Irritable bowel syndrome - an evidence-based approach to diagnosis

Getting the BS out of Irritable Bowel Syndrome with Diarrhea (IBS-D): Let's Make a Diagnosis

PURPOSE OF REVIEW

Irritable bowel syndrome with diarrhea (IBS-D) is diagnosed when chronic symptoms of abdominal pain accompany loose stools, and alarm features, such as fever, anemia, rectal bleeding, and weight loss are absent. This combination of symptoms makes structural disorders, such as inflammatory bowel disease or cancer, unlikely, but does not exclude other conditions that cause these symptoms. The question is whether making a "positive diagnosis" of IBS-D based on symptoms alone and instituting therapy based on that diagnosis still makes sense.

RECENT FINDINGS

Clinical observations suggest that at least two-thirds of cases of IBS-D can be explained by three mechanisms: a) food intolerances (~ 30-40%), b) bile acid diarrhea (~ 20-30%), and c) disturbed microbial flora (~ 15-20%). Other conditions that are less frequent but can cause IBS symptoms or be confused with IBS include: celiac disease, microscopic colitis, mastocytosis/mast cell activation, and drug side-effects. Many cases of IBS-D have a discoverable, underlying cause that can direct therapy more efficiently.

Identification of putative transcriptomic biomarkers in irritable bowel syndrome (IBS): Differential gene expression and regulation of TPH1 and SERT by vitamin D

Irritable bowel syndrome (IBS) is one of the most common gastrointestinal disorders and affects approximately 4% of the global population. The diagnosis of IBS can be made based on symptoms using the validated Rome criteria and ruling out commonly occurring organic diseases. Although biomarkers exist for "IBS mimickers" such as celiac disease and inflammatory bowel disease (IBD), no such test exists for IBS. DNA microarrays of colonic tissue have been used to identify disease-associated variants in other gastrointestinal (GI) disorders. In this study, our objective was to identify biomarkers and unique gene expression patterns that may define the pathological state of IBS. Mucosal tissue samples were collected from the sigmoid colon of 29 participants (11 IBS and 18 healthy controls). DNA microarray analysis was used to assess gene expression profiling. Extraction and purification of RNA were then performed and used to synthesize cDNA. Reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) was employed to identify differentially expressed genes in patients diagnosed with IBS compared to healthy, non-IBS patient-derived cDNA. Additional testing probed vitamin D-mediated regulation of select genes associated with serotonergic metabolism. DNA microarray analyses led to the identification of 858 differentially expressed genes that may characterize the IBS pathological state. After screening a series of genes using a combination of gene ontological analysis and RT-qPCR, this spectrum of potential IBS biomarkers was narrowed to 23 genes, some of which are regulated by vitamin D. Seven putative IBS biomarkers, including genes involved in serotonin metabolism, were identified. This work further supports the hypothesis that IBS pathophysiology is evident within the human transcriptome and that vitamin D modulates differential expression of genes in IBS patients. This suggests that IBS pathophysiology may also involve vitamin D deficiency and/or an irregularity in serotonin metabolism.

Meta-analysis of the relation between irritable bowel syndrome and antibodies against endogenous gonadotropin-releasing hormone and its receptor

This meta-analysis assessed the association between gonadotropin hormone-releasing hormone (GnRH) antibodies and irritable bowel syndrome (IBS). We defined a search strategy and implemented it with PubMed, Ovid, Scopus, and Web of Science databases for English language publications. The data were evaluated for acceptability, and randomized controlled studies as well as case-control, cross-sectional, and cohort studies reporting the prevalence of GnRH antibodies in IBS patients were included. The total number of patients in the included studies was 1095: 270 patients in the IBS group and 825 patients in the control group. By comparing the IBS group and the control group, we found a statistically significant association between IBS and the increased prevalence of GnRH IgM antibodies (risk ratio = 2.29, 95% confidence interval = 1.58 to 3.31, P < 0.0001). We also found a statistically significant association between IBS and increased prevalence of GnRH receptor IgM antibodies compared with controls (risk ratio = 3.80, 95% confidence interval = 1.72 to 8.38, P = 0.001). The meta-analysis revealed a statistically significant association between IBS and increased prevalence of GnRH IgM and GnRH receptor IgM antibodies.

Zinc nutritional status, mood states and quality of life in diarrhea-predominant irritable bowel syndrome: a case-control study

Zinc is an important trace element for structure, and regulation in the central nervous system, as well as the gut homeostasis. There are several mental disorders associated with zinc deficiency. The relationship between zinc nutritional status with mood states and quality of life (QoL) in diarrhea-predominant irritable bowel syndrome (IBS-D) has not been studied yet. This case-control study aimed to investigate the association between zinc nutritional status with mood states and QoL in IBS-D patients. Sixty-one newly diagnosed patients with IBS-D and 61 matched healthy controls were enrolled. Dietary zinc intakes and serum zinc levels were measured. Mood states and QoL were evaluated by validated questionnaires. Logistic regression was used to estimate the odds of IBS-D in relation to zinc deficiency. Decreased serum zinc levels were observed in the IBS-D group than in the controls (p = 0.001). There were higher scores of depression (p = 0.014), anxiety (p = 0.005), and stress (p = 0.001) among IBS-D patients. Moreover, overall QoL, physical and psychological health were lower in IBS-D patients compared to the controls (p < 0.001). "Food avoidance" had the lowest, while the "relationship" had the highest score among the patients (51.09 ± 26.80 and 78.14 ± 23.30, respectively). Dietary zinc intake was positively correlated with psychological health in the controls (r = 0.295, p = 0.022) and with body image in the patients (r = 0.266, p = 0.044). According to the logistic regression, zinc deficiency was not significantly associated with odds of IBS-D. Findings show that zinc deficiency may be associated with some parameters of IBS-D. Further clinical studies are needed to explore the causal relationship between zinc status and IBS pathogenesis.

The patient with irritable bowel syndrome-type symptoms: when to investigate and how?

PURPOSE OF REVIEW

Irritable bowel syndrome (IBS) is a very common disorder whose clinical presentation varies considerably between patients as well as within the same individual over time. Many of its symptoms, such as pain, diarrhea, constipation and bloating, may be manifestations of a host of other gastrointestinal diseases; some accompanied by increased mortality. This presents the clinician with a real dilemma: how to sensibly investigate the patient in which one suspects IBS but there is a nagging doubt that 'it could be something else'? Could one miss 'something serious'? This short review attempts to provide both an evidence-based response to these vexing questions and a practical guide to detecting alternative diagnoses in the subject with IBS-type symptoms.

RECENT FINDINGS

Clinical features, patient demographics and the clinical context can help to significantly narrow the differential diagnosis of the individual with IBS-type symptoms and may permit a positive diagnosis of IBS. The advent of noninvasive serological and stool tests has greatly facilitated differentiation from celiac disease and inflammatory bowel disease, respectively. In the older, female diarrhea sufferer microscopic colitis should be considered. The role of bile acid diarrhea in the individual with diarrhea-predominant IBS is emphasized; the status of small intestinal bacterial overgrowth in IBS remain uncertain.

