Common Cause Of Chronic Diarrhea Research Articles

PWE-123 Response to bile acid sequestrants is poor in patients with equivocal SeHCAT results

IntroductionBile acid malabsorption (BAM) is a common cause of chronic diarrhoea that can be diagnosed by the SeHCAT test and treated with bile acid sequestrants (BAS). The purpose of this...

PTU-112 Presentation, treatment and clinical outcome of collagenous and lymphocytic colitis over a 6-year period in a single UK centre

IntroductionCollagenous colitis (CC) and lymphocytic colitis (LC) are referred to collectively as microscopic colitis (MC). CC and LC represent an increasingly common cause of chronic diarrhoea. However, clinical and epidemiological...

PWE-124 Colesevelam use and efficacy for bile acid malabsorption

IntroductionBile acid malabsorption (BAM) is a common cause of chronic diarrhoea that can be diagnosed by the SeHCAT test and treated with bile acid sequestrants (BAS). Colestyramine, the most commonly...

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

BackgroundOften previously overlooked, microscopic colitis, including collagenous colitis and lymphocytic colitis, has now emerged as a common cause of chronic diarrhoea. AimsTo evaluate the prevalence and incidence of microscopic colitis in patients with diarrhoea of unknown aetiology. Methods271 consecutive patients who were referred to the General Hospital of Tomelloso from April 2008 to December 2010 for diarrhoea of unknown aetiology underwent a full colonoscopy to obtain biopsy samples to diagnose microscopic colitis on the basis of commonly accepted histological criteria. All patients were classified according to the Roma III criteria for diarrhoea-dominant irritable bowel syndrome. ResultsIn 234/271 consecutive patients with normal endoscopic appearance we observed 32/234 patients with microscopic colitis (30 lymphocytic colitis and 2 collagenous colitis) with a prevalence of microscopic colitis of 48 cases/100,000 inhabitants (95%CI: 30–65) and mean annual standardised incidence of 18 cases/100,000 inhabitants (95%CI: 16.0–20.0). Analysing only the patients that met the Roma III criteria (84/271), we observed 10.7% microscopic colitis diagnosis, with higher risk in the presence of autoimmune disease, seronegative celiac disease and intake of non-steroidal anti-inflammatory drugs. ConclusionsMicroscopic colitis was found in 13.7% of patients with chronic diarrhoea. Microscopic colitis is present in a relevant proportion of symptomatic patients meeting diagnostic criteria for irritable bowel syndrome (10.7%).

Gene expression of selected signature cytokines of T cell subsets in duodenal tissues of dogs with and without inflammatory bowel disease

Inflammatory bowel disease (IBD) is a common cause of chronic diarrhoea in dogs. In people, specific cytokine patterns attributed to T cell subsets, especially T helper cell [Th]1, Th17 and regulatory T(reg) cells have emerged in IBD. In contrast, no specific involvement of a distinct T cell subset has been described so far in canine IBD. Thus, the aim of the present study was to assess gene expression of signature cytokines in duodenal tissues from 18 German shepherd dogs with IBD (group 1), 33 dogs of other breeds with IBD (group 2) and 15 control dogs (group 3). Relative quantification of IL-17A, IL-22, IL-10, IFNy and TGFβ was performed. Expression of IL-17A was significantly lower in groups 1 and 2 compared to group 3 (p=0.014), but no difference in the expression of IL-22 (p=0.839), IFNγ (p=0.359), IL-10 (p=0.085) or TGFβ (p=0.551) across groups was detected. Thus, no clear evidence for the involvement of Th-17 signature cytokines in canine IBD at the mRNA level could be shown. The contribution of specific T cell subsets to the pathogenesis of canine IBD warrants further investigation.

