Post-infectious irritable bowel syndrome in patients with Shigella infection

BACKGROUND AND AIMS: Bacterial gastroenteritis has been known as a risk factor of irritable bowel syndrome (IBS). Several risk factors of post-infectious IBS (PI-IBS) have been documented. The aims of this study were to verify the role of bacterial gastroenteritis in the development of IBS and the risk factors for the development of PI-IBS. The clinical course of PI-IBS was also investigated. METHODS: We recruited 143 patients with shigellosis during its outbreak and 113 controls. Both groups were followed up for 12 months. Bowel symptoms were evaluated by use of questionnaires at 3, 6 and 12 months after the initial recruitment. RESULTS: Complete data were obtained from 101 patients (70.6%) and 102 healthy controls (90.3%). At 12 months, 15 patients and six controls had IBS (adjusted OR; 2.9, 95% CI; 1.1-7.9). Of the 15 patients, five had IBS symptoms consistently for 12 months, three did not have IBS symptoms initially and seven had fluctuating bowel symptoms. The duration of diarrhea was an independent risk factor of PI-IBS. CONCLUSIONS: Bacterial gastroenteritis is a risk factor of IBS and the duration of diarrhea as the index of severity of initial illness is an independent risk factor of PI-IBS. The clinical course of PI-IBS is variable over the 1 year of follow-up.     

Prognosis in post-infective irritable bowel syndrome: a six year follow up study

BACKGROUND: Irritable bowel syndrome developing following infective gastroenteritis accounts for approximately 1 in 10 of unselected IBS patients. AIMS: To define the long term natural history of post-infective IBS (PI-IBS). METHODS: A total of 436 individuals, who had previously responded to a questionnaire on their bowel habits following an acute episode of gastroenteritis, were sent a questionnaire about their current bowel habits and physical and mental health six years after their initial illness. RESULTS: Complete data on original bowel habit, episodes of gastroenteritis, mental health history, and subsequent bowel habit at six years were obtained in 192 individuals. Of these, there were 14 cases of "post-infective IBS" (PI-IBS) and 13 who had IBS prior to infection (previous IBS). Over the six year follow up period there were 20 "new non-infective IBS cases" (new IBS). The strongest risk factor for developing any type of IBS was female sex (relative risk 2.2, p<0.05). Compared with new IBS, those with PI-IBS had significantly more days with loose stools (p<0.05) but a similar number of days with pain, urgency, and bloating. Six of 14 (43%) PI-IBS and four of 13 (31%) previous IBS patients recovered by six years (NS). Of 27 IBS patients followed for six years, only 1/8 with a history of anxiety or depression recovered compared with 9/19 without such a history (p=0.19). CONCLUSION: PI-IBS differs from non-infective IBS by having more diarrhoeal features. Less than half of both PI-IBS and non-infective IBS cases recover over six years. A history of anxiety and depression severe enough to warrant treatment may impair recovery but larger numbers are needed to prove this.     

Incidence and epidemiology of irritable bowel syndrome after a large waterborne outbreak of bacterial dysentery

BACKGROUND & AIMS: Postinfectious irritable bowel syndrome (PI-IBS) is a common clinical phenomenon. To better define its incidence and epidemiology, a large cohort study was initiated after the contamination of a municipal water supply led to a large outbreak of acute Escherichia coli 0157:H7 and Campylobacter jejuni gastroenteritis. METHODS: Local residents were invited to undergo structured assessments at research clinics established 2 years after the outbreak. Permanent adult residents with no prior history of inflammatory bowel disease or IBS were eligible. Standardized questionnaires defined past and current health. The cohort was divided into controls without gastroenteritis, subjects with clinically suspected gastroenteritis, and subjects with only self-reported gastroenteritis that could not be substantiated by another source. A modified Bowel Disease Questionnaire identified IBS according to Rome criteria. The incidence and epidemiology of PI-IBS was characterized. Risk factors were assessed using multiple logistic regression. RESULTS: There were 2069 eligible study participants. Rome I criteria were met by 71 of 701 controls (10.1%) vs 249 of 904 subjects with self-reported gastroenteritis (27.5%) and 168 of 464 subjects with clinically suspected gastroenteritis (36.2%) (all comparisons, P < 001). Independent risk factors for PI-IBS included younger age, female sex, bloody stools, abdominal cramps, weight loss, and prolonged diarrhea. PI-IBS was more likely than sporadic IBS to show diarrhea-predominant features. CONCLUSIONS: PI-IBS is common after gastroenteritis from water contamination and often is diarrhea-predominant. Characteristics of the acute illness identify patients at increased risk for PI-IBS.     

