New clinical method for distinguishing D-IBS from other gastrointestinal conditions causing diarrhea: the LA/IBS diagnostic strategy

Current and future pharmacotherapies for the management of constipation-predominant irritable bowel syndrome

INTRODUCTION

Irritable bowel syndrome (IBS) is a common gastrointestinal disorder affecting 9-23% of the world's population, with a higher prevalence among women. IBS is a complex disorder influenced by psychosocial, physiological, and genetic factors, exacerbated by stress.

AREAS COVERED

Research confirms that the most common subtype of IBS is IBS-C. Therefore, new therapies are being developed to speed up bowel movement and reduce constipation, with drugs such as linaclotide, plecanatide, lubiprostone, or tegaserod available to reduce IBS-C symptoms. In addition, patients' condition is improved by foods rich in fiber and low in FODMAP and the use of biotics.

EXPERT OPINION

The topic is of great importance due to the growing number of patients suffering from IBS-C and its significant impact on quality of life. Current clinical trials of new therapeutic options are not too successful, and it seems that one of the plausible treatment options could be the multi-drug cocktail with some, or perhaps even all its ingredients emerging from drug re-purposing. Another important path that needs to be explored further in IBS-C patients is the adjustment of dietary habits and/or introduction of dietary or nutritional intervention.

A Smartphone Application Using Artificial Intelligence Is Superior To Subject Self-Reporting When Assessing Stool Form

INTRODUCTION

Stool form assessment relies on subjective patient reports using the Bristol Stool Scale (BSS). In a novel smartphone application (app), trained artificial intelligence (AI) characterizes digital images of users' stool. In this study, we evaluate this AI for accuracy in assessing stool characteristics.

METHODS

Subjects with diarrhea-predominant irritable bowel syndrome image-captured every stool for 2 weeks using the app, which assessed images for 5 visual characteristics (BSS, consistency, fragmentation, edge fuzziness, and volume). In the validation phase, using 2 expert gastroenterologists as a gold standard, sensitivity, specificity, accuracy, and diagnostic odds ratios of subject-reported vs AI-graded BSS scores were compared. In the implementation phase, agreements between AI-graded and subject-reported daily average BSS scores were determined, and subject BSS and AI stool characteristics scores were correlated with diarrhea-predominant irritable bowel syndrome symptom severity scores.

RESULTS

In the validation phase (n = 14), there was good agreement between the 2 experts and AI characterizations for BSS (intraclass correlation coefficients [ICC] = 0.782-0.852), stool consistency (ICC = 0.873-0.890), edge fuzziness (ICC = 0.836-0.839), fragmentation (ICC = 0.837-0.863), and volume (ICC = 0.725-0.851). AI outperformed subjects' self-reports in categorizing daily average BSS scores as constipation, normal, or diarrhea. In the implementation phase (n = 25), the agreement between AI and self-reported BSS scores was moderate (ICC = 0.61). AI stool characterization also correlated better than subject reports with diarrhea severity scores.

DISCUSSION

A novel smartphone application can determine BSS and other visual stool characteristics with high accuracy compared with the 2 expert gastroenterologists. Moreover, trained AI was superior to subject self-reporting of BSS. AI assessments could provide more objective outcome measures for stool characterization in gastroenterology.

GC-MS Analysis and In Vivo and Ex Vivo Antidiarrheal and Antispasmodic Effects of the Methanolic Extract of Acacia nilotica

