Review article: abdominal bloating and distension in functional gastrointestinal disorders--epidemiology and exploration of possible mechanisms

Thoracoabdominal Wall Motion-Guided Biofeedback Treatment of Abdominal Distention: A Randomized Placebo-Controlled Trial

BACKGROUND & AIMS

Abdominal distention results from abdominophrenic dyssynergia (ie, diaphragmatic contraction and abdominal wall relaxation) in patients with disorders of gut-brain interaction. This study aimed to validate a simple biofeedback procedure, guided by abdominothoracic wall motion, for treating abdominal distention.

METHODS

In this randomized, parallel, placebo-controlled trial, 42 consecutive patients (36 women and 6 men; ages 17-64 years) with meal-triggered visible abdominal distention were recruited. Recordings of abdominal and thoracic wall motion were obtained using inductance plethysmography via adaptable belts. The signal was shown to patients in the biofeedback group, who were taught to mobilize the diaphragm. In contrast, the signal was not shown to the patients in the placebo group, who were given a placebo capsule. Three sessions were performed over a 4-week intervention period, with instructions to perform exercises (biofeedback group) or to take placebo 3 times per day (control group) at home. Outcomes were assessed through response to an offending meal (changes in abdominothoracic electromyographic activity and girth) and clinical symptoms measured using daily scales for 7 days.

RESULTS

Patients in the biofeedback group (n = 19) learned to correct abdominophrenic dyssynergia triggered by the offending meal (intercostal activity decreased by a mean ± SE of 82% ± 10%, anterior wall activity increased by a mean ± SE of 97% ± 6%, and increase in girth was a mean ± SE of 108% ± 4% smaller) and experienced improved clinical symptoms (abdominal distention scores decreased by a mean ± SE of 66% ± 5%). These effects were not observed in the placebo group (all, P < .002).

CONCLUSIONS

Abdominothoracic wall movements serve as an effective biofeedback signal for correcting abdominophrenic dyssynergia and abdominal distention in patients with disorders of gut-brain interaction. ClincialTrials.gov, Number: NCT04043208.

Efficacy and Safety of Pea Protein and Xyloglucan Versus Simethicone in Functional Abdominal Bloating and Distension

BACKGROUND

Functional Abdominal Bloating and Distension (FABD) is a multifaceted condition related in part to trapped gas, with changes in the intestinal barrier and small intestinal bacterial overgrowth (SIBO), which lead to gas production. Currently, there are no treatments targeting the etiology of FABD.

METHODS

This double-blind, multicenter, randomized study evaluated the safety and efficacy of a product containing xyloglucan and pea proteins (XG + PP) compared with simethicone, both administered orally (three times daily) for 20 consecutive days. Eighty-eight patients with FABD were randomly assigned to the two groups in a 1:1 ratio. Primary outcome was safety; secondary outcomes were (i) efficacy in alleviating the symptoms of FABD and (ii) efficacy in reducing SIBO, as assessed by hydrogen breath test (HBT).

RESULTS

No Adverse Events or Serious Unexpected Adverse Reactions were reported during the study. XG + PP showed a faster onset of action and a significant reduction in bloating and abdominal pain compared with simethicone. At Day 20, XG + PP drastically reduced abdominal girth when compared with simethicone, with an average reduction of 4.7 cm versus 1.8 cm. At Day 20, the XG + PP arm showed a significant reduction in HBT compared to baseline.

CONCLUSIONS

This study supports the evidence that FABD patients may benefit from a XG + PP-based treatment that acts on etiology and not just the symptoms.

Prevalence and Burden of Illness of Rome IV Irritable Bowel Syndrome in the United States: Results From a Nationwide Cross-Sectional Study

BACKGROUND & AIMS

The estimated prevalence of irritable bowel syndrome (IBS) using Rome IV criteria in the United States (US) ranges from 4.7% to 5.3%, although these estimates arise from studies with relatively small sample sizes. This study assessed the prevalence of IBS and its associated burden of illness using a nationally representative data set with nearly 89,000 people in the US.

METHODS

From May 3 to June 24, 2020, we performed an online survey described to participating adults aged ≥18 years old as a "national health survey." We recruited a representative sample of people in the US to complete the survey, which included the Rome IV IBS questionnaire, National Institutes of Health Patient-Reported Outcome Measurement Information System (PROMIS) gastrointestinal scales, and questions on health care-seeking behavior.

RESULTS

Overall, 88,607 people completed the survey, of whom 5414 (6.1%) met Rome IV IBS criteria: mixed IBS (n = 1838 [33.9%]), constipation-predominant IBS (n = 1819 [33.6%]), diarrhea-predominant IBS (n = 1521 [28.1%]), and unsubtyped IBS (n = 236 [4.4%]). Women had higher odds for IBS compared with men, whereas racial/ethnic minorities had lower odds for IBS vs non-Hispanic Whites. Across the 3 main subtypes, 68.2% to 73.2% of people reported ever seeking care for their IBS symptoms, whereas 53.8% to 58.9% did so in the past 12 months.

CONCLUSIONS

In this nationwide US survey, we found that Rome IV IBS is slightly more prevalent (6.1%) vs prior estimates (4.7%-5.3%). Additional research is needed to determine whether this higher prevalence is in part due to the coronavirus disease 2019 pandemic during which this study was conducted.

An Exploratory Study Investigating the Prevalence of Gastrointestinal Symptoms in Collegiate Division I American Football Athletes

Gastrointestinal (GI) symptoms may limit performance, but their prevalence and impact among team sports athletes is not well-documented. The objective of this study was to examine the prevalence of GI symptoms in a small sample of collegiate DI American football athletes, using a survey including the Gastrointestinal Symptoms Ratings Scale (GSRS). Forty-six athletes responded to the survey and reported scores for the 15-question GSRS with additional questions about dietary habits and supplement use. A total of 44 athletes were included in the study (45% of the current roster, age: 20.7 ± 1.7 years, 50% Afro-American or black, 39% skill position, 18% NSAIDs use, and 41% reporting protein supplement use); approximately half of the athletes (52%) reported experiencing GI complaints during exercise. Two-thirds of the athletes (61%) reported at least one or more GI symptoms in general, and 50% reported at least four moderate complaints. Seven athletes (16%) reported ≥2 severe GI symptoms with 5-13 moderate complaints. The most reported symptom was stomach pain (39%, n = 17), followed by hunger pain (36%, n = 16). Athletes reporting the use of protein supplements reported a higher GSRS score (22.0 and interquartile range (IQR) 17.0-31.8) vs. athletes not reporting protein use (15.0 and IQR 15.0-19.3), p = 0.001. Most athletes surveyed reported experiencing GI symptoms. A small group of these athletes reported multiple, varied, and severe symptoms that were associated with self-reported protein supplement use. In conclusion, the number of complaints varied among athletes, confirming the value of integrating the GSRS for screening purposes, and the expected need for individual dietary treatment approaches.

Abdominophrenic Dyssynergia: A Narrative Review

Chronic bloating and abdominal distension are common and highly bothersome gastrointestinal symptoms. Although the differential diagnoses for bloating and distension are broad, these symptoms are frequently associated with disorders of the gut-brain interaction. Functional abdominal bloating may be a result of visceral hypersensitivity, whereas abdominal distension seems to be a somatic behavioral response associated with abdominophrenic dyssynergia, featuring diaphragmatic contraction and abdominal wall relaxation. We review the available literature regarding abdominophrenic dyssynergia and comment on its epidemiology, diagnosis, treatment, and avenues to address in the near future.

Pelvic floor biofeedback is an effective treatment for severe bloating in disorders of gut-brain interaction with outlet dysfunction

BACKGROUND

The pathophysiology of bloating is partially understood. We investigated in patients with disorders of gut-brain interaction (DGBI) the relationship between severity of bloating, abdominal girth changes and defecation pattern, and the efficacy of pelvic floor biofeedback treatment on bloating.

METHODS

Disorders of gut-brain interaction patients with severe bloating as the main complaint were prescribed 2 weeks dietary advice and underwent abdominal girth measurements. At the first visit, all patients underwent a questionnaire on the subjective improvement of bloating, a (0-100) VAS abdominal bloating, and abdominal girth measurement. Patients reporting inadequate bloating relief underwent a standardized balloon expulsion test. Furthermore, they were invited to undergo pelvic floor electromyography and biofeedback treatment previously used for constipation due to dyssynergic defecation. The primary outcome was bloating improvement on a 5-point Likert scale. The secondary outcomes were the effect of diet intervention and pelvic floor biofeedback treatment on bloating severity and quality of life changes as well as the effect of pelvic floor biofeedback treatment on BET and EMG on straining.

