Lansoprazole-associated microscopic colitis: a case series

Colon perforation due to collagenous colitis: A case report

Collagenous colitis (CC) is generally benign, and serious complications are rare. It is important to note that spontaneous perforation of CC is a possible complication. In the case of colon perforation of unknown origin, CC should be considered.

Diagnosis and Management of Microscopic Colitis in Pediatric Patients

Microscopic colitis (MC) is an inflammatory disease of the colon, characterized by chronic watery diarrhea with distinguishing histologic findings despite normal endoscopic appearance of the colonic mucosa. MC is a common cause of diarrhea in older adults, though it has been infrequently reported in children and adolescents. As MC is rare in the pediatric population, and the clinical presentation is non-specific, increased awareness of this disease amongst pediatric clinicians and pathologists is essential for timely diagnosis, which requires performing colonoscopy with biopsy. The etiology of MC is incompletely understood, but current theories in pathogenesis inform management strategies. The goals of management in pediatric MC should be to achieve symptomatic improvement while minimizing adverse effects of treatment. Many patients who achieve clinical response have symptomatic recurrence after discontinuation of initial therapy, and may require maintenance medication therapy to sustain remission. This review aims to summarize the epidemiology and risk factors, clinical features, diagnosis, theories regarding pathogenesis, and suggested management approaches for MC in the pediatric population.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSION

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

Colitis nucleomigrans: The third type of microscopic colitis (part 1)

Microscopic colitis (MC), encompassing collagenous colitis and lymphocytic colitis, is featured by chronic diarrhea, normal‐looking endoscopic findings and unique microscopic appearance. After reviewing biopsied nonspecific colitis, we propose the third type of MC: colitis nucleomigrans (CN). Histopathological criteria of CN included: (i) chained nuclear migration to the middle part of the surface‐lining columnar epithelium; (ii) apoptotic nuclear debris scattered below the nuclei; and (iii) mild/moderate chronic inflammation in the lamina propria. Thirty‐three patients (M:F = 20:13; median age 63 years, range 17–88) fulfilled our criteria. Seven cases demonstrated MC‐like clinical/endoscopic features. Mucosal reddening with or without erosion/aphtha was endoscopically observed in the remaining 26 cases with inflammatory bowel disease (IBD)‐like features: occult/gross hematochezia seen in 19, abdominal pain in two and mucin secretion in two. Cleaved caspase‐3‐immunoreactive apoptotic debris appeared more frequently in IBD‐like CN than in MC‐like CN, while CD8‐positive intraepithelial lymphocytes comparably appeared in both. Proton pump inhibitors (PPIs) were administered in five (71%) cases with MC‐like features, and in three diarrhea improved after drug cessation. In IBD‐like CN cases, eight (31%) received PPIs. Four patients received chemotherapy against malignancies. Four patients associated immune‐related disorders. Microscopic appearance of CN also appeared in a remission state of ulcerative colitis (12/20 lesions).

Microscopic colitis impacts quality of life in older people

This report describes a frail 92-year-old woman with dementia who presented with a year's history of chronic watery non-bloody diarrhoea. She had abdominal bloating, weight loss, faecal urgency, nocturnal stools and developed faecal incontinence. Her serum C reactive peptide and faecal calprotectin were elevated. Flexible sigmoidoscopy was macroscopically normal, but demonstrated histological features of microscopic colitis (MC) in sigmoid colon and rectal biopsies. Polypharmacy was reviewed for possible medication-induced MC. Ranitidine, donepezil and simvastatin were discontinued. She was started on oral budesonide with improvement in the abdominal and bowel symptoms. Stool frequency and consistency normalised, and the faecal incontinence resolved with treatment. The outcomes were an improved quality of life, reduced functional dependency, reduced carer strain and avoidance of premature transition from her home into a long-term/institutional care setting. We briefly review terminology, basic epidemiology, notable associations, the importance of establishing a diagnosis and some treatment considerations for MC.