SUMMARY

Attention to detail in the clinical evaluation of the individual with IBS-like symptoms will facilitate a selective and targeted approach to investigation. Wherever indicated, widely available serological and fecal tests will serve to bolster the diagnosis by excluding other options. Proceeding to more invasive testing should be dictated by clinical presentation and scenario with the threshold for intervention being generally lower among those with prominent diarrhea.

Clinical response to linaclotide at week 4 predicts sustained response in irritable bowel syndrome with constipation and improvements in digestive and extra-digestive symptoms

BACKGROUND

Linaclotide is approved for the treatment of moderate-to-severe irritable bowel syndrome (IBS) with constipation (IBS-C) in adults. This study aimed to assess factors predictive of a clinical response and improvements in non-IBS symptoms with linaclotide treatment in a Spanish patient population.

METHODS

In this open-label phase IIIb study, patients with moderate-to-severe IBS-C received linaclotide 290 μg once daily for 12 weeks. The primary endpoint was clinical response at week 12, defined as >30% reduction in IBS symptom severity score (IBS-SSS) or IBS-SSS <75 plus self-reported response of feeling 'better' or 'much better' versus the baseline. Digestive nonintestinal and extra-digestive symptom scores were assessed. Baseline characteristics and week 4 clinical response were assessed as predictors of week 12 clinical response.

RESULTS

A total of 96 patients were eligible; 91 were female and the mean age was 47.4 years. Mean (SD) baseline IBS-SSS was 371 (72.5). In the intention-to-treat and per-protocol populations, 22.9% and 31.7% were clinical responders at week 4, respectively, and 25.0% and 36.7% were clinical responders at week 12. Digestive nonintestinal and extra-digestive symptom scores were significantly improved at weeks 4 and 12. Baseline characteristic was not associated with week 12 clinical response; however, clinical response at week 4 was predictive of response at week 12 (OR: 6.5; 95%IC: 2.1-19.8). The most common adverse event was diarrhea inclusive of loose or watery stools (35.4%).

CONCLUSIONS

Linaclotide improves IBS-C symptoms, including digestive nonintestinal and extra-digestive symptoms. A clinical response at week 4 may predict response at week 12.

Treatment of irritable bowel syndrome

Irritable bowel syndrome is a chronic functional gastrointestinal disorder that presents with abdominal pain related to defecation accompanied by a change in stool frequency or form Despite its impact on a patient’s quality of life it has no effect on mortality

A positive clinical diagnosis should be made if the characteristic symptoms are present and red flags are absent Red flags should prompt specialist referral

Consultations should be provided in an empathetic manner addressing the concerns of the patient while providing reassurance

Manipulating diet with the assistance of a dietitian is an appropriate initial treatment for irritable bowel syndrome A low-FODMAP diet is an effective therapy

Quantifying positive communication: Doctor's language and patient anxiety in primary care consultations

OBJECTIVE

Positive communication is advocated for physicians during consultations with patients presenting medically unexplained symptoms (MUS), but studies generally focus on what is said rather than how it is said. This study quantified language use differences of general practitioners (GPs), and assessed their relation to patient anxiety.

METHODS

Language use of 18 Dutch GPs during 82 consultations was compared for patients with MUS versus medically explained symptoms (MES). Message content (positive or negative) was differentiated from its directness (direct or indirect), and related to changes in patient's state anxiety (abbreviated State Trait Anxiety Inventory; STAI).

RESULTS

In total, 2590 clauses were identified. GPs approached patients with MES with relatively more direct (vs. indirect) positive and indirect (vs. direct) negative messages (OR 1.91, 95% CI 1.42-2.59). Anxiety of both patient groups increased when GPs used more direct (vs. indirect) negative messages (b = 0.67, 95% CI 0.07-1.27) CONCLUSIONS: GPs use different language depending on the content of messages for patients with MES, but not MUS. Direct negative messages relate to an increase in patient anxiety.

PRACTICE IMPLICATIONS

GPs could manage patient's state anxiety by expressing negative messages in an indirect rather than direct manner.

Referrals to a tertiary hospital: A window into clinical management issues in functional gastrointestinal disorders

BACKGROUND AND AIM

To investigate the quality of and reasons for referrals of patients with likely functional gastrointestinal disorders (FGID) and explore patients' experience of clinical management.

METHODS

A cross sectional, mixed-methods study was undertaken. Referrals (July 2013-2015) to one gastroenterology outpatient department triaged as "likely FGID", the referred patients and their referring primary healthcare providers were examined.

RESULTS

A total of 69% of patients reported not yet receiving an initial diagnosis, 52% reported persistent/distressing symptoms or reduced quality of life, 24% feared missed or worsening pathology, and 35% were seeking repeat specialist consultation. Most patients were dissatisfied (40%) or only partially satisfied (36%) with current management. Dissatisfaction was significantly related to the lack of provision of a diagnosis and effective treatment options (P < 0.001). Referral quality was poor and with the reason for referral clearly communicated in only 25%. Common referral reasons included repeat presentations (n = 32), diagnostic uncertainty (n = 19), to ensure nothing is missed (n = 19), patient request (n = 17), no response to treatment (n = 16), and to allay patient fears (n = 14). A total of 28/60 primary healthcare providers were confident that their patient had a FGID, yet sought confirmation (n = 16), second opinion (n = 8), or advice (n = 4).

CONCLUSION

Current management of FGID in usual care is suboptimal, as evidenced by the tertiary referral load, patient dissatisfaction, and the lack of provision of diagnoses and effective treatment options. Some clinicians lack confidence in effectively identifying and managing these conditions. Resources and supports to equip and assist clinicians to identify and manage FGID successfully may enhance patient care.

Economic burden of inadequate symptom control among US commercially insured patients with irritable bowel syndrome with diarrhea

AIMS

To assess healthcare resource use and costs among irritable bowel syndrome (IBS) with diarrhea (IBS-D) patients with and without evidence of inadequate symptom control on current prescription therapies and estimate incremental all-cause costs associated with inadequate symptom control.

METHODS

IBS-D patients aged ≥18 years with ≥1 medical claim for IBS (ICD-9-CM 564.1x) and either ≥2 claims for diarrhea (ICD-9-CM 787.91, 564.5x), ≥1 claim for diarrhea plus ≥1 claim for abdominal pain (ICD-9-CM 789.0x), or ≥1 claim for diarrhea plus ≥1 pharmacy claim for a symptom-related prescription within 1 year of an IBS diagnosis were identified from the Truven Health MarketScan database. Inadequate symptom control, resource use, and costs were assessed up to 1 year following the index date. Inadequate symptom control included any of the following: (1) switch or (2) addition of new symptom-related therapy; (3) IBS-D-related inpatient or emergency room (ER) admission; (4) IBS-D-related medical procedure; (5) diagnosis of condition indicating treatment failure; or (6) use of a more aggressive prescription. Generalized linear models assessed incremental costs of inadequate symptom control.