Microscopic Colitis in Patients with Diarrhea of Unknown Etiology: Diagnosis and Treatment

Chronic diarrhea is a common reason for referral to a gastroenterologist. Microscopic colitis (MC) is fairly common cause of chronic non-bloody diarrhea. Microscopic colitis which was previously regarded rare, now has emerged as a common cause of chronic diarrhea. The condition is characterized clinically by chronic non bloody diarrhea, a macroscopically normal or near-normal colonic mucosa, but microscopic examination of mucosal biopsies reveals diagnostic histopathological changes. Microscopic colitis mainly includes two diseases, collagenous colitis (CC) and lymphocytic colitis (LC). In CC the most characteristic feature is thickening of the sub-epithelial collagen layer (SCL) beneath the basal membrane intra-epithelial lymphocyte (IEL) infiltration although not asprominent as in LC. The diagnosis of LC relies on a characteristic increase of IELs, which exceeds 20 IEL/100 surface epithelial cells compared with < 5 IEL/100 surface epithelial cells in normal colonic mucosa. Randomized controlled trials (RCTs) assessing therapies for microscopic colitis have been performed. A previously published review showed that budesonide was effective in producing both clinical and histological responses in patients with collagenous colitis. This review will focus on epidemiology, clinical features and treatment of MC. Keywords : chronic diarrhea, microscopic colitis, lymphocytic and collagenous colitis

Derivation of a Microscopic Colitis Disease Activity Index (MCDAI)

Purpose: Microscopic colitis is a common cause of chronic diarrhea, often with additional symptoms. No validated instruments exist to assess disease activity in microscopic colitis, making it difficult to draw meaningful conclusions regarding efficacy between treatments in clinical series and controlled trials. We aimed to identify the clinical features which independently predicted physician global assessment (PGA) of disease severity and create a microscopic colitis disease activity index (MCDAI). Methods: A cohort of patients with microscopic colitis was prospectively administered a survey assessing a number of GI symptoms, as well as their global assessment (GA) of disease activity on a 10-point scale. A single physician also scored a physician global assessment (PGA) on a 10-point scale, considering the individual symptoms recorded by the patient, but blinded to the patient's GA. The primary analysis utilized a multiple linear regression model to identify which individual patient-reported symptoms were independently associated with the PGA using a backward variable selection approach. Due to some outlier values, individual data points were first transformed to rank scale. We also assessed the degree of agreement between the patient's GA and the PGA. Results: Of 165 patients enrolled, 14 (8.5%) did not complete the survey. The remaining 151 patients had a median age of 66 years (range, 1-87); 74% were female. Five symptoms were independently associated with the PGA (in order of strength of correlation: # unformed bowel movements (BM) per day, incontinence, abdominal pain, # nocturnal BM, weight loss). When combined, these scores strongly predicted the PGA (R2 = 0.84): X1(#BM) + X2 (#incontinence episodes per month) + X3 (abdominal pain [scored 1-10]) + X4 (# nocturnal BM) + X5(weight loss in pounds). Urgency and the use of anti-diarrheal medications were not associated with PGA. The patient's GA had good agreement with the PGA (concordance correlation coefficient = 0.63); 60% of the time, these scores were within +/- 1 point. PGA was >= 2 points higher than the patient's score in 11% and >= 2 points lower in 29%. Conclusion: Five symptoms independently correlated with disease activity as measured by PGA. Scores for these symptoms were combined to create an MCDAI that strongly predicted the PGA. PGA had good correlation with patient's GA. This index can be used to objectively and consistently score disease severity in clinical trials and case series. This work was supported by a clinical research grant from the American College of Gastroenterology.

Review of the Microscopic Colitides

Microscopic colitis is a common cause of chronic diarrhea in predominantly older adults. Incidence rates of microscopic colitis (including lymphocytic and collagenous colitis) have increased over time to levels comparable to other forms of inflammatory bowel disease. The possibility of drug-induced microscopic colitis is an important consideration when evaluating these patients, although this concept requires further investigation. There are few controlled treatment trials in microscopic colitis, with much of the data on treatment coming from retrospective studies. In patients with microscopic colitis, a systematic approach to therapy often leads to satisfactory control of symptoms. In this review, we will provide an updated assessment of the epidemiology, diagnosis, and treatment of microscopic colitis.

