Diagnosis and treatment of irritable bowel syndrome: State of the art

The underlying mechanism, efficiency, and safety of manual therapy for functional gastrointestinal disorders: A narrative review

INTRODUCTION

Functional gastrointestinal disorders encompass a range of conditions resulting from complicated gut-brain interactions, which can negatively impact sufferers' lives. They are prevalent in clinical practice and the community, with a lifetime prevalence of almost 40 % worldwide. The challenge in diagnosing these disorders lies in the non-specificity of symptoms and the absence of reliable biomarkers. The existing literature suggests a multidisciplinary approach, including cognitive-behavioral therapy, dietary changes, psychotropic drug therapy, and improving gastrointestinal motility. Manual therapy applied to the abdomen and adjacent areas can potentially enhance gastrointestinal motility.

OBJECTIVES

This review aims to examine the types of manual interventions, their mechanisms, efficiency, and safety in managing functional disorders of the digestive system.

METHODS

We searched PubMed and Google Scholar in English from May 2022 to February 2023 with no date restriction. We prioritized systematic reviews, meta-analyses, and clinical trials and did not exclude any data sources.

RESULTS AND CONCLUSION

s: Initial evidence suggests that manual interventions on the abdomen and adjacent areas are effective in managing functional gastrointestinal disorders, with no reported adverse events and relatively low costs. However, further studies with rigorous scientific methodology are needed to understand better the unknown dimensions influencing the outcomes observed with abdominal massage and its positive impact on patients. Manual abdominal techniques are a promising therapy option for functional gastrointestinal disorders, and their efficacy, safety, and cost-effectiveness should be further explored.

Major depressive disorder and irritable bowel syndrome risk: A Mendelian randomization study

BACKGROUND

Previous studies have revealed a connection between major depressive disorder (MDD) and irritable bowel syndrome (IBS), but it remains obscure if the two diseases are related causally. Mendelian randomization was utilized in this investigation to ascertain whether MDD contributed to the emergence of IBS.

METHODS

To examine possible connections between MDD and IBS, we used two-sample Mendelian randomization (MR) utilizing summary data from genome-wide association studies (GWAS). The Psychiatric Genomics Consortium (PGC) provided information on genetic associations with MDD (cases: 135,458; controls: 344,901). The Medical Research Council Integrative Epidemiology Unit (MRC-IEU) provided information on genetic associations with IBS (cases:10,939; controls:451,994). Inverse Variance Weighted (main analyses), MR-Egger regression, Weighted mode, and Weighted Median were the four MR methods used in this investigation. In addition, we also performed multiplicity and heterogeneity analyses to eliminate possible biases.

RESULTS

In the standard Inverse Variance Weighting (IVW) method, an increased risk of IBS was linked to a genetic susceptibility to MDD (OR: 1.01; 95% CI: 1.006 to 1.014, p = 1.02E-07). In addition, neither significant heterogeneity (IVW Q = 24.80, p = 0.73) nor horizontal pleiotropy (MR Egger p = 0.17; MRPRESSO p = 0.54) were detected in this MR analysis. The bidirectional analysis, however, did not show a genetic link between IBD and MDD (p steiger <0.01).

CONCLUSION

A direct causal relationship between MDD and IBS was revealed by Mendelian randomization study, which contributes to the effective clinical management of both diseases.

The Impact of an Individual Educational Program on the Quality of Life and Severity of Symptoms of Patients with Irritable Bowel Syndrome

Background: Irritable bowel syndrome (IBS) is one of the most common functional diseases of the gastrointestinal tract. A typical symptom is changed bowel patterns: diarrhea, constipation, or alternation of the two. Abdominal pains vary in intensity and location, with periods of exacerbation and remission, causing disorganization in everyday life and work. Educational intervention could be one strategy to improve the well-being of IBS patients. Only a few trials have examined this hypothesis. The aim of this study was to examine the effect of an educational program combined with elements of behavioral therapy, individualized for each patient, on quality of life (QOL) and severity of pain of patients with IBS. Methods: In total, 150 IBS patients and 100 healthy persons in the control group were included. QOL (36-Item Short Form Health Survey, SF-36) and pain severity (Visual Analogue Scale) were measured at baseline and six months after education of IBS patients. Results: At baseline, patients with IBS showed highly significantly worse QOL. In the IBS group, significantly higher physical component summary (PCS) and mental component summary (MCS) scores were noted for 35- to 50-year-old patients compared to other patients. Six months after education and behavioral therapy, significant improvement in QOL and a significant decrease in the subjective perception of pain severity were noted compared to values before therapeutic education. Conclusion: An educational program combined with elements of behavioral therapy, individualized for patients with IBS, is an important part of therapy for these patients.