KEY RESULTS

One hundred and fifty six patients (129 F, 39.3 ± 11.7 mean age) completed the 2-week run-in period. 105 patients were diet non-responder and underwent balloon expulsion test, with the vast majority (64%) failing the test. Patients who scored higher bloating on VAS had a significant association with failed balloon expulsion test (adjusted B 0.4 [95% CI 10.8-25.7], p < 0.0001). 63% agreed to perform pelvic floor biofeedback treatment at Verona center, 54% became responders reporting fair or major improvement/cure (ITT analysis, McNemar test, p < 0.0001), and all of them showed a 50% decrease in bloating severity.

CONCLUSIONS AND INFERENCES

Disordered defecation is a prevalent etiology in DGBI patients with bloating unresponsive to conservative measures; pelvic floor biofeedback treatment to improve the defecation effort significantly relieved bloating (http://www.isrctn.com, ISRCTN17004079).

Improvement in constipation and diarrhea is associated with improved abdominal pain in patients with functional bowel disorders

BACKGROUND

Abdominal pain is a bothersome and lifestyle limiting symptom in patients with functional bowel disorders. It is associated with decreased quality of life in affected individuals, as well as significant annual healthcare expenditure. Knowledge of specific factors that predict improvement in abdominal pain in those with functional bowel disorders is thus far limited.

METHODS

Consecutive patients presenting for outpatient care at a major academic medical center between October 2017 and March 2020 completed an electronic symptom survey prior to initial clinic visit, and again after 3 months. The Rome IV questionnaires for functional dyspepsia, irritable bowel syndrome, functional constipation, and functional diarrhea were all included. Additionally, all subjects completed the Patient Reported Outcomes Measurement Information System Anxiety, Depression, and sleep disturbance questionnaires. Patients with a diagnosis of a Rome IV functional gastrointestinal disorder without any organic cause for symptoms were identified based on both chart review as well as survey response data. Univariable and multivariable analysis was used to assess predictors of improved abdominal pain after 3 months.

KEY RESULTS

180 patients with a mean age of 45.3 years were included in the final analysis. 78.3% of patients were female, and 77.2% met Rome IV criteria for irritable bowel syndrome. On multivariable analysis, improvement in constipation and diarrhea were both independent predictors of improved abdominal pain after 3 months.

CONCLUSIONS AND INFERENCES

Improvement in constipation and diarrhea both predicted improvement in abdominal pain, suggesting that addressing these factors is central to the management of abdominal pain in functional gastrointestinal disorders.

Beneficial Effects on Abdominal Bloating with an Innovative Food-Grade Formulation of Curcuma longa and Boswellia serrata Extracts in Subjects with Irritable Bowel Syndrome and Small Bowel Dysbiosis

Bloating is a symptom frequently reported by subjects with irritable bowel syndrome (IBS) and small bowel dysbiosis, and Low FODMAP’s diet (LFD) has been used to treat them. Extracts of Curcumalonga and Boswelliaserrata share anti-inflammatory and antimicrobial effects that could be useful in the management of these clinical conditions. The aim of this study was to evaluate the efficacy of curcumin and boswellia extracts (as Curcumin Boswellia Phytosome, CBP) and LFD on the relief of abdominal bloating in IBS subjects with small bowel dysbiosis, in comparison to LFD alone, in a 30-day supplementation, randomized trial. IBS participants were randomized to either the intervention (500 mg bid of CBP and LFD) or control arm (LFD). Small bowel dysbiosis has been defined by an increase of urinary indican with normal urinary skatole. A total of 67 subjects were recruited. The intervention group (33 subjects) showed a significant decrease (p < 0.0001) of bloating, abdominal pain, and indican values at the end of the study, when compared to the control group (34 subjects). Moreover, the subjects of the intervention group showed a significantly better (p < 0.0001) global assessment of efficacy (GAE) as compared to controls. In conclusion, in subjects with IBS and small bowel dysbiosis, abdominal bloating can be successfully reduced with a supplementation with CBP and LFD.

Effectiveness and safety of kamikihito, a traditional Japanese medicine, in managing anxiety among female patients with intractable chronic constipation

BACKGROUND AND PURPOSE

The prevalence of anxiety in patients with chronic constipation is particularly high and these individuals are not necessarily satisfied by normal treatments targeting the gastrointestinal tract. Kamikihito, a traditional Japanese Kampo medicine, has been widely used to date in treating anxiety and neurosis in Japan. We conducted a single-arm, open-label pilot study of female patients with intractable chronic constipation and anxiety who took kamikihito by mouth for 12 weeks.

MATERIALS AND METHODS

Validated symptom questionnaires on anxiety and gastrointestinal symptoms [the Profile of Mood States, second edition (POMS2); the State-Trait Anxiety Inventory (STAI); and the Gastrointestinal Symptom Rating Scale (GSRS)] were completed at each study visit. Plasma, salivary, and stool samples were also assessed to evaluate levels of clinical bioactive substances linked to stress and inflammation, oxidative levels, the metabolome profile, and gut microbiota.

RESULTS

Twenty-four patients completed this study. Anxiety was significantly reduced at four and 12 weeks (Tension-Anxiety subscale of the POMS2, p = 0.006 and p = 0.039; Trait anxiety score of the STAI, p < 0.001 and p = 0.034), while the total GSRS score was improved at 12 weeks (p = 0.039). Targeted metabolomics in plasma showed significant alterations in some metabolites associated with psychological symptoms, such as O-phosphoethanolamine. No significant differences were found between pre- and posttreatment levels of clinical bioactive substances related to stress and inflammation, oxidative levels, and the gut microbiota in this cohort. No serious adverse events occurred.

CONCLUSION

Kamikihito ameliorated psychological and gastrointestinal symptoms in patients with chronic constipation. In parallel with the onset of efficacy, kamikihito modulated some anxiety-related metabolites. Kamikihito was safe and well-tolerated.

A randomized double-blind placebo-controlled crossover pilot study: Acute effects of the enzyme α-galactosidase on gastrointestinal symptoms in irritable bowel syndrome patients

BACKGROUND

Postprandial symptoms presumably related to intestinal gas production are common in patients with irritable bowel syndrome (IBS). The aim of the study was to assess if oral α-galactosidase is superior to placebo in reducing gastrointestinal (GI) symptoms and intestinal gas production after ingestion of carbohydrate-rich meals in adult patients with IBS.

METHODS

We studied the effect of 1200 GaIU/meal α-galactosidase (Nogasin^® ) or placebo capsules on GI symptoms in patients with IBS after three standardized, meals high in oligosaccharides, in a randomized, double-blind, crossover study. The intensity of eight GI symptoms was rated, and breath hydrogen and methane were measured every 30 min during 7.5 h. The severity of GI symptoms the following morning was assessed and compared with baseline.

S KEY RESULTS

Twenty adult patients with IBS (19 females), mean age 49 years (range 22-75 years), were included. All test meals were well tolerated but induced a gradual increase in GI symptom severity. Neither GI symptom ratings over time, nor hydrogen and methane concentrations differed between the days with α-galactosidase or placebo. The severity of abdominal pain and bloating was lower the following morning, but with no differences between α-galactosidase and placebo.

CONCLUSIONS & INFERENCES

The use of α-galactosidase together with meals high in oligosaccharides was in this pilot study not superior to placebo in reducing postprandial GI symptoms or the concentration of hydrogen and methane in expired air in IBS.