This present study evaluated and rationalized the medicinal use of the fruit part of Acacia nilotica methanolic extract. The phytochemicals were detected using gas chromatography−mass spectrometry (GC−MS) while the in vivo antidiarrheal test was done using Swiss albino mice. To determine the details of the mechanism(s) involved in the antispasmodic effect, isolated rat ileum was chosen using different ex vivo assays by maintaining a physiological environment. GC−MS results showed that A. nilotica contained pyrogallol as the major polyphenol present (64.04%) in addition to polysaccharides, polyphenol, amino acid, steroids, fatty acid esters, and triterpenoids. In the antidiarrheal experiment, A. nilotica inhibited diarrheal episodes in mice significantly (p < 0.05) by 40% protection of mice at 200 mg/kg, while 80% protection was observed at 400 mg/kg by the orally administered extract. The highest antidiarrheal effect was observed with loperamide (p < 0.01), used as a control drug. In the ex vivo experiments, A. nilotica inhibited completely in increasing concentrations (0.3 to 10 mg/mL) the carbachol (CCh; 1 µM) and high K+ (80 mM)-evoked spasms in ileum tissues at equal potencies (p > 0.05), similar to papaverine, a dual inhibitor of the phosphodiesterase enzyme (PDE) and Ca++ channels. The dual inhibitory-like effects of A. nilotica on PDE and Ca++ were further validated when A. nilotica extract (1 and 3 mg/mL)-pre-incubated ileum tissues potentiated and shifted isoprenaline relaxation curves towards lower doses (leftward), similar to papaverine, thus confirming the PDE inhibitory-like mechanism whereas its CCB-like effect of the extract was confirmed at 3 and 5 mg/mL by non-specific inhibition of CaCl2-mediated concentration response curves towards the right with suppression of the maximum peaks, similar to verapamil, used as standard CCB. Thus, this study characterized the chemical composition and provides mechanistic support for medicinal use of A. nilotica in diarrheal and hyperactive gut motility disorders.

Impact of Diet on Symptoms of the Irritable Bowel Syndrome

Irritable bowel syndrome (IBS), with its key features of abdominal pain and disturbed bowel habit, is thought by both patients and clinicians to be strongly influenced by diet. However, the complexities of diet have made identifying specific food intolerances difficult. Eating disorders can masquerade as IBS and may need specialist treatment. While typical food allergy is readily distinguished from IBS, the mechanisms of gut-specific adverse reactions to food are only just being defined. These may include gut-specific mast cell activation as well as non-specific activation by stressors and certain foods. Visceral hypersensitivity, in some cases mediated by mast cell activation, plays a key part in making otherwise innocuous gut stimuli painful. Rapidly fermented poorly absorbed carbohydrates produce gaseous distension as well as short-chain fatty acids and lowering of colonic pH which may cause symptoms in IBS patients. Limiting intake of these in low FODMAP and related diets has proven popular and apparently successful in many patients. Existing diet, colonic microbiota and their metabolic products may be helpful in predicting who will respond. Wheat intolerance may reflect the fact that wheat is often a major source of dietary FODMAPs. It may also be either a forme fruste of coeliac disease or non-specific immune activation. Wheat exclusion can be successful in some of these patients. More research is needed to fully understand the mechanisms of food intolerances and how to best ameliorate them in a personalised medicine approach to diet in IBS.

In Silico, Ex Vivo and In Vivo Studies of Roflumilast as a Potential Antidiarrheal and Antispasmodic agent: Inhibition of the PDE-4 Enzyme and Voltage-gated Ca++ ion Channels

The aim of the present study was to evaluate the possible gut inhibitory role of the phosphodiesterase (PDE) inhibitor roflumilast. Increasing doses of roflumilast were tested against castor oil-induced diarrhea in mice, whereas the pharmacodynamics of the same effect was determined in isolated rabbit jejunum tissues. For in silico analysis, the identified PDE protein was docked with roflumilast and papaverine using the Autodock vina program from the PyRx virtual screening tool. Roflumilast protected against diarrhea significantly at 0.5 and 1.5 mg/kg doses, with 40% and 80% protection. Ex vivo findings from jejunum tissues show that roflumilast possesses an antispasmodic effect by inhibiting spontaneous contractions in a concentration-dependent manner. Roflumilast reversed carbachol (CCh, 1 µM)-mediated and potassium (K+, 80 mM)-mediated contractile responses with comparable efficacies but different potencies. The observed potency against K+ was significantly higher in comparison to CCh, similar to verapamil. Experiments were extended to further confirm the inhibitory effect on Ca++ channels. Interestingly, roflumilast deflected Ca++ concentration–response curves (CRCs) to the right with suppression of the maximum peak at both tested doses (0.001-0.003 mg/mL), similar to verapamil. The PDE-inhibitory effect was authenticated when pre-incubation of jejunum tissues with roflumilast (0.03-0.1 mg/mL) produced a leftward deflection of isoprenaline-mediated inhibitory CRCs and increased the tissue level of cAMP, similar to papaverine. This idea was further strengthened by molecular docking studies, where roflumilast exhibited a better binding affinity (-9.4 kcal/mol) with the PDE protein than the standard papaverine (-8.3 kcal/mol). In conclusion, inhibition of Ca++ channels and the PDE-4 enzyme explains the pharmacodynamics of the gut inhibitory effect of roflumilast.