RESULTS

Of 20,624 IBS-D patients (mean age = 48.5 years; 77.8% female), 66.4% had evidence of inadequate symptom control. Compared to those without inadequate symptom control, patients with evidence of inadequate symptom control had significantly more hospitalizations (12.0% vs 6.0%), ER visits (37.1% vs 22.6%), use of outpatient services (73.0% vs 60.7%), physician office visits (mean 11.0 vs 8.1), and prescription fills (mean 40.0 vs 26.7) annually (all p < .01). Incremental costs associated with inadequate symptom control were $3,065 (2013 US dollars), and were driven by medical service costs ($2,391; 78%).

LIMITATIONS

Study included US commercially insured patients only and inferred IBS-D status and inadequate symptom control from claims.

CONCLUSIONS

Inadequate symptom control associated with available IBS-D therapies represents a significant economic burden for both payers and IBS-D patients.

Diarrhea-predominant irritable bowel syndrome: Diagnosis, etiology, and new treatment considerations

PURPOSE

To provide an overview of irritable bowel syndrome (IBS), specifically the efficacy and tolerability of treatment options for diarrhea-predominant IBS (IBS-D).

DATA SOURCES

Research articles available via PubMed were reviewed.

CONCLUSIONS

IBS is a chronic multifactorial disorder that has a negative impact on patient-related quality of life. Genetic factors, psychosociologic factors, alterations in the gut microbiota, and changes in immune, motor, and sensory responses to various stimuli all may be involved in the development of IBS. While pharmacologic therapies for IBS-D have historically been limited (e.g., alosetron), newer therapies (eluxadoline and rifaximin), both approved in the United States in 2015, may be considered for appropriate patients for the management of IBS-D.

IMPLICATIONS FOR PRACTICE

Nurse practitioners play an important role in the diagnosis, care, and management of patients with IBS-D. The goals of therapy should be to reach a correct diagnosis before initiating therapy, provide reassurance to the patient, educate the patient on potential treatment options, improve IBS-D symptoms, minimize risk of harm with treatment, and maximize patient-related quality of life. The authors present a treatment algorithm to guide nurse practitioners on the management of patients with IBS-D.

Health-related quality of life, work productivity, and indirect costs among patients with irritable bowel syndrome with diarrhea

Background

Irritable bowel syndrome (IBS) affects 10–15% of adults in the US, and is associated with significant impairment in health-related quality of life (HRQoL); however, information specific to the diarrhea subtype (IBS-D) is lacking. We assessed the impact of IBS-D on HRQoL, work productivity, and daily activities, and the associated indirect costs, among a sample of the US population.

Methods

Respondents (≥18 years) from the 2012 US National Health and Wellness Survey who reported an IBS-D diagnosis by a physician or symptoms consistent with Rome II criteria for IBS-D were identified as having IBS-D. Controls included respondents without IBS-D or inflammatory bowel disease. HRQoL was assessed via the Short Form 36 Health Survey version 2 questionnaire and summarized into Mental and Physical Component Summary (MCS; PCS) scores and a Short Form-6 dimension (SF-6D) utility score. Work and activity impairment were assessed via the Work Productivity and Activity Impairment Questionnaire: General Health version (WPAI:GH), which measures absenteeism, presenteeism, overall work productivity loss, and daily activity impairment. Indirect costs were calculated using unit cost data from the Bureau of Labor Statistics and variables from the WPAI:GH. Generalized linear models were used to examine differences in health outcomes between respondents with IBS-D and controls, controlling for demographic and health characteristics.

Results

In total, 66,491 respondents (1102 IBS-D; 65,389 controls) were analyzed. Mean age was 48.7 years; 50% were female. Compared with controls, the IBS-D cohort reported significantly lower HRQoL (mean MCS: 45.16 vs. 49.48; p < 0.001; mean PCS: 47.29 vs. 50.67; p < 0.001; mean SF-6D: 0.677 vs. 0.741; p < 0.001) and greater absenteeism (5.1% vs. 2.9%; p = 0.004), presenteeism (17.9% vs. 11.3%; p < 0.001), overall work productivity loss (20.7% vs. 13.2%; p < 0.001), and activity impairment (29.6% vs. 18.9%; p < 0.001). Respondents with IBS-D also incurred an estimated $2486 more in indirect costs ($7008 vs. $4522; p < 0.001).

Conclusions

Compared with controls, IBS-D is associated with significantly lower HRQoL, greater impairments in work and daily activities, and higher indirect costs, imposing a substantial burden on patients and employers. These findings suggest a significant unmet need exists for effective IBS-D treatments.

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Zusammenfassung. Funktionelle Magen-Darm-Beschwerden sind in der Allgemeinbevölkerung weit verbreitet, und das Reizdarmsyndrom (Irritable Bowel Syndrome, IBS) ist eines der häufigsten gastroenterologischen Krankheitsbilder. Trotz individuell sehr unterschiedlicher klinischer Präsentation berichtet ein Grossteil der Patienten über eine Abhängigkeit ihrer Beschwerden von der Nahrungsaufnahme bzw. von bestimmten Nahrungsmitteln. Die FODMAP-arme Diät, durch eine spezialisierte Ernährungsberatung instruiert, zeigt sich sehr wirksam zur Symptomreduktion bei IBS-Patienten. Sie basiert auf einer Reduktion fermentierbarer Kohlenhydrate. Ziel der Diät ist es, potenzielle nutritive Auslöser abdominaler Symptome zu identifizieren und diese in der täglichen Ernährung zu meiden.

Economic Burden of Irritable Bowel Syndrome with Diarrhea: Retrospective Analysis of a U.S. Commercially Insured Population

BACKGROUND

The economic burden associated with irritable bowel syndrome with diarrhea (IBS-D) is not well understood.

OBJECTIVES

To (a) evaluate total annual all-cause, gastrointestinal (GI)-related, and symptom-related (i.e., IBS, diarrhea, abdominal pain) health care resource use and costs among IBS-D patients in a U.S. commercially insured population and (b) estimate incremental all-cause health care costs of IBS-D patients versus matched controls.

METHODS

Patients aged ≥ 18 years with 12 months of continuous medical and pharmacy benefit eligibility in 2013 were identified from the Truven Health MarketScan research database. The study sample included patients with ≥ 1 medical claim with an International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) diagnosis code in any position for IBS (ICD-9-CM 564.1x) and either (a) ≥ 2 claims for diarrhea (ICD-9-CM 787.91, 564.5x) on different service dates in 2013, or (b) ≥ 1 claim for diarrhea plus ≥ 1 claim for abdominal pain (ICD-9-CM 789.0x) on different service dates in 2013, or (c) ≥ 1 claim for diarrhea plus ≥ 1 pharmacy claim for a symptom-related prescription on different service dates in 2013. Controls included patients with no claims for IBS, diarrhea, abdominal pain, or symptom-related prescriptions in 2013. Controls were randomly selected and matched with IBS-D patients in a 1:1 ratio based on age (± 4 years), gender, geographic location, and health plan type. All-cause health care resource utilization included medical and pharmacy claims for health care services associated with any condition. Total health care costs were defined as the sum of health plan-paid and patient-paid direct health care costs from prescriptions and medical services, including inpatient, emergency department (ED), and physician office visits, and other outpatient services. A total cost approach was used to assess all-cause, GI-related, and symptom-related health care costs for IBS-D patients. An incremental cost approach via generalized linear models was used to assess the excess all-cause costs attributable to IBS-D after adjusting for demographics and general and GI comorbidities.