Review article: microscopic colitis - lymphocytic, collagenous and ‘mast cell’ colitis

Microscopic colitis is a relatively common cause of chronic diarrhoea in predominantly older adults, traditionally termed lymphocytic colitis and collagenous colitis. Increased mast cells found in the colonic biopsies of some patients with chronic diarrhoea may represent a distinct type of microscopic colitis. To provide an updated review of the epidemiology, diagnosis and treatment of microscopic colitis, and to discuss the role of mast cells in the gastrointestinal tract and their potential role in cases of functional diarrhoea. A MEDLINE literature search was performed to identify pertinent articles. Relevant clinical abstracts were also reviewed. Incidence rates of microscopic colitis (lymphocytic and collagenous colitis) have increased over time, to levels comparable with other forms of inflammatory bowel disease. The possibility of drug-induced microscopic colitis and concomitant coeliac sprue are important considerations when evaluating these patients. There are few controlled treatment trials in microscopic colitis, with much of the data on treatment coming from retrospective studies. Mast cells have been implicated in functional bowel disorders, with increased mast cells possibly contributing to cases of otherwise unexplained chronic diarrhoea, although this concept requires further investigation. In patients with microscopic colitis, a systematic approach to therapy often leads to satisfactory control of symptoms. The role of mast cells in chronic diarrhoea represents an evolving field, with the potential to offer alternative treatment pathways in patients with otherwise unexplained functional diarrhoea.

A Study of the Prevalence of Genetic Polymorphisms in Bile Acid Diarrhea Patients

Introduction Bile acid diarrhoea (BAD) is a common cause of chronic diarrhoea and results from high concentrations of bile acids in the colon. It has recently been suggested that impaired production of fibroblast growth factor 19 (FGF19) in the ileum can result in excessive hepatic bile acid synthesis through reduced negative feedback regulation, and this, rather than malabsorption, is the cause of the diarrhoea. The reason for the reduced ileal FGF19 production remains unclear but it has been established that ileal FGF19 synthesis is markedly stimulated by bile acids binding to the farnesoid X receptor (FXR). In the liver, FGF19 acts through the FGFR4 receptor and its co-receptor Klotho β. Organic solute transporter α (OSTα) is the ileal basolateral bile acid transporter. The aim of this study was to determine the prevalence of 6 common single nucleotide polymorphisms (SNPs) in four genes involved in bile acid metabolism and FGF19 action, comparing the prevalence in patients with primary BAD, a similar number of controls with diarrhoea, and a larger numbers of healthy controls. Methods Two common SNPs (rs948992 and rs1789170) in the FGF19 gene were analysed as well as 2 SNPs (M173T, rs61755050 and −1g>t, rs56163822) in the FXR gene. Mutations in FXR are implicated in patients with obstetric cholestasis and have been shown to reduce function and translation efficiency of FXR. A SNP in Klotho β (rs17618244) has been associated with colonic transit in IBS-D patients. A further SNP in the OSTα gene (rs939885) was also studied. Genomic DNA was extracted from 92 primary BAD patients diagnosed on the basis of an abnormal ( Results Polymorphisms in all the genes studied were detectable in controls and in cases. No significant differences in the genotypes and allele frequencies were found in the Caucasian cohorts in the control and primary BAD groups (p > 0.1). Further analysis of patients of different ethnic origin again did not show significant differences in the allele frequencies. Conclusion Major differences in the frequency of genetic polymorphisms in four candidate genes involved with FGF19 and bile acid metabolism are unlikely to be associated with primary BAD. However, the SNPs identified may contribute small effects, with a combination of SNPs in several genes producing a cumulative effect. Larger numbers of cases are required to define specific interactions or minor effects. At present the cause of the reduced FGF19 action in BAD remains uncertain.

