Bacillary dysentery as a causative factor of irritable bowel syndrome and its pathogenesis.
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BACKGROUND AND AIMS: The incidence of irritable bowel syndrome (IBS) or functional bowel disorders (FBD) after bacillary dysentery (BD) has not been extensively evaluated, and little is known of the pathogenesis of post-infective (PI) IBS. Therefore, we investigated the incidence of IBS and FBD in a Chinese patient population who had recovered from BD. To further elucidate its pathogenesis, neuroimmunological changes, including interleukins (IL), mast cells, neuropeptides, and the relationship between mast cells and intestinal nerves, were investigated. METHODS: A cohort study of 295 patients who had recovered from BD (shigella identified from stool in 71.4%) and 243 control subjects consisting of patient siblings or spouses who had not been infected with BD were included in the study. All subjects were followed up using questionnaires for 1-2 years to explore the incidence of FBD and IBS, as defined by the Rome II criteria. In 56 cases of IBS (PI and non-PI) from another source, the number of mast cells in biopsy specimens from the intestinal mucosa were stained with antitryptase antibody and counted under light microscopy. Also, the relationship of mast cells to neurone specific enolase (NSE), substance P (SP), 5-hydroxytryptamine (5-HT), or calcitonin gene related peptide positive nerve fibres was observed using double staining with alcian blue and neuropeptide antibodies. In 30 cases of IBS (PI-IBS, n = 15) taken at random from the 56 cases, expression of interleukin (IL)-1alpha, IL-1beta, and IL-1 receptor antagonist (IL-1ra) mRNAs in intestinal mucosa were identified using reverse transcription-polymerase chain reaction. The above results were compared with 12 non-IBS controls. RESULTS: In the BD infected cohort, the incidences of FBD and IBS were 22.4% and 8.1% (in total)-10.2% (among those in who shigella were identified) respectively, which were significantly higher (p<0.01) than the incidences of FBD (7.4%) and IBS (0.8%) in the control cohort. A longer duration of diarrhoea (>or=7 days) was associated with a higher risk of developing FBD (odds ratio 3.49 (95% confidence interval 1.71-7.13)). Expression of IL-1beta mRNA in terminal ileum and rectosigmoid mucosa was significantly higher in PI-IBS patients (p<0.01). The number of mast cells in the terminal ileum mucosa in PI-IBS (11.19 (2.83)) and non-PI-IBS patients (10.78 (1.23)) was significantly increased compared with that (6.05 (0.51)) in control subjects (p<0.01). Also, in the terminal ileum and rectosigmoid mucosa of IBS patients, the density of NSE, SP, and 5-HT positively stained nerve fibres increased (p<0.05) and appeared in clusters, surrounding an increased number of mast cells (p<0.01 compared with controls). CONCLUSIONS: BD is a causative factor in PI-IBS. The immune and nervous system may both play important roles in the pathogenesis of PI-IBS. (+info)
Altered visceral perceptual and neuroendocrine response in patients with irritable bowel syndrome during mental stress.
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BACKGROUND AND AIMS: Stress often worsens the symptoms of irritable bowel syndrome (IBS). We hypothesised that this might be explained by altered neuroendocrine and visceral sensory responses to stress in IBS patients. SUBJECTS AND METHODS: Eighteen IBS patients and 22 control subjects were assessed using rectal balloon distensions before, during, and after mental stress. Ten controls and nine patients were studied in supplementary sessions. Rectal sensitivity (thresholds and intensity-visual analogue scale (VAS)) and perceived stress and arousal (VAS) were determined. Plasma levels of corticotropin releasing factor (CRF), adrenocorticotropic hormone (ACTH), cortisol, noradrenaline, and adrenaline were analysed at baseline, immediately after stress, and after the last distension. Heart rate was recorded continuously. RESULTS: Thresholds were increased during stress in control subjects (p<0.01) but not in IBS patients. Both groups showed lower thresholds after stress (p<0.05). Repeated distensions without stress did not affect thresholds. Both groups showed increased heart rate (p<0.001) and VAS ratings for stress and arousal (p<0.05) during stress. Patients demonstrated higher ratings for stress but lower for arousal than controls. Basal CRF levels were lower in patients (p<0.05) and increased significantly during stress in patients (p<0.01) but not in controls. Patients also responded with higher levels of ACTH during stress (p<0.05) and had higher basal levels of noradrenaline than controls (p<0.01). Controls, but not patients, showed increased levels of adrenaline and noradrenaline in response to stress (p<0.05). CONCLUSIONS: Stress induced exaggeration of the neuroendocrine response and visceral perceptual alterations during and after stress may explain some of the stress related gastrointestinal symptoms in IBS. (+info)
Prevalence of irritable bowel syndrome according to different diagnostic criteria in a non-selected adult population.