RESULTS

Of 39,306 patients (n = 19,653 each for IBS-D and matched controls) included, mean (± SD) age was 47 (± 17) years and 76.5% were female. Compared with controls, IBS-D patients had a significantly higher mean annual number of hospitalizations, ED visits, office visits, and monthly (30-day) prescription fills. Mean annual all-cause health care costs for IBS-D patients were $13,038, with over half (58.4%) attributable to office visits and other outpatient services (e.g., diagnostic tests and laboratory or radiology services), and remaining costs attributable to prescriptions (19.5%), inpatient admissions (13.6%), and ED visits (8.5%). GI-related ($3,817) and symptom-related ($1,693) costs were also primarily driven by other outpatient service costs. After adjusting for demographics and comorbidities, incremental annual all-cause costs associated with IBS-D were $2,268 ($9,436 for IBS-D patients vs. $7,169 for matched controls; P < 0.001) per patient/year, of which 78% were from medical costs and 22% were from prescription costs.

CONCLUSIONS

IBS-D was associated with a substantial burden in direct costs in this population. Compared with matched controls, IBS-D patients had greater medical service use and incurred significantly more annual all-cause health care costs, even after controlling for demographics and comorbidities. Incremental costs associated with IBS-D were primarily attributable to increased use of medical services rather than pharmacy costs.

DISCLOSURES

This study was funded by Allergan. The authors received no compensation related to the development of the manuscript. Buono and Andrae are employees of Allergan. Mathur is an employee of Axtria. Averitt was an employee of Axtria at the time this study was conducted. Data from this manuscript have previously been presented in poster format by Buono at the American College of Gastroenterology Annual Scientific Meeting; Honolulu, Hawaii; October 16-21, 2015. Mathur and Averitt were involved in conducting the study analyses. All authors were involved in the study design, interpretation of the data, and preparation of the manuscript. The authors take full responsibility for the scope, direction, and content of the manuscript and have approved the submitted manuscript.

Development and validation of a biomarker for diarrhea-predominant irritable bowel syndrome in human subjects

Diarrhea-predominant irritable bowel syndrome (IBS) is diagnosed through clinical criteria after excluding “organic” conditions, and can be precipitated by acute gastroenteritis. Cytolethal distending toxin B (CdtB) is produced by bacteria that cause acute gastroenteritis, and a post-infectious animal model demonstrates that host antibodies to CdtB cross-react with vinculin in the host gut, producing an IBS-like phenotype. Therefore, we assessed circulating anti-CdtB and anti-vinculin antibodies as biomarkers for D-IBS in human subjects. Subjects with D-IBS based on Rome criteria (n=2375) were recruited from a large-scale multicenter clinical trial for D-IBS (TARGET 3). Subjects with inflammatory bowel disease (IBD) (n=142), subjects with celiac disease (n=121), and healthy controls (n=43) were obtained for comparison. Subjects with IBD and celiac disease were recruited based on the presence of intestinal complaints and histologic confirmation of chronic inflammatory changes in the colon or small intestine. Subjects with celiac disease were also required to have an elevated tTG and biopsy. All subjects were aged between 18 and 65 years. Plasma levels of anti-CdtB and anti-vinculin antibodies were determined by ELISA, and compared between groups. Anti-CdtB titers were significantly higher in D-IBS subjects compared to IBD, healthy controls and celiac disease (P<0.001). Anti-vinculin titers were also significantly higher in IBS (P<0.001) compared to the other groups. The area-under-the-receiver operating curves (AUCs) were 0.81 and 0.62 for diagnosis of D-IBS against IBD for anti-CdtB and anti-vinculin, respectively. Both tests were less specific in differentiating IBS from celiac disease. Optimization demonstrated that for anti-CdtB (optical density≥2.80) the specificity, sensitivity and likelihood ratio were 91.6%, 43.7 and 5.2, respectively, and for anti-vinculin (OD≥1.68) were 83.8%, 32.6 and 2.0, respectively. These results confirm that anti-CdtB and anti-vinculin antibodies are elevated in D-IBS compared to non-IBS subjects. These biomarkers may be especially helpful in distinguishing D-IBS from IBD in the workup of chronic diarrhea.

Prevalence, investigational pathways and diagnostic outcomes in differing irritable bowel syndrome subtypes

BACKGROUND

There has been increasing interest in subclassifying irritable bowel syndrome (IBS) to make a positive diagnosis.

AIM

The aim of this study was to assess the population prevalence of differing subtypes, investigational pathways and diagnostic outcomes.

MATERIALS AND METHODS

Data were prospectively collected from three groups between 2005 and 2012. Group 1 [n=1002, 55% female, mean age 39 years (range 16-93 years)] comprised healthy volunteers who were interviewed using the Rome III diagnostic questionnaire. In secondary care, group 2 [n=64, 80% female, mean age 44 years (range 23-79 years)] comprised patients with constipation-predominant IBS (IBS-C) and group 3 [n=333, 66% female, mean age 51 years (range 23-92 years)] comprised patients with diarrhoea-predominant IBS (IBS-D). In groups 2 and 3, demographic data and diagnostic yield of investigations were evaluated as per normal clinical practice.

RESULTS

IBS prevalence in group 1 was 6% (60/1002). IBS-C patients were significantly older than those with IBS-D (mean age 45 vs. 30 years, P=0.027). In groups 2 and 3, patients with IBS-C underwent a total of 56 additional investigations (mean 0.88 per patient), which was significantly lower than the number of investigations undertaken in the IBS-D group of 734 (mean 2.2 per patient, P<0.001). Further investigations in group 3 (IBS-D) identified an alternative diagnosis in 22%, whereas in group 2 (IBS-C) this was 0% (P<0.0001).

CONCLUSION

This is the first study to evaluate the population prevalence of different IBS subtypes within a UK population. Although further investigations in IBS-D patients have led to alternative diagnoses, none were identified in the IBS-C population. The merits of investigating IBS-C patients should be questioned.

A case of parasite invasion of the intestinal tract: a missed diagnosis in irritable bowel syndrome

Irritable bowel syndrome (IBS) is a gastrointestinal disorder characterized by chronic abdominal pain and altered bowel habits in the absence of any organic cause. As the clinical manifestations are very diverse and associated with nonspecific symptoms, research seeking to identify organic causes to rule out IBS and to enable differential diagnosis is required. A 24-year-old man was referred to our hospital for specialized management of IBS. He had a 7-month history of intermittent epigastric and lower abdominal pain. On the basis of clinical examination, he was diagnosed with IBS and administered medication at a primary clinic. However, his symptoms did not improve after treatment. We performed capsule endoscopy at our hospital and identified a parasite (Ancylostoma duodenale) in the proximal jejunum. We therefore report a case of parasitic infection found by additional examination while evaluating symptoms associated with a previous diagnosis of refractory IBS.