Variation in Care for Patients with Irritable Bowel Syndrome in the United States

Objectives

Irritable bowel syndrome (IBS) affects nearly one in seven Americans. Significant national variations in care may exist, due to a current lack of standardized diagnosis and treatment algorithms; this can translate into a substantial additional economic burden. The study examines healthcare resource utilization in patients with IBS and in the subset of IBS patients with constipation (IBS-C) and analyzes the variation of IBS care for these patients across the United States (US).

Methods

Healthcare resource use (HRU), including gastrointestinal (GI) procedures and tests, all-cause and intestinal-related medical visits, GI specialist visits, and constipation or diarrhea pharmacy prescriptions for IBS patients enrolled in a large US administrative claims database (2001–2012) were analyzed for the 24-month period surrounding first diagnosis. Multivariate regression models, adjusting for age, gender, year of first diagnosis, insurance type, and Charlson comorbidity index, compared HRU across states (each state vs. the average of all other states).

Results

Of 201,322 IBS patients included, 77.2% were female. Mean age was 49.4 years. One in three patients had ≥3 distinct GI medical procedures or diagnostic tests; 50.1% visited a GI specialist. Significant HRU differences were observed in individual states compared to the national average. IBS-C patients had more medical visits, procedures, and pharmacy prescriptions for constipation/diarrhea than IBS patients without constipation.

Conclusions

This study is the first to identify considerable regional variations in IBS healthcare across the US and to note a markedly higher HRU by IBS-C patients than by IBS patients without constipation. Identifying the reasons for these variations may improve quality of care and reduce the economic burden of IBS.

Psychosocial impact of irritable bowel syndrome: A brief review

Irritable bowel syndrome (IBS) is a common disorder of the gastrointestinal tract with unclear etiology and no reliable biomarker. Like other chronic and functional disorders, medical treatments for IBS are suboptimal and the overall illness burden is high. Patients with IBS report high rates of psychopathology, low quality of life, and increased suicidal ideation. These patients also miss more days of work, are less productive at work, and use many healthcare resources. However, little is known about the burden of IBS on daily functioning. The primary aim of this paper is to review the current literature on the burden of IBS and to highlight the need for further research to evaluate the impact of IBS on daily activities. This research would contribute to our existing understanding of the impact of IBS on overall quality of life and well-being.

Inhibition of ileal bile acid transporter: An emerging therapeutic strategy for chronic idiopathic constipation

Chronic idiopathic constipation is a common disorder of the gastrointestinal tract that encompasses a wide profile of symptoms. Current treatment options for chronic idiopathic constipation are of limited value; therefore, a novel strategy is necessary with an increased effectiveness and safety. Recently, the inhibition of the ileal bile acid transporter has become a promising target for constipation-associated diseases. Enhanced delivery of bile acids into the colon achieves an accelerated colonic transit, increased stool frequency, and relief of constipation-related symptoms. This article provides insight into the mechanism of action of ileal bile acid transporter inhibitors and discusses their potential clinical use for pharmacotherapy of constipation in chronic idiopathic constipation.

A biomarker panel and psychological morbidity differentiates the irritable bowel syndrome from health and provides novel pathophysiological leads

BACKGROUNDS

The development of a reliable biomarker for irritable bowel syndrome (IBS) remains one of the major aims of research in functional gastrointestinal disorders (FGIDs) and is complicated by the absence of a perfect reference standard. Previous efforts based on genetic and immune markers have showed promise, but have not been robust.

