Altered rectal perception in irritable bowel syndrome is associated with symptom severity

Irritable bowel syndrome: When food is a pain in the gut

Irritable bowel syndrome (IBS) is a chronic gastrointestinal condition associated with altered bowel habits and recurrent abdominal pain, often triggered by food intake. Current treatments focus on improving stool pattern, but effective treatments for pain in IBS are still lacking due to our limited understanding of pathophysiological mechanisms. Visceral hypersensitivity (VHS), or abnormal visceral pain perception, underlies abdominal pain development in IBS, and mast cell activation has been shown to play an important role in the development of VHS. Our work recently revealed that abdominal pain in response to food intake is induced by the sensitization of colonic pain-sensing neurons by histamine produced by activated mast cells following a local IgE response to food. In this review, we summarize the current knowledge on abdominal pain and VHS pathophysiology in IBS, we outline the work leading to the discovery of the role of histamine in abdominal pain, and we introduce antihistamines as a novel treatment option to manage chronic abdominal pain in patients with IBS.

The impact of transcutaneous electrical acustimulation (TEA) on rectal distension-induced pain in patients with irritable bowel syndrome (IBS)-A study to determine the optimal TEA delivery modalities and effects on rectal sensation and autonomic function

BACKGROUND

Treatment options for abdominal pain in IBS are inadequate. TEA was reported effective treatment of disorders of gut-brain interaction but its mechanism of action and optimal delivery method for treating pain in IBS are unknown. This study aims to determine the most effective TEA parameter and location to treat abdominal pain in patients with IBS-Constipation and delineate the effect of TEA on rectal sensation and autonomic function.

METHODS

Nineteen IBS-C patients underwent TEA at acupoints ST36 (leg), PC6 (wrist), or sham-acupoint. Each patient was studied in five randomized sessions on separate days: (1) TEA/ST36-100 Hz; (2) TEA/ST36-25 Hz; (3) TEA/PC6-100 Hz; (4) TEA/PC6-25 Hz; (5) TEA/Sham-25 Hz. In each session, barostat-guided rectal distention (RD) was performed before and after TEA. Patients graded the RD-induced pain and recorded three rectal sensation thresholds. A heart rate variability (HRV) signal was derived from the electrocardiogram for autonomic function assessment.

KEY RESULTS

Studied patients were predominantly female, young, and Caucasian. Compared with baseline, patients treated with TEA/ST36-100 Hz had significantly decreased pain scores at RD pressure-points 20-50 mmHg (p < 0.04). The average pain reduction was 40%. Post-treatment scores did not change significantly with other TEA modalities except with sham-TEA (lesser degree compared to ST36-100 Hz, p = 0.04). TEA/ST36-100, but not other modalities, increased the rectal sensation threshold (first sensation: p = 0.007; urge to defecate: p < 0.026). TEA/ST36-100 Hz was the only treatment that significantly decreased sympathetic activity and increased parasympathetic activity with and without RD (p < 0.04).

CONCLUSIONS & INFERENCES

TEA at ST36-100 Hz is superior stimulation point/parameter, compared to TEA at PC-6/sham-TEA, to reduce rectal distension-induced pain in IBS-C patients. This therapeutic effect appears to be mediated through rectal hypersensitivity reduction and autonomic function modulation.

Sex Differences in Visceral Pain and Comorbidities: Clinical Outcomes, Preclinical Models, and Cellular and Molecular Mechanisms

Sexual dimorphism of visceral pain has been documented in clinics and experimental animal models. Aside from hormones, emerging evidence suggests the sex-differential intrinsic neural regulation of pain generation and maintenance. According to the International Association for the Study of Pain (IASP) and the American College of Gastroenterology (ACG), up to 25% of the population have visceral pain at any one time, and in the United States 10-15 percent of adults suffer from irritable bowel syndrome (IBS). Here we examine the preclinical and clinical evidence of sex differences in visceral pain focusing on IBS, other forms of bowel dysfunction and IBS-associated comorbidities. We summarize preclinical animal models that provide a means to investigate the underlying molecular mechanisms in the sexual dimorphism of visceral pain. Neurons and nonneuronal cells (glia and immune cells) in the peripheral and central nervous systems, and the communication of gut microbiota and neural systems all contribute to sex-dependent nociception and nociplasticity in visceral painful signal processing. Emotion is another factor in pain perception and appears to have sexual dimorphism.

Irritable bowel syndrome (IBS): could we decide what is behind?

Functional visceral problems are frequently present nowadays in the medical practice probably due to the significant mental and emotional load on people. Although physicians and psychophysiologists are active on the field, still we are far from a complete knowledge, despite the fact that scientists like the Hungarian Professor György Ádám already had initiated a new approach called visceral psychophysiology already a long time ago. In this article, we commemorate Professor Ádám by analyzing one of the most frequent functional disorders, irritable bowel syndrome (IBS), calling psychophysiology for help. First, we try to give a definition, then show the general descriptions and characteristics of IBS. Factors like stress, gender, and gastrointestinal pain are followed by the potential role of the immune system and the neuronal factors as well as the supposed brain mechanisms. We hope that this overview of the IBS-history would show how significant scientists can be decisive in certain fields of the science and practice.

Vague sensations. About the background and consequences of discordance between actual and perceived physiological changes

Empirical evidence consistently shows that discordance, also called dissociation or discrepancy, between actual physiological (mainly visceral) events and their perceived counterparts is substantial. On the one hand, we typically do not perceive actual visceral events occurring in our bodies; on the other hand, sometimes we do perceive bodily changes that do not really take place. This narrative review presents the available empirical findings on the discordance, and summarizes possible explanations that approach the phenomenon from the viewpoint of evolution, cognitive development, and predictive processing. Also, the role of top-down factors, such as expectations and experiences is discussed. Finally, practically relevant consequences of the discordance are presented using the examples of mind-body practices, the placebo and nocebo phenomenon, and medically unexplained symptoms. It is concluded that the discordance between actual and perceived body changes can have a negative impact on health, mainly through issues with adherence and other behavioral factors. The existence of actual-perceived discordance should be taught and demonstrated in the elementary and high school, as well as in many areas of higher education.

The aging gut: Symptoms compatible with disorders of gut-brain interaction (DGBI) in older adults in the general population

BACKGROUND

Little is known about changes in gastrointestinal symptoms compatible with disorders of gut-brain interaction (DGBI) with increasing age at the population level. The objective of this study was to describe the patterns of DGBI in individuals 65 years of age and above and contrasting them with those of younger adults.

METHODS

A community sample of 6300 individuals ages 18 and older in the US, UK, and Canada completed an online survey. Quota-based sampling was used to ensure equal proportion of sex and age groups (40% aged 18-39, 40% aged 40-64, 20% aged 65+) across countries, and to control education distributions. The survey included the Rome IV Diagnostic Questionnaire for DGBI, demographic questions, questionnaires measuring overall somatic symptom severity and quality of life, and questions on healthcare utilization, medications, and surgical history.

RESULTS

We included 5926 individuals in our analyses; 4700 were 18-64 years of age and 1226 were ages 65+. Symptoms compatible with at least one DGBI were less prevalent in participants ages 65+ vs. ages 18-64 years (34.1% vs. 41.3%, p < 0.0001). For symptoms compatible with upper GI DGBI, lower prevalence for most disorders was noted in the 65+ group. For lower GI DGBI, a different pattern was seen. Prevalence was lower in ages 65+ for irritable bowel syndrome and anorectal pain, but no differences from younger participants for the disorders defined by abnormal bowel habits (constipation and/or diarrhea) were seen. Fecal incontinence was the only DGBI that was more common in ages 65+. Having a DGBI was associated with reduced quality of life, more severe non-GI somatic symptoms, and increased healthcare seeking, both in younger and older participants.

CONCLUSION

Symptoms compatible with DGBI are common, but most of these decrease in older adults at the population level, with the exception of fecal incontinence which increases. This pattern needs to be taken into account when planning GI health care for the growing population of older adults.

Not a general, symptom-unspecific, transdiagnostic marker for functional symptoms: sensorimotor processing of head control is intact in chronic pain

Introduction

Functional disorders are prevalent in all medical fields and pose a tremendous public health problem, with pain being one of the most common functional symptoms. Understanding the underlying, potentially unifying mechanism in functional (pain) disorders is instrumental in facilitating timely diagnosis, stigma reduction, and adequate treatment options. Neuroscientific models of perception suggest that functional symptoms arise due to dysregulated sensorimotor processing in the central nervous system, with brain-based predictions dominating the eventual percept. Experimental evidence for this transdiagnostic mechanism has been established in various functional symptoms. The goal of the current study was to investigate whether erroneous sensorimotor processing is an underlying transdiagnostic mechanism in chronic (functional) pain.

Method

A total of 13 patients with chronic (functional) pain [three patients with chronic (functional) pain disorder, F45.40, ICD-10; 10 patients with chronic pain disorder with somatic and psychological factors, F45.41, ICD-10]; and 15 healthy controls performed large combined eye-head gaze shifts toward visual targets, naturally and with increased head moment of inertia. We simultaneously measured participants' eye and head movements to assess head oscillations at the end of the gaze shift, which are an established indicator of (transdiagnostic) sensorimotor processing deficits of head control.

Results

Using a Bayesian analysis protocol, we found that patients with chronic (functional) pain and control participants stabilized their heads equally well (Bayes Factor 01 = 3.7, Bayes Factor exclusion = 5.23; corresponding to substantial evidence) during all sessions of the experiment.

Conclusion

Our results suggest that patients with chronic (functional) pain do not show measurable symptom-unspecific sensorimotor processing deficits. We discuss outcome parameter choice, organ system specificity, and selection of patient diagnoses as possible reasons for this result and recommend future avenues for research.