Functional disorders of the gastrointestinal tract: Cost effectiveness review

BACKGROUND

The project aim was to review current cost-effectiveness research for each functional gastrointestinal disorder, as defined by the Rome III classification system.

METHODS

Biomedical databases were searched for articles with the functional gastrointestinal disorders and their pseudonyms included in the title, abstract, or medical subject headings, plus the terms benefit, cost, effectiveness, outcomes, test, utility, or utilization in any search field.

RESULTS

Highly prevalent conditions such as dyspepsia and irritable bowel syndrome have advanced cost-effectiveness analyses including cost-utility studies that have helped support current management guidelines. The rarer functional gastrointestinal disorders have few or no published cost-effectiveness analyses, but the Rome III classification system provides a framework for identifying the specific cost data or outcomes measures available or needed for future research.

CONCLUSIONS

The Rome process has provided a useful system for defining the functional gastrointestinal disorders and identifying specific clinical questions to be examined using cost-effectiveness analysis techniques.

An evaluation of the FDA responder endpoint for IBS-C clinical trials: analysis of data from linaclotide Phase 3 clinical trials

BACKGROUND

Our objective was to evaluate the performance of the Food and Drug Administration (FDA) Responder Endpoint for clinical trials in IBS-C, using data from two large Phase 3 clinical trials of linaclotide. The FDA interim endpoint requires that, for 50% of trial weeks, patients report ≥30% decrease in Abdominal Pain at its worst and (in the same week) an increase in Complete Spontaneous Bowel Movements (CSBMs) of ≥1 from baseline.

METHODS

Anchor-based methodology was used to estimate thresholds of clinically meaningful change using symptom-specific patient rating of change questions (PRCQs) and symptom severity questions. The diagnostic accuracy of the FDA Responder Endpoint was assessed using sensitivity/specificity-based methods.

KEY RESULTS

Using anchor-based methods, the estimates of the clinically meaningful improvement thresholds for Abdominal Pain ranged from 25.9% to 32.4% and thresholds for increase in weekly CSBM rate ranged from 1.4 to 1.6 CSBMs per week. Compared with the symptom-specific PRCQs for patient rating of relief, the FDA Responder Endpoint has a sensitivity of 60.7%, a specificity of 93.5%, and an accuracy of 82.0%. Changing the number of weeks required to be a responder or the percentage improvement in the Abdominal Pain criteria did not result in notable improvement in the accuracy of the FDA Responder Endpoint.

CONCLUSIONS & INFERENCES

The FDA Responder Endpoint for IBS-C clinical trials represents clinically meaningful improvements in IBS-C symptoms for patients with excellent specificity and reasonable sensitivity.

Treatment of functional diarrhea

Functional diarrhea (FD), one of the functional gastrointestinal disorders, is characterized by chronic or recurrent diarrhea not explained by structural or biochemical abnormalities. The treatment of FD is intimately associated with establishing the correct diagnosis. First, FD needs to be distinguished from diarrhea-predominant irritable bowel syndrome (IBS), in which, unlike in FD, abdominal pain is a primary diagnostic criterion. Next, FD must be differentiated from the myriad organic causes of chronic diarrhea. Unlike IBS, in which a positive diagnosis can be made with an acceptable level of confidence using symptom-based criteria and minimal testing, the diagnosis of FD is still primarily a diagnosis of exclusion. Thus, the onus is on the physician to eliminate potential underlying causes, both common and uncommon, in the proper clinical setting. Once the diagnosis has been established, the clinician and patient should first focus on identifying, eliminating, and/or treating aggravating factors. These may include physiologic factors (eg, small bowel bacterial overgrowth), psychological factors (eg, stress and anxiety), and dietary factors (eg, carbohydrate malabsorption). Thereafter, appropriate treatment for functional diarrhea may be instituted. Treatment options include dietary and lifestyle modification, pharmacologic therapies, and alternative modalities. Although many of these strategies have been studied in IBS, almost none of them has been examined specifically in FD. Furthermore, given the poorly understood pathophysiologic basis of FD, these treatments primarily target a patient's symptoms and presumed altered physiology rather than underlying etiologic mechanisms. Therefore, we stress that treatment must be approached in an individualized manner and that dietary and pharmacologic therapies should be part of a comprehensive therapeutic approach in which education and reassurance form the foundation. In general, we attempt to remove dietary triggers and recommend increased fiber intake. We then add anticholinergic, antispasmodic, antimotility, and antidiarrheal agents as the first line of pharmacotherapy. Should a patient not respond to these, and for patients who have a significant degree of psychological dysfunction, central acting agents, including antidepressants and/or anxiolytics, may be beneficial. During the treatment period, we also recommend that physicians keep an open mind. If signs or symptoms that suggest an ongoing or previously unrecognized organic process develop, then a re-evaluation of the clinical picture is indicated.

Systematic review of diagnostic criteria for IBS demonstrates poor validity and utilization of Rome III

BACKGROUND

In the absence of a clear biomarker for irritable bowel syndrome (IBS), clinical criteria are used. In this study, we conduct a systematic review to examine the validation and utilization of IBS criteria.

METHODS

A systematic review was performed in two stages. The first was a review of literature from 1978 validating IBS diagnostic criteria. The second stage of review was to select studies published in IBS between 1992 and 2011. This time period was divided into three segments (Rome I era from 1992 to 1999, Rome II era from 2000 to 2006, and Rome III era from 2007 to 2011). The number and type of study (RCT or other) and criteria used were evaluated for each era.

KEY RESULTS

The first stage of the systematic review identified only 14 published studies validating diagnostic tests for IBS (with three studies evaluating more than one criterion). There were eight validations for Manning, three validations for Kruis, four validations for Rome I, three validations for Rome II, and no validation for Rome III. In the second review of utilization of Rome criteria, only 25.7% of published IBS papers used Rome III criteria during the Rome III era (Rome II was used most in 64.8% of studies).

CONCLUSIONS & INFERENCES

This review identified that comparator groups varied widely between studies making comparison of criteria impossible. Manning criteria are the most valid and accurate criteria. More importantly, Rome III is not validated and is poorly adopted in clinical research trial enrollment.

Sleep disruption secondary to overnight call shifts is associated with irritable bowel syndrome in residents: a cross-sectional study

OBJECTIVES

Sleep disruption has been associated with irritable bowel syndrome (IBS). We hypothesized that residents with greater sleep disruption secondary to intermittent overnight call shifts would have a higher prevalence of IBS.

METHODS

Postgraduate residents completed a Web-based survey including demographic data, frequency and characteristics of call shifts, the Rome III questionnaire, and the IBS-quality of life measure.

RESULTS

For every hour of sleep deprivation while on call vs. off call, the odds ratio for an increased likelihood of IBS was 1.32, after adjustment for age and gender. The mean number of calls per block, sleep deprivation while on call, and specialty program vs. family practice each predicted the severity of IBS.