AIM

To evaluate an extensive panel of gene expression and serology markers combined with psychological measures in differentiating IBS from health and between subtypes of IBS.

METHODS

Of subjects eligible for analysis (N = 244), 168 met criteria for IBS (60 IBS-C, 57 IBS-D and 51 mixed), while 76 were free of any FGID. A total of 34 markers were selected based on pathways implicated in pathophysiology of IBS or whole human genome screening. Psychological measures were recorded that covered anxiety, depression and somatisation. Models differentiating disease and health were based on unconditional logistic regression and performance assessed through area under the receiver-operator characteristic curve (AUC), sensitivity and specificity.

RESULTS

The performance of a combination of 34 markers was good in differentiating IBS from health (AUC = 0.81) and was improved considerably with the addition of four psychological markers (combined AUC = 0.93). Of the 34 markers considered, discrimination was derived largely from a small subset. Good discrimination was also obtained between IBS subtypes with the best being observed for IBS-C vs. IBS-D (AUC = 0.92); however, psychological variables provided almost no incremental discrimination subtypes over biological markers (combined AUC = 0.94).

CONCLUSIONS

A combination of gene expression and serological markers in combination with psychological measures shows exciting progress towards a diagnostic test for IBS compared with healthy subjects, and to discriminate IBS-C from IBS-D.

The gut microbiota and irritable bowel syndrome: friend or foe?

Progress in the understanding of the pathophysiology of irritable bowel syndrome (IBS), once thought to be a purely psychosomatic disease, has advanced considerably and low-grade inflammation and changes in the gut microbiota now feature as potentially important. The human gut harbours a huge microbial ecosystem, which is equipped to perform a variety of functions such as digestion of food, metabolism of drugs, detoxification of toxic compounds, production of essential vitamins, prevention of attachment of pathogenic bacteria to the gut wall, and maintenance of homeostasis in the gastrointestinal tract. A subset of patients with IBS may have a quantitative increase in bacteria in the small bowel (small intestinal bacterial overgrowth). Qualitative changes in gut microbiota have also been associated with IBS. Targeting the gut microbiota using probiotics and antibiotics has emerged as a potentially effective approach to the treatment of this, hitherto enigmatic, functional bowel disorder. The gut microbiota in health, quantitative and qualitative microbiota changes, and therapeutic manipulations targeting the microbiota in patients with IBS are reviewed in this paper.

The potential role of probiotics in the management of childhood autism spectrum disorders

Gastrointestinal (GI) dysfunction has been reported in a substantial number of children with autism spectrum disorders (ASD). Activation of the mucosal immune response and the presence of abnormal gut microbiota are repeatedly observed in these children. In children with ASD, the presence of GI dysfunction is often associated with increased irritability, tantrums, aggressive behaviour, and sleep disturbances. Moreover, modulating gut bacteria with short-term antibiotic treatment can lead to temporary improvement in behavioral symptoms in some individuals with ASD. Probiotics can influence microbiota composition and intestinal barrier function and alter mucosal immune responses. The administration of probiotic bacteria to address changes in the microbiota might, therefore, be a useful novel therapeutic tool with which to restore normal gut microbiota, reduce inflammation, restore epithelial barrier function, and potentially ameliorate behavioural symptoms associated with some children with ASD. In this review of the literature, support emerges for the clinical testing of probiotics in ASD, especially in the context of addressing GI symptoms.

Common component classification: what can we learn from machine learning?

