microscopic colitis is important because of the burden of this disease. Thus, any case that can be cured by withdrawal of a drug must be identified. In this report, we propose a scoring system for drug-induced microscopic colitis, adapting existing criteria of drug causality, and review the literature using this framework. Based on this review, several drugs are identified with intermediate or high likelihood of inducing microscopic colitis. Finally, we suggest how to treat individual patients suspected of having drug-induced colitis according to the level of evidence for that particular drug.

Collagenous mucosal inflammatory diseases involve the columnar-lined gastric and intestinal mucosa and have become recognized increasingly as a significant cause of symptomatic morbidity, particularly in middle-aged and elderly women, especially with watery diarrhea. Still, mechanisms involved in the pathogenesis of this diarrhea remain poorly understood and require further elucidation. The prognosis and long-term outcome of these disorders has been documented only to a limited extent. Recent clinical and pathologic studies have indicated that collagenous mucosal inflammatory disease is a more extensive pathologic process that concomitantly may involve several sites in the gastric and intestinal mucosa. The dominant pathologic lesion is a distinct subepithelial hyaline-like deposit that has histochemical and ultrastructural features of collagen overlying a microscopically defined inflammatory process. An intimate relationship with other autoimmune connective tissue disorders is evident, particularly celiac disease. This is intriguing because these collagenous disorders have not been shown to be gluten dependent. Collagenous mucosal inflammatory disorders may represent a relatively unique but generalized inflammatory response to a multitude of causes, including celiac disease, along with a diverse group of pharmacologic agents. Some recent reports have documented treatment success but histopathologic reversal has been more difficult to substantiate owing to the focal, sometimes extensive nature, of this pathologic process.

To conduct a systematic review to determine effective treatments for patients with clinically active collagenous colitis.

Relevant articles were identified via the MEDLINE, PUBMED, and Cochrane Collaboration databases, manual searches of the references of identified articles, and review articles on collagenous or microscopic colitis, as well as searches of abstracts from major gastroenterological meetings.

Five randomized trials assessing treatments for collagenous colitis were identified. One trial studying bismuth subsalicylate (nine 262 mg tablets daily for 8 wk) included 9 patients. Patients who received the bismuth preparation were more likely to have clinical (p= 0.003) and histological (p= 0.003) improvement than those who received placebo. In a trial comparing prednisolone (50 mg daily for 2 wk) to a placebo in 11 patients, a trend toward clinical response in patients on prednisone was reported (p= 0.064). The effect of prednisolone on histological improvement was not studied. A total of 94 patients were enrolled in three trials studying budesonide (9 mg daily or in a tapering schedule for 6-8 wk). The pooled odds ratio for clinical response to treatment with budesonide was 12.32 (95% CI: 5.53-27.46). The NNT (number of patients needed to treat with budesonide to achieve 1 improved patient) was 2 patients. This therapy was well tolerated. There was significant histological improvement with treatment in all three trials studying budesonide therapy.

There is strong evidence that budesonide is effective and well tolerated for the treatment of collagenous colitis. The evidence for benefit with bismuth subsalicylate or prednisolone is weaker. It is not clear that any of these agents produce actual remission, as opposed to clinical and histological improvement of the disease.

Microscopic colitis is an increasingly common cause of chronic diarrhea, and often causes abdominal pain and weight loss. The colonic mucosa appears normal or nearly normal endoscopically, and the diagnosis is made in the appropriate clinical setting when there is intraepithelial lymphocytosis and a mixed lamina propria inflammatory infiltrate. The 2 subtypes, collagenous and lymphocytic colitis, are similar clinically and histologically, and are distinguished by the presence or absence of a thickened subepithelial collagen band. Many potential pathophysiologic mechanisms have been proposed, but no convincing unifying mechanism has been identified. There are many anecdotal reports on treatment, but few controlled trials have been performed in these patients, although a systematic approach to therapy often leads to the satisfactory control of symptoms.