CONCLUSIONS

Sleep disruption secondary to overnight call in residents was associated with an increased prevalence of IBS.

A cross-sectional study of the association between overnight call and irritable bowel syndrome in medical students

BACKGROUND

Shift work has been associated with irritable bowel syndrome (IBS), which includes gastrointestinal symptoms such as abdominal pain, constipation and diarrhea. Overnight call shifts also lead to a disruption of the endogenous circadian rhythm.

HYPOTHESIS

Medical students who perform intermittent overnight call shifts will demonstrate a higher prevalence of IBS symptoms when compared with medical students who perform no overnight call shifts.

METHODS

First- and second-year (preclinical) medical students have no overnight call requirements, whereas third- and fourth-year medical (clerkship) students do have overnight call requirements. All medical students at the Schulich School of Medicine and Dentistry (London, Ontario) were invited to complete an anonymous, web-based survey or an identical paper copy that included demographic data, the Rome III questionnaire and the IBS-Quality of Life measure (IBS-QOL). The prevalence of IBS symptoms and quality of life secondary to those symptoms were determined.

RESULTS

Data were available for 247 medical students (110 preclinical students, 118 clerkship students and 19 excluded surveys). There was no significant difference in the presence of IBS between preclinical and clerkship students (21 of 110 [19.1%] versus 26 of 118 [22.0%]; P=0.58). The were no significant differences in mean (± SD) IBS-QOL score of those with IBS between preclinical (43.5±8.3) and clerkship students (45.7±13.8) (P=0.53).

CONCLUSIONS

Participation in overnight call was not associated with the development of IBS or a lower quality of life secondary to IBS in medical students.

The search for reliable biomarkers of disease in multiple chemical sensitivity and other environmental intolerances

Whilst facing a worldwide fast increase of food and environmental allergies, the medical community is also confronted with another inhomogeneous group of environment-associated disabling conditions, including multiple chemical sensitivity (MCS), fibromyalgia, chronic fatigue syndrome, electric hypersensitivity, amalgam disease and others. These share the features of poly-symptomatic multi-organ cutaneous and systemic manifestations, with postulated inherited/acquired impaired metabolism of chemical/physical/nutritional xenobiotics, triggering adverse reactions at exposure levels far below toxicologically-relevant values, often in the absence of clear-cut allergologic and/or immunologic involvement. Due to the lack of proven pathogenic mechanisms generating measurable disease biomarkers, these environmental hypersensitivities are generally ignored by sanitary and social systems, as psychogenic or "medically unexplained symptoms". The uncontrolled application of diagnostic and treatment protocols not corresponding to acceptable levels of validation, safety, and clinical efficacy, to a steadily increasing number of patients demanding assistance, occurs in many countries in the absence of evidence-based guidelines. Here we revise available information supporting the organic nature of these clinical conditions. Following intense research on gene polymorphisms of phase I/II detoxification enzyme genes, so far statistically inconclusive, epigenetic and metabolic factors are under investigation, in particular free radical/antioxidant homeostasis disturbances. The finding of relevant alterations of catalase, glutathione-transferase and peroxidase detoxifying activities significantly correlating with clinical manifestations of MCS, has recently registered some progress towards the identification of reliable biomarkers of disease onset, progression, and treatment outcomes.

Irritable bowel syndrome: diagnostic approaches in clinical practice

BACKGROUND

Irritable bowel syndrome (IBS), a functional gastrointestinal disorder long considered a diagnosis of exclusion, has chronic symptoms that vary over time and overlap with those of non-IBS disorders. Traditional symptom-based criteria effectively identify IBS patients but are not easily applied in clinical practice, leaving >40% of patients to experience symptoms up to 5 years before diagnosis.

OBJECTIVE

To review the diagnostic evaluation of patients with suspected IBS, strengths and weaknesses of current methodologies, and newer diagnostic tools that can augment current symptom-based criteria.

METHODS

The peer-reviewed literature (PubMed) was searched for primary reports and reviews using the limiters of date (1999-2009) and English language and the search terms irritable bowel syndrome, diagnosis, gastrointestinal disease, symptom-based criteria, outcome, serology, and fecal markers. Abstracts from Digestive Disease Week 2008-2009 and reference lists of identified articles were reviewed.

RESULTS

A disconnect is apparent between practice guidelines and clinical practice. The American Gastroenterological Association and American College of Gastroenterology recommend diagnosing IBS in patients without alarm features of organic disease using symptom-based criteria (eg, Rome). However, physicians report confidence in a symptom-based diagnosis without further testing only up to 42% of the time; many order laboratory tests and perform sigmoidoscopies or colonoscopies despite good evidence showing no utility for this work-up in uncomplicated cases. In the absence of diagnostic criteria easily usable in a busy practice, newer diagnostic methods, such as stool-form examination, fecal inflammatory markers, and serum biomarkers, have been proposed as adjunctive tools to aid in an IBS diagnosis by increasing physicians' confidence and changing the diagnostic paradigm to one of inclusion rather than exclusion.

CONCLUSION

New adjunctive testing for IBS can augment traditional symptom-based criteria, improving the speed and safety with which a patient is diagnosed and avoiding unnecessary, sometimes invasive, testing that adds little to the diagnostic process in suspected IBS.

Optimal management of chronic cyclical pelvic pain: an evidence-based and pragmatic approach

This article reviews the literature on management of chronic cyclical pelvic pain (CCPP). Electronic resources including Medline, PubMed, CINAHL, The Cochrane Library, Current Contents, and EMBASE were searched using MeSH terms including all subheadings and keywords: "cyclical pelvic pain", "chronic pain", "dysmenorrheal", "nonmenstrual pelvic pain", and "endometriosis". There is a dearth of high-quality evidence for this common problem. Chronic pelvic pain affects 4%-25% of women of reproductive age. Dysmenorrhea of varying degree affects 60% of women. Endometriosis is the commonest pathologic cause of CCPP. Other gynecological causes are adenomyosis, uterine fibroids, and pelvic floor myalgia, although other systems disease such as irritable bowel syndrome or interstitial cystitis may be responsible. Management options range from simple to invasive, where simple medical treatment such as the combined oral contraceptive pill may be used as a first-line treatment prior to invasive management. This review outlines an approach to patients with CCPP through history, physical examination, and investigation to identify the cause(s) of the pain and its optimal management.

Importance of early diagnosis in patients with irritable bowel syndrome

Patients with irritable bowel syndrome (IBS) account for >$20 billion in direct and indirect costs annually, a large portion of which relates to making the diagnosis. The diagnosis of IBS is challenging because symptoms can vary between patients and overlap with those of other disorders. This review examines the current diagnostic approach in IBS and discusses new tools that may improve diagnostic confidence earlier in the process. The prevalence of organic disease among patients who meet symptom-based criteria for IBS (eg, Rome III) is generally low; therefore, in the absence of "alarm features," the probability for organic disease is very low. Increased public awareness of IBS symptoms and physician awareness of symptom-based criteria for IBS are needed to facilitate earlier diagnosis. Accumulating evidence suggests that fecal and/or serum biomarkers may be helpful in differentiating IBS from non-IBS disorders. These tools may help minimize unnecessary testing and diagnostic delays. As biomarkers are further studied and developed, they are likely to become an integral part of the diagnosis of IBS and reduce the potential for incorrect diagnosis and treatment delays.