Smoking is Associated with an Increased Risk of Microscopic Colitis: Results From Two Large Prospective Cohort Studies of US Women

BACKGROUND

Long-term data on the influence of smoking on risk of microscopic colitis are limited. We therefore sought to examine and characterize the association between smoking and risk of incident microscopic colitis in two large prospective cohorts of women.

METHODS

We conducted a prospective study of 231015 women enrolled in the Nurses' Health Study [NHS] and NHSII. Information regarding smoking, other lifestyle factors and medications were collected biennially from 1976 to 2012 in NHS and from 1989 to 2013 in NHSII. Incident cases of microscopic colitis were confirmed through physician medical record review. We used Cox proportional hazards modelling to examine the association between smoking and risk of microscopic colitis.

RESULTS

We documented 166 incident cases of microscopic colitis over 6122779 person-years of follow up. Compared to non-smokers, the multivariable-adjusted hazard ratio [HR] for microscopic colitis was 2.52 (95% confidence interval [CI] 1.59-4.00) amongst current smokers and 1.54 [95% CI 1.09-2.17] amongst past smokers. The risk increased with higher pack-years of smoking [p trend = 0.001] and diminished following smoking cessation [p trend = 0.017]. Current smoking appeared to be more strongly associated with risk of collagenous colitis [HR 3.68; 95% CI 1.94-6.97] than lymphocytic colitis [HR 1.71; 95% CI 0.83-3.53].

CONCLUSION

In two large prospective cohort studies, we observed an association between current smoking and risk of microscopic colitis. Risk of microscopic colitis appeared to increase with higher pack-years and diminish following smoking cessation. Future studies focused on characterizing the biological mechanisms underlying these associations are warranted.

Development of collagenous colitis in inflammatory bowel disease: two case reports and a review of the literature

The occurrence of collagenous colitis (CC) in patients with pre-existing inflammatory bowel diseases (IBD) is rare, with only seven cases reported in the past. Herein, we report two IBD cases who developed CC after successful treatment of their IBD with two different tumor necrosis factor (TNF)-α inhibitors, which have been previously reported to successfully treat refractory CC. This report highlights the need to do random biopsies of the colon for CC diagnosis in IBD patients with symptoms of diarrhea after complete mucosal healing. The report also reviews plausible mechanisms as to how CC may develop, including the role of multiple medications.

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

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

Cytokine expression of microscopic colitis including interleukin-17

Background/Aims

Microscopic colitis is characterized by chronic watery diarrhea with specific pathological changes that can be diagnosed by microscopic examination. We performed immunohistochemical analysis of proinflammatory cytokines to investigate the pathogenic mechanism of microscopic colitis.

Methods

This study consisted of six patients with lymphocytic colitis, six patients with collagenous colitis, and six patients with functional diarrhea but normal pathology. We performed an immunohistochemical analysis of the colonic mucosal biopsies to assess the expression of cyclo-oxygenase-2, interleukin-17, nuclear factor-κB, interferon-γ, inducible nitric oxide synthase, and tumor necrosis factor-α. We compared the quantity score of immunohistochemical staining among the groups.

Results

The microscopic colitis group showed significantly higher expression of cyclo-oxygenase-2, interleukin-17, nuclear factor-κB, and interferon-γ compared with the control group. Cytokine expression was similar between collagenous colitis and lymphocytic colitis. However, the expression of cyclo-oxygenase-2 was higher in collagenous colitis.

Conclusions

Proinflammatory cytokines, including interleukin-17 and interferon-γ, are highly expressed in microscopic colitis. The expression of cyclo-oxygenase-2 was higher in collagenous colitis than in lymphocytic colitis. This study is the first on interleukin-17 expression in microscopic colitis patients.

Microscopic colitis

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.

Clinical characteristics of collagenous colitis with linear ulcerations

BACKGROUND

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.

PATIENTS AND METHODS

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.

RESULTS

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.