Validity and Reliability of the Malay Versions of Bloating Severity (BSQ-M) and Quality of Life (BLQoL-M) Questionnaires

Abdominal bloating (AB) is a prevalent and bothersome symptom, but there are no specific measures for severity and quality of life (QoL) other than the Bloating Severity Questionnaire (BSQ) and Bloating Quality of Life (BLQoL). We aimed to translate the BSQ and BLQoL into the Malay language and to validate them using exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) approaches. The 12-item BSQ has two components, seven-item severity in general (SevGen) and five-item severity in the past 24 h (Sev24), and BLQOL has five items. Translation to the Malay language (BSQ-M and BLQoL-M) was performed using standard forward and backward processes. EFA followed by CFA were performed in participants with AB due to functional bowel disorders, with the purpose of examining the validity and reliability of the questionnaires translated into Malay. After EFA with 152 participants, all the items of BSQ-M remained in the model. Total variance extracted was 53.26% for BSQ-M and 58.79% for BLQoL-M. The internal consistency based on Cronbach's alpha values was 0.52 for SevGen, 0.86 for Sev24, and 0.81 for BLQoL-M. After performing CFA with another 323 participants, the final measurement model for BSQ-M and BLQoL-M fit the data well in terms of several fit indices (BSQ-M: root mean square error of approximation (RMSEA) = 0.050, Comparative Fit Index (CFI) = 0.966, Tucker-Lewis Fit Index (TLI) = 0.956, and standardized root mean squared residual (SRMR) = 0.051; BLQoL-M: RMSEA = 0.071, CFI = 0.985, TLI = 0.962, SRMR = 0.021). The composite reliability for BSQ-M and BLQoL-M were satisfactory (SevGen = 0.83, Sev24 = 0.89, BLQoL = 0.80). The intraclass correlation (ICC) results showed excellent stability for BSQ-M and BLQoL-M, ranging from 0.74 to 0.93. The Malay language versions of BSQ-M and BLQoL-M are valid and reliable instruments for measuring the severity and QoL of AB for the Asian population with functional bowel disorders.

Functional Gastrointestinal Disorders and the Microbiome-What Is the Best Strategy for Moving Microbiome-based Therapies for Functional Gastrointestinal Disorders into the Clinic?

There have been numerous human studies reporting associations between the intestinal microbiome and functional gastrointestinal disorders (FGIDs), and independently animal studies have explored microbiome-driven mechanisms underlying FGIDs. However, there is often a disconnect between human and animal studies, which hampers translation of microbiome findings to the clinic. Changes in the microbiota composition of patients with FGIDs are generally subtle, whereas changes in microbial function, reflected in the fecal metabolome, appear to be more precise indicators of disease subtype-specific mechanisms. Although we have made significant progress in characterizing the microbiome, to effectively translate microbiome science in a timely manner, we need concurrent and iterative longitudinal studies in humans and animals to determine the precise microbial functions that can be targeted to address specific pathophysiological processes in FGIDs. A systems approach integrating multiple data layers rather than evaluating individual data layers of symptoms, physiological changes, or -omics data in isolation will allow for validation of mechanistic insights from animal studies while also allowing new discovery. Patient stratification for clinical trials based on functional microbiome alterations and/or pathophysiological measurements may allow for more accurate determination of efficacy of individual microbiome-targeted interventions designed to correct an underlying abnormality. In this review, we outline current approaches and knowledge, and identify gaps, to provide a potential roadmap for accelerating translation of microbiome science toward microbiome-targeted personalized treatments for FGIDs.

Patient Perspectives on Short-Course Pharmacotherapy: Barriers and Facilitators to Medication Adherence

Background:

Medication nonadherence is a public health issue that contributes to poor health outcomes and health-care costs. Factors influencing long-term medication adherence are known; however, little is known about short-course medication adherence.

Objective:

This study examined patient perspectives on adherence and factors that influence adherence to short-course pharmacotherapy in diarrhea-predominant irritable bowel syndrome.

Method:

Twenty-seven participants were interviewed to identify their perceptions of barriers and facilitators to thrice-daily, 14-day rifaximin.

Results:

Participants were primarily female (89%), aged 18 to 65 years. Sixty-eight percent of interviewees were identified as “low-adherers,” meaning the percentage of days with correct daily dosing of rifaximin was <80%. The final coding framework identified social/economic-related (family support and medication expense), system-related (relationship with provider and medication knowledge), condition-related (symptom severity), therapy-related (inconvenient dosing), and patient-related (forgetfulness and busyness of daily life) factors that influenced adherence.

Conclusion:

The resulting patient perspectives highlight a diverse set of factors that influence short-course adherence and the need for tailored interventions that address these various factors resulting in enhanced patient outcomes.

Effects of the DASH Diet and Sodium Intake on Bloating: Results From the DASH-Sodium Trial

INTRODUCTION

Bloating is one of the most common gastrointestinal complaints. Evidence has linked fiber and sodium to bloating; however, randomized trials examining these diet components are lacking. Here, we used a randomized trial to examine the effects of the high-fiber DASH diet and dietary sodium intake on abdominal bloating. We hypothesized that both the high-fiber DASH diet and higher sodium intake would increase bloating.

METHODS

The DASH-Sodium trial (1998-1999) randomized healthy adults to a high-fiber (32 g/d) DASH or low-fiber (11 g/d) Western diet (control). On their assigned diet, participants ate 3 sodium levels (50, 100, and 150 mmol/d at 2100 kcal) in 30-day periods in random order, with 5-day breaks between each period. The participants reported the presence of bloating at baseline and after each feeding period. Statistical analyses included log-binomial models to evaluate the risk of bloating.

RESULTS

Of 412 participants (mean age 48 years; 57% women; 57% black), 36.7% reported bloating at baseline. Regardless of the diet, high sodium intake increased the risk of bloating (risk ratio = 1.27; 95% confidence interval: 1.06-1.52; P = 0.01). The high-fiber DASH diet also increased the risk of bloating over all sodium levels (risk ratio = 1.41; 95% confidence interval: 1.22-1.64; P < 0.001). The effect of high-fiber DASH on bloating was greater in men than in women (P for interaction = 0.001).

DISCUSSION

Higher dietary sodium increased bloating, as did the high-fiber DASH diet. Although healthful high-fiber diets may increase bloating, these effects may be partially mitigated by decreasing dietary sodium intake. Future research is needed to explore mechanisms by which sodium intake and diet can influence bloating.

Fasting breath H2 and gut microbiota metabolic potential are associated with the response to a fermented milk product in irritable bowel syndrome

OBJECTIVES

Aim of this study was to assess the effect of a fermented milk product containing Bifidobacterium lactis CNCM I-2494 (FMP) on gastrointestinal (GI) symptoms and exhaled H2 and CH4 during a nutrient and lactulose challenge in patients with irritable bowel syndrome (IBS).

METHODS

We included 125 patients with IBS (Rome III). Fasted subjects were served a 400ml liquid test meal containing 25g lactulose. The intensity of eight GI symptoms and the amount of exhaled H2 and CH4 were assessed before and during 4h after meal intake. The challenge was repeated after 14 days consumption of FMP or a control product in a double-blind, randomized, parallel design. The metabolic potential of fecal microbiota was profiled using 16S MiSeq analysis of samples obtained before and after the intervention.

RESULTS

106 patients with IBS were randomized. No difference between FMP or control groups was found on GI symptoms or breath H2 and CH4 in the whole cohort. A post-hoc analysis in patients stratified according to their fasting H2 levels showed that in high H2 producers (fasting H2 level≥10ppm, n = 35), FMP consumption reduced fasting H2 levels (p = 0.003) and H2 production during the challenge (p = 0.002) and tended to decrease GI discomfort (p = 0.05) vs. control product. The Prevotella/Bacteroides metabolic potential at baseline was higher in high H2 producers (p<0.05) vs. low H2 producers and FMP consumption reduced this ratio (p<0.05) vs. control product.

CONCLUSIONS

The response to a fermented milk product containing Bifidobacterium lactis CNCM I-2494 (FMP) in patients with IBS seems to be associated with the metabolic potential of the gut microbiota.

TRIAL REGISTRATION

ClinicalTrial.gov NCT01252550. These results were presented as congress posters at Digestive Disease Week 2016 in San Diego, USA and United European Gastroenterology Week 2016 in Vienna, Austria.

Gastrointestinal Gas and Abdominal Fat Quantity Measured by Three-Dimensional Abdominal Computed Tomography in Patients with Functional Bloating

Background/Aims

The aim of this study was to assess whether increased intestinal gas or fat content in the abdominal cavity is related to abdominal bloating, using three-dimensional abdominal computed tomography scan.

Methods

Twenty-nine healthy individuals without abdominal bloating and organic disease (15 women; mean age, 49 years; range of age, 23-73 years) and 30 patients with chronic recurrent abdominal bloating-diagnosed with functional bloating (10 women; mean age, 53 years; range of age, 35-75 years) - participated in this study. The mean values of measured parameters were compared using independent sample t-test.