Machine learning methods have been applied to classifying fMRI scans by studying locations in the brain that exhibit temporal intensity variation between groups, frequently reporting classification accuracy of 90% or better. Although empirical results are quite favorable, one might doubt the ability of classification methods to withstand changes in task ordering and the reproducibility of activation patterns over runs, and question how much of the classification machines' power is due to artifactual noise versus genuine neurological signal. To examine the true strength and power of machine learning classifiers we create and then deconstruct a classifier to examine its sensitivity to physiological noise, task reordering, and across-scan classification ability. The models are trained and tested both within and across runs to assess stability and reproducibility across conditions. We demonstrate the use of independent components analysis for both feature extraction and artifact removal and show that removal of such artifacts can reduce predictive accuracy even when data has been cleaned in the preprocessing stages. We demonstrate how mistakes in the feature selection process can cause the cross-validation error seen in publication to be a biased estimate of the testing error seen in practice and measure this bias by purposefully making flawed models. We discuss other ways to introduce bias and the statistical assumptions lying behind the data and model themselves. Finally we discuss the complications in drawing inference from the smaller sample sizes typically seen in fMRI studies, the effects of small or unbalanced samples on the Type 1 and Type 2 error rates, and how publication bias can give a false confidence of the power of such methods. Collectively this work identifies challenges specific to fMRI classification and methods affecting the stability of models.

Pilot study: a randomised, double blind, placebo controlled trial of pancrealipase for the treatment of postprandial irritable bowel syndrome-diarrhoea

OBJECTIVE: To evaluate the efficacy of pancrealipase (PEZ) compared with placebo in the reduction of postprandial irritable bowel syndrome-diarrhoea (IBS-D). DESIGN: An intention to treat, double blind, randomised, crossover trial comparing PEZ to placebo for reduction of postprandial IBS-D. Patients had to recognise at least two different triggering foods, be willing to consume six baseline 'trigger meals' and again blinded with PEZ and placebo. Patients then chose which drug they preferred for another 25 meals. SETTING: Outpatient internal medicine practice clinic. PATIENTS: 255 patients were screened; 83 met the criteria, including 5 years of symptoms, recognised 'food triggers', no other identifiable cause for the symptoms, either a normal colonoscopy or barium enema while symptomatic and able to discontinue all anticholinergic medications. 69 patients were enrolled, 20 withdrew before randomisation, leaving 49 patients: 14 men, 35 women, mean age 52 years (SD 15.3). Over 60% had experienced symptoms for 11-30 years and 16% for more than 40 years. INTERVENTIONS: After completing six baseline meals, patients were randomised in blocks of four to receive either identical PEZ or a placebo for another six meals, and after a washout period of time received the alternative drug. MAIN OUTCOME MEASURES: The primary analysis was number of patients who chose PEZ over placebo for the extended use. RESULTS: Overall, 30/49 (61%) would have chosen PEZ (p=0.078), with first drug preference for PEZ at 0.002. Among the PEZ subgroup, PEZ use compared with placebo, demonstrated improvement in all symptoms (p≤0.001) for cramping, bloating, borborygami, urge to defecate, global pain and decrease stooling with increase in stool firmness. CONCLUSIONS: PEZ was found in a small group of patients to reduce postprandial IBS-D symptoms and deserves further evaluation.

Irritable bowel syndrome and small intestinal bacterial overgrowth

In the last 3 decades, there has been a growing appreciation for the role of gut bacteria in gastrointestinal disease. Although inflammatory bowel disease and peptic ulcer disease have established a role for gut bacteria for more than 20 years, there is now increasing evidence that intestinal bacteria may play a role in irritable bowel syndrome as well. In this review, the current evidence for bacteria in irritable bowel syndrome will be examined.

Increased colonic motility in a rat model of irritable bowel syndrome is associated with up-regulation of L-type calcium channels in colonic smooth muscle cells

OBJECTIVE

This paper aimed to investigate the relationship between up-regulation of L-type calcium channels and altered motility disorder in a rat model of irritable bowel syndrome (IBS).

METHODS

Male Sprague-Dawley rats were subjected to neonatal maternal separation (NMS) from postnatal day 2-14 or normal handling (NH), and used when weighted 250-300 g. Colonic smooth muscle contractions was studied in an organ bath system. L-type Ca(2+) channel alpha(1c) subunit expression in smooth muscles from rat colon were studied by immunofluorescence and Western blotting analysis. The intracellular calcium concentration ([Ca(2+)](i)) of enzymatically isolated single colonic smooth muscle cell was studied with laser confocal fluorescent microscopy.