CONCLUSION

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

Proton pump inhibitors are not the key for therapying non-steroidal anti-inflammatory drugs-induced small intestinal injury

The ability of non-steroidal anti-inflammatory drugs (NSAIDs) to injure the small intestine has been well established in humans and animals. Proton pump inhibitors (PPIs) are frequently prescribed to reduce gastric and duodenal injury caused in high-risk patients taking NSAIDs. However, scarce information is available concerning the effects of PPIs on intestinal damage induced by NSAIDs, and the suppression of gastric acid secretion by PPIs is hard to provide any protection against the damage caused by NSAIDs in the small intestine. The present study was designed to examine the effects of intragastric treatment of two PPIs widely used in clinical practice, namely omeprazole and pantoprazole, on the intestinal damage induced by administration of diclofenac in rat. Male SD rats were treated with omeprazole or pantoprazole for 9 days, with concomitant treatment with anti-inflammatory doses of diclofenac on the final 5 days. The anatomical lesion, villous height, the thickness, and the section area of small intestine were quantitatively analyzed. The change of ultrastructural organization was observed. Endotoxin level in blood was measured by photometry. Epidermal growth factor was observed by immunohistochemistry. Omeprazole and pantoprazole didn't decrease the macroscopic and histologic damage induced by diclofenac in the rat's small intestine. In the two PPI groups, villous height was (89.6 ± 11.8 and 92.6 ± 19.3 μm) lower than which of the control group (P < 0.05). The thickness became thinning, and the section area became small. LPS levels in the portal blood of omeprazole and pantoprazole were (4.36 ± 1.26 and 4.25 ± 1.17 EU/ml), significantly higher than in controls (P < 0.05). The EFG of PPI group descended significantly compared with the control group (P < 0.05). Omeprazole and pantoprazole cannot protect the small intestine from the damage induced by diclofenac in the conscious rat. PPIs cannot repair NSAID-induced intestinal damage at least in part because of significant lesion in mechanical barrier function and reduction in epidermal growth factor.

An epidemiological study of collagenous colitis in southern Sweden from 2001-2010

AIM: To estimate the incidence of collagenous colitis (CC) in southern Sweden during 2001-2010.

METHODS: Cases were identified by searching for CC in the diagnostic registers at the Pathology Departments in the county of Skåne. The catchment area comprised the south-west part of the county (394 307 inhabitants in 2010) and is a mixed urban and rural type with limited migration. CC patients that had undergone colonoscopy during the defined period and were living in this area were included in the study regardless of where in Skåne they had been diagnosed. Medical records were scrutinized and uncertain cases were reassessed to ensure that only newly diagnosed CC cases were included. The diagnosis of CC was based on both clinical and histopathological criteria. The clinical criterion was non-bloody watery diarrhoea. The histopathological criteria were a chronic inflammatory infiltrate in the lamina propria, a thickened subepithelial collagen layer ≥ 10 micrometers (μm) and epithelial damage such as flattening and detachment.

RESULTS: During the ten year period from 2001-2010, 198 CC patients in the south-west part of the county of Skåne in southern Sweden were newly diagnosed. Of these, 146 were women and 52 were men, i.e., a female: male ratio of 2.8:1. The median age at diagnosis was 71 years (range 28-95/inter-quartile range 59-81); for women median age was 71 (range 28-95) years and was 73 (range 48-92) years for men. The mean annual incidence was 5.4/10⁵ inhabitants. During the time periods 2001-2005 and 2006-2010, the mean annual incidence rates were 5.4/10⁵ for both periods [95% confidence interval (CI): 4.3-6.5 in 2001-2005 and 4.4-6.4 in 2006-2010, respectively, and 4.7-6.2 for the whole period]. Although the incidence varied over the years (minimum 3.7 to maximum 6.7/10⁵) no increase or decrease in the incidence could be identified. The odds ratio (OR) for CC in women compared to men was estimated to be 2.8 (95% CI: 2.0-3.7). The OR for women 65 years of age or above compared to below 65 years of age was 6.9 (95% CI: 5.0-9.7), and for women 65 years of age or above compared to the whole group the OR was 4.7 (95% CI: 3.6-6.0). The OR for age in general, i.e., above or 65 years of age compared to those younger than 65 was 8.3 (95% CI: 6.2-11.1). During the last decade incidence figures for CC have also been reported from Calgary, Canada during 2002-2004 (4.6/10⁵) and from Terrassa, Spain during 2004-2008 (2.6/10⁵). Our incidence figures from southern Sweden during 2001-2010 (5.4/10⁵) as well as the incidence figures presented in the studies during the 1990s (Terrassa, Spain during 1993-1997 (2.3/10⁵), Olmsted, United States during 1985-2001 (3.1/10⁵), Örebro, Sweden during 1993-1998 (4.9/10⁵), and Iceland during 1995-1999 (5.2/10⁵) are all in line with a north-south gradient, something that has been suggested before both for CC and inflammatory bowel disease.