Evaluation of a blocking ELISA for the detection of antibodies against Lawsonia intracellularis in pig sera

BackgroundLawsonia intracellularis is a common cause of chronic diarrhoea and poor performance in young growing pigs. Diagnosis of this obligate intracellular bacterium is based on the demonstration of the microbe or microbial DNA in tissue specimens or faecal samples, or the demonstration of L. intracellularis-specific antibodies in sera. The aim of the present study was to evaluate a blocking ELISA in the detection of serum antibodies to L. intracellularis, by comparison to the previously widely used immunofluorescent antibody test (IFAT).MethodsSera were collected from 176 pigs aged 8-12 weeks originating from 24 herds with or without problems with diarrhoea and poor performance in young growing pigs. Sera were analyzed by the blocking ELISA and by IFAT. Bayesian modelling techniques were used to account for the absence of a gold standard test and the results of the blocking ELISA was modelled against the IFAT test with a "2 dependent tests, 2 populations, no gold standard" model.ResultsAt the finally selected cut-off value of percent inhibition (PI) 35, the diagnostic sensitivity of the blocking ELISA was 72% and the diagnostic specificity was 93%. The positive predictive value was 0.82 and the negative predictive value was 0.89, at the observed prevalence of 33.5%.ConclusionThe sensitivity and specificity as evaluated by Bayesian statistic techniques differed from that previously reported. Properties of diagnostic tests may well vary between countries, laboratories and among populations of animals. In the absence of a true gold standard, the importance of validating new methods by appropriate statistical methods and with respect to the target population must be emphasized.

* A study of the prevalence of genetic polymorphisms in bile acid diarrhoea patients

IntroductionBile acid diarrhoea (BAD) is a common cause of chronic diarrhoea and results from high concentrations of bile acids in the colon. It has recently been suggested that impaired production...

Performance of microscopy for detection of microsporidial spores from stool samples of HIV infected individuals with diarrhoea