The Anti-diarrheal Activity of the Non-toxic Dihuang Powder in Mice

Dihuang powder (DHP) has been used in the traditional Chinese medicine for the treatment of diarrhea in some regions of China. But up to now, the anti-diarrheal activity of DHP haven't been performed with modern pharmacological technology. This study aims to investigate the quality control, the potential toxicity and anti-diarrheal activity of Dihuang powder in mice. High performance liquid chromatography (HPLC) and thin layer chromatography (TLC) were used to detect five active compounds in DHP for quality control, and the acute toxicity and sub-acute toxicity for 28-day oral administration of DHP were then evaluated. The anti-diarrheal activity was investigated using mouse model. Results showed that the levels of quercetin and berberine in DHP were 0.054 and 0.632 mg/g, respectively, and atractylodin, matrine, and patehouli aleohal were also detected in DHP. At the given doses, DHP was safe in terms of acute and sub-acute toxicity. Meanwhile, DHP exhibited strong anti-diarrheal effects as well as decreased gastrointestinal motility and the secretions induced by Sennae and castor oil in a dose-dependent manner. It could decrease the content of IL-1β, IL-6, and TNF-α in the small intestine, and improve the histopathological changes of small intestine and large intestine induced by Sennae. The antinociceptive and anti-inflammatory activities in vivo also were presented. Based on all of the results, we thought that DHP has anti-diarrheal activity, and could be used to treat diarrhea as well as alleviate the pain and inflammation induced by diarrhea. This study provides a theoretical basis for the clinical use of DHP and may assist in the development of new drugs for the treatment of diarrhea. The mechanism of the anti-diarrheal activity should be investigated in the future.

Therapeutic significance and pharmacological activities of antidiarrheal medicinal plants mention in Ayurveda: A review

Diarrhea is a serious problem affecting 3-5 billion people per year around the world, especially children of below 5 years. 70% of the world population uses traditional and indigenous medicine for their primary health care. The facts of these indigenous remedies are passed verbally and sometimes as documents. Since ancient time, Ayurveda is the main system of healing in South East Asian countries. Indian literature from ayurvedic texts and other books claim the potency of several plants in the treatment of diarrhea. As the global prospective of ayurvedic medicine is increasing, interest regarding the scientific basis of their action is parallely increasing. Researchers are doing experiments to establish the relation between the claimed action and observed pharmacological activities. In the present article, an attempt was made to compile the scientific basis of medicinal plants used to cure diarrhea in Ayurveda. Literature was collected via electronic search (PubMed, ScienceDirect, Medline, and Google Scholar) from published articles that reports antidiarrheal activity of plants that were mentioned in Ayurveda classics. A total of 109 plant species belonging to 58 families were reported for their antidiarrheal activity. Several Indian medicinal plants have demonstrated promising antidiarrheal effects, but the studies on the antidiarrheal potentials of these plants are not taken beyond proof of concept stage. It is hoped that the article would stimulate future clinical studies because of the paucity of knowledge in this area.