Distinctive clinical,psychological, and histological features of postinfective irritable bowel syndrome

OBJECTIVE: Irritable bowel syndrome after gastroenteritis is well recognized. Our aim was to determine whether postinfective IBS (PI-IBS) has histological or clinical features that are distinct from those of IBS patients with no history of preceding infection. METHODS: A total of 75 consecutive IBS outpatients and 36 healthy control subjects completed a questionnaire detailing symptoms, mode of onset, and previous psychiatric history. All underwent a full diagnostic workup including rectal biopsy, which included immunostaining and quantification for lamina propria or intraepithelial T lymphocytes, serotonin-containing enterochromaffin (EC), and mast cells. Patients were divided according to onset of symptoms into PI-IBS (n = 23) or non-PI-IBS (n = 52) patients. RESULTS: Diarrhea predominance occurred more frequently in PI-IBS (70%) than in non-PI-IBS (42%) patients (p = 0.03). A history of previous treatment for anxiety or depression was present in 26% of PI-IBS patients compared to 54% of non-PI-IBS (p = 0.02). Biopsy results for all patients were normal using conventional criteria; however, quantification revealed that PI-IBS showed increased EC cells compared to those of non-PI-IBS patients (p = 0.017) and controls (p = 0.02). Lamina propria T lymphocytes were increased in PI-IBS (p = 0.026) and non-PI-IBS (p = 0.011) patients compared to controls. Mast cells were increased in non-PI-IBS patients (p = 0.054) compared to controls. CONCLUSIONS: Individuals with PI-IBS are a clinically distinct subgroup characterized by diarrheal symptoms, less psychiatric illness, and increased serotonin-containing EC cells compared to those with non-PI-IBS.     

Post-infectious irritable bowel syndrome

Irritable bowel syndrome (IBS) affects 8% to 22% of the general population. Although patients describe an insidious onset of symptoms, including abdominal pain relieved with bowel movements, excessive intestinal gas, variable bowel habits, and abdominal bloating, a subgroup of individuals describe the onset of IBS symptoms following an episode of acute gastroenteritis, known as post-infectious IBS (PI-IBS). Several studies have demonstrated the development of IBS following infection. Risk factors for the development of PI-IBS are female sex and longer duration of initial illness. Although the underlying mechanism of PI-IBS is unclear, ongoing inflammation is clearly a factor in the pathogenesis. The underlying inflammatory process results in increased enterochromaffin cells, T-lymphocytes, intestinal permeability, colonic transit time, and a variety of immunologic abnormalities. PI-IBS patients tend to have a better prognosis than do those with idiopathic IBS, with resolution of symptoms within 5 to 6 years. Treatment is similar to that of idiopathic IBS.     

The pathophysiology of irritable bowel syndrome: inflammation and motor disorder]

Irritable bowel syndrome (IBS) is one of the most common disorders and a heterogeneous condition in view of symptoms and underlying mechanisms. Though underlying causes of pathophysiologic changes remain unclear, low grade mucosal inflammation and abnormal intestinal motility are accepted mechanisms which alter gut function and generate symptoms of IBS. First, before 1980s, abnormal colonic and rectal motor functions were regarded as the main pathophysiology of IBS, but only 25-75% of IBS patients have apparent motor abnormalities which differ from the motor functions in normal controls. So, various gastrointestinal motility tests were not indicated for the diagnosis of IBS. The high-amplitude propagating contractions of colon in IBS patients may be related to the visceral pain perception. Second, the low grade mucosal inflammation may be involved in the pathophysiology of visceral hypersensitivity. Post infectious IBS (PI-IBS) occupied 6-17% of the total IBS and some previous prospective studies reported that 7-33% of acute bacterial enteritis patients developed IBS after 6-12 months of infection. The relative risk of IBS in the gastroenteritis cohort was 11.9 and the strongest risk factor is the duration of diarrhea. After enteritis event, the increased number of immunocytes, mast cells and large amount of lymphocytes infiltration were revealed in mucosa and enteric nervous system of the gut. Beside the inflammatory cells, enterochromaffin cells, cytokines and inducible nitric oxide may be related to the pathophysiologic mechanism of PI-IBS. Lastly, the abnormalities in the gastrointestinal autonomic nervous system can induce constipation or motor disorders, but further research should elucidate it.     