Results

The mean volume of total colon gas in bloated patients was similar to that in control subjects. The distribution of intra-abdominal gas was also similar between the two groups. However, the amount of gas in the transverse colon tended to be significantly higher in patients with bloating than in controls (p=0.06). Body mass index was similar between the two groups (23.4±3.2 kg/m² and 22.3±3.1 kg/m², respectively). Moreover, no significant differences with respect to circumferential area, subcutaneous fat, visceral fat area, and total fat area were found between the two groups.

Conclusions

Bloating might not just be the result of gastrointestinal gas or intra-abdominal fat. Other contributing factors, such as localized abnormality in gas distribution and visceral hypersensitivity, may be involved.

Low-FODMAP vs regular rye bread in irritable bowel syndrome: Randomized SmartPill® study

AIM

To compare the effects of regular vs low-FODMAP rye bread on irritable bowel syndrome (IBS) symptoms and to study gastrointestinal conditions with SmartPill^®.

METHODS

Our aim was to evaluate if rye bread low in FODMAPs would cause reduced hydrogen excretion, lower intraluminal pressure, higher colonic pH, different transit times, and fewer IBS symptoms than regular rye bread. The study was a randomized, double-blind, controlled cross-over meal study. Female IBS patients (n = 7) ate study breads at three consecutive meals during one day. The diet was similar for both study periods except for the FODMAP content of the bread consumed during the study day. Intraluminal pH, transit time, and pressure were measured by SmartPill, an indigestible motility capsule.

RESULTS

Hydrogen excretion (a marker of colonic fermentation) expressed as area under the curve (AUC)_{(0-630 min)} was [median (range)] 6300 (1785-10800) ppm∙min for low-FODMAP rye bread and 10 635 (4215-13080) ppm∙min for regular bread (P = 0.028). Mean scores of gastrointestinal symptoms showed no statistically significant differences but suggested less flatulence after low-FODMAP bread consumption (P = 0.063). Intraluminal pressure correlated significantly with total symptom score after regular rye bread (ρ = 0.786, P = 0.036) and nearly significantly after low-FODMAP bread consumption (ρ = 0.75, P = 0.052). We found no differences in pH, pressure, or transit times between the breads. Gastric residence of SmartPill was slower than expected. SmartPill left the stomach in less than 5 h only during one measurement (out of 14 measurements in total) and therefore did not follow on par with the rye bread bolus.

CONCLUSION

Low-FODMAP rye bread reduced colonic fermentation vs regular rye bread. No difference was found in median values of intraluminal conditions of the gastrointestinal tract.

Food consumption and dietary intakes in 36,448 adults and their association with irritable bowel syndrome: Nutrinet-Santé study

INTRODUCTION

Diet plays an important role for patients with irritable bowel syndrome (IBS). The aim of this study was to compare the diets in terms of food consumption and nutrient intake between subjects with IBS and controls in a large French population.

METHODS

This study included 36,448 subjects from the Nutrinet-Santé cohort study, who completed a questionnaire pertaining to functional bowel disorders based on the Rome III criteria. Dietary data were obtained from at least three self-administered 24 h records via the internet. Association between IBS and diet was evaluated by comparison tests controlled for gender, age and total energy intake (ANCOVA tests).

RESULTS

Subjects included were mainly women (76.9%) and the mean age was 50.2 ± 14.2 years. Among these individuals, 1870 (5.1%) presented with IBS. Compared to healthy controls, they had significantly lower consumption of milk (74.6 versus 88.4 g/day; p < 0.0001), yogurt (108.4 versus 115.5 g/day; p = 0.001), fruits (192.3 versus 203.8 g/day; p < 0.001), and higher soft non-sugared beverages (1167.2 versus 1122.9 ml/day; p < 0.001). They had higher total energy intake (2028.9 versus 1995.7 kcal/day; p < 0.001), with higher intakes of lipids (38.5 versus 38.1% of total energy intake; p = 0.001) and lower intakes of proteins (16.4 versus 16.8% of total energy intake; p < 0.0001), as well as micronutrients (calcium, potassium, zinc and vitamins B2, B5 and B9, all p < 0.0001).

CONCLUSIONS

In this large sample, these findings suggest that dietary intake of subjects suffering from IBS differs from that of control subjects. They may have adapted their diet according to symptoms following medical or non-medical recommendations.

Correction of Abdominal Distention by Biofeedback-Guided Control of Abdominothoracic Muscular Activity in a Randomized, Placebo-Controlled Trial

BACKGROUND & AIMS

Abdominal distention is produced by abnormal somatic postural tone. We developed an original biofeedback technique based on electromyography-guided control of abdominothoracic muscular activity. We performed a randomized, placebo-controlled study to demonstrate the superiority of biofeedback to placebo for the treatment of abdominal distention.

METHODS

At a referral center in Spain, we enrolled consecutive patients with visible abdominal distention who fulfilled the Rome III criteria for functional intestinal disorders (47 women, 1 man; 21-74 years old); 2 patients assigned to the placebo group withdrew and 2 patients assigned to biofeedback were not valid for analysis. Abdominothoracic muscle activity was recorded by electromyography. The patients in the biofeedback group were shown the signal and instructed to control muscle activity, whereas patients in the placebo received no instructions and were given oral simethicone. Each patient underwent 3 sessions over a 10-day period. The primary outcomes were subjective sensation of abdominal distention, measured by graphic rating scales for 10 consecutive days before and after the intervention.

RESULTS

Patients in the biofeedback group effectively learned to reduce intercostal activity (by a mean 45% ± 3%), but not patients in the placebo group (reduced by a mean 5% ± 2%; P < .001). Patients in the biofeedback group learned to increase anterior wall muscle activity (by a mean 101% ± 10%), but not in the placebo group (decreased by a mean 4% ± 2%; P < .001). Biofeedback resulted in a 56% ± 1% reduction of abdominal distention (from a mean score of 4.6 ± 0.2 to 2.0 ± 0.2), whereas patients in the placebo group had a reduction of only 13% ± 8% (from a mean score of 4.7 ± 0.1 to 4.1 ± 0.4) (P < .001).

CONCLUSIONS

In a randomized trial of patients with a functional intestinal disorder, we found that abdominal distention can be effectively corrected by biofeedback-guided control of abdominothoracic muscular activity, compared with placebo. ClincialTrials.gov no: NCT01205100.

Irritable Bowel Syndrome, Particularly the Constipation-Predominant Form, Involves an Increase in Methanobrevibacter smithii, Which Is Associated with Higher Methane Production

BACKGROUND/AIMS

Because Methanobrevibacter smithii produces methane, delaying gut transit, we evaluated M. smithii loads in irritable bowel syndrome (IBS) patients and healthy controls (HC).

METHODS

Quantitative real-time polymerase chain reaction for M. smithii was performed on the feces of 47 IBS patients (Rome III) and 30 HC. On the lactulose hydrogen breath test (LHBT, done for 25 IBS patients), a fasting methane result ≥10 ppm using 10 g of lactulose defined methane-producers.

RESULTS

Of 47, 20 had constipation (IBS-C), 20 had diarrhea (IBS-D) and seven were not sub-typed. The M. smithii copy number was higher among IBS patients than HC (Log₁₀5.4, interquartile range [IQR; 3.2 to 6.3] vs 1.9 [0.0 to 3.4], p<0.001), particularly among IBS-C compared to IBS-D patients (Log₁₀6.1 [5.5 to 6.6] vs 3.4 [0.6 to 5.7], p=0.001); the copy number negatively correlated with the stool frequency (R=-0.420, p=0.003). The M. smithii copy number was higher among methane-producers than nonproducers (Log₁₀6.4, IQR [5.7 to 7.4] vs 4.1 [1.8 to 5.8], p=0.001). Using a receiver operating characteristic curve, the best cutoff for M. smithii among methane producers was Log₁₀6.0 (sensitivity, 64%; specificity, 86%; area under curve [AUC], 0.896). The AUC for breath methane correlated with the M. smithii copy number among methane producers (r=0.74, p=0.008). Abdominal bloating was more common among methane producers (n=9/11 [82%] vs 5/14 [36%], p=0.021).

CONCLUSIONS

Patients with IBS, particularly IBS-C, had higher copy numbers of M. smithii than HC. On LHBT, breath methane levels correlated with M. smithii loads.