Irritable bowel syndrome: epidemiology, diagnosis and treatment: an update for health-care practitioners

Irritable bowel syndrome (IBS), a chronic gastrointestinal disorder, affects from 3-20% of the US population, depending on sociocultural and comorbid factors. IBS is characterized by a symptom complex of abdominal pain and abnormal bowel habits that present as diarrhea or constipation, and general physical weakness in the absence of abnormal morphological, histological or inflammatory markers. The main diagnostic Rome III criteria as established by international professional organizations are based on exclusion criteria and the occurrence and rate of symptoms. Because the pathophysiology and causes of IBS are poorly understood, treatment approaches are mainly focused on symptom management to maintain everyday functioning and improve quality of life for persons with IBS. The mainstay of intervention is pharmacological treatment with antispasmodics and antidiarrheals for diarrhea, prokinetics and high-fiber diets for constipation, and supportive therapy with low-dose antidepressants to normalize gastrointestinal motility. Other interventions include lifestyle and dietary changes, psychotherapy, herbal therapies and acupuncture. The purpose of this review is to critically assess benefits and risks of current treatment approaches as well as promising complementary and alternative therapies.

Human methanogen diversity and incidence in healthy and diseased colonic groups using mcrA gene analysis

BACKGROUND

The incidence and diversity of human methanogens are insufficiently characterised in the gastrointestinal tract of both health and disease. A PCR and clone library methodology targeting the mcrA gene was adopted to facilitate the two-fold aim of surveying the relative incidence of methanogens in health and disease groups and also to provide an overview of methanogen diversity in the human gastrointestinal tract.

RESULTS

DNA faecal extracts (207 in total) from a group of healthy controls and five gastrointestinal disease groups were investigated. Colorectal cancer, polypectomised, irritable bowel syndrome and the control group had largely equivalent numbers of individuals positive for methanogens (range 45-50%). Methanogen incidence in the inflammatory bowel disease groups was reduced, 24% for ulcerative colitis and 30% for Crohn's disease. Four unique mcrA gene restriction fragment length polymorphism profiles were identified and bioinformatic analyses revealed that the majority of all sequences (94%) retrieved from libraries were 100% identical to Methanobrevibacter smithii mcrA gene. In addition, mcrA gene sequences most closely related to Methanobrevibacter oralis and members of the order Methanosarcinales were also recovered.

CONCLUSION

The mcrA gene serves as a useful biomarker for methanogen detection in the human gut and the varying trends of methanogen incidence in the human gut could serve as important indicators of intestinal function. Although Methanobrevibacter smithii is the dominant methanogen in both the distal colon of individuals in health and disease, the diversity of methanogens is greater than previously reported. In conclusion, the low incidence of methanogens in Inflammatory Bowel Disease, the functionality of the methanogens and impact of methane production in addition to competitive interactions between methanogens and other microbial groups in the human gastrointestinal tract warrants further investigation.

Irritable bowel syndrome: current approach to symptoms, evaluation, and treatment

There are frequent advances in knowledge about the clinical presentation, pathophysiology, and treatment of irritable bowel syndrome. It is important for clinicians to be aware of available therapies and the supporting evidence for those therapies to increase patient satisfaction. This is best achieved with a collaborative and long-term clinician-patient relationship and mutual commitment to modify therapy and try new modalities until the greatest relief of symptoms and improvement in health-related quality of life is achieved. This article reviews symptoms, comorbidities, gender differences, and measure of severity in irritable bowel syndrome and current and evidence-based approaches to evaluation and treatment, and the new symptom-based Rome III diagnostic criteria are reviewed and explained.

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.

Development and psychometric testing of the Visual Analogue Scale for Irritable Bowel Syndrome (VAS-IBS)

BACKGROUND

The aim of this study was to develop and psychometrically test a short, patient-reported questionnaire to be used in clinical practice for patients with Irritable Bowel Syndrome (IBS). The Visual Analogue Scale for Irritable Bowel Syndrome (VAS-IBS) questionnaire was designed to measure the treatment response of symptoms and well-being in patients suffering from IBS.

METHODS

The VAS-IBS was psychometrically tested for content and criterion validity, scale acceptability, item-reduction, internal reliability consistency, simplicity, and speed. Two samples were used. One expert panel (five physicians and four registered nurses), who gave their opinion on the content validity, and one of 71 patients with IBS (mean age 38 years SD +13, range 19-65), who completed the VAS-IBS, as well as the Gastrointestinal Symptom Rating Scale and the Psychological General Well-Being Index for criterion validity.

RESULTS

The items in the VAS-IBS capture the main physical concerns women with IBS might present and the psychometric testing confirmed that the VAS-IBS is an acceptable homogeneous patient-reported questionnaire indicated by Cronbach's alpha internal consistency reliability coefficient, with a value of 0.85. All correlations to test the criterion validity performed by using Pearson's correlation test, were statistically significant (p < 0.0001) and in the expected directions. The VAS-IBS is easy to complete and unproblematic to calculate.

CONCLUSION

The VAS-IBS appears to be reliable and user-friendly, for patients as well as for health professionals. The final version of the VAS-IBS including nine items needs to be further tested in clinical practice cross-culturally in women as well as in men.

The central role of gastrointestinal-specific anxiety in irritable bowel syndrome: further validation of the visceral sensitivity index

OBJECTIVES

The Visceral Sensitivity Index (VSI) was developed as the first instrument to assess gastrointestinal-specific anxiety, the cognitive, affective, and behavioral response to fear of gastrointestinal sensations, symptoms, and the context in which these visceral sensations and symptoms occur. The purpose of the current study was to a) replicate the previously reported psychometric properties of the VSI, b) assess the known-groups and concurrent validity of the instrument, and c) test conceptual hypotheses regarding gastrointestinal-specific anxiety in comparison to other general measures of psychological distress as a crucial mechanism (mediator/moderator) underlying irritable bowel syndrome diagnosis and its symptoms.

METHODS

Two undergraduate student samples (n > 500) were administered the VSI along with measures assessing presence of lower gastrointestinal symptoms, nongastrointestinal pain, health-service utilization, anxiety, depression, vitality, neuroticism, and anxiety sensitivity. Path analyses tested the hypothesis that gastrointestinal-specific anxiety mediates the relationship between affective variables and irritable bowel syndrome diagnosis and symptoms. A 'known-groups' validity approach elucidated the relevance of gastrointestinal-specific anxiety across a spectrum of irritable bowel syndrome patients.