Relationship between infectious gastroenteritis and irritable bowel syndrome

A newly recognized causative factor in a subset of patients with irritable bowel syndrome (IBS) is called post-infectious IBS (PI-IBS). IBS symptoms frequently develop after an acute episode of infectious gastroenteritis. Several studies have been made in our understanding of the concept of PI-IBS. Recent studies suggest that transient or chronic gastrointestinal inflammation may play a role in IBS pathogenesis. PI-IBS can be regarded as a natural experiment model in which an insult in the form of an infective disease impacts on subjects with underlying genetic and psychosocial predispositions who then develop IBS. IBS is likely to be a complex trait wherein variability in clinical presentation is partially explained by heterogeneity in underlying genetic and environmental risk factors for PI-IBS. Further studies on PI-IBS are needed to understand the pathophysiology of functional gastrointestinal disorders and to develop new promising management for such patients.     

Microbial signatures in post-infectious irritable bowel syndrome – toward patient stratification for improved diagnostics and treatment

Irritable bowel syndrome (IBS) is a multifactorial and heterogeneous disorder estimated to affect over 10% of the Western population. A subset of the patients reports the start of the disease after an episode of gastroenteritis. The alterations in the intestinal microbiota of the post-infectious IBS (PI-IBS) patients were recently investigated in a British cohort and shown to differentiate from the healthy controls and resemble that of diarrhea-predominant IBS (IBS-D) patients. The altered 27 genus-like groups created a microbial signature, which could be used to objectively stratify patients and healthy controls. In this addendum, we combine the microbiota data derived from the British cohort with that of a recently reported Swedish PI-IBS cohort. Remarkably, robust and reproducible microbiota signatures were observed in these PI-IBS patients. We discuss these results with attention on the emerging role of microbiota in the classification, development and treatment of PI-IBS.     

Post-infectious irritable bowel syndrome

Post-infectious irritable bowel syndrome （PI-IBS） is a common disorder wherein symptoms of IBS begin after an episode of acute gastroenteritis. Published studies have reported incidence of PI-IBS to range between 5% and 32%. The mechanisms underlying the development of PI-IBS are not fully understood, but are believed to include persistent sub-clinical inflammation, changes in intestinal permeability and alteration of gut flora. Individual studies have suggested that risk factors for PI-IBS include patients＇ demographics, psychological disorders and the severity of enteric illness. However, PI-IBS remains a diagnosis of exclusion with no specific disease markers and, to date, no definitive therapy exists. The prognosis of PI- IBS appears favorable with spontaneous and gradual resolution of symptoms in most patients.     

Almost all irritable bowel syndromes are post-infectious and respond to probiotics: controversial issues

Acute infectious gastroenteritis is the strongest known risk factor for the development of irritable bowel syndrome (IBS), one of the most common functional gastrointestinal disorders. However, knowledge about the incidence and prevalence of post-infectious IBS (PI-IBS) in the general population is still limited. Some of the published epidemiological studies on PI-IBS lack an appropriate control population, and were limited by a short follow-up symptom assessment post-infection. A number of risk factors have been associated with the development of PI-IBS, including the virulence of the pathogen, younger age, female sex, the long duration of the initial illness and the presence of psychological disturbances. However, much work has to be done to establish whether multifactorial mechanisms actually concur to the pathophysiology of PI-IBS. The discovery that an infective episode may trigger the development of IBS has not substantially changed the clinical management of this subset of patients compared to the classical (non-infective) form of IBS. Probiotics have been claimed to be of some benefit in IBS, but the majority of studies have been performed in non-specific IBS rather than in PI-IBS and a number of issues still remain to be elucidated.     