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BACKGROUND: Prevalence of irritable bowel syndrome shows great variation among epidemiological studies, which may be due to different diagnostic criteria. AIM: To assess prevalence of irritable bowel syndrome according to various diagnostic criteria and to study differences in symptom severity, psychopathology, and use of health care resources between subjects fulfilling different diagnostic criteria. METHODS: A questionnaire was mailed to 5000 randomly selected adults. Presence of irritable bowel syndrome was assessed by four diagnostic criteria: Manning 2 (at least two Manning symptoms), Manning 3 (at least three Manning symptoms), Rome I and Rome II. RESULTS: Response rate was 73%. Prevalence of irritable bowel syndrome by Manning 2, Manning 3, Rome I and Rome II criteria was 16.2%, 9.7%, 5.6%, and 5.1% respectively. Of those fulfilling Rome II criteria, 97% fulfilled Manning 2. Severe or very severe abdominal pain was reported by 27-30% of Manning-positive subjects, and 44% of Rome-positives. Prevalence of depression in Manning 2, and Rome II groups was 30.6 and 39.3%. CONCLUSIONS: Prevalence of irritable bowel syndrome by Rome II criteria is considerably lower than by Manning criteria. Subjects fulfilling Rome criteria form a subgroup of Manning-positive subjects with more severe abdominal symptoms, more psychopathology, and more frequent use of the health care system. (+info)
The burden of illness of irritable bowel syndrome: current challenges and hope for the future.
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OBJECTIVES: To review unmet medical needs associated with irritable bowel syndrome (IBS), to discuss factors that contribute to these unmet needs, and to provide an overview of advancements in IBS diagnosis and treatment options that may influence treatment strategies. SUMMARY: IBS is characterized by a multiple symptom complex of abdominal pain or discomfort and altered bowel habits (i.e., constipation, diarrhea, or both in alternation) and is associated with a large unmet medical need. IBS symptoms are chronic and bothersome, and they have a profound negative impact on patients. quality of life (i.e., affecting sleep, personal relationships, travel, diet, and sexual functioning). IBS imposes a substantial economic burden in direct medical costs and in indirect social costs such as absenteeism from work and school and lost productivity, along with the less-measurable costs of a decreased quality of life. The annual cost of IBS treatment in the United States has been estimated to be between $1.7 billion and $10 billion in direct medical costs (excluding prescription and over-the-counter [OTC] drug costs) and $20 billion for indirect costs. The goals of IBS therapy are to provide global relief of the multiple symptoms of IBS and to relieve single IBS symptoms. Although traditional IBS therapies (e.g., laxatives, antidepressants, antispasmodics, and bulking agents) are useful for some patients in relieving single IBS symptoms, patients generally are dissatisfied with their overall efficacy and tolerability. These agents have not been proven in randomized, controlled clinical trials to be more effective than placebo in providing global relief of the multiple symptoms of IBS. Over the past 2 decades, numerous advancements in the diagnosis and management of IBS have provided hope for the future, including research strides in our understanding of the underlying pathophysiology of IBS; new diagnostic and management recommendations based on a stepwise, symptom-based approach; and the development of novel pharmacologic agents. CONCLUSION: IBS imposes a high socioeconomic burden on its sufferers and on society. Research strides in the underlying pathophysiology of this disorder have enhanced our understanding of IBS, but many questions remain to be answered. Development of evidence-based guidelines on the stepwise, symptom-based approach to IBS diagnosis and the continuing efforts to develop unique pharmacologic classes targeted at the multiple symptoms of this disorder are steps in the right direction. Though cost-effectiveness data on specific pharmacologic classes are not yet available, these ongoing efforts may help promote timely IBS diagnosis and patient satisfaction with care, optimally decreasing the use of health care resources. (+info)
The validity and accuracy of the Work Productivity and Activity Impairment questionnaire--irritable bowel syndrome version (WPAI:IBS).
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BACKGROUND: Irritable bowel syndrome is a common chronic functional gastrointestinal disorder characterized by recurrent abdominal pain and discomfort associated with alterations in bowel habit. Irritable bowel syndrome affects patients' quality of life and increases productivity loss. AIM: To assess validity and accuracy of the Work Productivity and Activity Impairment questionnaire in irritable bowel syndrome as a tool for quantifying the effects of irritable bowel syndrome on productivity and daily activities. METHODS: Validity and accuracy were evaluated in 135 irritable bowel syndrome patients relative to three measures of irritable bowel syndrome disease severity; a debriefing questionnaire; retrospective diary; Work Limitations Questionnaire, and an activity impairment measure (Dimensions of Daily Activities). RESULTS: Symptom severity scores, diary scores, Work Limitations Questionnaire and Dimensions of Daily Activities were significant predictors of work productivity and activity impairment questionnaire in irritable bowel syndrome measures of work time missed, and work and activity productivity loss (P = 0.04 to < 0.0001). Impairment due to irritable bowel syndrome was estimated to be 2.9-4.3% for work time missed and 22-32% for impairment at work, the equivalent of 9.7 -14 h lost productivity per week. Activity impairment was 24-41%. CONCLUSIONS: Discriminative validity of the Work Productivity and Activity Impairment questionnaire in irritable bowel syndrome was established, making it the only validated tool for measuring the relative differences between disease severity groups and quantifying work productivity loss and activity impairment in irritable bowel syndrome patients. (+info)
Ovarian hormone modulates 5-hydroxytryptamine 3 receptors mRNA expression in rat colon with restraint stress-induced bowel dysfunction.