Sir, Intestinal microsporidiosis is the most common cause of chronic diarrhoea in treatment-naive HIV infected patients1. Intestinal microsporidiosis due to Encephalitozoon (Septata) intestinalis and Enterocytozoon bieneusi are also most frequently reported among immunocompromised patients such as transplant recipients2–4. Laboratory diagnosis of microsporidiosis was initially based on the detection of microsporidial spores in stool specimens by light microscopy using special stains5. Electron microscopy, wherever possible, was also used for detection of microsporidia6–8. Diagnosis of intestinal microsporidiosis has been markedly improved by the use of Weber's chromotrope stain and its modified procedure1,5,9, and fluorescence staining with fluorochromes such as Uvitex 2B or calcoflour white which binds to the chitin in the endospore layer of the microsporidial spore1,8,10,11. Molecular technique such as polymerase chain reaction (PCR) became available later for confirmation of micropsoridia. Additionally, species specific PCR can be used to identify different species of microsporidia12–16. However, due to resource constraints, most laboratories rely on the use of microscopy of stool samples for diagnosis of intestinal microsporidiosis. Limited studies have been carried out in India on detection of microsporidia8,17,18. We compared light microscopy with modified trichome stain, fluorescence microscopy using Uvitex 2B and PCR to detect microsporidia in HIV infected individuals with diarrhoea during January 2009 to May 2010 on consecutive HIV infected patients with diarrhoea admitted at Naidu Municipal Corporation Hospital, Pune. The study protocol was approved by the institutional ethics committee & Naidu Municipal Corporation Hospital. The study included 331 patients [65 (51 males, 14 females)] HIV infected adults >18 yr and 266 HIV (uninfected individuals) with diarrhoea. This study was carried out only on HIV infected individuals with diarrhoea. Study patients were interviewed using the structured questionnaire. Diarrhoea was defined as two or more liquid or three or more soft stools per day All the patients had history of diarrhoea of <14 days and were treatment-naive HIV-infected individuals. Stool samples were collected in wide mouth, leak proof, clean sterile containers and then transported to National AIDS Research Institute (NARI) within 4 h of collection. If there was a delay in the transportation, the samples were preserved at 4o C. The samples were immediately processed after receiving at NARI for microscopy by the conventional method8. Stool samples were stained by modified trichome and Uvitex 2B by the method described earlier4,6,8, and were subjected to light microscopy and fluorescence microscopy, respectively. A portion of the stool was stored at -70°C for further molecular analysis. DNA was extracted from frozen samples using the QIA amplication DNA tissue kit (Qiagen, Inc, Germany). PCR was performed using specific primers as described by Najla et al19. The median duration of diarrhoea was found to be 3 days (IQR 2.75 - 5) and median number of episodes of diarrhoea was noted as 6 in HIV-infected individuals (n=65). The mean age was found to be 35.1 yr ranging from 18-60 yr. Male (n=51) outnumbered the females (n=14). The CD4 counts were available only for 35 patients [CD4 count 200-499 cells/μl (n= 29) and CD4 count ≥500 cells /μl (n=6)] Examination of 65 stool samples from 331 patients by light microscopy with modified trichome stain showed microsporidial spores (oval shaped, measuring 1-2 μm in diameter under oil immersion) in four samples. Fluorescence microscopy using Uvitex 2B also showed microsporidial spores in the same four (6.2%) HIV-infected individuals. PCR detected microsporidial spores in stool samples of five (7.7%) individuals including four found positive by light and fluorescent microscopy (Fig.). Of these five samples positive by PCR, three were identified as Enterocytozoon bieneusi and two were identified as Encephalitozoon intestinalis. A repeat light microscopy and fluorescent microscopy on one sample positive only by PCR did not yield positive results. Thus, the results, though limited by a small number of positives, indicate that trichome and Uvitex 2B stains work well for diagnosis of intestinal microsporidiosis. PCR as expected was more sensitive and yielded one additional positive sample. Fig. (a) Stool smear stained with modified trichome stain showing microsporidial spores (arrow); (b) Stool smear stained by Uvitex 2B & examined with UV light. spores of microsporidia show typical elongated shape (arrow); (c) Agaraose gel electrophoresis ... In conclusion, with well trained laboratory staff both the Uvitex 2B and modified trichome stain can be used for microsporidia detection. PCR can increase sensitivity and species identification. The study was limited by small sample size and small number of positives and hence warrants additional testing on a large number of samples.

Small intestinal bacterial overgrowth: histopathologic features and clinical correlates in an underrecognized entity.

Abstract Context Small intestinal bacterial overgrowth (SIBO) is a common cause of chronic diarrhea and malabsorption. Morphologic changes associated with this condition have not, to our knowledge,...

Small Intestinal Bacterial Overgrowth: Histopathologic Features and Clinical Correlates in an Underrecognized Entity

Small intestinal bacterial overgrowth (SIBO) is a common cause of chronic diarrhea and malabsorption. Morphologic changes associated with this condition have not, to our knowledge, been studied in detail. To better characterize the histopathologic changes associated with SIBO by comparing the clinicopathologic features of patients with SIBO (duodenal aspirate cultures with > or =10(5) colony-forming units [CFUs]/mL) to controls with cultures found to be negative (<10(5) CFUs/mL). We included 67 consecutive patients with SIBO and 55 controls in the series. Each duodenal biopsy was assessed for the following features: villous to crypt ratio, intraepithelial lymphocytosis, crypt apoptoses, basal plasmacytosis, cryptitis/villitis, peptic duodenitis, erosions/ulcers, eosinophilia, and absence of goblet and Paneth cells; and correlated with clinical features and culture results. Decreased villous to crypt ratio (<3ratio1) was more frequent in SIBO than controls (24% versus 7%; P = .01). Duodenal biopsies from patients with SIBO were slightly less likely to be judged within reference range than were controls (52% versus 64%; P = .27). There were no significant differences in any of the other histologic features. Clinically, patients in the SIBO group were older than the age of controls (mean, 60 years versus 52 years; P = .02), and they were more likely to have one of the known predisposing factors for bacterial overgrowth (66% versus 36%; P = .002). Other clinical features, including presenting symptoms, were similar. Villous blunting is the only feature more common to SIBO than to controls. More than half of biopsies from SIBO patients are histologically unremarkable. Therefore, SIBO needs to be considered as a potential etiology for gastrointestinal symptoms even when duodenal biopsies are found to be normal.