Irritable bowel syndrome: new insights into symptom mechanisms and advances in treatment

Despite being one of the most common conditions leading to gastroenterological referral, irritable bowel syndrome (IBS) is poorly understood. However, recent years have seen major advances. These include new understanding of the role of both inflammation and altered microbiota as well as the impact of dietary intolerances as illuminated by magnetic resonance imaging (MRI), which has thrown new light on IBS. This article will review new data on how excessive bile acid secretion mediates diarrhea and evidence from post infectious IBS which has shown how gut inflammation can alter gut microbiota and function. Studies of patients with inflammatory bowel disease (IBD) have also shown that even when inflammation is in remission, the altered enteric nerves and abnormal microbiota can generate IBS-like symptoms. The efficacy of the low FODMAP diet as a treatment for bloating, flatulence, and abdominal discomfort has been demonstrated by randomized controlled trials. MRI studies, which can quantify intestinal volumes, have provided new insights into how FODMAPs cause symptoms. This article will focus on these areas together with recent trials of new agents, which this author believes will alter clinical practice within the foreseeable future.

Irritable bowel syndrome

Irritable bowel syndrome (IBS) is a functional gastrointestinal disease with a high population prevalence. The disorder can be debilitating in some patients, whereas others may have mild or moderate symptoms. The most important single risk factors are female sex, younger age and preceding gastrointestinal infections. Clinical symptoms of IBS include abdominal pain or discomfort, stool irregularities and bloating, as well as other somatic, visceral and psychiatric comorbidities. Currently, the diagnosis of IBS is based on symptoms and the exclusion of other organic diseases, and therapy includes drug treatment of the predominant symptoms, nutrition and psychotherapy. Although the underlying pathogenesis is far from understood, aetiological factors include increased epithelial hyperpermeability, dysbiosis, inflammation, visceral hypersensitivity, epigenetics and genetics, and altered brain-gut interactions. IBS considerably affects quality of life and imposes a profound burden on patients, physicians and the health-care system. The past decade has seen remarkable progress in our understanding of functional bowel disorders such as IBS that will be summarized in this Primer.

Bowel Disorders

Functional bowel disorders are highly prevalent disorders found worldwide. These disorders have the potential to affect all members of society, regardless of age, gender, race, creed, color or socioeconomic status. Improving our understanding of functional bowel disorders (FBD) is critical as they impose a negative economic impact to the global health care system in addition to reducing quality of life. Research in the basic and clinical sciences during the past decade has produced new information on the epidemiology, etiology, pathophysiology, diagnosis and treatment of FBDs. These important findings created a need to revise the Rome III criteria for FBDs, last published in 2006. This manuscript classifies the FBDs into five distinct categories: irritable bowel syndrome (IBS); functional constipation (FC); functional diarrhea (FDr); functional abdominal bloating/distention (FAB/D); and unspecified FBD (U-FBD). Also included in this article is a new sixth category, opioid induced constipation (OIC) which is distinct from the functional bowel disorders (FBDs). Each disorder will first be defined, followed by sections on epidemiology, rationale for changes from prior criteria, clinical evaluation, physiologic features, psychosocial features and treatment. It is the hope of this committee that this new information will assist both clinicians and researchers in the decade to come.

Antidiarrheal effect of Alpinia oxyphylla Miq. (Zingiberaceae) in experimental mice and its possible mechanism of action

ETHNOPHARMACOLOGICAL RELEVANCE

The fructus Alpinia oxyphylla Miq. (AOM) has been used for treating diarrhea with spleen deficiency and gastralgia for thousands of years. A number of traditional Chinese medicine formulae provide AOM as an alternative herbal treatment for diarrhea, but the scientific basis for this usage has not been well defined.

AIM OF THE STUDY

In this study, we tried to investigate the antidiarrheal activity and possible mechanisms of Fructus AOM, aiming to enrich our understanding to the scientific meanings and theoretical significance of Fructus AOM in clinical practice.

MATERIALS AND METHODS

The fructus of AOM collected from Hainan province in China were macerated in the 95% ethanol to obtain the crude 95% ethanol extract, followed by subjected to chromatographic separation over a Diaion HP20 column to obtain 90% and 50% ethanol eluted fractions. The activities of the crude extract and fractions on castor oil induced acute diarrhea, rhubarb induced chronic diarrhea, gastrointestinal transit (GIT) in mice, and contractions of isolated guinea-pig ileum were evaluated. Additionally, nitric oxide (NO), gastrointestinal peptides gastrin (GAS), motilin (MTL) and somatostatin (SS) levels that related to gastrointestinal motilities were detected to demonstrate the potential mechanisms. Ultimately, LC-MS/MS method was utilized to ensure the chemical consistency.