RESULTS

The fecal pellets during 1 h water avoidance stress (WAS) were significantly increased; the amplitude of spontaneous contractions and contractions induced by Bay K 8644 (10 nM-1 microM), KCl (10-60 mM) and ACh (100 nM-10 microM) were significantly increased in NMS rats, when comparing with that of NH rats. [Ca(2+)]i induced by Bay K 8644 (1 microM), KCl (40 mM), and ACh (10 microM) significantly increased in muscle cells of NMS rats than NH rats. Further, alpha(1c) protein expression was significantly up-regulated in colonic smooth muscle of NMS rats than NH rats.

CONCLUSION

These results suggest that NMS lead to up-regulation of L-type Ca(2+) channels expression in the colon, which contributes to the colonic motility disorder. Our findings provide direct evidence to help understanding the underlying mechanism of chronic stress-induced colonic motility disorder in IBS.

Analgesic effects of JCM-16021 on neonatal maternal separation-induced visceral pain in rats

AIM: To investigate the pharmacological effect of JCM-16021, a Chinese herbal formula, and its underlying mechanisms.

METHODS: JCM-16021 is composed of seven herbal plant materials. All raw materials of the formula were examined according to the quality control criteria listed in the Chinese Pharmacopeia (2005). In a neonatal maternal separation (NMS) model, male Sprague-Dawley rats were submitted to daily maternal separation from postnatal day 2 to day 14, or no specific handling (NH). Starting from postnatal day 60, rats were administered JCM-16021 (2, 4, 8 g/kg per day) orally twice a day for 28 d. Pain threshold pressure and electromyographic activities of external oblique muscles in response to colorectal distention recorded with a Power Lab System (AD Instruments International), were tested as pain indices. Changes in serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) concentrations in the colon of rats were analyzed; the enterochromaffin cell numbers and serotonin transporter in the colon of rats were also evaluated with an immunohistochemistry method.

RESULTS: NMS treatment significantly reduced pain threshold pressure (37.4 ± 1.4 mmHg), as compared to that of NH rats (57.7 ± 1.9 mmHg, P < 0.05). After JCM-16021 treatment, the pain threshold pressure significantly increased when compared to that before treatment (34.2 ± 0.9 mmHg vs 52.8 ± 2.3 mmHg in the high dose group, 40.2 ± 1.6 mmHg vs 46.5 ± 1.3 mmHg in the middle dose group, and 39.3 ± 0.7 mmHg vs 46.5 ± 1.6 mmHg in the low dose group, P < 0.05). Also JCM-16021 significantly and dose-dependently decreased electromyographic activity to the graded colorectal distension (CRD), (the mean ΔAUC values were: 0.17 ± 0.03, 0.53 ± 0.15, 1.06 ± 0.18, 1.22 ± 0.24 in the high dose group; 0.23 ± 0.04, 0.68 ± 0.17, 1.27 ± 0.26, 1.8 ± 0.3 in the middle dose group; and 0.29 ± 0.06, 0.8 ± 0.16, 1.53 ± 0.24, 2.1 ± 0.21 in the low dose group for the pressures 20, 40, 60, 80 mmHg), as compared to the NMS vehicle group. The mean ΔAUC values were: 0.57 ± 0.12, 1.33 ± 0.18, 2.57 ± 0.37, 3.08 ± 0.37 for the pressures 20, 40, 60, 80 mmHg (P < 0.05). JCM-16021 treatment significantly reduced the 5-HT concentrations (from high, middle and low dosage groups: 60.25 ± 5.98 ng/100 mg, 60.32 ± 4.22 ng/100 mg, 73.31 ± 7.65 ng/100 mg), as compared to the NMS vehicle groups (93.11 ± 9.85 ng/100 mg, P < 0.05); and increased the 5-HIAA concentrations (after treatment, from high, middle and low dosage groups: 54.24 ± 3.27 ng/100 mg, 50.34 ± 1.26 ng/100 mg, 51.37 ± 2.13 ng/100 mg) when compared to that in the NMS vehicle group (51.75 ± 1.98 ng/100 mg, P < 0.05); but did not change the enterochromaffin cell numbers in the colon of rats. In addition, NMS rats had higher SERT expression (n = 10) than NH rats (n = 8, P < 0.05). JCM-16021 treatment significantly decreased SERT expression when compared to the NMS group (P < 0.01-0.001).