CONCLUSION: The observed incidence of CC is comparable with previous reports from northern Europe and America. The incidence is stable but the female: male ratio seems to be decreasing.

Clinical Characteristics of Microscopic Colitis in Korea: Prospective Multicenter Study by KASID

BACKGROUND/AIMS

Microscopic colitis (MC) encompasses collagenous and lymphocytic colitis and is characterized by chronic diarrhea. In cases of MC, colonic mucosae are macroscopically normal, and diagnostic histopathological features are observed only upon microscopic examination. We designed a prospective multicenter study to determine the clinical features, pathological distribution in the colon and prevalence of MC in Korea.

METHODS

We prospectively enrolled patients having watery diarrhea no more than 3 times a day between March 2008 and February 2009. We obtained patient histories and performed colonoscopies with random biopsies at each colon segment.

RESULTS

A total of 100 patients with chronic diarrhea were enrolled for a normal colonoscopy and stool exam. MC was observed in 22 patients (22%) (M:F 1.2:1; mean age, 47.5 years). Of those 22 patients, 18 had lymphocytic colitis and 4 had collagenous colitis. The entire colon was affected in only 3 cases (13.6%), the ascending colon in 6 cases (27.2%), the transverse colon in 3 cases (13.6%), and the left colon in 3 cases (13.6%). More than 2 segments were affected in 7 cases (31.8%). Nonsteroidal anti-inflammatory drug-associated MCs were observed in 4 cases (18.2%), 3 of which showed improved diarrhea symptoms following discontinuation of the medication. Frequently associated symptoms were abdominal pain and weight loss. Autoimmune diseases were observed in 4 cases (18.2%). Half of the 22 patients with MC improved with conservative care by loperamide or probiotics.

CONCLUSIONS

In a prospective multicenter study of Korean patients with chronic diarrhea, the frequency of MC was found to be approximately 20%, similar to the percentage observed in Western countries. Therefore, the identification of MC is important for the adequate management of Korean patients with chronic diarrhea.

Lansoprazole-associated collagenous colitis: diffuse mucosal cloudiness mimicking ulcerative colitis

There have only been a few reports on lansoprazole-associated collagenous colitis. Colonic mucosa of collagenous colitis is known to be endoscopically normal. We present a case of collagenous colitis where the mucosa showed diffuse cloudiness mimicking ulcerative colitis. A 70-year-old woman developed watery diarrhea four to nine times a day. She had interstitial pneumonia at 67 and reflux esophagitis at 70 years. Lansoprazole 30 mg/d had been prescribed for reflux esophagitis for nearly 6 mo. Lansoprazole was withdrawn due to its possible side effect of diarrhea. Colonoscopy disclosed diffuse cloudiness of the mucosa which suggested ulcerative colitis. Consequently sulfasalazine 2 g/d was started. The patient's diarrhea dramatically disappeared on the following day. However, biopsy specimens showed subepithelial collagenous thickening and infiltration of inflammatory cells in the lamina propria, confirming the diagnosis of collagenous colitis. One month after sulfasalazine therapy was initiated, colonoscopic and histological abnormalities resolved completely. Five months later the diarrhea recurred. The findings on colonoscopy and histology were the same as before, confirming a diagnosis of collagenous colitis relapse. We found that the patient had begun to take lansoprazole again 3 mo ahead of the recent diarrhea. Withdrawal of lansoprazole promptly resolved the diarrhea. Endoscopic and histological abnormalities were also completely resolved, similar to the first episode. Retrospectively, the date of commencement of sulfasalazine and discontinuation of lansoprazole in the first episode was found to be the same. We conclude that this patient had lansoprazole-associated collagenous colitis.