RESULTS

The 95% ethanol extract and 90% ethanol eluted fraction significantly delayed the onset time and decreased the wet faeces proportion compared with control group in the castor oil induced acute diarrhea mice. In terms of further evaluation of antidiarrheal activity, the 95% ethanol extract and 90% ethanol elution displayed significant inhibition of the intestinal propulsion at the two highest oral doses of 20 g crude drug/kg and 1g/kg. Moreover the 95% ethanol extract (10 and 20 g crude drug/kg) and 90% ethanol elution (0.5 and 1g/kg) could significantly inhibit the GIT, which was partially attributed to the increase in NO and SS levels, and the decreased MTL. In vitro spontaneous contractions of the isolated guinea pig ileum induced by carbachol, neostigmine and histamine were attenuated by both the extract and elution. Phytochemical analysis of 95% ethanol extract and its fractions identified the presence of diphenylheptanes, sesquiterpenes, and flavones as the major components.

CONCLUSIONS

Our in vivo and in vitro data could partly support and justify the traditional usage of Fructus AOM on the treatment of diarrhea in traditional medicine.

Autoimmunity Links Vinculin to the Pathophysiology of Chronic Functional Bowel Changes Following Campylobacter jejuni Infection in a Rat Model

BACKGROUND

Acute gastroenteritis can precipitate irritable bowel syndrome (IBS) in humans. Cytolethal distending toxin is common to all pathogens causing gastroenteritis. Its active subunit, CdtB, is associated with post-infectious bowel changes in a rat model of Campylobacter jejuni infection, including small intestinal bacterial overgrowth (SIBO).

AIM

To evaluate the role of host antibodies to CdtB in contributing to post-infectious functional sequelae in this rat model.

METHODS

Ileal tissues from non-IBS human subjects, C. jejuni-infected and control rats were immunostained with antibodies to CdtB, c-Kit, S-100, PGP 9.5 and vinculin. Cytosolic and membrane proteins from mouse enteric neuronal cell lysates were immunoprecipitated with anti-CdtB and analyzed by mass spectrometry. ELISAs were performed on rat cardiac serum using CdtB or vinculin as antigens.

RESULTS

Anti-CdtB antibodies bound to a cytosolic protein in interstitial cells of Cajal (ICC) and myenteric ganglia in C. jejuni-infected and naïve rats and human subjects. Mass spectrometry identified vinculin, confirmed by co-localization and ELISAs. Anti-CdtB antibodies were higher in C. jejuni-infected rats (1.27 ± 0.15) than controls (1.76 ± 0.12) (P < 0.05), and rats that developed SIBO (2.01 ± 0.18) vs. rats that did not (1.44 ± 0.11) (P = 0.019). Vinculin expression levels were reduced in C. jejuni-infected rats (0.058 ± 0.053) versus controls (0.087 ± 0.023) (P = 0.0001), with greater reductions in rats with two C. jejuni infections (P = 0.0001) and rats that developed SIBO (P = 0.001).

CONCLUSIONS

Host anti-CdtB antibodies cross-react with vinculin in ICC and myenteric ganglia, required for normal gut motility. Circulating antibody levels and loss of vinculin expression correlate with number of C. jejuni exposures and SIBO, suggesting that effects on vinculin are important in the effects of C. jejuni infection on the host gut.

Gastro 2013 APDW/WCOG Shanghai working party report: chronic diarrhea: definition, classification, diagnosis