CONCLUSION: JCM-16021 can attenuate visceral hypersensitivity, and this analgesic effect may be mediated through the serotonin signaling pathway in the colon of rats.

Serotoninergic and non-serotoninergic effects of two tricyclic antidepressants on visceral nociception in a rat model

OBJECTIVE

Tricyclic antidepressants (TCAs) are well established in the treatment of patients with irritable bowel syndrome (IBS). The effects are believed to be linked to serotoninergic antinociceptive properties, but data on the antinociceptive effects of various TCAs with variable serotoninergic and non-serotoninergic properties have not been investigated. The aim of this study was to compare the antinociceptive effects of different TCAs.

MATERIAL AND METHODS

Colorectal distension (CRD) using a barostat device was carried out in rats and the visceromotor response (VMR) to CRD was quantified by abdominal wall electromyography. Prior to CRD, saline (control), amitriptyline (AM), desipramine (DES), reserpine (RES) or a combination of TCAs and RES (AM + RES or DES + RES) was applied intraperitoneally. Serum 5-HT levels were determined using high-performance liquid chromatography (HPLC). RES was used to antagonize the serotoninergic actions of TCAs in order to discriminate between these effects and others.

RESULTS

Both TCAs decreased the VMR compared to placebo. After RES application without TCAs, the VMR was increased compared to controls (6403 microV+/-1772 microV). Co-administration of AM and RES resulted in a modest decrease in VMR (5774 microV+/-1953 microV), while in rats treated with RES and DES the VMR again was significantly lower (3446 microV (+/-1347 microV; p <0.05)). 5-HT levels were higher in TCA pretreated rats than those in controls and significantly lower 5-HT levels were found in all rats pretreated with RES.

CONCLUSIONS

AM and DES have antinociceptive properties while RES is pro-nociceptive. The antinociceptive effects of DES are not abolished by RES pretreatment, while AM only attenuates the pro-nociceptive effects of RES. The non-serotoninergic properties of TCAs substantially contribute to the differences in the antinococeptive effects of various TCAs.

Comparison of subjective grading of limbal redness by eyecare practitioners in three countries

OBJECTIVES

To compare grading of a biomicroscopy sign between eye care practitioners in three countries of widely different geographies-the United States, Australia, and Germany-and to test the accuracy of grading the sign within each country.

METHODS

Four eye care practitioners licensed in the practice of optometry in each country were sent sets of limbal redness images that were printed from the Efron Grading Scale morphing program. Each set consisted of 18 images randomly selected over the range of 0 to 4, inclusive. Each image was printed on a separate page with the grade scale from 0 to 4 with 0.5 steps. Each practitioner received the same set of images that were packaged in random order. Seventy-two (72) grades were collected from each country, which exceeded the sample size estimates for both the between and within country objectives.

RESULTS

No statistically significant differences were found between countries for pairwise comparisons (P<0.02, McNemar test, adjusted for multiple comparisons). No statistically significant differences were found within each country between observed and expected values for grades from Germany and Australia (P>0.05, chi test); however, a statistically significant difference was found for the United States (P<0.05, chi test).

CONCLUSIONS

These findings support the generalization of results of limbal redness grades from trials that are conducted in several countries or in one country and used in another, i.e., practitioners may expect similar findings for this sign among their patients no matter which of their colleagues are investigators. They also indicate that different strategies for grading limbal redness may exist among practitioners in the countries tested. Study sponsors may want to include standardized training for investigators.

Daily stress and gastrointestinal symptoms in women with irritable bowel syndrome

BACKGROUND

Stress has been implicated as contributing to the initiation and exacerbation of bowel and discomfort symptoms in patients with irritable bowel syndrome (IBS).

OBJECTIVE

To examine the relationships of daily self-reported stress to gastrointestinal (GI) and psychological distress symptoms both across women and within woman in a comparison group of women without IBS and among subgroups of women with IBS.