Prevalence of microscopic colitis in patients with diarrhea of unknown etiology in Turkey

AIM: To investigate the prevalence and demography of microscopic colitis in patients with diarrhea of unknown etiology and normal colonoscopy in Turkey.

METHODS: Between March, 1998 to July, 2005, 129 patients with chronic non-bloody diarrhea of unexplained etiology who had undergone full colonoscopy with no obvious abnormalities were included in the study. Two biopsies were obtained from all colonic segments and terminal ileum for diagnosis of microscopic colitis. On histopathologic examination, criteria for lymphocytic colitis (intraepithelial lymphocyte ≥ 20 per 100 intercryptal epithelial cells, change in surface epithelium, mononuclear infiltration of the lamina propria) and collagenous colitis (subepithelial collagen band thickness ≥ 10 &mgr;m) were explored.

RESULTS: Lymphocytic colitis was diagnosed in 12 (9%) patients (Female/Male: 7/5, mean age: 45 year, range: 27-63) and collagenous colitis was diagnosed in only 3 (2.5%) patients (all female, mean age: 60 years, range: 54-65).

CONCLUSION: Biopsy of Turkish patients with the diagnosis of chronic non-bloody diarrhea of unexplained etiology and normal colonoscopic findings will reveal microscopic colitis in approximately 10% of the patients. Lymphocytic colitis is 4 times more frequent than collagenous colitis in these patients.

Collagenous colitis: oral low-dose methotrexate for patients with difficult symptoms: long-term outcomes

AIM

To perform a qualitative retrospective review of identified cases of collagenous colitis within the patient databases of local clinicians, with particular attention to the use and effectiveness of oral low-dose methotrexate.

METHODS

Gastroenterologists in the referral area were invited to identify collagenous colitis cases from their own databases for inclusion in the study. Patients were considered eligible if they had a symptom history and colonic mucosal histology consistent with collagenous colitis. The retrospective analysis identified age at diagnosis, previous therapies, date of commencement and duration and effectiveness of methotrexate, side-effects, and repeat colonic mucosal histology (if available) after a period of treatment.

RESULTS

Between 1986 and 2003, 43 eligible patients were identified, ranging in age from 32 years to 88 years at the time of diagnosis. Nineteen of the 43 received methotrexate over varying periods, and in 16 of these the clinical response was considered either 'Good' (14) or 'Partial' (2). In the methotrexate group 10 of the 19 underwent repeat colonoscopy and mucosal biopsy at some stage after commencing methotrexate. Of these, five had normal histology in comparison with pretreatment abnormal histology, two had improvement but not normalization of histology, and three had unchanged abnormal histology.

CONCLUSION

The data from this retrospective review suggest that methotrexate may have a beneficial effect on symptoms of collagenous colitis and may improve the underlying histological abnormality. A controlled trial of adequate power and duration is needed to further clarify the usefulness of methotrexate in this condition.

Clostridium difficile-associated disease: changing epidemiology and implications for management

Clostridium difficile-associated disease (CDAD) is increasingly being reported in many regions throughout the world. The reasons for this are unknown, are likely to be multifactorial, and are the subject of several current investigations. In addition to the upsurge in frequency of CDAD, an increased rate of relapse/recurrence, disease severity and refractoriness to traditional treatment have also been noted. Moreover, severe disease has been reported in non-traditional hosts (e.g. younger age, seemingly healthy, non-institutionalised individuals residing in the community, and some without apparent antimicrobial exposure). A previously uncommon and more virulent strain of C. difficile has been reported at the centre of multiple transcontinental outbreaks. The appearance of this more virulent strain, in association with certain environmental and antimicrobial exposure factors, may be combining to create the 'perfect storm'. It is human nature to be reactive; however, the successful control of C. difficile will require healthcare systems (including administrators, and leadership within several departments such as environmental services, infection control, infectious diseases, gastroenterology, surgery, microbiology and nursing), clinicians, long-term care and rehabilitation facilities, and patients themselves to be proactive in a collaborative effort. Guidelines for the management of CDAD were last published over a decade ago, with the next iteration due in the fall (autumn) of 2007. Several newer therapies are under investigation but it is unclear whether they will be superior to current treatment options.