Prevalence and Associated Factors of Bloating: Results From the Rome Foundation Global Epidemiology Study

BACKGROUND & AIMS

Bloating is a common symptom in the general population and among disorders of gut-brain interaction, although its prevalence has not been well characterized. The aim of this study was to report the prevalence of bloating as a symptom in the worldwide population and to identify factors associated with this symptom in the general population.

METHODS

Rome Foundation Global Epidemiology Study internet survey data were analyzed. After excluding respondents with potential organic causes of bowel symptoms, the current analysis included 51,425 individuals in 26 countries. Data included diet, medical history, quality of life, and Rome IV diagnostic questions. Presence of bloating was defined as experiencing bloating at least once per week for the last 3 months. Descriptive statistics estimated prevalence by country, region, and disorder of gut-brain interaction diagnosis. Logistic regression evaluated predictors of bloating.

RESULTS

Nearly 18% of the global study population reported bloating (ranging from 11% in East Asia to 20% in Latin America). Prevalence decreased with age and women were approximately twice as likely as men to report bloating. More than one-half of respondents who reported weekly epigastric pain (71.39%), nausea (59.7%), or abdominal pain (61.69%) also reported bloating at least once per week. In logistic regression, the strongest associations were with abdominal pain (odds ratio, 2.90) and epigastric pain (odds ratio, 2.07).

CONCLUSIONS

Bloating is common throughout the world. Nearly 18% of the general population experience bloating at least once per week. Reported bloating prevalence is lower in older age groups, most common in women, and strongly associated with abdominal pain.

Associations between postprandial symptoms, hydrogen and methane production, and transit time in irritable bowel syndrome

BACKGROUND

Abnormal oroanal transit time (OATT) and visceral hypersensitivity are key pathophysiological factors in irritable bowel syndrome (IBS). The lactulose nutrient challenge test (LNCT) has been developed to assess the postprandial symptoms and gut microbial fermentation. We aimed to investigate associations between OATT, rectal sensitivity, and LNCT in IBS patients.

METHODS

We included 263 IBS patients from two study cohorts, where the link between pathophysiology and symptoms was investigated. During the LNCT, severity of postprandial symptoms was graded, and breath hydrogen/methane concentrations were measured after ingestion of a combined lactulose nutrient drink every 15 min for 4 h. The patients underwent rectal sensitivity (rectal barostat) and OATT (radiopaque markers) investigations. Comorbid conditions (functional dyspepsia, anxiety, depression, and somatization) were assessed with questionnaires.

KEY RESULTS

After controlling for comorbid conditions, rectal sensitivity was associated with abdominal pain (p < 0.05), and more rapid OATT was associated with higher severity of abdominal discomfort, rumbling, nausea, and urgency (p < 0.05 for all) both pre- and post-prandially. Postprandial nausea, urgency, and abdominal pain changed differently over time depending on OATT (p < 0.05 for all). OATT, but not rectal sensitivity, was associated with hydrogen and methane concentrations (p = 0.002 for both). Trajectories over time of postprandial symptoms and exhaled hydrogen/methane concentrations were correlated with different correlations depending on OATT.

CONCLUSION AND INFERENCES

This study highlights the importance of oroanal transit and hydrogen and methane production in the pathophysiology of IBS and increases our understanding of pathophysiological factors involved in postprandial symptom generation. Treatments targeting oroanal transit and hydrogen and methane production may improve specific postprandial symptoms.

Targeting the endocannabinoid system for the treatment of abdominal pain in irritable bowel syndrome

The management of visceral pain in patients with disorders of gut-brain interaction, notably irritable bowel syndrome, presents a considerable clinical challenge, with few available treatment options. Patients are increasingly using cannabis and cannabinoids to control abdominal pain. Cannabis acts on receptors of the endocannabinoid system, an endogenous system of lipid mediators that regulates gastrointestinal function and pain processing pathways in health and disease. The endocannabinoid system represents a logical molecular therapeutic target for the treatment of pain in irritable bowel syndrome. Here, we review the physiological and pathophysiological functions of the endocannabinoid system with a focus on the peripheral and central regulation of gastrointestinal function and visceral nociception. We address the use of cannabinoids in pain management, comparing them to other treatment modalities, including opioids and neuromodulators. Finally, we discuss emerging therapeutic candidates targeting the endocannabinoid system for the treatment of pain in irritable bowel syndrome.

Altered sensorimotor processing in irritable bowel syndrome: Evidence for a transdiagnostic pathomechanism in functional somatic disorders

OBJECTIVE

A recent hypothesis suggests that functional somatic symptoms are due to altered information processing in the brain, with rigid expectations biasing sensorimotor signal processing. First experimental results confirmed such altered processing within the affected symptom modality, e.g., deficient eye-head coordination in patients with functional dizziness. Studies in patients with functional somatic symptoms looking at general, trans-symptomatic processing deficits are sparse. Here, we investigate sensorimotor processing during eye-head gaze shifts in irritable bowel syndrome (IBS) to test whether processing deficits exist across symptom modalities.

METHODS

Study participants were seven patients suffering from IBS and seven age- and gender-matched healthy controls who performed large gaze shifts toward visual targets. Participants performed combined eye-head gaze shifts in the natural condition and with experimentally increased head moment of inertia. Head oscillations as a marker for sensorimotor processing deficits were assessed. Bayes statistics was used to assess evidence for the presence or absence of processing differences between IBS patients and healthy controls.

RESULTS

With the head moment of inertia increased, IBS patients displayed more pronounced head oscillations than healthy controls (Bayes Factor 10 = 56.4, corresponding to strong evidence).

CONCLUSION

Patients with IBS show sensorimotor processing deficits, reflected by increased head oscillations during large gaze shifts to visual targets. In particular, patients with IBS have difficulties to adapt to the context of altered head moment of inertia. Our results suggest general transdiagnostic processing deficits in functional somatic disorders.

Type of Rectal Barostat Protocol Affects Classification of Hypersensitivity and Prediction of Symptom Severity in Irritable Bowel Syndrome

Background/Aims

Visceral hypersensitivity is an important pathophysiologic mechanism in irritable bowel syndrome (IBS). We compared 2 barostat distension protocols and their ability to distinguish between IBS patients and healthy controls, identify subjects with rectal hypersensitivity, and their associations with gastrointestinal symptom severity.

Methods

We retrospectively reviewed all patients at our unit that had undergone barostat investigations 2002-2014. Protocol 1 (n = 369) used phasic isobaric distensions with stepwise increments in pressure and protocol 2 (n = 153) used pressure controlled ramp inflations. Both protocols terminated when subjects reported pain or maximum pressure was reached. Thresholds for first sensation, urgency, discomfort and pain were established. Age- and gender-matched controls were used for comparison. The gastrointestinal symptom rating scale-IBS, and the hospital anxiety and depression scale were used for symptom reports.

Results

A significantly higher proportion of patients was classified as having hypersensitivity in protocol 1 vs protocol 2 for all thresholds (P < 0.001). Patients with visceral hypersensitivity, defined based on rectal pain thresholds in protocol 1 had more severe gastrointestinal symptoms overall as well as anxiety, whereas these associations were weaker or in most cases absent when visceral hypersensitivity was defined based on rectal pain thresholds in protocol 2.

Conclusion

Our study indicates that a rectal barostat protocol using phasic isobaric distensions with stepwise pressure increments is more sensitive in IBS patients with respect to identifying subjects with rectal hypersensitivity and a link with IBS symptoms.

Immune-mediated food reactions in irritable bowel syndrome

Irritable bowel syndrome (IBS) is a chronic functional gastrointestinal disorder characterized by recurrent abdominal pain and an altered defecation pattern. Depending on the criteria used, it affects between 5 and 10% of the general population and has a serious impact on quality of life. Most patients with IBS show an induction or exacerbation of their symptoms, particularly abdominal pain, after eating certain foods. This raises the question of the role played by food in IBS pathophysiology. In this review, we describe the multiple risk factors of IBS, and we give an overview of the role of food as a trigger of IBS, distinguishing between immune and non-immune reactions to food. We finally highlight recent findings identifying an immune-mediated mechanism underlying food-induced abdominal pain in IBS.

Epigenetic modulation of visceral nociception

Epigenetics is a process that alters gene activity or phenotype without any changes in the underlying DNA sequence or genotype. These biological changes may have deleterious effects and can lead to various human diseases. Ongoing research is continuing to illuminate the role of epigenetics in a variety of pathophysiologic processes. Several categories of epigenetic mechanisms have been studied including chromatin remodeling, DNA methylation, histone modification, and non-coding RNA mechanisms. These epigenetic changes can have a long-term effect on gene expression without any underlying changes in the DNA sequences. The underlying pathophysiology of disorders of brain-gut interaction and stress-induced visceral pain are not fully understood and the role of epigenetic mechanisms in these disorders are starting to be better understood. Current work is underway to determine how epigenetics plays a role in the neurobiology of patients with chronic visceral pain and heightened visceral nociception. More recently, both animal models and human studies have shown how epigenetic regulation modulates stress-induced visceral pain. While much more work is needed to fully delineate the mechanistic role of epigenetics in the neurobiology of chronic visceral nociception, the current study by Louwies et al., in Neurogastroenterology and Motility provides additional evidence supporting the involvement of epigenetic alterations in the central nucleus of the amygdala in stress-induced visceral hypersensitivity in rodents.