Indirect evidence for increased mechanosensitivity of jejunal secretomotor neurones in patients with idiopathic bile acid malabsorption

The interdigestive motor rhythm, the migrating motor complex (MMC), is accompanied by active secretion of chloride during periods of distally propagating maximal motor activity (MMC phase III). We studied the behaviour of this system in bile acid malabsorption (BAM), a relative common cause of chronic diarrhoea. We measured motor activity and transmucosal potential difference (PD, reflecting active chloride secretion), in the proximal jejunum in healthy controls (n = 18) and in a group of patients with BAM (n = 11). The phase III-generated voltage was related to the degree of BAM quantified by the (75)SeHCAT test. We used a multi-channel intestinal infusion system to simultaneously measure jejunal pressure and PD. Saline passing calomel half-cells was infused into the jejunum and subcutaneously. Pressure and PD were recorded in the fasting state and after a test meal. In the absence of motor activity, jejunal PD was not significantly different from zero in either group. During MMC phase III, PD reached significantly higher mean and peak levels in BAM patients. The product of MMC phase III length multiplied by voltage, over 3 h, was also significantly higher in BAM patients (controls: median 307 mV x cm, range 70-398; BAM: median 511, range 274-2271, P < 0.01). This value was also significantly correlated with the degree of BAM as reflected by the (75)SeHCAT test (P < 0.05). Phase III induced jejunal secretion may be upregulated in BAM patients, resulting in overload of colonic reabsorption capacity.

Therapeutic Evaluation of Polyamine Analogue Drug Candidates against Enterocytozoon bieneusi in a SCID Mouse Model

Enterocytozoon bieneusi is the most common cause of chronic diarrhea in individuals with human immunodeficiency virus infection or AIDS, and there is no effective therapy. The inhibitory activities of polyamine analogues (PG-11157, PG-11158, and PG-11302) against E. bieneusi infection were evaluated in SCID mice preconditioned with anti-gamma interferon monoclonal antibody intraperitoneally (i.p.). Mice were challenged orally with 10(4) E. bieneusi spores, and groups of mice were treated orally or i.p. 14 days later for 7 days. The inhibitory activities of the drugs against infection were determined by enumerating the E. bieneusi spores in feces three times a week by an immunofluorescence assay. Immunohistochemistry staining confirmed the infection within enterocytes. Oral administration of the analogues PG-11157 (at 150 or 75 mg/kg of body weight/day) and PG-11302 (at 250 mg/kg/day) had significant inhibitory activity (96.2 to 99.6%) that was slightly better than that of fumagillin (1 mg/kg/day; 93.7%). The inhibitory activity with i.p. injection was significant only with PG-11302 at 20 mg/kg/day. While the treatments considerably reduced the levels of spore excretion, neither polyamine analogues nor fumagillin was able to completely eliminate E. bieneusi, as excretion reappeared within 7 days after the end of treatment. Drug toxicity was apparent during treatment, but it disappeared at the end of treatment. These results warrant further examination of the analogues PG-11157 and PG-11302.