Microbial signatures in post-infectious irritable bowel syndrome – toward patient stratification for improved diagnostics and treatment

Irritable bowel syndrome (IBS) is a multifactorial and heterogeneous disorder estimated to affect over 10% of the Western population. A subset of the patients reports the start of the disease after an episode of gastroenteritis. The alterations in the intestinal microbiota of the post-infectious IBS (PI-IBS) patients were recently investigated in a British cohort and shown to differentiate from the healthy controls and resemble that of diarrhea-predominant IBS (IBS-D) patients. The altered 27 genus-like groups created a microbial signature, which could be used to objectively stratify patients and healthy controls. In this addendum, we combine the microbiota data derived from the British cohort with that of a recently reported Swedish PI-IBS cohort. Remarkably, robust and reproducible microbiota signatures were observed in these PI-IBS patients. We discuss these results with attention on the emerging role of microbiota in the classification, development and treatment of PI-IBS.Key words: irritable bowel syndrome, IMD, microbiota, PI-IBS     

Dyspepsia and irritable bowel syndrome after a Salmonella gastroenteritis outbreak: one-year follow-up cohort study

BACKGROUND & AIMS: It has been reported that some patients develop functional digestive disorders, particularly irritable bowel syndrome (IBS), after acute gastroenteritis (AGE). However, the presence of dyspepsia has not been specifically addressed. We prospectively evaluated development of dyspepsia and IBS during a 1-year follow-up in a cohort of adult patients affected by a Salmonella enteritidis AGE outbreak. METHODS: Questionnaires were sent to 1878 potential participants at baseline and 3, 6, and 12 months; 677 had experienced a Salmonella enteritidis AGE on June 23, 2002, and 1201 had not (randomly selected controls, matched for village of residence, age, and sex). At 12 months, 271 patients and 335 controls returned the questionnaires. Data permitted the establishment of dyspepsia and IBS diagnosis by Rome II criteria. RESULTS: Before the AGE outbreak, the prevalence of dyspepsia was similar in cases and controls (2.5% vs 3.8%); the prevalence of IBS was also similar (2.9% vs 2.3%). At 3, 6, and 12 months, the prevalence of both dyspepsia and IBS had increased significantly in exposed compared with unexposed subjects. Overlap between dyspepsia and IBS was frequent. At 1 year, the relative risk for development of dyspepsia was 5.2 (95% confidence interval, 2.7-9.8) and for IBS was 7.8 (95% confidence interval, 3.1-19.7). Prolonged abdominal pain and vomiting during AGE were positive predictors of dyspepsia. No predictive factors for IBS were found. CONCLUSIONS: Salmonella gastroenteritis is a significant risk factor not only for IBS but also for dyspepsia; at 1 year of follow-up, 1 in 7 and 1 in 10 subjects developed dyspepsia or IBS, respectively.     

Postinfection Irritable Bowel Syndrome

Following acute gastroenteritis (AGE) due to bacteria, viruses, or protozoa, a subset of patients develop new onset Rome criteria positive irritable bowel syndrome (IBS), called postinfection IBS (PI-IBS). The pooled prevalence of PI-IBS following AGE was 11.5%. PI-IBS is the best natural model that suggests that a subset of patients with IBS may have an organic basis. Several factors are associated with a greater risk of development of PI-IBS following AGE including female sex, younger age, smoking, severity of AGE, abdominal pain, bleeding per rectum, treatment with antibiotics, anxiety, depression, somatization, neuroticism, recent adverse life events, hypochondriasis, extroversion, negative illness beliefs, history of stress, sleep disturbance, and family history of functional gastrointestinal disorders (FGIDs), currently called disorder of gut-brain interaction. Most patients with PI-IBS present with either diarrhea-predominant IBS or the mixed subtype of IBS, and overlap with other FGIDs, such as functional dyspepsia is common. The drugs used to treat non-constipation IBS may also be useful in PI-IBS treatment. Since randomized controlled trials on the efficacy of drugs to treat PI-IBS are rare, more studies are needed on this issue.     