Irritable bowel syndrome: Factors of importance for disease-specific quality of life

BACKGROUND

Irritable bowel syndrome patients report reduced disease-specific quality of life (IBSQOL). Factors of potential relevance for QOL include gastrointestinal (GI), psychological, and somatic symptoms, demographics, and GI motor and sensory abnormalities.

OBJECTIVE

The aim of our study was to evaluate the relative importance of these factors on the different IBSQOL dimensions.

METHODS

We included irritable bowel syndrome (IBS) patients who completed validated questionnaires to assess QOL, stool form and frequency, GI symptom severity, psychological distress, GI-specific anxiety, sense of coherence, and overall somatic symptom severity. Patients also underwent tests for oroanal transit time and rectal sensitivity. The nine dimensions of IBSQOL and their average (overall IBSQOL) were used as outcome variables, and factors associated with these were assessed using general linear models.

RESULTS

We included 314 IBS patients (74% female, mean age 36.3 ± 12.2 years). Higher stool frequency, GI and overall somatic symptom severity, psychological distress, and GI-specific anxiety were independently associated with reduced overall IBSQOL, with the model explaining 60% of the variance (p < 0.001). In models using each of the nine dimensions as outcomes, different association of demographic factors, GI symptoms, overall somatic symptom severity, psychological factors and sense of coherence were associated with reduced IBSQOL, explaining 20%-60% of the variance, with GI-specific anxiety being the factor that contributed most frequently. Rectal sensitivity or oroanal transit time were not independently associated with any of the dimensions.

CONCLUSION

Different combinations of demographic factors, GI and somatic symptoms, and psychological factors are of importance for the nine IBSQOL dimensions. Gastrointestinal-specific anxiety was the most important factor contributing to the majority of those dimensions in patients with IBS.

Abnormal Perception of Urge to Defecate: An Important Pathophysiological Mechanism in Women With Chronic Constipation

INTRODUCTION

Although the association of absent or attenuated "call to stool" with constipation is well-recognized, no studies have systematically evaluated the perception of urge to defecate in a well-defined cohort of patients with chronic constipation (CC).

METHODS

A prospective study of 43 healthy adult women and 140 consecutive adult women attending a tertiary center for investigation of CC. All participants completed a 5-day viscerosensory questionnaire, and all women with CC also underwent anorectal physiologic investigations. Normal urge perception and abnormal urge perception were defined using a Naive Bayes model trained in healthy women (95% having normal urge).

RESULTS

In total, 181 toilet visits in healthy women and 595 in women with CC were analyzed. Abnormal urge perception occurred in 70 (50.0%) women with CC. In this group, the urge to defecate was more often experienced as abdominal sensation (69.3% vs 41.4%; P < 0.0001), and the viscerosensory referral area was 81% larger (median pixels anterior: 1,849 vs 1,022; P < 0.0001) compared to women with CC and normal urge perception. Abnormal (vs normal) urge in women with CC was associated with more severe constipation (Cleveland Clinic constipation score: 19 vs 15 P < 0.0001), irritable bowel syndrome (45.7% vs 22.9% P < 0.0001), and a functional evacuation disorder on defecography (31.3% vs 14.3% P = 0.023). A distinct pattern of abnormal urge was found in women with CC and rectal hyposensitivity.

DISCUSSION

Abnormal urge perception was observed in 50% of women with CC and was frequently described as abdominal sensation, supporting the concept that sensory dysfunction makes an important contribution to the pathophysiology of constipation.

Intrathecally administered substance P activated the spinal defecation center and enhanced colorectal motility in anesthetized rats

Noxious stimuli on the colorectum cause colorectal contractions through activation of descending monoaminergic pathways projecting from the supraspinal defecation center to the spinal defecation center. Since it is known that substance P is involved in the response to peripheral noxious stimuli in the spinal cord, we investigated the effects of intrathecally administered substance P at L6-S1 levels on colorectal motility in rats that were anesthetized with α-chloralose and ketamine. Intrathecally administered substance P enhanced colorectal motility, even after transection of the thoracic spinal cord at the T4 level. Severing the pelvic nerves, but not the colonic nerves, abolished substance P enhanced colorectal motility. In the spinal cord at L6-S1 levels, expression of mRNA coding neurokinin (NK) 1-3 receptors was detected by RT-PCR. Immunohistological experiments revealed that preganglionic neurons of the pelvic nerves express NK1 receptors, whereas expression of NK2 receptors was not found. In addition, substance P-containing fibers densely innervated around the preganglionic neurons expressing NK1 receptors. An intrathecally administered NK1 receptor antagonist (spantide) attenuated capsaicin-induced colorectal contractions. These results suggest that the colokinetic action of substance P is mediated by the NK1 receptor in the spinal defecation center. Our findings indicate that substance P may function as a neurotransmitter in the spinal defecation center.NEW & NOTEWORTHY We found that intrathecally administered substance P enhanced colorectal motility in anesthetized rats. Neurokinin (NK) 1 receptors, but not NK2 receptors, were detected in preganglionic neurons of the pelvic nerves. Blockade of NK1 receptors in the spinal cord attenuated the enhanced colorectal motility in response to intracolonic noxious stimuli. The findings indicate that substance P may function as a neurotransmitter in the spinal reflex pathway controlling defecation.

Immune activation in irritable bowel syndrome: what is the evidence?

Irritable bowel syndrome (IBS) is a chronic functional gastrointestinal disorder that is characterized by abdominal pain and an altered defecation pattern. It affects between 5 and 20% of the general population and can seriously impact quality of life. The pathophysiology of IBS is rather complex and multifactorial including, for example, altered signalling by the gut-brain axis, dysbiosis, abnormal visceral pain signalling and intestinal immune activation. The latter has gained particular interest in recent years, with growing insight into the bidirectional communication between the nervous system and the immune system. In this Review, we detail the current evidence suggesting that immune activation contributes to the pathology seen in patients with IBS and discuss the potential mechanisms involved. Moreover, we describe how immune mediators, particularly those released by mast cells, can directly activate or sensitize pain-transmitting nerves, leading to increased pain signalling and abdominal pain. Finally, we discuss the potential of interventions targeting immune activation as a new therapeutic strategy for patients suffering from IBS.

Local immune response as novel disease mechanism underlying abdominal pain in patients with irritable bowel syndrome

OBJECTIVES

Irritable bowel syndrome (IBS) is the most frequently diagnosed functional gastrointestinal disorder, with a prevalence of up to 25% of the global population. IBS patients suffer from abnormal abdominal pain, or visceral hypersensitivity (VHS), associated with altered bowel habits in the absence of an organic detectable cause. The pathophysiology of the disease is incompletely understood, but the dysregulation of the brain-gut axis is well established in IBS.

METHODS

IBS onset is mainly triggered by infectious gastroenteritis, psychological factors, and dietary factors, but genetic predispositions and intestinal dysbiosis might also play a role. Additionally, immune activation, and particularly chronic mast cell activation, have been shown to underlie the development of abdominal pain in IBS.

RESULTS

By releasing increased levels of mediators, including histamine, mast cells sensitize enteric nociceptors and lead to VHS development. The mechanisms underlying aberrant mast cell activation in IBS are still under investigation, but we recently showed that a local break in oral tolerance to food antigens led to IgE-mediated mast cell activation and food-induced abdominal pain in preclinical models and in IBS patients.

CONCLUSION

The concept of food-mediated VHS highlights the potential of therapies targeting upstream mechanisms of mast cell sensitization to treat IBS.

Efficacy of Linaclotide in Reducing Abdominal Symptoms of Bloating, Discomfort, and Pain: A Phase 3B Trial Using a Novel Abdominal Scoring System

INTRODUCTION

Linaclotide improves abdominal pain and constipation in patients with constipation-predominant irritable bowel syndrome (IBS-C). Patients report additional bothersome abdominal symptoms of bloating and discomfort. The intention of this study was to evaluate linaclotide's efficacy in relieving IBS-C-related abdominal symptoms (bloating, discomfort, and pain) using a novel multi-item Abdominal Score (AS).

METHODS

Patients with IBS-C with abdominal pain ≥3 (0-10 scale) were randomized to linaclotide 290 μg or placebo daily for 12 weeks. The AS, derived from the Diary for IBS Symptoms-Constipation, is the average of abdominal bloating, discomfort, and pain at their worst (0 = none, 10 = worst possible). The primary end point was overall change from baseline (CFB) in AS. Secondary end points included CFB in 12-week AS evaluated using cumulative distribution function and 6-week/12-week AS responder (AS improvement ≥2 points for ≥6-week/12-week).

RESULTS

Overall, 614 patients (mean age 46.7 years; 81% female) were randomized. All prespecified end points showed significant benefit of linaclotide vs placebo. The mean overall CFB AS reduction for linaclotide was -1.9 vs -1.2 for placebo (P < 0.0001); the 6-week/12-week AS responder rate was 40.5% for linaclotide vs 23.4% for placebo (odds ratio = 2.2 [95% confidence interval, 1.55-3.12; P < 0.0001]). Diarrhea was the most common treatment-emergent adverse event (linaclotide = 4.6%, placebo = 1.6%).

DISCUSSION

Linaclotide significantly reduced multiple abdominal symptoms important to patients with IBS-C (bloating, discomfort, and pain) compared with placebo, as measured by a novel multi-item AS. The AS, derived from the Diary for IBS Symptoms-Constipation, should be considered for use in future IBS-C clinical studies to measure clinically meaningful improvements beyond traditional end points.