Refining Ovarian Cancer Test accuracy Scores (ROCkeTS): protocol for a prospective longitudinal test accuracy study to validate new risk scores in women with symptoms of suspected ovarian cancer

INTRODUCTION

Ovarian cancer (OC) is associated with non-specific symptoms such as bloating, making accurate diagnosis challenging: only 1 in 3 women with OC presents through primary care referral. National Institute for Health and Care Excellence guidelines recommends sequential testing with CA125 and routine ultrasound in primary care. However, these diagnostic tests have limited sensitivity or specificity. Improving accurate triage in women with vague symptoms is likely to improve mortality by streamlining referral and care pathways. The Refining Ovarian Cancer Test Accuracy Scores (ROCkeTS; HTA 13/13/01) project will derive and validate new tests/risk prediction models that estimate the probability of having OC in women with symptoms. This protocol refers to the prospective study only (phase III).

METHODS AND ANALYSIS

ROCkeTS comprises four parallel phases. The full ROCkeTS protocol can be found at http://www.birmingham.ac.uk/ROCKETS. Phase III is a prospective test accuracy study. The study will recruit 2450 patients from 15 UK sites. Recruited patients complete symptom and anxiety questionnaires, donate a serum sample and undergo ultrasound scored as per International Ovarian Tumour Analysis (IOTA) criteria. Recruitment is at rapid access clinics, emergency departments and elective clinics. Models to be evaluated include those based on ultrasound derived by the IOTA group and novel models derived from analysis of existing data sets. Estimates of sensitivity, specificity, c-statistic (area under receiver operating curve), positive predictive value and negative predictive value of diagnostic tests are evaluated and a calibration plot for models will be presented. ROCkeTS has received ethical approval from the NHS West Midlands REC (14/WM/1241) and is registered on the controlled trials website (ISRCTN17160843) and the National Institute of Health Research Cancer and Reproductive Health portfolios.

Bloating: Avicenna's Perspective and Modern Medicine

Bloating and abdominal distention are common complaints present in quite a number of organic and functional diseases. An important subject in traditional Persian medicine is digestive disorders, particularly bloating and its etiology. This is a literature review study conducted on The Canon in Medicine written by Avicenna and using the keywords: bloating, gas. In this article, causes for bloating, according to Avicenna, include diet causes, inappropriate lifestyle, gastrointestinal, and miscellaneous reasons. These were compared with causes suggested in modern medicine. Avicenna classifies causes based on the place of origin into upper part of the abdomen (stomach) and intestinal part of the abdomen. Also, 38 medicinal plants used as remedies were listed. Modern scientific data support all bloating causes that have been mentioned in the canon. Obviously, some causes such as uterine disorders and posterior nasal discharge need to be studied further.

Intestinal gas content and distribution in health and in patients with functional gut symptoms

BACKGROUND

The precise relation of intestinal gas to symptoms, particularly abdominal bloating and distension remains incompletely elucidated. Our aim was to define the normal values of intestinal gas volume and distribution and to identify abnormalities in relation to functional-type symptoms.

METHODS

Abdominal computed tomography scans were evaluated in healthy subjects (n = 37) and in patients in three conditions: basal (when they were feeling well; n = 88), during an episode of abdominal distension (n = 82) and after a challenge diet (n = 24). Intestinal gas content and distribution were measured by an original analysis program. Identification of patients outside the normal range was performed by machine learning techniques (one-class classifier). Results are expressed as median (IQR) or mean ± SE, as appropriate.

KEY RESULTS

In healthy subjects the gut contained 95 (71, 141) mL gas distributed along the entire lumen. No differences were detected between patients studied under asymptomatic basal conditions and healthy subjects. However, either during a spontaneous bloating episode or once challenged with a flatulogenic diet, luminal gas was found to be increased and/or abnormally distributed in about one-fourth of the patients. These patients detected outside the normal range by the classifier exhibited a significantly greater number of abnormal features than those within the normal range (3.7 ± 0.4 vs 0.4 ± 0.1; p < 0.001).

CONCLUSIONS & INFERENCES

The analysis of a large cohort of subjects using original techniques provides unique and heretofore unavailable information on the volume and distribution of intestinal gas in normal conditions and in relation to functional gastrointestinal symptoms.

Visceral pain and gastrointestinal microbiome

A complex set of interactions between the microbiome, gut and brain modulate responses to visceral pain. These interactions occur at the level of the gastrointestinal mucosa, and via local neural, endocrine or immune activity; as well as by the production of factors transported through the circulatory system, like bacterial metabolites or hormones. Various psychological, infectious and other stressors can disrupt this harmonious relationship and alter both the microbiome and visceral pain responses. There are critical sensitive periods that can impact visceral pain responses in adulthood. In this review we provide a brief background of the intestinal microbiome and emerging concepts of the bidirectional interactions between the microbiome, gut and brain. We also discuss recent work in animal models, and human clinical trials using prebiotics and probiotics that alter the microbiome with resultant alterations in visceral pain responses.

Abdominothoracic mechanisms of functional abdominal distension and correction by biofeedback

BACKGROUND & AIMS

In patients with functional gut disorders, abdominal distension has been associated with descent of the diaphragm and protrusion of the anterior abdominal wall. We investigated mechanisms of abdominal distension in these patients.

METHODS

We performed a prospective study of 45 patients (42 women, 24-71 years old) with functional intestinal disorders (27 with irritable bowel syndrome with constipation, 15 with functional bloating, and 3 with irritable bowel syndrome with alternating bowel habits) and discrete episodes of visible abdominal distension. Subjects were assessed by abdominothoracic computed tomography (n = 39) and electromyography (EMG) of the abdominothoracic wall (n = 32) during basal conditions (without abdominal distension) and during episodes of severe abdominal distension. Fifteen patients received a median of 2 sessions (range, 1-3 sessions) of EMG-guided, respiratory-targeted biofeedback treatment; 11 received 1 control session before treatment.

RESULTS

Episodes of abdominal distension were associated with diaphragm contraction (19% ± 3% increase in EMG score and 12 ± 2 mm descent; P < .001 vs basal values) and intercostal contraction (14% ± 3% increase in EMG scores and 6 ± 1 mm increase in thoracic antero-posterior diameter; P < .001 vs basal values). They were also associated with increases in lung volume (501 ± 93 mL; P < .001 vs basal value) and anterior abdominal wall protrusion (32 ± 3 mm increase in girth; P < .001 vs basal). Biofeedback treatment, but not control sessions, reduced the activity of the intercostal muscles (by 19% ± 2%) and the diaphragm (by 18% ± 4%), activated the internal oblique muscles (by 52% ± 13%), and reduced girth (by 25 ± 3 mm) (P ≤ .009 vs pretreatment for all).

CONCLUSIONS

In patients with functional gut disorders, abdominal distension is a behavioral response that involves activity of the abdominothoracic wall. This distension can be reduced with EMG-guided, respiratory-targeted biofeedback therapy.

Outcomes following implementation of symptom triggered diagnostic testing for ovarian cancer

OBJECTIVES

UK is the first country to implement symptom triggered testing for suspected ovarian cancer (OC) following guidance from National Institute of Clinical Excellence in 2011. We evaluated its impact on cancer outcomes and implications on clinical practice.

STUDY DESIGN

This is a cohort study and we analysed data for all new urgent referrals for suspected OC from two large teaching hospitals using a prospectively collected electronic referral database, supplemented with clinical data from electronic records. We evaluated outcomes prior to (2011) and after (2013) implementation of guidance to evaluate stage shift, referrals workload and surgical procedures generated.

RESULTS

Secondary care received 2185 new referrals from primary care for women with suspected gynaecological cancer in post guideline cohort. Of these, 217 women were referred for suspected OC. 90% of primary care referrals were not compliant with guidance. Following implementation of guidance, more women with OC were diagnosed through urgent referral (rapid access clinics): Almost double, 21 of the total 67 (31.34%) OCs in 2013 (post guidance) in comparison to only 11 of 69 OCs (15.94%) were diagnosed in 2011 (pre guidance) through urgent referrals, p=0.03. The predictive value of detecting cancer through rapid access clinics increased, from 4.5% to 9.6%, p=0.04; however, no stage shift was noted. Over 25% of patients underwent surgeries for non-malignant conditions in the post-guideline cohort. No increase was seen in workload of cancer clinics.

CONCLUSION

Implementation of Symptom-triggered testing is challenging in clinical practice. Such testing results in more patients with OC accessing expedited care pathways leading to streamlined routes of diagnosis and care. However, current implementation does not lead to stage shift in diagnosis and may not achieve significant mortality benefit.