METHODS

Women with IBS (n = 181; age = 18-49 years) who were divided into subgroups based on bowel pattern (constipation, n = 52; diarrhea, n = 67; alternating, n = 62) were compared to a group of women without IBS (n = 48). Self-report stress measures; abdominal (abdominal pain, bloating, and intestinal gas), bowel pattern (constipation, diarrhea), and intestinal gas; and psychological (anxiety and depression) distress symptoms were obtained daily over 1 month. Across-women and within-woman analyses were used.

RESULTS

There were significant across-women correlations among mean daily stress, psychological distress, and GI symptoms in the total IBS group and the IBS bowel pattern subgroups. The across-women relationships between daily stress and GI symptoms were diminished when anxiety and depression were controlled in the analyses. Within-woman analyses showed little evidence of relationship between day-to-day variations in stress and day-to-day variations in GI symptoms; however, stress was strongly related to anxiety and depression.

DISCUSSION

Gastrointestinal symptom distress is associated with self-reported stress in women with IBS. Psychological distress moderates the effects of stress on GI symptoms. The IBS treatment protocols that incorporate strategies that decrease stress and psychological distress are likely to reduce GI symptoms.

Translating symptoms into mechanisms: functional GI disorders

Functional gastrointestinal disorders are the most common problem in gastroenterological practice. They are defined by chronic abdominal symptom complexes that occur in the absence of underlying structural abnormalities. The pathogenesis of these disorders is heterogeneous and involves behavioral, infective, and inflammatory components. Common symptoms are abdominal pain, diarrhea, constipation, and bloating. Mechanisms underlying these symptoms include alterations in gastrointestinal motility, visceral perception, altered epithelial function, and disturbances in fermentation activity by gut commensal bacteria.

Women with irritable bowel syndrome and their perception of a good quality of life

Irritable bowel syndrome has a negative impact on a person's quality of life, but only a few existing studies have been based on patients' own perceptions. This study therefore aimed to collect information on the view of female patients with irritable bowel syndrome regarding what constitutes a good quality of life for them and to create a healthcare model for these patients. For the study, 30 women with irritable bowel syndrome (median age, 38.5 years; range, 20-65 years) responded in writing to a single, all-inclusive question: "What is your perception of a good quality of life?" When the questionnaires were returned, there was time for a short dialogue, and notes of the conversations were made. Data were analyzed qualitatively according to Burnard's method of thematic content analysis. The answers also were counted and thereby quantified. The women's perception of a good quality of life could be divided into five categories: (a) physical and mental health, (b) social well-being, (c) welfare, (d) strength and energy, and (e) self-fulfillment. According to the results, a healthcare model for patients with irritable bowel syndrome should include four main areas: (a) treatment of the patient's symptoms, (b) confirmation of the patient, (c) confirmation of the diagnosis, and (d) instruction for the patient. The healthcare model should be focused on the primary care level and should include a longitudinal plan of healthcare that also describes the secondary care level.

Review article: the role of antibiotics vs. conventional pharmacotherapy in treating symptoms of irritable bowel syndrome

BACKGROUND

The concept of augmenting the management of irritable bowel syndrome with antibiotics is evolving, and many questions remain regarding this therapy relative to known and hypothesized irritable bowel syndrome pathophysiology. The clinical evidence of small intestinal bacterial overgrowth as an important aetiology of irritable bowel syndrome continues to accumulate. Clinical symptoms of bacterial overgrowth and irritable bowel syndrome are similar; however, a definitive cause-and-effect relationship remains unproven. It is unclear whether motility dysfunction causes bacterial overgrowth or gas products of enteric bacteria affect intestinal motility in irritable bowel syndrome.

AIM

To discusses the efficacy and tolerability of current symptom-directed pharmacotherapies and of antibiotics in the treatment of irritable bowel syndrome.

METHODS

A computerized search of PubMed was performed with search terms "IBS", "pharmacotherapy" and "antibiotics". Relevant articles were selected, and the reference list of selected articles was reviewed to identify additional references.