Sex- and Gender-Related Differences in Common Functional Gastroenterologic Disorders

Functional gastrointestinal (GI) disorders (FGIDs) result from central and peripheral mechanisms, cause chronic remitting-relapsing symptoms, and are associated with comorbid conditions and impaired quality of life. This article reviews sex- and gender-based differences in the prevalence, pathophysiologic factors, clinical characteristics, and management of functional dyspepsia (FD) and irritable bowel syndrome (IBS) that together affect approximately 1 in 4 people in the United States. These conditions are more common in women. Among patients with IBS, women are more likely to have severe symptoms and coexistent anxiety or depression; constipation or bloating and diarrhea are more common in women and men, respectively, perhaps partly because defecatory disorders, which cause constipation, are more common in women. Current concepts suggest that biological disturbances (eg, persistent mucosal inflammation after acute gastroenteritis) interact with other environmental factors (eg, abuse) and psychological stressors, which influence the brain and gut to alter GI tract motility or sensation, thereby causing symptoms. By comparison to a considerable understanding of sex-based differences in the pathogenesis of visceral hypersensitivity in animal models, we know less about the contribution of these differences to FGID in humans. Slow gastric emptying and colon transit are more common in healthy women than in men, but effects of gonadal hormones on colon transit are less important than in rodents. Although increased visceral sensation partly explains symptoms, the effects of sex on visceral sensation, colonic permeability, and the gut microbiome are less prominent in humans than rodents. Whether sex or gender affects response to medications or behavioral therapy in FD or IBS is unclear because most patients in these studies are women.

Central regulatory mechanisms of visceral sensation in response to colonic distension with special reference to brain orexin

Visceral hypersensitivity is a major pathophysiology in irritable bowel syndrome (IBS). Although brain-gut interaction is considered to be involved in the regulation of visceral sensation, little had been known how brain controls visceral sensation. To improve therapeutic strategy in IBS, we should develop a novel approach to control visceral hypersensitivity. Here, we summarized recent data on central control of visceral sensation by neuropeptides in rats. Orexin, ghrelin or oxytocin in the brain is capable of inducing visceral antinociception. Dopamine, cannabinoid, adenosine, serotonin or opioid in the central nervous system (CNS) plays a role in the visceral hyposensitivity. Central ghrelin, levodopa or morphine could induce visceral antinociception via the orexinergic signaling. Orexin induces visceral antinociception through dopamine, cannabinoid, adenosine or oxytocin. Orexin nerve fibers are identified widely throughout the CNS and orexins are implicated in a number of functions. With regard to gastrointestinal functions, in addition to its visceral antinociception, orexin acts centrally to stimulate gastrointestinal motility and improve intestinal barrier function. Brain orexin is also involved in regulation of sleep/awake cycle and anti-depressive action. From these evidence, we would like to make a hypothesis that decreased orexin signaling in the brain may play a role in the pathophysiology in a part of patients with IBS who are frequently accompanied with sleep disturbance, depressive state and disturbed gut functions such as gut motility disturbance, leaky gut and visceral hypersensitivity.

Visceral hypersensitivity is together with psychological distress and female gender associated with severity of IBS-like symptoms in quiescent ulcerative colitis

BACKGROUND

A subset of ulcerative colitis (UC) patients in remission demonstrate IBS-like symptoms. Visceral hypersensitivity is a key pathophysiological mechanism in IBS, but its relevance to IBS-like symptoms in inactive UC remains unclear.

METHODS

UC patients in remission (UCR) were screened for IBS-like symptoms. Rectal sensitivity was assessed with rectal balloon distensions, with determination of sensory thresholds and unpleasantness/pain intensity ratings. Patients completed questionnaires evaluating gastrointestinal (GI) and psychological symptoms. Age- and gender-matched IBS subjects and healthy controls (HC) also underwent a rectal sensitivity test.

KEY RESULTS

We included 36 UCR patients (18 with IBS-like symptoms (UCR + IBS) and 18 without (UCR - IBS)), 36 IBS subjects, and 14 HC. UCR and IBS patients were more sensitive to rectal balloon distensions than HC, but no differences between UCR and IBS patients were observed. UCR + IBS patients had lower sensory thresholds and higher unpleasantness ratings than UCR - IBS. In UCR patients, the overall GI symptom severity, pain, and bloating, but not diarrhea, constipation or satiety, were associated with rectal sensitivity. In multivariate analyses, rectal sensitivity, psychological distress, and female gender were identified as factors independently associated with GI symptom severity. 61% of UCR patients demonstrated rectal hypersensitivity, and these patients more commonly reported at least mild bloating and pain, and overall GI symptoms, compared to those with normal rectal sensitivity.

CONCLUSION & INFERENCES

Visceral hypersensitivity was associated with IBS-like symptoms, in particular pain and bloating, in inactive UC. Together with psychological factors and female gender, visceral hypersensitivity seems to be involved in GI symptom generation in quiescent UC.

Solitary rectal ulcer syndrome in 102 patients: Do different phenotypes make sense?

BACKGROUND

Little is known about the pathophysiological mechanisms of solitary rectal ulcer syndrome (SRUS).

AIMS

We aim to identify the different phenotypes, taking into account complaints, anatomy and anorectal physiology.

METHODS

Complaints, endoscopy results, and physiology data of patients with histologically proven SRUS were collected and analysed. The associated anorectal diseases were faecal incontinence and obstructed defecation. The clinical aspects of SRUS were compared, and factors associated with anorectal diseases were identified.

RESULTS

Overall, 102 consecutive patients were included. The predominant lesion was a rectal ulcer (66%), and inflammation of the rectal wall was present in 42% of patients. Abnormal rectal capacities and/or rectal perception was observed in more than half. Nearly half (52%) of the patients met the criteria for obstructed defecation and they tended to more frequently have psychiatric disease (66.7% vs 33.3%; p=0.07). Patients with faecal incontinence (17%) reported more self-perception of anal procidentia (p=0.01) and were more likely to have inflammation of the rectal wall (p=0.02), high-grade internal rectal procidentia (p=0.06) and anal hypotonia (p=0.004); their maximum tolerable volume was lower (p=0.004).

CONCLUSION

The characteristics of patients with SRUS suggest different phenotypes. This may be a way to develop a comprehensive treatment strategy.

Sexually dimorphic response of colorectal motility to noxious stimuli in the colorectum in rats

KEY POINTS

This study showed a remarkable sex difference in responses of colorectal motility to noxious stimuli in the colorectum in rats: colorectal motility was enhanced in response to intracolonic administration of a noxious stimulant, capsaicin, in male rats but not in female rats. The difference in descending neurons from the brain to spinal cord operating after noxious stimulation could be responsible for the sex difference. In male rats, serotoninergic and dopaminergic neurons are dominantly activated, both of which activate the spinal defaecation centre. In female rats, GABAergic neurons in addition to serotoninergic neurons are activated. GABA may compete for facilitative action of 5-HT in the spinal defaecation centre, and thereby colorectal motility is not enhanced in response to intracolonic administration of capsaicin. The findings provide a novel insight into pathophysiological mechanisms of sex differences in functional defaecation disorders such as irritable bowel syndrome.

ABSTRACT

We previously demonstrated that noxious stimuli in the colorectum enhance colorectal motility through activation of descending pain inhibitory pathways in male rats. It can be expected that the regulatory mechanisms of colorectal motility differ in males and females owing to remarkable sex differences in descending pain inhibitory pathways. Thus, we aimed to clarify sex differences in responses of colorectal motility to noxious stimuli in rats. Colorectal motility was measured in vivo in anaesthetized rats. Administration of a noxious stimulant, capsaicin, into the colorectal lumen enhanced colorectal motility in male rats but not in female rats. Quantitative PCR and immunohistochemistry showed that TRPV1 expression levels in the dorsal root ganglia and in the colorectal mucosa were comparable in male and female rats. When a GABA_A receptor inhibitor was intrathecally administered to the L6-S1 level of the spinal cord, colorectal motility was facilitated in response to intracolonic capsaicin even in female rats. The capsaicin-induced response in the presence of the GABA blocker in female rats was inhibited by intrathecal administration of 5-HT2 and -3 receptor antagonists but not by a D2-like dopamine receptor antagonist. Our findings demonstrate that intracolonic noxious stimulation activates GABAergic and serotoninergic descending neurons in female rats, whereas serotoninergic and dopaminergic neurons are dominantly activated in male rats. Thus, the difference in the descending neurons operating after noxious stimulation would be responsible for the sexually dimorphic responses of colorectal motility. Our findings provide a novel insight into pathophysiological mechanisms of sex differences in functional defaecation disorders such as irritable bowel syndrome.

Irritable bowel syndrome

Irritable bowel syndrome is a functional gastrointestinal disorder with symptoms including abdominal pain associated with a change in stool form or frequency. The condition affects between 5% and 10% of otherwise healthy individuals at any one point in time and, in most people, runs a relapsing and remitting course. The best described risk factor is acute enteric infection, but irritable bowel syndrome is also more common in people with psychological comorbidity and in young adult women than in the rest of the general population. The pathophysiology of irritable bowel syndrome is incompletely understood, but it is well established that there is disordered communication between the gut and the brain, leading to motility disturbances, visceral hypersensitivity, and altered CNS processing. Other less reproducible mechanisms might include genetic associations, alterations in gastrointestinal microbiota, and disturbances in mucosal and immune function. In most people, diagnosis can be made on the basis of clinical history with limited and judicious use of investigations, unless alarm symptoms such as weight loss or rectal bleeding are present, or there is a family history of inflammatory bowel disease or coeliac disease. Once the diagnosis is made, an empathetic approach is key and can improve quality of life and symptoms, and reduce health-care expenditure. The mainstays of treatment include patient education about the condition, dietary changes, soluble fibre, and antispasmodic drugs. Other treatments tend to be reserved for people with severe symptoms and include central neuromodulators, intestinal secretagogues, drugs acting on opioid or 5-HT receptors, or minimally absorbed antibiotics (all of which are selected according to predominant bowel habit), as well as psychological therapies. Increased understanding of the pathophysiology of irritable bowel syndrome in the past 10 years has led to a healthy pipeline of novel drugs in development.