Diarrhea is best defined as passage of loose stools often with more frequent bowel movements. For clinical purposes, the Bristol Stool Form Scale works well to distinguish stool form and to identify loose stools. Laboratory testing of stool consistency has lagged behind. Acute diarrhea is likely to be due to infection and to be self-limited. As diarrhea becomes chronic, it is less likely to be due to infection; duration of 1 month seems to work well as a cut-off for chronic diarrhea, but detailed scientific knowledge is missing about the utility of this definition. In addition to duration of diarrhea, classifications by presenting scenario, by pathophysiology, and by stool characteristics (e.g. watery, fatty, or inflammatory) may help the canny clinician refine the differential diagnosis of chronic diarrhea. In this regard, a careful history remains the essential part of the evaluation of a patient with diarrhea. Imaging the intestine with endoscopy and radiographic techniques is useful, and biopsy of the small intestine and colon for histological assessment provides key diagnostic information. Endomicroscopy and molecular pathology are only now being explored for the diagnosis of chronic diarrhea. Interest in the microbiome of the gut is increasing; aside from a handful of well-described infections because of pathogens, little is known about alterations in the microbiome in chronic diarrhea. Serological tests have well-defined roles in the diagnosis of celiac disease but have less clearly defined application in autoimmune enteropathies and inflammatory bowel disease. Measurement of peptide hormones is of value in the diagnosis and management of endocrine tumors causing diarrhea, but these are so rare that these tests are of little value in screening because there will be many more false-positives than true-positive results. Chemical analysis of stools is of use in classifying chronic diarrhea and may limit the differential diagnosis that must be considered, but interpretation of the results is still evolving. Breath tests for assessment of carbohydrate malabsorption, small bowel bacterial overgrowth, and intestinal transit are fraught with technical limitations that decrease sensitivity and specificity. Likewise, tests of bile acid malabsorption have had limited utility beyond empirical trials of bile acid sequestrants.

Report from the multinational irritable bowel syndrome initiative 2012

In 2012, a group of 29 internationally recognized experts in the pathophysiology, diagnosis, and treatment of irritable bowel syndrome (IBS) convened to audit the current state of IBS research. The meeting was preceded by a comprehensive online survey that focused on research needs for IBS diagnosis (particularly the strengths and shortcomings of current criteria), definitions used in clinical trials for IBS patients and "healthy controls," potential biomarkers for IBS, and outcome measures in drug trials. While the purpose of the meeting was not to make binding recommendations, participants developed a framework for future questions and research needs in IBS. First, participants indicated the need for revised criteria for the diagnosis of IBS; in particular, inclusion of bloating and de-emphasis of pain as criteria were considered critical needs. Second, participants noted that definitions of normal, healthy controls varied widely among clinical trials; these definitions need to be standardized not only to improve the reliability of results, but also to better facilitate inter-trial comparisons and data synthesis. Third, participants highlighted the need for accurate biomarkers of disease. Fourth and finally, participants noted that further defining outcome measures, so that they are functionally relevant and reflect normalization of bowel function, is a critical need. Together, the discussions held at this workshop form a framework to address future research in IBS.

Antibiotics for irritable bowel syndrome: rationale and current evidence

Irritable bowel syndrome (IBS) is the most common gastrointestinal condition effecting adults in developed countries worldwide. Over the last decade, evidence has emerged suggesting that gut bacteria play a role in the pathophysiology of IBS. While difficult to identify using noninvasive means, one of the most common attributable bacterial concepts in IBS is the small intestinal bacterial overgrowth hypothesis (SIBO). In this article, we review the different mechanisms by which gut flora and, specifically, SIBO may contribute to IBS and the evidence supporting the use of various antibiotic therapies in treating IBS.

Role of Cytolethal Distending Toxin in Altered Stool Form and Bowel Phenotypes in a Rat Model of Post-infectious Irritable Bowel Syndrome

BACKGROUND/AIMS

Campylobacter jejuni infection is a leading cause of acute gastroenteritis, which is a trigger for post-infectious irritable bowel syndrome (PI-IBS). Cytolethal distending toxin (CDT) is expressed by enteric pathogens that cause PI-IBS. We used a rat model of PI-IBS to investigate the role of CDT in long-term altered stool form and bowel phenotypes.

METHODS

Adult Sprague-Dawley rats were gavaged with wildtype C. jejuni (C+), a C. jejunicdtB knockout (CDT-) or saline vehicle (controls). Four months after gavage, stool from 3 consecutive days was assessed for stool form and percent wet weight. Rectal tissue was analyzed for intraepithelial lymphocytes, and small intestinal tissue was stained with anti-c-kit for deep muscular plexus interstitial cells of Cajal (DMP-ICC).