Postinfectious irritable bowel syndrome--a meta-analysis

OBJECTIVES: Irritable bowel syndrome (IBS) is a heterogeneous disorder affecting 12% of the population worldwide. Several studies identify IBS as a sequela of infectious gastroenteritis (IGE) with reported prevalence ranging from 4% to 31% and relative risk from 2.5 to 11.9. This meta-analysis was conducted to explore the differences between reported rates and provide a pooled estimate of risk for postinfectious irritable bowel syndrome (PI-IBS). DATA SOURCES: Electronic databases (MEDLINE, OLDMEDLINE, EMBASE, Cochrane database of clinical trials) and pertinent reference lists (including other review articles). REVIEW METHODS: Data were abstracted from included studies by two independent investigators; study quality, heterogeneity, and publication bias were assessed; sensitivity analysis was performed; and a summative effect estimate was calculated for risk of PI-IBS. RESULTS: Eight studies were included for analysis and all reported elevated risk of IBS following IGE. Median prevalence of IBS in the IGE groups was 9.8% (IQR 4.0-13.3) and 1.2% in control groups (IQR 0.4-1.8) (sign-rank test, p= 0.01). The pooled odds ratio was 7.3 (95% CI, 4.7-11.1) without significant heterogeneity (chi2 heterogeneity statistic, p= 0.41). Subgroup analysis revealed an association between PI-IBS risk and IGE definition used. CONCLUSIONS: This study provides supporting evidence for PI-IBS as a sequela of IGE and a pooled risk estimate revealing a sevenfold increase in the odds of developing IBS following IGE. The results suggest that the long-term benefit of reduced PI-IBS may be gained from primary prevention of IGE.     

Relative importance of enterochromaffin cell hyperplasia, anxiety, and depression in postinfectious IBS

BACKGROUND & AIMS: Both psychological and mucosal changes (increased enterochromaffin [EC] cells and T lymphocytes) have been associated with postinfectious irritable bowel syndrome (PI-IBS). However, previous studies have been underpowered to determine the relative importance of these changes in predicting the development of PI-IBS. Our aim was to prospectively determine the relative importance of both psychological and histologic factors in the development of PI-IBS after Campylobacter infection. METHODS: Questionnaires detailing psychological and bowel symptoms were sent to 1977 patients 3 months after infection. Twenty-eight patients with new-onset PI-IBS, 28 age- and sex-matched patient controls who were asymptomatic after infection, and 34 healthy volunteers underwent rectal biopsy, which was assessed for serotonin-containing EC cells, mast cells, and lamina propria T lymphocytes. RESULTS: PI-IBS, predominantly of the diarrhea-predominant subtype, occurred in 103 of 747 (13.8%) of those infected. EC cell counts per high-power field (hpf) were higher in patients with PI-IBS (35.8 +/- 1.2) compared with patient controls (30.6 +/- 1.9; P = 0.022) and volunteers (29.1 +/- 1.8; P = 0.006). Lamina propria T lymphocytes per hpf were higher in patients with PI-IBS (127.1 +/- 8.7) and patient controls (113.4 +/- 6.2) in contrast to healthy volunteers (97.1 +/- 5.7) (P = 0.006 and P = 0.058, respectively). Anxiety, depression, and fatigue were significantly increased in patients with PI-IBS compared with patient controls. Multivariate analysis indicated that increased EC cell counts and depression were equally important predictors of developing PI-IBS (relative risk, 3.8 and 3.2 for each standard deviation increase in respective values). CONCLUSIONS: Both increased EC cells and depression are important independent predictors of developing PI-IBS.     

Irritable bowel syndrome and inflammatory bowel disease: infectious gastroenteritis-related disorders?