Prevalence of functional bowel disorders and faecal incontinence: an Australian primary care survey

AIM

Interest in functional bowel disorders (FBDs) and faecal incontinence (FI) has increased amongst coloproctologists. The study aimed to assess the prevalence of FBDs and FI (including its severity) among Australian primary healthcare seekers using objective criteria.

METHOD

A cross-sectional survey was conducted in a primary care setting in Sydney, Australia. A self-administered questionnaire was used to collect demographic information and diagnose FBDs (irritable bowel syndrome, constipation, functional bloating and functional diarrhoea) based on Rome III criteria. The severity of FI was determined using the Vaizey incontinence score. Associations with medical/surgical history and healthcare utilization were assessed.

RESULTS

Of 596 subjects approached, 396 (66.4%) agreed to participate. Overall, 33% had FBD and/or FI. Irritable bowel syndrome was present in 11.1% and these participants were more likely to report anxiety/depression (P < 0.01) and to have had a previous colonoscopy (P < 0.001) or cholecystectomy (P = 0.02). Functional constipation was present in 8.1%, and functional bloating and functional diarrhoea were diagnosed in 6.1%, and 1.5%, respectively. FI was present in 12.1% with the majority (52%) reporting moderate/severe incontinence (Vaizey score > 8). Participants with FI were more likely to have irritable bowel syndrome, urinary incontinence and previous anal surgery (P < 0.01).

CONCLUSION

FBDs and FI are prevalent conditions amongst primary healthcare seekers and the needs of those affected appear to be complex given their coexisting symptoms and conditions. Currently, the majority do not reach colorectal services, although increased awareness by primary care providers could lead to sufferers being referred for specialist management.

Bloating and functional gastro-intestinal disorders: Where are we and where are we going?

Bloating is one of the most common and bothersome symptoms complained by a large proportion of patients. This symptom has been described with various definitions, such as sensation of a distended abdomen or an abdominal tension or even excessive gas in the abdomen, although bloating should probably be defined as the feeling (e.g. a subjective sensation) of increased pressure within the abdomen. It is usually associated with functional gastrointestinal disorders, like irritable bowel syndrome, but when bloating is not part of another functional bowel or gastrointestinal disorder it is included as an independent entity in Rome III criteria named functional bloating. In terms of diagnosis, major difficulties are due to the lack of measurable parameters to assess and grade this symptom. In addition, it is still unclear to what extent the individual patient complaint of subjective bloating correlates with the objective evidence of abdominal distension. In fact, despite its clinical, social and economic relevance, bloating lacks a clear pathophysiology explanation, and an effective management endorsement, turning this common symptom into a true challenge for both patients and clinicians. Different theories on bloating etiology call into questions an increased luminal contents (gas, stools, liquid or fat) and/or an impaired abdominal empting and/or an altered intra-abdominal volume displacement (abdomino-phrenic theory) and/or an increased perception of intestinal stimuli with a subsequent use of empirical treatments (diet modifications, antibiotics and/or probiotics, prokinetic drugs, antispasmodics, gas reducing agents and tricyclic antidepressants). In this review, our aim was to review the latest knowledge on bloating physiopathology and therapeutic options trying to shed lights on those processes where a clinician could intervene to modify disease course.

The spectra, symptom profiles and overlap of Rome III functional gastrointestinal disorders in a tertiary center in South China

OBJECTIVE

Most previous studies exploring the overlap of functional gastrointestinal disorders (FGID) focus on the overlap between functional dyspepsia (FD) and irritable bowel syndrome (IBS). In this study, we aimed to explore the spectra, symptom profiles and overlap of all FGID using the validated Chinese version of the Rome III questionnaire.

METHODS

Consecutive newly diagnosed FGID patients who were admitted to the Outpatient Gastroenterology Clinic from 10 May to 10 September 2012 were recruited in the study. All the patients complained of gastrointestinal (GI) symptoms for at least 3 months with a symptom onset of at least 6 months before diagnosis after excluded organic diseases. Patients who met the inclusion criteria were asked to complete the scoring algorithm for the Rome III integrated questionnaire.

RESULTS

Among 350 eligible patients, 302 (86.3%) returned completed questionnaires. A total of six major domains including 17 disorders were diagnosed. The four most prevalent FGID were FD (54.6%), IBS (40.7%), unspecified functional bowel disorder (13.9%) and functional constipation (12.6%). The three most prevalent symptoms in FGID were abdominal pain (66.2%), loose stool (58.3%) and abdominal bloating/distension (56.3%). Of the 302 patients, 152 (50.3%) had one to five overlapping FGID. Only functional bloating had no overlap. Six patients had five overlapping FGID simultaneously. In all, 63 patients had overlapping FD and IBS.

CONCLUSIONS

This study provided the detailed spectra and symptom profiles for all FGID. Overlapping FGID are common in China.

Irritable bowel syndrome: the problem and the problem of treating it - is there a role for probiotics?

The aim of this review is to highlight the impact of irritable bowel syndrome (IBS) in those patients who consult the medical profession and examine the therapeutic potential of probiotics in this condition, where there is a strong need for new treatment options. Traditionally, IBS is frequently regarded as a trivial condition which is certainly not life threatening and mainly psychological in origin. However, these preconceptions are misplaced, as in some patients the condition can be devastating with the pain being as severe as that of childbirth coupled with incapacitating bowel dysfunction. In addition, patients suffer from a variety of non-colonic symptoms such as low backache, constant lethargy, nausea and genito-urinary problems, all of which lead to these patients having extremely poor quality of life. Unfortunately, the treatment of IBS is very unsatisfactory with only one new medication being developed for this condition in the last 25 years. It is now recognised that IBS is a multifactorial condition with symptoms being triggered by a variety of factors, some of which appear to be influenced by probiotics, resulting in speculation that they may have therapeutic potential in this condition. There have been over thirty controlled clinical trials of probiotics in IBS with approximately two-thirds of these studies showing evidence of an improvement in symptoms. However, not all probiotics appear to be effective with different symptoms being improved by different strains and some improving symptoms more than others. Consequently, the ideal probiotic for the treatment of IBS has yet to be defined, but the evidence is good enough to encourage further research with the aim of identifying an optimal strain or strains.

Irritable bowel syndrome: The evolution of multi-dimensional looking and multidisciplinary treatments

Irritable bowel syndrome (IBS) is common in the society. Among the putative pathogeneses, gut dysmotility results in pain and disturbed defecation. The latter is probably caused by the effect of abnormal gut water secretion. The interaction between abnormal gas accumulation, abdominal pain and bloating remains controversial. Visceral hypersensitivity and its modification along with the central transmission are the characteristics of IBS patients. The identification of biologic markers based on genetic polymorphisms is undetermined. Imbalanced gut microbiota may alter epithelial permeability to activate nociceptive sensory pathways which in turn lead to IBS. Certain food constituents may exacerbate bowel symptoms. The impact of adult and childhood abuses on IBS is underestimated. Using the concept of biopsychosocial dysfunction can integrate multidimensional pathogeneses. Antispasmodics plus stool consistency modifiers to treat the major symptoms and defecation are the first-line drug treatment. New drugs targeting receptors governing bowel motility, sensation and secretion can be considered, but clinicians must be aware of their potential serious side effects. Psychiatric drugs and modalities may be the final options for treating intractable subjects. Probiotics of multi-species preparations are safe and worth to be considered for the treatment. Antibiotics are promising but their long-term safety and effectiveness are unknown. Diet therapy including exclusion of certain food constituents is an economic measure. Using relatively safe complementary and alternative medicines (CAMs) may be optional to those patients who failed classical treatment. In conclusion, IBS is a heterogeneous disorder with multidimensional pathogeneses. Personalized medicines with multidisciplinary approaches using different classes of drugs, psychiatric measures, probiotics and antibiotics, dietary therapy, and finally CAMs, can be considered.