RESULTS

Antibiotic treatment benefits a subset of irritable bowel syndrome patients. The non-absorbed antibiotic rifaximin has a favourable safety and tolerability profile compared with systemic antibiotics and demonstrates a therapeutic efficacy comparable with symptom-based irritable bowel syndrome pharmacotherapies.

CONCLUSION

Rifaximin is the only antibiotic with demonstrated sustained benefit beyond therapy cessation in irritable bowel syndrome patients in a placebo-controlled trial. Whether antibiotics can improve quality of life in patients with irritable bowel syndrome warrants further research.

Irritable bowel syndrome and chronic constipation: emerging drugs, devices, and surgical treatments

Irritable bowel syndrome (IBS) and chronic constipation (CC) are two of the most common functional disorders of the gut. CC and IBS are estimated to affect up to 20% and 27% of the North American population respectively. Although not life-threatening, CC and IBS can profoundly and negatively affect quality of life and are associated with a significant economic burden related to direct and indirect annual health-care costs. Possible etiologies for IBS and CC include alterations in visceral sensation and gastrointestinal motility. IBS may be caused by disturbances in brain-gut interactions affecting gastrointestinal motility and visceral sensitivity. Research efforts in CC have begun to identify abnormalities in myenteric neurons, alterations in neurotransmitters and their receptors, and incoordination of the muscles of the pelvic floor or anorectum. Both disorders may be influenced by genetic predisposition, environmental factors, and stress. In this article, the safety and efficacy of traditional and emerging therapies for CC and IBS are examined. In addition, their pathophysiology and symptoms are briefly reviewed.

The AmpliChip CYP450 test: principles, challenges, and future clinical utility in digestive disease

Understanding genetically encoded inherited differences in drug metabolism and targets (ie, receptors, transporters) offers the promise of minimizing adverse drug reactions and improving therapies. Among the enzymes involved in drug metabolism, the cytochromes P450 (CYP450) hold a central position. In fact, CYP450 are involved in the biotransformation of most drugs used in clinical practice. Recent advances in the development of DNA-based diagnostics, coupled with a better understanding of genetic polymorphisms in influencing pharmacologic responses, have provided the foundation for novel in vitro tests that may predict side effects and/or therapeutic responses. The AmpliChip CYP450 test was developed as a clinical test to evaluate an individual's metabolic capacity for certain drugs by identifying polymorphisms of 2 CYP450 enzymes (ie, CYP2D6 and CYP2D19). Even though the AmpliChip CYP450 has been approved by the US Food and Drug Administration, its practical clinical utility has not yet been determined, and there is a paucity of data related to gastrointestinal and liver diseases. An understanding of the principles and opportunities provided by this new category of diagnostic test is key before planning the necessary studies to evaluate the usefulness of AmpliChip CYP450 in gastroenterologic clinical practice.

General medical and psychiatric perspectives on somatoform disorders: separated by an uncommon language

PURPOSE OF REVIEW

While Diagnostic and Statistical Manual of Mental Disorders-IV provided updated definitions and diagnostic criteria for the diagnoses subsumed under the category of somatoform disorders, various nosological questions are still unresolved. We assessed current research activity on important key concepts related to nosology, validity, and reliability of the Diagnostic and Statistical Manual of Mental Disorders-IV somatoform diagnoses.

RECENT FINDINGS

The initial Medline search for articles from 2000 through 2005 yielded a total of 912 articles. After checking for redundancy and excluding publications using other than Diagnostic and Statistical Manual of Mental Disorders-IV diagnostic criteria, a total of 101 articles was further reviewed. Heterogeneity of papers precluded statistical approaches; thus, a descriptive and narrative review was pursued.

SUMMARY

It appears that applying the specific categories and criteria as proposed by Diagnostic and Statistical Manual of Mental Disorders-IV only captures a small proportion of the phenomena of interest at the interface of medicine and psychiatry. A paradigm shift towards 'general medical/psychiatry interface disorders' in exchange for the current dichotomy of 'mind' vs. 'body' disorders, may reduce stigma associated with current diagnostic labeling, improve user acceptability, and stimulate research in this important but still fragmented clinical area that still lacks agreed-upon diagnostic definitions.