Mesalazine with or without cholestyramine in the treatment of microscopic colitis: randomized controlled trial

BACKGROUND

Collagenous colitis (CC) and lymphocytic colitis (LC) are chronic inflammatory diseases of the colon with a benign and sometimes relapsing course. Frequency among patients with chronic diarrhea and normal looking colonoscopy is around 10-15%. To date, treatment of CC and LC is not well defined. Data about these conditions are mostly derived from retrospective studies. The aim of the present study was to evaluate the response to treatment and the clinical course of CC and LC in a large group of patients prospectively diagnosed.

METHODS AND RESULTS

A total of 819 patients underwent a colonoscopy because of chronic watery diarrhea and among them we found 41 patients with LC and 23 with CC. These patients were later randomized and assigned to treatment with mesalazine or mesalazine + cholestyramine for 6 months. Fifty-four patients (84.37%) had resolved diarrhea in less than 2 weeks. After 6 months a colonoscopy with biopsies was repeated. Clinical and histological remission was achieved in 85.36% of patients with LC and in 91.3% with CC, with a better result in patients with CC treated with mesalazine + cholestyramine. During a mean period of 44.9 months, 13% of patients relapsed; four with LC and three with CC. They were retreated for another 6 months. At the end of this period one patient with CC was still symptomatic and persistence of CC was confirmed at histology.

CONCLUSIONS

Treatment with mesalazine seems to be an effective therapeutic option for LC to date, while mesalazine + cholestyramine seems to be more useful in the treatment of CC.

Protective effects of proton pump inhibitors against indomethacin-induced lesions in the rat small intestine

Proton pump inhibitors (PPIs) have been shown to be effective in preventing gastric and duodenal ulcers in high-risk patients taking nonsteroidal anti-inflammatory drugs (NSAIDs); by contrast, scarce information is available concerning the effects of PPIs on intestinal damage induced by NSAIDs in humans or in experimental animals. We examined the effects of lansoprazole and omeprazole on the intestinal injury induced by indomethacin in the conscious rat. PPIs were administered by the intragastric route at 30, 60 and 90 micromol/kg, 12 h and 30 min before and 6 h after indomethacin treatment. The effects of omeprazole and lansoprazole were evaluated on: (1) macroscopic and histologic damage; (2) mucosal polymorphonuclear cell infiltration; (3) oxidative tissue damage and (4) bacterial translocation from lumen into the intestinal mucosa. Lansoprazole and omeprazole (at 90 micromol/kg) significantly decreased (P<0.01) the macroscopic and histologic damage induced by indomethacin in the rat small intestine. Furthermore, both drugs greatly reduced (P<0.01) the associated increases in myeloperoxidase levels and lipid peroxidation induced by indomethacin, whereas they only moderately affected (P<0.05) the translocation of enterobacteria from lumen into the intestinal mucosa. These data demonstrate that omeprazole and lansoprazole can protect the small intestine from the damage induced by indomethacin in the conscious rat. The intestinal protection, possibly related to antioxidant and anti-inflammatory properties of these drugs, may suggest new therapeutic uses of PPIs in intestinal inflammatory diseases.

Resolution of paraneoplastic collagenous enterocolitis after resection of colon cancer

A 52-year-old woman developed severe watery diarrhea, weight loss, anemia and hypoalbuminemia. A localized colon cancer was detected. Subsequently, extensive collagenous mucosal involvement of the small and large intestine was discovered. After resection of the colon cancer, her symptoms resolved. In addition, resolution of the inflammatory process occurred, including the subepithelial collagen deposits. Despite extensive small and large intestinal involvement, both clinical and histological resolution of collagenous inflammatory disease was evident. Collagenous enterocolitis is an inflammatory process that may represent a distinctive and reversible paraneoplastic phenomenon.