Chronic functional bowel syndrome enhances gut-brain axis dysfunction, neuroinflammation, cognitive impairment, and vulnerability to dementia

The irritable bowel syndrome (IBS) is a common chronic functional gastrointestinal disorder world wide that lasts for decades. The human gut harbors a diverse population of microbial organisms which is symbiotic and important for well being. However, studies on conventional, germ-free, and obese animals have shown that alteration in normal commensal gut microbiota and an increase in pathogenic microbiota-termed "dysbiosis", impact gut function, homeostasis, and health. Diarrhea, constipation, visceral hypersensitivity, and abdominal pain arise in IBS from the gut-induced dysfunctional metabolic, immune, and neuro-immune communication. Dysbiosis in IBS is associated with gut inflammation. Gut-related inflammation is pivotal in promoting endotoxemia, systemic inflammation, and neuroinflammation. A significant proportion of IBS patients chronically consume alcohol, non-steroidal anti-inflammatories, and fatty diet; they may also suffer from co-morbid respiratory, neuromuscular, psychological, sleep, and neurological disorders. The above pathophysiological substrate is underpinned by dysbiosis, and dysfunctional bidirectional "Gut-Brain Axis" pathways. Pathogenic gut microbiota-related systemic inflammation (due to increased lipopolysaccharide and pro-inflammatory cytokines, and barrier dysfunction), may trigger neuroinflammation enhancing dysfunctional brain regions including hippocampus and cerebellum. These as well as dysfunctional vago-vagal gut-brain axis may promote cognitive impairment. Indeed, inflammation is characteristic of a broad spectrum of neurodegenerative diseases that manifest demntia. It is argued that an awareness of pathophysiological impact of IBS and implementation of appropriate therapeutic measures may prevent cognitive impairment and minimize vulnerability to dementia.

Abdominal bloating: pathophysiology and treatment

Abdominal bloating is a very common and troublesome symptom of all ages, but it has not been fully understood to date. Bloating is usually associated with functional gastrointestinal disorders or organic diseases, but it may also appear alone. The pathophysiology of bloating remains ambiguous, although some evidences support the potential mechanisms, including gut hypersensitivity, impaired gas handling, altered gut microbiota, and abnormal abdominal-phrenic reflexes. Owing to the insufficient understanding of these mechanisms, the available therapeutic options are limited. However, medical treatment with some prokinetics, rifaximin, lubiprostone and linaclotide could be considered in the treatment of bloating. In addition, dietary intervention is important in relieving symptom in patients with bloating.

Probiotics and irritable bowel syndrome

Irritable bowel syndrome (IBS) is common gastrointestinal problems. It is characterized by abdominal pain or discomfort, and is associated with changes in stool frequency and/or consistency. The etiopathogenesis of IBS may be multifactorial, as is the pathophysiology, which is attributed to alterations in gastrointestinal motility, visceral hypersensitivity, intestinal microbiota, gut epithelium and immune function, dysfunction of the brain-gut axis or certain psychosocial factors. Current therapeutic strategies are often unsatisfactory. There is now increasing evidence linking alterations in the gastrointestinal microbiota and IBS. Probiotics are living organisms which, when ingested in certain numbers, exert health benefits beyond inherent basic nutrition. Probiotics have numerous positive effects in the gastrointestinal tract. Recently, many studies have suggested that probiotics are effective in the treatment of IBS. The mechanisms of probiotics in IBS are very complex. The purpose of this review is to summarize the evidence and mechanisms for the use of probiotics in the treatment of IBS.

Refractory inflammatory bowel disease-could it be an irritable bowel?

Patients with IBD who are apparently in remission-as indicated by normal blood tests, endoscopic findings and ultrasonography results-often continue to experience symptoms. Furthermore, despite these negative findings, there is a temptation to increase their anti-inflammatory medication in the hope that this approach would lead to some improvement. However, this strategy often seems to fail and can sometimes lead to adverse events. Consequently, when evidence of continuing inflammatory activity is lacking it might be appropriate to consider the possibility of co-existent IBS in these patients and to treat them for this condition. Dietary manipulation, antispasmodic agents, antidepressants (especially of the tricyclic variety) and even behavioural treatments might result in a worthwhile improvement of symptoms.

Computed tomography assessment of intestinal gas volumes in functional gastrointestinal disorders

BACKGROUND/AIMS

Many patients with functional gastrointestinal disorders (FGIDs) rank sensations of bloating and distension among their most debilitating symptoms. Previous studies that have examined intestinal gas volume (IGV) in patients with FGIDs have employed a variety of invasive and imaging techniques. These studies are limited by small numbers and have shown conflicting results. The aim of our study was to estimate, using CT of the abdomen and pelvis (CTAP), IGV in patients attending FGID clinic and to compare IGV in patients with and without FGID.

METHODS

All CTAP (n = 312) performed on patients (n = 207) attending a specialized FGID clinic over 10-year period were included in this study. Patients were classified into one of 3 groups according to the established clinical grading system, as organic gastrointestinal disorder (OGID, ie, patients with an organic non-functional disorder, n = 84), FGID (n = 36) or organic and functional gastrointestinal disorder (OFGID, ie, patients with an organic and a functional disorder, n = 87). Two independent readers blinded to the diagnostic group calculated IGV using threshold based 3D region growing with OsiriX.

RESULTS

Median IGVs for the FGID, OGID, and OFGID groups were 197.6, 220.6 and 155.0 mL, respectively. Stepwise linear regression revealed age at study, gender, and calculated body mass index to predict the log IGV with an r(2) of 0.116, and P < 0.001. There was a significant positive correlation between age and IGV in OGID (Spearman's = 0.253, P = 0.02) but this correlation was non-significant in the other groups.

CONCLUSIONS

Although bloating is a classic symptom in FGID patients, IGV may not be increased compared with OGID and OFGID patients.

Intestinal gas: has diet anything to do in the absence of a demonstrable malabsorption state?

PURPOSE OF REVIEW

To summarize the relevant publications during the last 12 months supporting that diet can influence gas-related symptoms in the absence of a malabsorption state.

RECENT FINDINGS

Gas symptoms during carbohydrate fermentation: a diet incorporating beans is well tolerated by a majority of individuals involved in a program of heart disease biomarkers. By contrast, in patients with irritable bowel syndrome, a diet avoiding fermentable carbohydrates improved gas-related abdominal symptoms. The rate of fermentation determines the production of abdominal symptoms, and many slowly fermentable fibers have a rapid fermentation profile that can generate abdominal symptoms. Modulation of visceral sensitivity: diet can influence gas symptoms by increasing the tolerability of the intestine to gas. Capsaicin decreases visceral hyperalgesia and improved bloating in patients with irritable bowel syndrome. Changes in gas-producing bacteria: different strains of Lactobacillus have antimicrobial properties against gas-forming coliforms. New clinical studies show beneficial effects of prebiotics and probiotics on abdominal bloating.

SUMMARY

Actual data suggest that diet could improve gas-related abdominal symptoms acting on several mechanisms: gas production, visceral hypersensitivity and modulation of gas-producing enteric bacteria.

Functional abdominal bloating with distention

Ten to 25% of healthy persons experience bloating. It is particularly common in persons with the irritable bowel syndrome and constipation. While the cause of bloating remains unknown old explanations such as a excessive intestinal gas, exaggerated lumbar lordosis and psychiatric problems have been disproved. New suggestions include recent weight gain, weak or inappropriately relaxed abdominal muscles, an inappropriately contracted diaphragm and retained fluid in loops of distal small bowel. No treatment is of unequivocal benefit but a low FODMAPs diet, probiotics and the non-absorbable antibiotic rifaximin offer some hope. Treatment by weight loss, abdominal exercise, prokinetics and girdles need more study.

Diet in subjects with irritable bowel syndrome: a cross-sectional study in the general population

Background

Patients with irritable bowel syndrome (IBS) often relate symptoms to the intake of certain foods. This study assesses differences in diet in subjects with and without IBS.

Methods

The cross-sectional, population-based study was conducted in Norway in 2001. Out of 11078 invited subjects, 4621 completed a survey about abdominal complaints and intake of common food items. IBS and IBS subgroups were classified according to Rome II criteria.

Results

IBS was diagnosed in 388 subjects (8.4%) and, of these, 26.5% had constipation-predominant IBS (C-IBS), 44.8% alternating IBS (A-IBS), and 28.6% diarrhoea-predominant IBS (D-IBS). Low intake of dairy products (portions/day) (Odds Ratio 0.85 [CI 0.78 to 0.93], p = 0.001) and high intake of water (100 ml/day) (1.08 [1.02 to 1.15], p = 0.002), tea (1.05 [1.01 to 1.10], p = 0.019) and carbonated beverages (1.07 [1.01 to 1.14], p = 0.023) were associated with IBS. A lower intake of dairy products and a higher intake of alcohol and carbonated beverages were associated with D-IBS and a higher intake of water and tea was associated with A-IBS. In subjects with IBS the severity of symptoms was associated with a higher intake of vegetables and potatoes in subjects with C-IBS, with a higher intake of vegetables in subjects with A-IBS, and with a higher intake of fruits and berries, carbonated beverages and alcohol in subjects with D-IBS.