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AIM: To examine the effects of ovarian hormone on the expression of 5-hydroxytryptamine 3 receptors (5-HT3R) in rat colon of restraint stress-induced bowel dysfunction. METHODS: Twenty-four female Sprague-Dawley rats were randomly divided into three groups of 8 each: sham operation, ovariectomy (OVX) and ovariectomy with estrogen (E2) and progesterone (P) replacement therapy (OVX+E2+P). The rats were subjected to 1-h restraint stress 4 wk after operation. The changes of defecation were monitored by collection of fecal pellets. The gonadal steroids were measured in duplicate by radioimmunoassay (RIA). The expression of 5-HT3R mRNA in the colon was studied by RT-PCR. RESULTS: Compared with sham group and OVX+E2+P group, OVX group showed increase in fecal pellets and decrease in the time of vitreous pellets excretion (P<0.01). Serum levels of E2 and P were suppressed in OVX group and restored following treatment with ovarian steroids (P<0.01), and the levels of 5-HT3R mRNA in the colon of ovariectomized rats were significantly increased, the expression of 5-HT3R mRNA was significantly decreased in hormone replacement therapy group (P<0.01). CONCLUSION: Ovarian hormone plays a role in the regulation of 5-HT3R expressions in restraint stress-induced bowel dysfunction of rats. The interactions between ovarian steroids and gastrointestinal tract may have major pathophysiological implications in 5-HT-related disorders, such as irritable bowel syndrome (IBS). (+info)
Diagnostic accuracy of faecal calprotectin estimation in prediction of abnormal small bowel radiology.
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BACKGROUND: [corrected] Patients being investigated for symptoms of abdominal pain, diarrhoea and or weight loss often undergo small bowel radiology as part of their diagnostic workup mainly to exclude inflammatory bowel disease. AIM: To assess and compare the utility of a single faecal calprotectin estimation to barium follow through as well as conventional inflammatory markers such as erythrocyte sedimentation rate and C-reactive protein in exclusion of intestinal inflammation. METHODS: Seventy-three consecutive cases undergoing barium follow through for investigation of symptoms of diarrhoea and or abdominal pain with or without weight loss were studied. The control group comprised 25 cases with known active Crohn's disease (positive controls), 26 normal healthy volunteers (negative controls) and 25 cases of irritable bowel syndrome diagnosed by Rome II criteria. Symptoms, erythrocyte sedimentation rate and C-reactive protein were recorded at recruitment and a single stool sample assayed for calprotectin within 7 days prior to or after barium follow through. RESULTS: The median calprotectin value in the active Crohn's group, irritable bowel syndrome group and normal volunteers was 227 microg/g of stool, 19 and 10 microg/g respectively (P < 0.0001). A faecal calprotectin above a cut-off value of 60 microg/g was able to predict all nine cases with an abnormal barium follow through as well as all six cases with a normal barium follow through but with organic intestinal disease. The negative predictive value of a single calprotectin result below 60 microg/g of stool was 100% compared with 91% each for erythrocyte sedimentation rate > 10 mm and C-reactive protein > 6 mg/L and 84% for a combination of erythrocyte sedimentation rate and C-reactive protein in predicting absence of organic intestinal disease. CONCLUSION: A single stool calprotectin value < 60 microg/g of stool obviates the need for further barium radiology of the small bowel, is more accurate than measurement of erythrocyte sedimentation rate or C-reactive protein and effectively excludes Crohn's disease or non-functional gastrointestinal disease. (+info)
Probiotics and human health: a clinical perspective.
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There is unequivocal evidence that administration of probiotics could be effective in the treatment of acute infectious diarrhoea in children and the prevention of antibiotic associated diarrhoea and nosocomial/community acquired diarrhoea. Encouraging evidence is also emerging for the effectiveness of probiotics in the prevention and management of pouchitis and paediatric atopic diseases, and the prevention of postoperative infections. There is also strong evidence that certain probiotic strains are able to enhance immune function, especially in subjects with less than adequate immune function such as the elderly. Efficacy of probiotics in the prevention of traveller's diarrhoea, sepsis associated with severe acute pancreatitis, and cancers, the management of ulcerative colitis, and lowering of blood cholesterol remains unproven. In addition to firm evidence of efficacy (for a range of conditions), major gaps exist in our knowledge regarding the mechanisms by which probiotics modulate various physiological functions and the optimum dose, frequency, and duration of treatment for different probiotic strains. (+info)