Review article: drug-induced microscopic colitis - proposal for a scoring system and review of the literature

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.

Colonic toxicity of administered drugs and chemicals

Although uncommon, medication-induced colonotoxicity is important to recognize because medication cessation generally leads to prompt clinical improvement, while medication continuation results in disease exacerbation. This review categorizes the association between medications and colonotoxicity as "well-established" or "probable," according to the following criteria: total number of reported cases, number of different research groups reporting an association, experimental and pharmacologic evidence of an association, and validity of an association in each reported case. Cocaine, ergotamine, estrogen, sodium polystyrene, alosetron, amphetamines, pseudoephedrine, and vasopressin are associated with colonic ischemia. The mechanisms include vasospasm, thrombogenesis, and shunting of blood from mesenteric vessels. Narcotics, phenothiazines, vincristine, atropine, nifedipine, and tricyclic antidepressants are associated with colonic pseudo-obstruction. The mechanisms include antagonizing prokinetic neurotransmitters, stimulating antikinetic neurotransmitters, promoting dysmotility, relaxing smooth muscle, and injuring enteric neurons. Numerous antibiotics are associated with pseudomembranous colitis; ampicillin is associated with hemorrhagic colitis; chemotherapy is associated with neutropenic colitis; and deferoxamine is associated with Yersinia enterocolitis. Mechanisms of these toxicities include altering normal bowel flora, weakening immunologic defenses, promoting microorganism virulence, and mucosal injury. Gold compounds, nonsteroidal antiinflammatory drugs, alpha-methyldopa, salicylates, and sulfasalazine are associated with an inflammatory or cytotoxic colitis. The mechanisms include direct mucosal cytotoxicity, antimetabolite effects, or drug allergy. Nonsteroidal antiinflammatory drugs, cyclo 3 fort, flutamide, lansoprazole, and ticlopidine are associated with lymphocytic colitis. The mechanisms include immunologic activation or attenuated immunologic defenses. Chronic cathartic use leads to colonic hypomotility and abdominal distention. Intrarectally administered corrosive compounds can produce a toxic colitis.

The rates of common adverse events reported during treatment with proton pump inhibitors used in general practice in England: cohort studies

AIMS

To estimate the rates of common adverse events in patients treated with the proton pump inhibitors omeprazole, lansoprazole and pantoprazole in general practice in England.

METHODS

In prescription-event monitoring cohort studies, data on dispensed prescriptions prescribed by general practitioners in England soon after each drug was launched were linked to subsequent clinical events recorded by the prescriber. 16 205 patients prescribed omeprazole between June 1989 and June 1990, 17 329 patients prescribed lansoprazole between May and November 1994, and 11 541 patients prescribed pantoprazole between December 1996 and June 1997 were studied.

RESULTS

The commonest adverse events in the omeprazole, lansoprazole and pantoprazole cohorts were diarrhoea (incidence: 0. 18, 0.39 and 0.23 per 1000 days of exposure, respectively); nausea/vomiting (incidence: 0.16, 0.22 and 0.18 per 1000 days of exposure, respectively); abdominal pain (incidence: 0.17, 0.21 and 0. 17 per 1000 days of exposure, respectively); and headache (incidence rates: 0.10, 0.17 and 0.15 per 1000 days of exposure, respectively). The remaining adverse events occurred at rates of less than 0.11 per 1000 days of exposure. There were little absolute differences in the rates of most events between the three proton pump inhibitors. However, diarrhoea was more commonly associated with lansoprazole compared with omeprazole (rate difference: 0.21 per 1000 days of exposure; 95% CI 0.17, 0.25; rate ratio: 2.11; 1.78, 2.51), and there was a clear age-response relationship.

CONCLUSIONS

Adverse events occurred relatively infrequently in all three cohorts. There were only small absolute differences in event rates between the three drugs, although these data suggest the hypothesis that lansoprazole is associated with more frequent occurrence of diarrhoea, particularly in the elderly.