Conclusions

In this study, the diet differed in subjects with and without IBS and between IBS subgroups and was associated with the severity of symptoms.

Pelvic floor dysfunction predicts abdominal bloating and distension in eating disorder patients

OBJECTIVE

Little is known about the symptoms of abdominal bloating and distension in women with eating disorders (EDs). This study aimed to explore the prevalence and predictors of these symptoms in patients with EDs, by examining correlations with functional gastrointestinal disorders (FGIDs) including pelvic floor symptoms and other clinical features.

MATERIAL AND METHODS

184 ED inpatients, 16-55 years, completed on admission to hospital the ROME II symptom questionnaire, additional questions about abdominal bloating and distension, and psychological questionnaires. Prediction of abdominal bloating and distension was modeled using logistic regression analyses with individual FGIDs, psychological variables, ED type, and clinical features as the potential predictors.

RESULTS

Bloating (78%) was more common than distension (58%) in each ED type. In the final multivariate models, after controlling for BMI, the number of Rome II symptoms of pelvic floor dyssynergia (i.e., having to strain to pass a stool, feeling unable to empty the rectum, and having difficulty relaxing to evacuate the stool) was a significant predictor of both abdominal distension (p < 0.001) and bloating (p < 0.005). The presence of irritable bowel syndrome (IBS, 46%) was a significant predictor of bloating (p < 0.001) but not distension.

CONCLUSIONS

Symptoms of pelvic floor dysfunction, but not IBS, appear to be especially important in the genesis of abdominal distension in patients with ED.

Prevalence and co-occurrence of upper and lower functional gastrointestinal symptoms in patients eligible for bariatric surgery

BACKGROUND

Obesity is considered as a risk factor for many functional digestive disorders. The aim of the present study was to evaluate the prevalence and the association of functional digestive symptoms affecting the upper and the lower digestive tract in patients eligible for bariatric surgery.

METHODS

Before surgery, 120 consecutive patients with normal upper endoscopy (7.5% males, mean BMI 44 ± 6 m/kg(2)) have filled a standard questionnaire in order to evaluate the presence of depressive symptoms and functional digestive disorders according to the Rome criteria. The major symptoms (esophageal, gastroduodenal, anorectal, and abdominal pain) were coded as dichotomous variables. Data analysis was performed using multivariate logistic regression with a backwards selection procedure adjusted only for the variables that were significant in univariate analysis (p < 0.05).

RESULTS

Functional symptoms were present in 89% of the subjects (2.5 functional digestive symptoms/subject). Depression symptoms were found in 43% of the patients. Esophageal symptoms were independent predictors for the presence of gastric, bowel, and anorectal symptoms. Functional abdominal pain and bowel symptoms were present, respectively, in 19% and 84% of the patients. Approximately half of the patients have specific functional bowel disorders (28.6% constipation, 18% irritable bowel syndrome, 18% diarrhea, 1% bloating) and 35.7% have non-specific bowel disorders. Anorectal symptoms were found in 40% of the patients: difficult defecation in 32% and fecal incontinence in 9.8% of the patients. Depression was an independent predictor for anorectal symptoms.

CONCLUSIONS

This study shows the high prevalence of functional bowel symptoms in patients complaining of morbid obesity.

Randomised clinical trial: the efficacy of prucalopride in patients with chronic intestinal pseudo-obstruction--a double-blind, placebo-controlled, cross-over, multiple n = 1 study

BACKGROUND

Chronic intestinal pseudo-obstruction is a disabling condition for which there are no established drug therapies. The condition is caused by a diverse range of intestinal myopathies and neuropathies.

AIM

To assess the therapeutic efficacy of prucalopride, a selective high-affinity 5-HT(4) receptor agonist, we employed a multiple n = 1 study design. Each patient acted as his/her own control, each day counting as one treatment episode, allowing comparison of 168 days on each of active drug and placebo.

METHODS

Double-blind, randomised, placebo-controlled, cross-over trial of four 12-week treatment periods, with 2-4 mg prucalopride or placebo daily. In each of the first and second 6 months there was a prucalopride and a placebo treatment. Patients with proven chronic intestinal pseudo-obstruction, including dilated gut, were included. Evaluation was by patient diary and global evaluation.

RESULTS

Seven patients participated (mean 42 years, five female, median symptom duration 11 years). Three discontinued, two due to study length, and one on prucalopride due to unrelated malnutrition and bronchopneumonia. Four patients (three visceral myopathy and one visceral neuropathy) completed the study; prucalopride significantly improved pain in three of four patients, nausea in two, vomiting in one, bloating in four and analgesic intake. Bowel function was not changed substantially.

CONCLUSIONS

n = 1 studies in rare conditions allow drug efficacy assessment. Prucalopride relieves symptoms in selected patients with chronic pseudo-obstruction.

Abdominal bloating and distension: what is the role of the microbiota

Most patients with irritable bowel syndrome complain of a sensation of an increase in pressure within their abdomen during the course of the day which is called bloating and, in approximately half of these individuals, this symptom is accompanied by an actual increase in abdominal girth, which is referred to as distension. The pathophysiology of these two phenomena is somewhat different and it is now recognised that a whole variety of overlapping mechanisms are involved. Some of these are potentially amenable to treatment by modification of the bacterial flora of the gut and this article reviews the evidence for this.

Relationships among the lactulose breath test, intestinal gas volume, and gastrointestinal symptoms in patients with irritable bowel syndrome

BACKGROUND AND AIMS

Irritable bowel syndrome (IBS) patients frequently complain of gas-related symptoms, and the lactulose breath test (LBT) is a test that assesses the amount of fermented gas generated by bacteria in the bowel. We aimed to assess the relationship among intestinal gas volume, LBT result, and gastrointestinal symptom score in healthy control and functional bowel disorder (FBD) subjects.

METHOD

In 84 IBS subjects, 24 FBD subjects other than IBS, and 25 healthy controls, a symptom questionnaire that enquired about seven main symptoms, plain abdominal radiography and a LBT were checked on the same day. The intestinal gas volume was calculated as the gas volume score (GVS) with a digitalized image of plain supine abdominal radiographs.

RESULTS

The GVS was greater in the LBT (+) group compared to the LBT (-) group (P = 0.02). The GVS was greater in the FBD and IBS groups than in the control group (P < 0.01). The GVS showed low but positive correlations with the severity and frequency of bloating, flatulence, abdominal pain, constipation, and tenesmus (P < 0.05). The severity of flatulence (P = 0.02) and the frequency of bloating (P = 0.02) in the LBT (+) group were significantly higher than those in the LBT (-) group.

CONCLUSIONS

Subjects with positive LBT had more gas-related symptoms and greater gas volume scores. Gas-related symptoms, positive LBT and increased GVS were significantly associated to each other. These findings can broaden the understanding of the pathophysiologic mechanisms of gas-related symptoms in IBS.

Abdomino-phrenic dyssynergia in patients with abdominal bloating and distension

OBJECTIVES

The abdomen normally accommodates intra-abdominal volume increments. Patients complaining of abdominal distension exhibit abnormal accommodation of colonic gas loads (defective contraction and excessive protrusion of the anterior wall). However, abdominal imaging demonstrated diaphragmatic descent during spontaneous episodes of bloating in patients with functional gut disorders. We aimed to establish the role of the diaphragm in abdominal distension.

METHODS

In 20 patients complaining of abdominal bloating and 15 healthy subjects, we increased the volume of the abdominal cavity with a colonic gas load, while measuring abdominal girth and electromyographic activity of the anterior abdominal muscles and of the diaphragm.

RESULTS

In healthy subjects, the colonic gas load increased girth, relaxed the diaphragm, and increased anterior wall tone. With the same gas load, patients developed significantly more abdominal distension; this was associated with paradoxical contraction of the diaphragm and relaxation of the internal oblique muscle.

CONCLUSIONS

In this experimental provocation model, abnormal accommodation of the diaphragm is involved in abdominal distension.