Mapping and Modeling of Discussions Related to Gastrointestinal Discomfort in French-Speaking Online Forums: Results of a 15-Year Retrospective Infodemiology Study

BACKGROUND

Gastrointestinal (GI) discomfort is prevalent and known to be associated with impaired quality of life. Real-world information on factors of GI discomfort and solutions used by people is, however, limited. Social media, including online forums, have been considered a new source of information to examine the health of populations in real-life settings.

OBJECTIVE

The aims of this retrospective infodemiology study are to identify discussion topics, characterize users, and identify perceived determinants of GI discomfort in web-based messages posted by users of French social media.

METHODS

Messages related to GI discomfort posted between January 2003 and August 2018 were extracted from 14 French-speaking general and specialized publicly available online forums. Extracted messages were cleaned and deidentified. Relevant medical concepts were determined on the basis of the Medical Dictionary for Regulatory Activities and vernacular terms. The identification of discussion topics was carried out by using a correlated topic model on the basis of the latent Dirichlet allocation. A nonsupervised clustering algorithm was applied to cluster forum users according to the reported symptoms of GI discomfort, discussion topics, and activity on online forums. Users' age and gender were determined by linear regression and application of a support vector machine, respectively, to characterize the identified clusters according to demographic parameters. Perceived factors of GI discomfort were classified by a combined method on the basis of syntactic analysis to identify messages with causality terms and a second topic modeling in a relevant segment of phrases.

RESULTS

A total of 198,866 messages associated with GI discomfort were included in the analysis corpus after extraction and cleaning. These messages were posted by 36,989 separate web users, most of them being women younger than 40 years. Everyday life, diet, digestion, abdominal pain, impact on the quality of life, and tips to manage stress were among the most discussed topics. Segmentation of users identified 5 clusters corresponding to chronic and acute GI concerns. Diet topic was associated with each cluster, and stress was strongly associated with abdominal pain. Psychological factors, food, and allergens were perceived as the main causes of GI discomfort by web users.

CONCLUSIONS

GI discomfort is actively discussed by web users. This study reveals a complex relationship between food, stress, and GI discomfort. Our approach has shown that identifying web-based discussion topics associated with GI discomfort and its perceived factors is feasible and can serve as a complementary source of real-world evidence for caregivers.

Constipation and Fecal Incontinence in the Elderly

PURPOSE OF REVIEW

To review the epidemiology, pathogenesis, clinical features, and management of primary constipation and fecal incontinence in the elderly.

RECENT FINDINGS

Among elderly people, 6.5%, 1.7%, and 1.1% have functional constipation, constipation-predominant IBS, and opioid-induced constipation. In elderly people, the number of colonic enteric neurons and smooth muscle functions is preserved; decreased cholinergic function with unopposed nitrergic relaxation may explain colonic motor dysfunction. Less physical activity or dietary fiber intake and postmenopausal hormonal therapy are risk factors for fecal incontinence in elderly people. Two thirds of patients with fecal incontinence respond to biofeedback therapy. Used in combination, loperamide and biofeedback therapy are more effective than placebo, education, and biofeedback therapy. Vaginal or anal insert devices are another option. In the elderly, constipation and fecal incontinence are common and often distressing symptoms that can often be managed by addressing bowel disturbances. Selected diagnostic tests, prescription medications, and, infrequently, surgical options should be considered when necessary.

Associations among neurophysiology measures in irritable bowel syndrome (IBS) and their relevance for IBS symptoms

Abnormal gut-brain interactions are common in irritable bowel syndrome (IBS), but the associations between neurophysiological measures and their relation to gastrointestinal (GI) symptoms are poorly understood. Our aim was to explore these relationships and define the most relevant neurophysiology measures for GI symptom severity in IBS. IBS patients underwent small intestinal motility (manometry; fasted and fed contraction frequency, phase III time) and secretion (transmural potential difference), rectal sensorimotor (barostat; sensory thresholds, tone response, compliance), autonomic nervous system (baroreceptor sensitivity and effectiveness), and colonic motor function (transit time) examinations. GI symptom severity (GSRS-IBS), and anxiety and depression (HAD) as a proxy measure of central nervous system (CNS) dysfunction, were assessed. In total 281 IBS patients (Rome II criteria) were included (74% females, median age 36 [interquartile range 28-50] years). Significant correlations between neurophysiology measures were stronger within, rather than between, different neurophysiological examinations. The strongest neurophysiology-symptom correlations occurred between a combination of CNS and visceral sensitivity parameters, and GSRS-IBS total score and pain domain (ρ = 0.40, p < 0.001, and ρ = 0.38, p < 0.001). Associations between GI symptoms in IBS and individual and combinations of neurophysiological factors occurred, primarily in CNS and visceral sensitivity measures, providing new insights into the clinical presentation of IBS.

Diagnostic value of the balloon expulsion test compared with anorectal manometry in Indian patients with dyssynergic defecation

INTRODUCTION

Digital rectal examination (DRE) and balloon expulsion test (BET) are simple tests to diagnose dyssynergic defecation (DD).

AIM

To determine differences in symptoms and manometry findings in patients with abnormal BET and normal BET. The secondary objective was to ascertain the sensitivity and specificity of BET and DRE + BET for the diagnosis of DD in an Indian setting using ARM findings as the gold standard.

MATERIAL AND METHODS

Retrospective analysis of patients with chronic constipation referred for anorectal manometry (ARM) between December 2012 and March 2019. DD was diagnosed using ARM. Findings on BET and, in a subset of cases, on DRE + BET were compared with ARM findings. The data were analyzed for sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). Agreement of BET and DRE + BET with ARM was calculated using Cohen's κ coefficient. A p-value of < 0.05 was considered significant.

RESULTS

A total of 1006 cases (734 males, 73%) formed the study cohort. Patients with abnormal BET more frequently reported digitation, bleeding per rectum, and straining (p < 0.00001). Moreover, they had a significantly higher median basal pressure compared to those with normal BET (80 vs. 67, p = 0.03). DD was significantly more common in those with abnormal BET. The sensitivity, specificity, PPV, and NPV of BET in detecting DD were 28.29%, 97.15%, 81.13%, and 75.78%, respectively. The percentage of agreement was 76.34%, and there was fair degree of correlation between the two tests. In a smaller subset of cases (166), DRE and BET findings were both available for analysis. We noted that the sensitivity, specificity, PPV, and NPV of combined DRE + BET were 57.63%, 88.79%, 73.91%, and 79.17%, respectively. The Cohen's κ correlation coefficient was 0.49, suggesting moderate agreement.

CONCLUSIONS

Patients with abnormal BET more frequently report digitation, straining, and bleeding per rectum, and have higher resting anal pressure. BET is a good screening test for DD in an Indian setting.

Serotonin transporter and cholecystokinin in diarrhea-predominant irritable bowel syndrome: Associations with abdominal pain, visceral hypersensitivity and psychological performance

BACKGROUND

Visceral hypersensitivity and psychological performance are the main pathophysiological mechanisms of irritable bowel syndrome (IBS). Previous studies have found that cholecystokinin (CCK) can enhance colon movement and that serotonin transporter (SERT) is a transmembrane transport protein with high affinity for 5-hydroxytryptamine, which can rapidly reuptake 5-hydroxytryptamine and then regulate its action time and intensity. We speculate that SERT and CCK might play a role in the pathogenesis of diarrhea-predominant IBS (IBS-D) by affecting visceral sensitivity and the brain-gut axis.

AIM

To determine SERT and CCK levels in IBS-D patients diagnosed using Rome IV criteria and to analyze their associations with abdominal pain, visceral hypersensitivity and psychological performance.

METHODS

This study collected data from 40 patients with IBS-D at the China-Japan Friendship Hospital from September 2017 to April 2018 and 18 healthy controls. The severity of abdominal pain, visceral sensitivity and psychological performance were evaluated in IBS-D patients and healthy controls, the levels of SERT and CCK in plasma and colonic mucosa were evaluated, and the correlations between them were analyzed.

RESULTS

There were significant differences in the initial sensation threshold (31.00 ± 8.41 mL vs 52.22 ± 8.09 mL, P < 0.001), defecating sensation threshold (51.75 ± 13.57 mL vs 89.44 ± 8.73 mL, P < 0.001) and maximum tolerable threshold (97.25 ± 23.64 mL vs 171.11 ± 20.83 mL, P < 0.001) between the two groups. IBS-D patients had more severe anxiety (7.78 ± 2.62 vs 2.89 ± 1.02, P < 0.001) and depressive (6.38 ± 2.43 vs 2.06 ± 0.73, P < 0.001) symptoms than healthy controls. Significant differences were also found in mucosal CCK (2.29 ± 0.30 vs 1.66 ± 0.17, P < 0.001) and SERT (1.90 ± 0.51 vs 3.03 ± 0.23, P < 0.001) between the two groups. There was a significant positive correlation between pain scores and mucosal CCK (r = 0.96, 0.93, 0.94, P < 0.001). Significant negative correlations between anxiety (r = -0.98; P < 0.001), depression (r = -0.99; P < 0.001), pain evaluation (r = -0.96, -0.93, -0.95, P < 0.001) and mucosal SERT were observed.

CONCLUSION

IBS-D patients had psychosomatic disorders and visceral hypersensitivity. SERT and CCK might be involved in the pathogenesis of IBS-D by regulating the brain-gut axis and affecting visceral sensitivity. This provides a new potential method for identifying a more specific and effective therapeutic target.