Infectious gastroenteritis may be one of the important factors in the development of irritable bowel syndrome (IBS), with affected individuals often categorized as having post-infectious IBS (PI-IBS), and is linked to the onset of symptoms in approximately 10–20% of patients diagnosed with IBS. Intestinal mucosal infiltration of T cells and mast cells, and enterochromaffin cell hyperplasia are significant immunological and pathological findings that reveal the pathogenesis of PI-IBS, and results of laboratory studies using animal models of PI-IBS clearly support clinical evidence. Recently, infectious gastroenteritis has also been suggested to be associated with the development of inflammatory bowel disease (IBD), and various studies have suggested that individuals with IBS or IBS-like symptoms may be susceptible to initiation of IBD. However, it is still unclear whether infectious gastroenteritis is directly or indirectly (through PI-IBS) linked to the initiation of IBD. Additional studies are necessary to understand the clinical overlap among infectious gastroenteritis, IBS, and IBD.     

感染对IBS患者肠黏膜细胞因子表达的影响

目的:探讨感染对肠易激综合征(irritable bowel syndrome,IBS)患者神经-免疫-内分泌网络的影响.方法:感染后肠易激综合征(postinfectious irritable bowel syndrome,PI-IBS)患者45例,non-PI-IBS患者60例及30例对照者,结肠镜下活检回盲部黏膜标本,采用免疫组织化学法检测其肠黏膜SP、IL-2、IFN-γ、SPR与5-HT的表达,肥大细胞(mast cells,MC)采用甲苯胺蓝染色.结果:PI-IBS患者的SP表达分别高于non-PI-IBS与对照组(t=2.5,2.8,P<0.01);PI-IBS患者的MC表达分别高于non-PI-IBS与对照组(t=11.5,12.1,P<0.01).PI-IBS患者的5-HT表达分别高于non-PI-IBS与对照组(t=13.6,14.1,P<0.01);PI-IBS患者的SPR表达分别高于non-PI-IBS与对照组(t=3.8,6.1,P<0.05);PI-IBS患者的IFN-γ表达分别高于non-PI-IBS与对照组(t=13.8,15.2,P<0.05);PI-IBS患者的IL-2表达分别高于non-PI-IBS与对照组(t=12.6,14.7,P<0.05).PI-IBS患者回盲部黏膜MC和SP的表达呈高度正相关(r=0.71,P<0.01).PI-IBS患者回盲部黏膜5-HT和SPR的表达呈密切相关(r=0.18,P<0.05).IFN-γIL-2阳性表达的PI-IBS患者,SP表达高于非PI-IBS组(r=2.2,2.3,P<0.05)和对照组(t=2.3,2.4,P<0.05).结论:肠道感染后,神经纤维在IBS的免疫-神经-内分泌发生机制中的作用至关重要.     

Postinfectious Irritable Bowel Syndrome—A Meta-Analysis

OBJECTIVES:  Irritable bowel syndrome (IBS) is a heterogeneous disorder affecting 12% of the population worldwide. Several studies identify IBS as a sequela of infectious gastroenteritis (IGE) with reported prevalence ranging from 4% to 31% and relative risk from 2.5 to 11.9. This meta-analysis was conducted to explore the differences between reported rates and provide a pooled estimate of risk for postinfectious irritable bowel syndrome (PI-IBS).
DATA SOURCES:  Electronic databases (MEDLINE, OLDMEDLINE, EMBASE, Cochrane database of clinical trials) and pertinent reference lists (including other review articles).
REVIEW METHODS:  Data were abstracted from included studies by two independent investigators; study quality, heterogeneity, and publication bias were assessed; sensitivity analysis was performed; and a summative effect estimate was calculated for risk of PI-IBS.
RESULTS:  Eight studies were included for analysis and all reported elevated risk of IBS following IGE. Median prevalence of IBS in the IGE groups was 9.8% (IQR 4.0–13.3) and 1.2% in control groups (IQR 0.4–1.8) (sign-rank test, p = 0.01). The pooled odds ratio was 7.3 (95% CI, 4.7–11.1) without significant heterogeneity (χ² heterogeneity statistic, p = 0.41). Subgroup analysis revealed an association between PI-IBS risk and IGE definition used.
CONCLUSIONS:  This study provides supporting evidence for PI-IBS as a sequela of IGE and a pooled risk estimate revealing a sevenfold increase in the odds of developing IBS following IGE. The results suggest that the long-term benefit of reduced PI-IBS may be gained from primary prevention of IGE.