RESULTS

Good concurrent, divergent and discriminant validity was demonstrated. Logistic regression revealed that gastrointestinal-specific anxiety is the key explanatory variable of irritable bowel syndrome diagnostic status. Path analysis demonstrated that gastrointestinal-specific anxiety mediates the relationship between general psychological distress measures and gastrointestinal symptom severity. The VSI was related to gastrointestinal, but not nongastrointestinal, symptom severity.

CONCLUSIONS

Overall, the VSI demonstrated excellent psychometric properties providing further support for its use in mechanistic studies of the role of anxiety in irritable bowel syndrome presentation.

Irritable bowel syndrome

Conceptually, the irritable bowel syndrome (IBS) has been considered a brain-gut functional disorder, but this paradigm is under serious challenge. There is increasing evidence that organic disease of the gastrointestinal tract can be identified in subsets of patients who fulfil the Rome criteria for IBS. Evidence for subtle inflammatory bowel disease, serotonin dysregulation, bacterial overgrowth and central dysregulation continue to accumulate. The underlying causes of IBS remain to be adequately identified, but postinfectious IBS is a clear-cut entity. Furthermore, a genetic contribution to IBS also seems likely. Diagnosis continues to be based on the symptom profile and the absence of alarm features. A heightened awareness of coeliac disease masquerading as IBS is becoming accepted. Management remains largely based on symptomatic rather than on disease-modifying therapy, but this is likely to change in the near future. Here, recent advances in the pathophysiology and management of IBS are considered.

Prevalence and management of abdominal cramping and pain: a multinational survey

BACKGROUND

Though functional gastrointestinal complaints are recognised as being common throughout the world, there have been few comparative studies of prevalence.

AIM

To compare the prevalence and management of abdominal cramping/pain in nine countries.

METHODS

In a two-stage community survey, approximately 1000 subjects were interviewed in each of nine countries to establish the demographics of individuals with abdominal cramping/pain (stage 1) followed by market research-driven interviews with >or=200 sufferers per country (stage 2).

RESULTS

9042 subjects were interviewed in stage 1. Mexico (46%) and Brazil (43%) had the highest prevalence of abdominal cramping/pain; Japan the lowest (10%). Abdominal cramping/pain was more common in women (12-55%) than in men (7-38%). About 1717 subjects participated in stage 2; 65% were women and the average age at symptom onset was 29 years. The frequency of episodes differed between countries, being highest in the US (61% suffered at least once in a week). Sufferers in the US and Latin America reported a higher usage of medications (around 90%) than those in Europe (around 72%). In most countries over-the-counter drugs were principally used. Antispasmodic drugs were most popular in Latin America and Italy, antacids in Germany and the UK. Drug therapy decreased the duration of episodes (by up to 81% in Brazil).

CONCLUSIONS

The community prevalence, severity, healthcare seeking and medication usage related to abdominal cramping/pain are high overall, but vary considerably between countries.

Role of partially hydrolyzed guar gum in the treatment of irritable bowel syndrome

Irritable bowel syndrome (IBS) is the world's most common gastrointestinal functional disorder and is associated with several social and economic costs. Health-related quality of life is often impaired in patients with IBS. The pathophysiologic mechanisms underlying IBS remain poorly defined. The therapeutic approach to patients with IBS is based on symptoms, and fibers may play an important role in treatment. Among the various types of fiber, water-soluble, non-gelling fibers seem to be a promising option for treatment of IBS. Partially hydrolyzed guar gum (PHGG) is a water-soluble, non-gelling fiber that has provided therapeutic benefits. In clinical trials, PHGG decreased symptoms in constipation-predominant and diarrhea-predominant forms of IBS and decreased abdominal pain. Further, an improvement in quality of life was observed in patients with IBS during and after treatment with PHGG. Moreover, PHGG seems to have prebiotic properties because it increases the colonic contents of short-chain fatty acids, Lactobacilli, and Bifidobacteria.

Functional diarrhea

Functional diarrhea occurs as part of the irritable bowel syndrome (IBS) and as an isolated symptom as functional (painless) diarrhea. Progress has been made in defining these disorders and in identifying new mechanisms involved in symptom production. A strong link exists between intestinal infection and IBS, as is the role of 5-hydroxytryptamine (5-HT). The importance of persistent subclinical inflammation is also emerging as a potential etiologic factor, particularly in post-infectious IBS. Although changes in the bacterial flora and bacterial overgrowth have been put forward as additional new contributors to symptom production, the case is not strong. These developments in pathogenesis have facilitated the introduction of new therapies. 5-HT(3) antagonists reduce bowel frequency and pain in women with diarrhea-predominant IBS, but their use is limited because of ischemic colitis. Prednisolone lacks efficacy, and early results with probiotics and herbal remedies are encouraging but require confirmation by larger trials.

A symptom-based approach to making a positive diagnosis of irritable bowel syndrome with constipation

Irritable bowel syndrome (IBS) is a common gastrointestinal disorder. Characterised by abdominal pain or discomfort, bloating and altered bowel habit, IBS is a chronic recurring condition, typically affecting up to 15% of the Western population, IBS can be subclassified into IBS with constipation (IBS-C), IBS with diarrhoea (IBS-D), or IBS with alternating constipation or diarrhoea symptoms (IBS-A). Conventional clinical diagnosis focuses on excluding all potential organic causes of patient symptoms. However, a positive diagnosis of IBS may be established using published criteria such as the Manning and/or Rome criteria. While these methods are useful to identify patients with IBS who are suitable for enrollment into clinical trials, the criteria are relatively complex and not readily applicable to general practice. In this review we present an 'identify, eliminate, probe' algorithm that may be appropriate to establish a positive diagnosis of patients with IBS-C, as symptoms characteristic of patients in this IBS subgroup are least likely to be confused with symptoms reflecting serious organic disease.

Training Room Management of Medical Conditions: Sports Gastroenterology

Gastrointestinal (GI) illnesses are common in athletes. Various causes include adverse physiologic adaptations of the gut during exercise; excess ingestion of carbohydrate drinks, alcohol, and anti-inflammatory medications; emotional stressors; exposure to pathogens in closed environments and during travel; trauma; and abdominal wall pressure overload. Unfortunately, evidence-based management of GI illnesses in athletes is limited because most studies have compared various GI illnesses between different sports, rather than comparing athletes to nonathletes. This article reviews the evidence that is available specifically relating to etiology, pathophysiology, clinical presentation, relevant differential diagnoses, acute management, and recommendations for specialist consultation of various GI illnesses in the training-room setting.

Recognizing and managing patients with irritable bowel syndrome

PURPOSE

To address the diagnosis and clinical management of irritable bowel syndrome (IBS) and provide a discussion of the available serotonergic agents.

DATA SOURCES

Recent studies examining the pathophysiology of IBS.

CONCLUSIONS

Diagnostic testing may be required in the subset of patients with IBS who present with alarm symptoms, or "red flags," suggestive of underlying organic disease. An important role has been suggested for the neurotransmitter serotonin in both gut motility and visceral pain sensitivity.

IMPLICATIONS FOR PRACTICE

A diagnosis of IBS is largely based on symptoms; therefore, effective clinician-patient communication and careful attention to details of patient presentation, history, and physical examination are essential.