Discriminant and convergent validity of the GSRS-IBS symptom severity measure for irritable bowel syndrome: A population study

BACKGROUND

The Gastrointestinal Symptom Rating Scale-Irritable Bowel Syndrome (GSRS-IBS) is a 13-item measure of IBS symptom severity. The scale has been used in several studies, but its psychometric properties have been insufficiently investigated and population-based data are not available.

OBJECTIVE

The objective of this article is to establish the factor structure and discriminant and convergent validity of the GSRS-IBS.

METHODS

The study was based on a Swedish population sample (the Popcol study), of which 1158 randomly selected participants provided data on the GSRS-IBS. We used confirmatory factor analysis (CFA) and compared total and subscales scores in different groups, including IBS diagnostic status, treatment-seeking behavior, and predominant bowel habits. The GSRS-IBS scores were also correlated with quality of life indexes.

RESULTS

The sample included 164 participants with a confirmed Rome III IBS diagnosis and 994 participants without the disease. The CFA confirmed the subscales with one exception, in which the incomplete bowel-emptying item belonged to the constipation subscale rather than the diarrhea subscale. The GSRS-IBS total score and subscales were associated with diagnostic status, treatment-seeking behavior, and quality of life dimensions. The relevant subscales scores also differed between the diarrhea- and constipation-predominant subtypes of IBS.

CONCLUSION

The GSRS-IBS total score and subscales have high discriminant and convergent validity. The CFA confirmed the overall validity of the subscales but suggest that a sense of incomplete emptying belongs to the constipation rather than the diarrhea symptom cluster. We conclude that the GSRS-IBS is an excellent measure of IBS symptom severity in the general population.

Mechanisms, Evaluation, and Management of Chronic Constipation

With a worldwide prevalence of 15%, chronic constipation is one of the most frequent gastrointestinal diagnoses made in ambulatory medicine clinics, and is a common source cause for referrals to gastroenterologists and colorectal surgeons in the United States. Symptoms vary among patients; straining, incomplete evacuation, and a sense of anorectal blockage are just as important as decreased stool frequency. Chronic constipation is either a primary disorder (such as normal transit, slow transit, or defecatory disorders) or a secondary one (due to medications or, in rare cases, anatomic alterations). Colonic sensorimotor disturbances and pelvic floor dysfunction (such as defecatory disorders) are the most widely recognized pathogenic mechanisms. Guided by efficacy and cost, management of constipation should begin with dietary fiber supplementation and stimulant and/or osmotic laxatives, as appropriate, followed, if necessary, by intestinal secretagogues and/or prokinetic agents. Peripherally acting μ-opiate antagonists are another option for opioid-induced constipation. Anorectal tests to evaluate for defecatory disorders should be performed in patients who do not respond to over-the-counter agents. Colonic transit, followed if necessary with assessment of colonic motility with manometry and/or a barostat, can identify colonic dysmotility. Defecatory disorders often respond to biofeedback therapy. For specific patients, slow-transit constipation may necessitate a colectomy. No studies have compared inexpensive laxatives with newer drugs with different mechanisms. We review the mechanisms, evaluation, and management of chronic constipation. We discuss the importance of meticulous analyses of patient history and physical examination, advantages and disadvantages of diagnostic testing, guidance for individualized treatment, and management of medically refractory patients.

Relationship of Cannabis Use Disorder and Irritable Bowel Syndrome (IBS): An Analysis of 6.8 Million Hospitalizations in the United States

Background: Irritable bowel syndrome (IBS) is a chronic multifactorial gastrointestinal condition that substantially affects the quality of life. Research have suggested an increasing trend in cannabis use to alleviate IBS-related psychiatric symptoms. Objectives: We aim to investigate the association of psychiatric comorbidities and cannabis use disorders (CUD) in hospitalized IBS patients. Methods: We analyzed 31,272 IBS hospitalizations in patients (aged 15-54 years) from the Nationwide Inpatient Sample (NIS). We utilized logistic regression to evaluate the adjusted odds ratio (aOR) of CUD and psychiatric comorbidities. Results: Anxiety (26.3%) and depressive (24.8%) disorders were prevalent and increased the odds for IBS-hospitalization by 2.5 and 1.8 times respectively. Tobacco use disorder was most prevalent (24.5%) followed by CUD (3.7%). After controlling for demographics, psychiatric and medical comorbidities, and other substance use disorders, CUD had higher odds for IBS hospitalizations (aOR 1.407, 95% CI 1.32-1.50). IBS hospitalizations with CUD increased by 32.8% from 2010 to 2014. CUD patients were younger (15-24 years, aOR 5.4, 95% CI 4.27-6.77), males (aOR 1.8, 95% CI 1.59-2.09) and African Americans (aOR 2.8, 95% CI 1.45-2.23) and from low-income families (aOR 1.9, 95% CI 1.58-2.39). Conclusions: We found that patients with CUD have 40.7% higher odds for IBS-hospitalizations with a rising trend of CUD and related psychiatric comorbidities which may further worsen IBS and health quality of life. With limited evidence of efficacy and safety of cannabis in IBS, larger, randomized controlled studies are required to examine its therapeutic efficacy.

Chronic Constipation

Constipation is a common symptom that may be primary (idiopathic or functional) or associated with a number of disorders or medications. Although most constipation is self-managed by patients, 22% seek health care, mostly to primary care physicians (>50%) and gastroenterologists (14%), resulting in large expenditures for diagnostic testing and treatments. There is strong evidence that stimulant and osmotic laxatives, intestinal secretagogues, and peripherally restricted μ-opiate antagonists are effective and safe; the lattermost drugs are a major advance for managing opioid-induced constipation. Constipation that is refractory to available laxatives should be evaluated for defecatory disorders and slow-transit constipation using studies of anorectal function and colonic transit. Defecatory disorders are often responsive to biofeedback therapies, whereas slow-transit constipation may require surgical intervention in selected patients. Both efficacy and cost should guide the choice of treatment for functional constipation and opiate-induced constipation. Currently, no studies have compared inexpensive laxatives with newer drugs that work by other mechanisms.

EphrinB2/ephB2-mediated myenteric synaptic plasticity: mechanisms underlying the persistent muscle hypercontractility and pain in postinfectious IBS

Patients with irritable bowel syndrome (IBS) show pain hypersensitivity and smooth muscle hypercontractility in response to colorectal distension (CRD). Synaptic plasticity, a key process of memory formation, in the enteric nervous system may be a novel explanation. This study aimed to explore the regulatory role of ephrinB2/ephB2 in enteric synaptic plasticity and colonic hyperreactive motility in IBS. Postinfectious (PI)-IBS was induced by Trichinella spiralis infection in rats. Isometric contractions of colonic circular muscle strips, particularly neural-mediated contractions, were recorded ex vivo. Meanwhile, ephrinB2/ephB2-mediated enteric structural and functional synaptic plasticity were assessed in the colonic muscularis, indicating that ephrinB2 and ephB2 were located on enteric nerves and up-regulated in the colonic muscularis of PI-IBS rats. Colonic hypersensitivity to CRD and neural-mediated colonic hypercontractility were present in PI-IBS rats, which were correlated with increased levels of cellular homologous fos protein (c-fos) and activity-regulated cystoskeleton-associated protein (arc), the synaptic plasticity-related immediate early genes, and were ameliorated by ephB2Fc (an ephB2 receptor blocker) or MK801 (an NMDA receptor inhibitor) exposure. EphrinB2/ephB2 facilitated synaptic sprouting and NMDA receptor-mediated synaptic potentiation in the colonic muscularis of PI-IBS rats and in the longitudinal muscle-myenteric plexus cultures, involving the Erk-MAPK and PI3K-protein kinase B pathways. In conclusion, ephrinB2/ephB2 promoted the synaptic sprouting and potentiation of myenteric nerves involved in persistent muscle hypercontractility and pain in PI-IBS. Hence, ephrinB2/ephB2 may be an emerging target for the treatment of IBS.-Zhang, L., Wang, R., Bai, T., Xiang, X., Qian, W., Song, J., Hou, X. EphrinB2/ephB2-mediated myenteric synaptic plasticity: mechanisms underlying the persistent muscle hypercontractility and pain in postinfectious IBS.

From Anticipation to the Experience of Pain: The Importance of Visceral Versus Somatic Pain Modality in Neural and Behavioral Responses to Pain-Predictive Cues

OBJECTIVE

The aim of this study was to compare behavioral and neural anticipatory responses to cues predicting either somatic or visceral pain in an associative learning paradigm.

METHODS

Healthy women (N = 22) underwent functional magnetic resonance imaging. During an acquisition phase, two different visual cues repeatedly signalled either experimental visceral or somatic pain. In a subsequent extinction phase, identical cues were presented without pain. Before and after each phase, cue valence and contingency awareness were assessed on visual analog scales.

RESULTS

Visceral compared to somatic pain-predictive cues were rated as more unpleasant after acquisition (visceral, 32.18 ± 13.03 mm; somatic, -18.36 ± 10.36 mm; p = .021) with similarly accurate cue-pain contingencies. After extinction, cue valence returned to baseline for both modalities (visceral, 1.55 ± 9.81 mm; somatic, -18.45 ± 7.12; p = .41). During acquisition, analyses of cue-induced neural responses revealed joint neural activation engaging areas associated with attention processing and cognitive control. Enhanced deactivation of posterior insula to visceral cues was observed, which correlated with enhanced responses within the salience network (anterior cingulate cortex, anterior insula) during visceral compared to somatic pain stimulation. During extinction, both pain modalities induced anticipatory neural activation in the extinction and salience network (all pFWE values < .05).