RESULTS

All 3 groups showed similar colonization and clearance parameters. Average 3-day stool dry weights were similar in all 3 groups, but day-to-day variability in stool form and stool dry weight were significantly different in the C+ group vs both controls (P < 0.01) and the CDT- roup (P < 0.01), but were not different in the CDT- vs controls. Similarly, rectal lymphocytes were significantly higher after C. jejuni (C+) infection vs both controls (P < 0.01) and CDT-exposed rats (P < 0.05). The counts in the latter 2 groups were not significantly different. Finally, c-kit staining revealed that DMP-ICC were reduced only in rats exposed to wildtype C. jejuni.

CONCLUSIONS

In this rat model of PI-IBS, CDT appears to play a role in the development of chronic altered bowel patterns, mild chronic rectal inflammation and reduction in DMP-ICC.

Diagnostic criteria in IBS: useful or not?

There are a number of reasons to establish the accurate diagnosis of irritable bowel syndrome (IBS): to relieve patient uncertainty; to avoid adverse effects of unnecessary medications or treatments; to avoid unnecessary diagnostic procedures and surgeries; to conserve limited healthcare resources; and, of course, to initiate the most appropriate treatment. However, making the diagnosis of IBS remains difficult because it is clinically heterogeneous, no biological marker to detect it exists, many other diseases share the same clinical manifestations and it is often difficult for both physicians and patients to accept the uncertainty of a symptom-based diagnosis. Different diagnostic criteria have been developed during the last 4 decades but none have proved to be an ideal method of accurately diagnosing IBS. Just as importantly, physicians are frequently unaware of published guidelines or consciously ignore these diagnostic criteria. Most clinicians still believe IBS is a diagnosis of exclusion and not a positive diagnosis based on history, physical examination, use of published diagnostic criteria such as the Rome III criteria, and the absence of alarm features. In the sections to follow we will address the inherent difficulties of diagnosing IBS, highlight the importance of symptom-based diagnoses to help reign in soaring healthcare costs, and discuss future strategies that may enable a more cost-efficient diagnosis of IBS.

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.

IBS patients show frequent fluctuations between loose/watery and hard/lumpy stools: implications for treatment

OBJECTIVES

The objectives of this study were to determine how variable stool consistency is in patients with irritable bowel syndrome (IBS) and to assess the relationship between stool consistency and gastrointestinal symptoms.

METHODS

Individuals with a physician diagnosis of IBS were recruited by advertisement. Enrollment questionnaires included the Rome III Diagnostic Questionnaire and IBS Symptom Severity Scale. Then, 185 patients meeting the Rome criteria for IBS rated the consistency (using the Bristol Stool Scale) of each bowel movement (BM) for 90 days and whether the BM was accompanied by pain, urgency, or soiling. Each night, they transferred BM ratings from a paper diary to an internet form and also reported the average daily intensity of abdominal pain, bloating, bowel habit dissatisfaction, and life interference of bowel symptoms. Only the longest sequence of consecutive days of diary data was used in the analysis (average of 73 days).

RESULTS

Patients were 89% females with average age 36.6 years. Among the patients, 78% had both loose/watery and hard/lumpy stools; the average was three fluctuations between these extremes per month. The proportion of loose/watery stools correlated r=0.78 between the first and second months and the proportion of hard/lumpy stools correlated r=0.85 between months. Loose/watery stools were associated with more BM-related pain, urgency, and soiling than hard/lumpy or normal stools; however, IBS-C patients had significantly more BM-unrelated abdominal pain, bloating, dissatisfaction with bowel habits, and life interference than IBS-D patients. Questionnaires overestimated the frequency of abnormal stool consistency and gastrointestinal symptoms compared with diaries.

CONCLUSIONS

Stool consistency varies greatly within individuals. However, stool patterns are stable within an individual from month to month. The paradoxical findings of greater symptom severity after individual loose/watery BMs vs. greater overall symptom severity in IBS-C implies different physiological mechanisms for symptoms in constipation compared with diarrhea. Daily symptom monitoring is more sensitive and reliable than a questionnaire.

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.

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.