Celiac disease: India on the global map

Celiac disease: India on the global map

Microscopic Colitis Is Not So Rare Disease in the Japanese Population

Background and study Aim: Microscopic colitis (MC) is recognized as a common cause of chronic diarrhea in the Western countries. However, in Japan, few cases of MC had been reported in the past and frequency of MC has not been clarified yet. The aim of this study is to clarify the frequency of MC in patients with chronic diarrhea in the Japanese population due to take biopsies during colonoscopies if there is no obvious finding of colitis. Methods: A total of 27 (male 11, female 16, mean age 56.4 years old) Japanese patients with chronic diarrhea underwent colonoscopies with biopsies during the period from April 2003 to January 2005. We retrospectively investigated frequency of cause of chronic diarrhea in the basis of pathological findings. Furthermore clinical and endoscopic characteristics of patients with MC were analyzed dividing into collagenous colitis (CC) and lymphocytic colitis (LC). In this study, pathological definitions of CC and LC were thickening of the subepithelial collagen band more than 7 μm and intraepithelial lymphocytosis more than 10 lymphocytes for every 100 epithelial cells, respectively (Am J Gastroenterol 2002:97;794-802). Results: 1. Frequency of cause of chronic diarrhea: CC 29.6% (8/27), LC 14.8% (4/27), Eosinophilic enterocolitis 3.7% (1/27), Infectious colitis 3.7% (1/37), Ischemic colitis 3.7% (1/37), Normal 44.5% (12/37), 2. Clinical and endoscopic characteristics of CC (n = 8) and LC (n = 4): a) Mean age: CC 66.3 yrs. LC 45.8 yrs. b) Gender (male:female): CC 1:1, LC 1:3, c) Frequency of diarrhea per day (mean): CC 5.9 ± 2.9, LC 7.8 ± 2.6, d) Mean duration of diarrhea (months): CC 2.0 ± 2.0, LC 3.3 ± 1.5, e) Past illness: CC; chronic renal failure 3, collagen disease 3, diabetes 1, LC; diabetes 1, f) Drug history: CC; lansoprazole 6, loxoprofen sodium 4, LC; none, g) Endoscopic feature: i) slight thickening of colonic mucosa; CC 75% (6/8), LC 75% (3/4), ii) proliferation of capillary vessels; CC 37.5% (3/8), LC 0% (0/4), iii) contact bleeding; CC 12.5% (1/8), LC 50% (2/4). Conclusions: MC (CC and LC) was major cause of chronic diarrhea in the Japanese population in our investigation. We could observe endoscopically slight mucosal abnormalities in most of CC and LC patients.

Mastocytic Enterocolitis: Increased Mucosal Mast Cells in Chronic Intractable Diarrhea

In some adult patients with chronic intractable diarrhea, the diagnosis remains elusive even after detailed evaluations, and colonic or duodenal biopsy specimens may appear unremarkable on routine hematoxylin-eosin staining. To assess the concentration of mast cells in colonic or duodenal biopsy specimens by immunohistochemical analysis for mast cell tryptase from patients with chronic intractable diarrhea and to evaluate their response to drugs affecting mast cell function. Mast cells per high-power field were assessed in biopsy specimens from 47 patients with chronic intractable diarrhea, from 50 control subjects, and from 63 patients with other specific diseases that cause chronic diarrhea (inflammatory bowel disease, celiac disease, collagenous colitis, and lymphocytic colitis). Patients with chronic intractable diarrhea who had more than 20 mast cells per high-power field were administered drugs affecting mast cell mediator function and release. The mean +/- SD concentration of mast cells in the 50 control subjects was 13.3 +/- 3.5 cells per high-power field; hence, patients with more than 20 mast cells per high-power field were considered to have increased mast cells. Thirty-three (70%) of 47 patients with chronic intractable diarrhea had increased mast cells, and symptoms were controlled by drug therapy in 22 (67%) of the 33 patients. No patient had systemic or cutaneous mastocytosis. No increase in mast cells was seen in patients with other common causes of chronic diarrhea. In chronic intractable diarrhea, colonic or duodenal biopsy specimens may appear unremarkable on routine hematoxylin-eosin staining, but increased mast cells may be demonstrated by immunohistochemistry for mast cell tryptase, with the novel term mastocytic enterocolitis describing this condition. Similar increases in mast cells are not apparent in control populations or in patients with other specific diseases that cause chronic diarrhea. The cause of the increased mast cells remains to be elucidated.