CONCLUSIONS

Conditioned emotional responses to pain-predictive cues are modality specific and enhanced for the visceral modality, suggesting that pain anticipation is shaped by the salience of painful stimuli. Common but also modality-specific neural mechanisms are involved during cue-pain learning, whereas extinction of cued responses seems unaffected by modality. Future research should examine potential implications for the pathophysiology of chronic pain conditions, especially chronic visceral pain.

Anxiety and depression in irritable bowel syndrome: Exploring the interaction with other symptoms and pathophysiology using multivariate analyses

BACKGROUND

Anxiety or depression, in other words, psychological distress, are common comorbidities in patients with irritable bowel syndrome (IBS), but their interaction with pathophysiological factors and other symptoms are unclear.

METHODS

Patients with IBS (Rome III criteria), thoroughly characterized regarding pathophysiology (colonic transit time, visceral sensitivity, and autonomic nervous system [ANS] function), symptom profile (IBS severity, somatic symptoms, gastrointestinal [GI]-specific anxiety and fatigue), and quality of life, were explored for differences regarding pathophysiology and symptoms between patients with and without reported psychological distress in univariate and multivariate analyses (Principal Component Analysis [PCA] with Hotelling's T² and Orthogonal Partial Least Squares-Discriminant Analysis [OPLS-DA]).

KEY RESULTS

When using Hospital Anxiety and Depression Scale score ≥8 as cut-off score, including both borderline and clinically significant cases, 345 (44.9%) out of 769 IBS patients reported anxiety, and 198 (25.7%) depression. In univariate analyses, patients reporting psychological distress demonstrated more severe GI and non-GI symptoms, fatigue, GI-specific anxiety and lower quality of life, and differences for some pathophysiological measures. IBS patients with and without reported psychological distress showed significant differences between the multivariate means in symptom reporting (PCA; both P < 0.001), and in pathophysiological measures in patients with and without anxiety (P = 0.018). Visceral hypersensitivity, altered ANS function, more severe GI-specific anxiety, fatigue, and higher somatic non-GI symptoms were the factors that most strongly separated patients with and without psychological distress (OPLS-DA).

CONCLUSIONS AND INFERENCES

Reported anxiety and depression are common in IBS patients, and our study demonstrates that they are interwoven in the complex pathophysiological and clinical picture of IBS.

Cumulative Effects of Psychologic Distress, Visceral Hypersensitivity, and Abnormal Transit on Patient-reported Outcomes in Irritable Bowel Syndrome

BACKGROUND & AIMS

Little is known about the link between pathophysiologic factors and symptoms of irritable bowel syndrome (IBS), or whether these factors have cumulative effects on patient-reported outcomes (PROs). We investigated whether pathophysiologic alterations associated with IBS have cumulative or independent effects on PROs.

METHODS

We performed a retrospective analysis of data from 3 cohorts of patients with IBS (n = 407; 74% female; mean age, 36 ± 12 years), based on Rome II or Rome III criteria, seen at a specialized unit for functional gastrointestinal disorders in Sweden from 2002 through 2014. All patients underwent assessments of colonic transit time (radiopaque markers); compliance, allodynia, and hyperalgesia (rectal barostat); anxiety and depression (Hospital Anxiety and Depression scale), as pathophysiologic factors. Dysfunction was defined by available normal values. PROs included IBS symptom severity, somatic symptom severity, and disease-specific quality of life.

RESULTS

Allodynia was observed in 36% of patients, hyperalgesia in 22%, accelerated colonic transit in 18%, delayed transit in 7%, anxiety in 52%, and depression in 24%: each of these factors was associated with severity of at least 1 symptom of IBS. Rectal compliance was not associated with more severe symptoms of IBS. At least 3 pathophysiologic factors were present in 20% of patients, 2 in 30%, 1 in 31%, and none in 18%. With increasing number of pathophysiologic abnormalities, there was a gradual increase in IBS symptom severity (P < .0001) and somatic symptom severity (P < .0001), and a gradual reduction in quality of life (P < .0001).

CONCLUSION

Visceral hypersensitivity, including allodynia and hyperalgesia, abnormal colonic transit, and psychologic factors are all associated with IBS symptoms. These factors have a cumulative effect on gastrointestinal and nongastrointestinal symptoms, as well as on quality of life, in patients with IBS and are therefore relevant treatment targets.

Visceral sensitivity remains stable over time in patients with irritable bowel syndrome, but with individual fluctuations

BACKGROUND

Visceral hypersensitivity in irritable bowel syndrome (IBS), measured with rectal balloon distensions, using a barostat, has been suggested to be a phenomenon that is reduced due to habituation at repeated investigations. We investigated the stability of rectal sensitivity in patients with IBS who had undergone a previous rectal barostat study and assessed variations in symptom pattern and severity in relation to rectal sensory function.

METHOD

Irritable bowel syndrome patients, who had previously been undergone a rectal barostat study, were included. All patients underwent a second study 8-12 years later. Symptoms were characterized by use of questionnaires.

KEY RESULTS

We included 26 subjects (17 females, median age at the index investigation 44.5 (21-61) years). Pressure and volume sensory thresholds were unchanged at the follow-up compared with the index investigation (P > 0.05 for all). At the index investigation, 8/26 patients had rectal hypersensitivity of which four were reclassified as normosensitive, and sixfrom normo- to hypersensitive, meaning that 10/26 patients were hypersensitive at the follow-up investigation. IBS-QOL had improved significantly in six of nine domains at follow-up (P < 0.05 for all). There were no differences in anxiety, depression, IBS symptom severity, or somatization (P > 0.05) at follow-up. None of these were associated with change in rectal sensitivity at follow-up.

CONCLUSIONS AND INFERENCES

Rectal hypersensitivity and IBS symptoms remained stable at the group level over 8-12 years in IBS patients, even though individual fluctuations were noted. Our findings contradict previous findings indicating that visceral hypersensitivity is an unstable trait.

Clinical and anorectal manometry profile of patients with functional constipation and constipation-predominant irritable bowel syndrome

BACKGROUND

Functional constipation (FC) and constipation-predominant irritable bowel syndrome (IBS-C) have significant healthcare impact. Clinical and investigative data of patients with these disorders in Indian population is scarce. We aimed to compare the clinical and anorectal manometric profile of patients with FC and IBS-C.

METHODS

Consecutive patients with chronic constipation undergoing anorectal manometry (ARM) and balloon expulsion test (BET) were enrolled. Thirty healthy volunteers served as controls (HC). Functional defecatory disorder (FDD) was diagnosed according to ROME IV criteria if both ARM and BET were abnormal.

RESULTS

Of the 231 patients enrolled (median age 47 years, 87.8% males), FC and IBS-C were diagnosed in 132 (57.1%) and 99 (42.9%) patients, respectively. Significant clinical differences between FC and IBS-C patients included older age, lower stool frequency/week, higher frequency of straining, and greater frequency  of incomplete evacuation (p < 0.001). ARM revealed abnormal defecatory pattern in 55.3% (n = 73) FC patients and 47.5% (n = 47) IBS-C patients. Of them, 54.7% (40/73) of FC patients had inadequate defecatory propulsion while 89.4% (42/47) of the IBS-C patients had dyssynergic defecation (p < 0.001). Abnormal BET was seen in 67.4% of FC patients and 43.4% of IBS-C patients. Thus, FDD was diagnosed in 55.3% and 46.5% of FC and IBS-C patients, respectively. Rectal hyposensitivity was present in 60.6% of FC patients compared with 2% of IBS-C patients (p < 0.001).

CONCLUSIONS

There were significant differences in clinical and manometric profile of FC and IBS-C patients. Compared with IBS-C patients, FC patients were older, had higher prevalence of FDD, less often had dyssynergic defecation, and had higher prevalence of rectal hyposensitivity.

The role of toll-like receptor 4 and mast cell in the ameliorating effect of electroacupuncture on visceral hypersensitivity in rats

BACKGROUND

Visceral hypersensitivity is one of the main pathogenesis of irritable bowel syndrome (IBS) and mast cell activation is closely related to visceral hypersensitivity. As a critical molecule of the innate immune system, toll-like receptor 4 (TLR4) may modulate the activation of mast cell. Alleviating effect of electroacupuncture (EA) on visceral hypersensitivity has been proved, whereas, whether the TLR4 and mast cell is involved in this process remains unclear.

METHODS

Forty Sprague-Dawley rats were randomly divided into five groups: control group, model group, EA group, sham EA group, and mast cell stabilizer (MCS) group. Visceral sensitivity during colorectal distension was assessed by the measurement of visceral motor reflex (VMR). TLR4 mRNA and protein expression were assessed by real-time PCR and immunohistochemistry, respectively. Mast cell number and mast cell tryptase (MCT) expression were detected. The level of inflammatory cytokine in serum was detected with ELISA.

KEY RESULTS

Visceral sensitivity was significantly higher in the model group than in the control group. EA and MCS significantly reduced VMR score at 0.8 mL and 1.2 mL distention pressures. Compared with model group, TLR4 mRNA expression, the protein expression of TLR4 and MCT, and the number of mast cells with degranulation in the colonic tissue, serum concentration of IL-1β and IL-8 were all significantly decreased in EA and MCS group.

CONCLUSIONS & INFERENCES

Electroacupuncture ameliorated visceral hypersensitivity in colon-sensitized model probably via decreasing the level of pro-inflammatory cytokines released by mast cell which were decreased when the TLR4 expression in the colonic tissue was downregulated by EA.