Lansoprazole is a potent proton pump inhibitor that has been well tolerated with minimal serious adverse events. One of the most commonly reported side effects is diarrhea in 3-8% of study patients. During 1997, approximately 850 veterans at our institution had their proton pump inhibitor converted from omeprazole to lansoprazole because of a formulary change. A number of patients subsequently developed chronic watery diarrhea. While evaluating six of these patients, we discovered microscopic colitis that resolved with discontinuation of lansoprazole. The diarrhea was described as three to 10 loose, nonbloody bowel movements per day with some abdominal cramping. Colonoscopy in five patients and flexible sigmoidoscopy in one patient revealed normal colonic mucosa, but random biopsies all supported microscopic colitis (five cases of lymphocytic colitis and one case of collagenous colitis). Complete symptom resolution occurred in all patients within 4 to 10 days of discontinuing lansoprazole. In all patients, follow-up biopsies demonstrated normalization of the colonic histology. This is the first published case series of patients with microscopic colitis that correlated clinically and histologically with the initiation and discontinuation of lansoprazole.

Microscopic colitis is a relatively common cause of chronic watery diarrhea, often accompanied by abdominal pain and weight loss. The colonic mucosa appears normal grossly, and the diagnosis is made when there is an intraepithelial lymphocytosis and a mixed inflammatory infiltrate in the lamina propria. The two main subtypes, collagenous and lymphocytic colitis, are similar clinically and histologically, distinguished by the presence or absence of a thickened subepithelial collagen band. Many potential pathophysiological mechanisms have been described, although none have been conclusively proved. There is a paucity of randomized treatment trials in these patients, although a rational approach to therapy often leads to satisfactory control of symptoms.

Collagenous colitis is a diarrheal illness of unknown cause. The purpose of this report is to describe a case of collagenous colitis related to lansoprazole exposure.

Case report.

A patient is described who developed clinical and pathologic findings of collagenous colitis during treatment with lansoprazole and omeprazole. Symptoms of diarrhea and histopathologic abnormalities resolved after drug withdrawal and recurred with re-exposure to lansoprazole.

The observations are compatible with collagenous colitis or lymphocytic colitis associated with exposure to lansoprazole.

Diarrhoea is a relatively frequent adverse event, accounting for about 7% of all drug adverse effects. More than 700 drugs have been implicated in causing diarrhoea; those most frequently involved are antimicrobials, laxatives, magnesium-containing antacids, lactose- or sorbitol-containing products, nonsteroidal anti-inflammatory drugs, prostaglandins, colchicine, antineoplastics, antiarrhythmic drugs and cholinergic agents. Certain new drugs are likely to induce diarrhoea because of their pharmacodynamic properties; examples include anthraquinone-related agents, alpha-glucosidase inhibitors, lipase inhibitors and cholinesterase inhibitors. Antimicrobials are responsible for 25% of drug-induced diarrhoea. The disease spectrum of antimicrobial-associated diarrhoea ranges from benign diarrhoea to pseudomembranous colitis. Several pathophysiological mechanisms are involved in drug-induced diarrhoea: osmotic diarrhoea, secretory diarrhoea, shortened transit time, exudative diarrhoea and protein-losing enteropathy, and malabsorption or maldigestion of fat and carbohydrates. Often 2 or more mechanisms are present simultaneously. In clinical practice, 2 major types of diarrhoea are seen: acute diarrhoea, which usually appears during the first few days of treatment, and chronic diarrhoea, lasting more than 3 or 4 weeks and which can appear a long time after the start of drug therapy. Both can be severe and poorly tolerated. In a patient presenting with diarrhoea, the medical history is very important, especially the drug history, as it can suggest a diagnosis of drug-induced diarrhoea and thereby avoid multiple diagnostic tests. The clinical examination should cover severity criteria such as fever, rectal emission of blood and mucus, dehydration and bodyweight loss. Establishing a relationship between drug consumption and diarrhoea or colitis can be difficult when the time elapsed between the start of the drug and the onset of symptoms is long, sometimes up to several months or years.

Microscopic colitis describes a subset of patients with chronic watery diarrhea of unknown origin, and normal endoscopic findings and microscopic evidence of an inflammatory infiltrate in the colonic mucosa. We report two cases associated with sicca syndrome.

A 56-year-old woman and a 76-year-old man presented with a history of lymphocytic colitis associated with sicca syndrome. Drugs or infectious agents were not implicated in the cause of lymphocytic colitis, suggesting that sicca syndrome may be involved in the pathogenesis of microscopic colitis.

These cases suggest that sicca syndrome should be detected in patients with lymphocytic colitis.