Fecal urgency is common in constipated patients and is associated with anxiety

BACKGROUND

Fecal urgency is a symptom generally associated with diarrhea but is also reported by patients with constipation. Our aim was to (a) assess the prevalence and burden of fecal urgency in constipated patients (b) evaluate gastrointestinal and psychiatric predictors of moderate to severe fecal urgency in these patients.

METHODS

Patients presenting consecutively to a tertiary outpatient gastroenterology clinic with constipation were included. Patients were considered to have moderate to severe fecal urgency if ≥50% of bowel movements (BMs) in the past 3 months were associated with fecal urgency. Anxiety, depression, and sleep disturbance were diagnosed using a Patient-Reported Outcomes Measurement Information System (PROMIS) t-score of ≥60. Abdominal pain and constipation severity were also assessed using PROMIS questionnaires. Univariable and stepwise logistic regression were used to identify predictors of moderate to severe fecal urgency.

KEY RESULTS

Of 139 constipated patients, 70.8% reported experiencing fecal urgency in the past 3 months and 25.8% reported being significantly bothered by it. Moderate to severe fecal urgency was reported by 27% of 139 patients. Frequency of loose stools (OR 1.5, 95% CI 1.1, 2.0) and presence of anxiety (OR 2.3, 95% CI 1.1, 5.0) were independent predictors of moderate to severe fecal urgency.

CONCLUSIONS AND INFERENCES

Fecal urgency is common in patients with constipation and is frequently bothersome to many patients. We identified clinical and psychiatric factors associated with moderate to severe fecal urgency in constipated patients with potential therapeutic implications if validated in future studies.

Evidence for an association of gut microbial Clostridia with brain functional connectivity and gastrointestinal sensorimotor function in patients with irritable bowel syndrome, based on tripartite network analysis

BACKGROUND AND AIMS

Evidence from preclinical and clinical studies suggests that interactions among the brain, gut, and microbiota may affect the pathophysiology of irritable bowel syndrome (IBS). As disruptions in central and peripheral serotonergic signaling pathways have been found in patients with IBS, we explored the hypothesis that the abundance of serotonin-modulating microbes of the order Clostridiales is associated with functional connectivity of somatosensory brain regions and gastrointestinal (GI) sensorimotor function.

METHODS

We performed a prospective study of 65 patients with IBS and 21 healthy individuals (controls) recruited from 2011 through 2013 at a secondary/tertiary care outpatient clinic in Sweden. Study participants underwent functional brain imaging, rectal balloon distension, a nutrient and lactulose challenge test, and assessment of oroanal transit time within a month. They also submitted stool samples, which were analyzed by 16S ribosomal RNA gene sequencing. A tripartite network analysis based on graph theory was used to investigate the interactions among bacteria in the order Clostridiales, connectivity of brain regions in the somatosensory network, and GI sensorimotor function.

RESULTS

We found associations between GI sensorimotor function and gut microbes in stool samples from controls, but not in samples from IBS patients. The largest differences between controls and patients with IBS were observed in the Lachnospiraceae incertae sedis, Clostridium XIVa, and Coprococcus subnetworks. We found connectivity of subcortical (thalamus, caudate, and putamen) and cortical (primary and secondary somatosensory cortices) regions to be involved in mediating interactions among these networks.

CONCLUSIONS

In a comparison of patients with IBS and controls, we observed disruptions in the interactions between the brain, gut, and gut microbial metabolites in patients with IBS-these involve mainly subcortical but also cortical regions of brain. These disruptions may contribute to altered perception of pain in patients with IBS and may be mediated by microbial modulation of the gut serotonergic system.

Descending monoaminergic pathways projecting to the spinal defecation center enhance colorectal motility in rats

The central regulating mechanisms of defecation, especially roles of the spinal defecation center, are still unclear. We have shown that monoamines including norepinephrine, dopamine, and serotonin injected into the spinal defecation center cause propulsive contractions of the colorectum. These monoamines are the main neurotransmitters of descending pain inhibitory pathways. Therefore, we hypothesized that noxious stimuli in the colorectum would activate the descending monoaminergic pathways projecting to the spinal defecation center and that subsequently released endogenous monoamine neurotransmitters would enhance colorectal motility. Colorectal motility was measured in rats anesthetized with α-chloralose and ketamine. As a noxious stimulus, capsaicin was administered into the colorectal lumen. To interrupt neuronal transmission in the spinal defecation center, antagonists of norepinephrine, dopamine, and/or serotonin receptors were injected intrathecally at the L6-S1 spinal level, where the spinal defecation center is located. Intraluminal administration of capsaicin, acting on the transient receptor potential vanilloid 1 channel, caused transient propulsive contractions. The effect of capsaicin was abolished by surgical severing of the pelvic nerves or thoracic spinal transection at the T4 level. Capsaicin-induced contractions were blocked by preinjection of D2-like dopamine receptor and 5-hydroxytryptamine subtype 2 and 3 receptor antagonists into the spinal defecation center. We demonstrated that intraluminally administered capsaicin causes propulsive colorectal motility through reflex pathways involving the spinal and supraspinal defecation centers. Our results provide evidence that descending monoaminergic neurons are activated by noxious stimulation to the colorectum, leading to facilitation of colorectal motility. NEW & NOTEWORTHY The present study demonstrates that noxious stimuli in the colorectum activates the descending monoaminergic pathways projecting to the spinal defecation center and that subsequently released endogenous monoamine neurotransmitters, serotonin and dopamine, enhance colorectal motility. Our findings provide a possible explanation of the concurrent appearance of abdominal pain and bowel disorder in irritable bowel syndrome patients. Thus the present study may provide new insights into understanding of mechanisms of colorectal dysfunction involving the central nervous system.

Impact of symptoms by gender and age in Japanese subjects with irritable bowel syndrome with constipation (IBS-C): a large population-based internet survey

Background

Irritable bowel syndrome with constipation (IBS-C) is a representative psychosomatic disorder. Several pathophysiological factors have been linked to IBS symptoms such as the modulation of gastrointestinal motility, visceral hypersensitivity, dysregulation of the gut-brain axis, genetic and environmental factors, sequelae of infection, and psychosocial disorders. It is likely that biopsychosocial aspects of IBS-C underlie its gender and age effects. However, the influence of each symptom of IBS-C by gender and age is not well understood. We hypothesized that the expression rate of each IBS-C symptom in females and in subjects aged 20–49 years was higher than that of subjects who were male and aged 50–79 years.

Methods

We conducted an internet survey of 30,000 adults from the general Japanese population. IBS-C subjects were asked to answer a questionnaire on the degree of anxiety, thoughts about bowel habits, and their dominant gastrointestinal symptoms together with exacerbation factors. The correlation between gender and age and IBS-C symptoms was analyzed.

Results

When analyzed by gender, the expression rate of abdominal discomfort, abdominal distention, and abdominal fullness was significantly higher in female than male IBS-C subjects (66.5% vs. 58.7%, p < 0.05; 54.7% vs. 43.6%, p < 0.01; 18.9% vs. 9.6%, p < 0.01, respectively). When analyzed by age, the expression rate of abdominal distention and abdominal pain was significantly higher among IBS-C subjects aged 20–49 years than those aged 50–79 years (55.7% vs. 46.8%, p < 0.05; 36.6% vs. 20.6%, p < 0.001, respectively). In contrast, there was no gender or age differences with regard to the most common and bothersome symptom (abdominal bloating) among IBS-C subjects.

Conclusions

The expression rate of some IBS-C symptoms was higher among females and those aged 20–49 years than males and those aged 50–79 years, respectively. It is important to understand the impact of symptoms by gender and age to evaluate the pathology of IBS-C from a biopsychosocial perspective.

Trial registration

Although this survey was an anonymous internet survey, we obtained informed consent for the study as an online response. The disclosure of this study was approved by the Ethics Committee of Tohoku University Graduate School of Medicine (approval number: 2015–1-405).

Risk Factors for Fecal Urgency Among Individuals With and Without Diarrhea, Based on Data From the National Health and Nutrition Examination Survey

BACKGROUND & AIMS

Fecal urgency is a common symptom among patients with gastrointestinal disorders, but can also occur in healthy individuals with normal bowel habits. There have been few studies of fecal urgency in the general population. We performed a cross-sectional analysis of data from the National Health and Nutrition Examination Survey (NHANES) to analyze the prevalence of and risk factors for this symptom.

METHODS

We analyzed data from 4676 persons who completed the Bowel Health Questionnaire from the NHANES, from 2009 through 2010. The NHANES sampled a nationally representative group of adults in the United States and provides information on demographics, medical comorbidities, and dietary habits of survey participants. The Bowel Health Questionnaire provided additional information about bowel symptoms such as urgency, incontinence, constipation, and diarrhea. We identified individuals with fecal urgency and calculated differences in fecal urgency among subgroups using chi-squared analysis. We used logistic regression to identify factors associated with urgency.

RESULTS

In our study population, the prevalence of fecal urgency was 3.3%; 29.5% of individuals with fecal urgency had diarrhea. The prevalence of fecal urgency was significantly higher in individuals who had diarrhea (14.8%) than in individuals without diarrhea (3.1%). Older age, female sex, poverty, urinary urge incontinence, diarrhea, and increased stool frequency were all associated with fecal urgency on multivariable analysis. Decreased fiber intake and increased carbohydrate intake were associated with urgency among individuals with diarrhea.

CONCLUSIONS

In an analysis of data from 4676 individuals who completed a Bowel Health Questionnaire from the NHANES, we found a significantly higher proportion of individuals with diarrhea to have fecal urgency. However, most individuals with fecal urgency do not have diarrhea. Factors associated with fecal urgency vary among individuals with and without diarrhea.