Abdominal Bloating

doi:10.1053/j.gastro.2005.06.062

Gastroenterology

Volume 129, Issue 3, September 2005, Pages 1060-1078

https://doi.org/10.1053/j.gastro.2005.06.062 Get rights and content

Abdominal bloating is a common and significant clinical problem that remains to be scientifically addressed. Bloating is one of the most bothersome complaints in patients with various functional gut disorders. However, in the current standard classification, abdominal bloating is merely regarded as a secondary descriptor, which masks its real clinical effect. Four factors are involved in the pathophysiology of bloating: a subjective sensation of abdominal bloating, objective abdominal distention, volume of intra-abdominal contents, and muscular activity of the abdominal wall. The primer to elicit subjective bloating may be any of the other 3 factors, or the sensation may be related to distorted perception. All of these mechanisms may play an independent role or may be interrelated. Gas transit studies have evidenced that patients with bloating have impaired reflex control of gut handling of contents. Segmental pooling, either of gas or of solid/liquid components, may induce a bloating sensation, particularly in patients with altered gut perception. Furthermore, altered viscerosomatic reflexes may contribute to abdominal wall protrusion and objective distention, even without major intra-abdominal volume increment. Bloating probably is a heterogeneous condition produced by a combination of pathophysiological mechanisms that differ among individual patients and that in most cases are subtle and undetectable by conventional methods. Further advances in the pathophysiology and clinical forms of bloating are warranted to develop mechanistic strategies rather than the current empiric treatment strategies for comprehensive and effective management of this problem.

Section snippets

Aims and Methods

Our aim was to clarify the concept, clinical importance, and pathophysiology of abdominal bloating and, thereby, to pave the way for the comprehensive management of this problem. Specifically, we performed a critical analysis of the following topics: the pathophysiological mechanisms involved in bloating, the various forms of presentation of bloating in clinical practice, and the current treatment options for this heterogeneous condition.

To this aim, a literature review was performed based on a

Pathophysiology of Bloating: Putative Factors and Mechanisms

Four factors are included in the pathophysiology of bloating: subjective sensation, objective girth changes, volume of intra-abdominal contents, and muscular activity of the abdominal walls (Figure 1). The primer to elicit subjective bloating may be any of the other 3 factors, or the sensation may be related to distorted perception. These mechanisms, ie, abnormal perception, objective distention, intra-abdominal volume increment, and abdominal wall dystony, may play an independent role or may

An Integrative Overview

Bloating may be produced by different mechanisms. The pathophysiology of bloating may be evident, for instance, in case of intra-abdominal volume increment, but in most patients, the dysfunction that leads to bloating is more subtle and difficult to detect by conventional methods. Gas transit studies have evidenced that patients with bloating have impaired reflex control of gut handling of contents (Figure 7). Segmental pooling, either of gas or of solid/liquid components, may induce a bloating

General Clinical Features

Abdominal bloating presents some characteristic and well-recognized features, but given the scarcity of systematic investigations, data are mostly based on physicians’ impressions. Recently, Whitehead’s group (personal communication, December 2003) has initiated a large-scale study to characterize the diverse clinical presentations of bloating; this study may yield useful information.

Bloating, as with most functional gastrointestinal symptoms, is much more frequent in women than in men.1, 4 The

Management

As described previously, abdominal bloating is a multifactorial and multimorphic clinical condition. The management of these patients is mostly unclear, but in some subgroups, specific recommendations can be made.

Conclusion

Bloating is being increasingly recognized as an important clinical problem. Predictably, in the next few years this condition will elicit a concerted effort to understand its pathogenetic mechanisms and to develop effective therapy. In this review, we have proposed a framework for the investigation of bloating, taking into account both the clinical and the laboratory perspectives. Given the paucity of prior solid information on bloating, rather than providing answers, we aimed at formulating a

Acknowledgment

The authors thank Gloria Santaliestra for secretarial assistance.

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Abdominal Bloating in the United States: Results of a Survey of 88,795 Americans Examining Prevalence and Healthcare Seeking
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Citation Excerpt :
Concomitant GI symptoms experienced in patients with organic GI diseases may contribute to this finding and can be postulated from our study as well because concomitant symptoms of abdominal pain, constipation, and excess gas were associated with increased bloating and its severity. This also is consistent with clinical practice because bloating often is reported as a nonspecific symptom or intermixed with other symptoms.1 Thus, it is important that providers proactively screen for bloating in patients with IBS and other chronic GI conditions, or in individuals who have concomitant GI symptoms.
Although abdominal bloating is a common symptom, comparatively little is known about its prevalence in the community. This study aimed to examine the prevalence of bloating and assess related health care seeking using survey data from a nationally representative sample of nearly 89,000 Americans.
Participants completed the National Gastrointestinal (GI) Survey II to measure the presence and severity of GI symptoms including bloating. We assessed the prevalence of bloating in the past 7 days, as well as severity and health care seeking for bloating. Multivariable regression was performed to identify associations between the outcomes and covariates.
Of 88,795 survey completers, 12,324 (13.9%) reported bloating in the past 7 days. Women and those with comorbidities (eg, irritable bowel syndrome, chronic constipation, ulcerative colitis) and concomitant GI symptoms (eg, abdominal pain, excess gas) had higher odds for bloating (all P < .001). These factors were also associated with more severe bloating (all P < .001). Among those who reported recent bloating, 58.5% never sought care for bloating—29% of whom were self-managing symptoms or were uncomfortable discussing symptoms with their providers.
Bloating is common in the community because nearly 1 in 7 Americans have experienced this symptom in the past week. Women and those with certain comorbidities and concomitant GI symptoms are more likely to experience bloating and have more severe symptoms. Nearly one third of sufferers who have not sought care are managing symptoms on their own or are uncomfortable discussing it with their providers, emphasizing that efforts should be made to proactively inquire about bloating.
Understanding small intestinal dysmotility symptoms: Bloating, distension, and gas
2023, Handbook of Gastrointestinal Motility and Disorders of Gut-Brain Interactions, Second Edition
Abdominal bloating, defined as sensation of increased abdominal pressure, and visible abdominal distension may be associated or may present independently. Intestinal dysmotility and intestinal gas retention are very uncommon causes of abdominal bloating and distension. Abdominal bloating is generally associated with other symptoms of functional gut disorders, is produced by the same pathophysiological mechanisms, particularly intestinal hypersensitivity, and responds to the same treatments. Visible abdominal distention is by-and-large a conditioned somatic response with abnormal postural tone (abdominophrenic dyssynergia) that can be corrected by behavioral (biofeedback) treatment.
Intestinal gas production by the gut microbiota: A review
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In addition to causing embarrassment, intestinal gas can be associated with more serious symptoms. This review provides an overview of gas production by the human gut microbiome and outlines foods associated with intestinal gas. Bacteroides, Ruminococcus, Roseburia, Clostridium, Eubacterium, Desulfovibrio, and Methanobrevibacter are among the most abundant microbes responsible for intestinal gas. More than 99% of intestinal gas is composed of hydrogen, carbon dioxide, and methane, while less than 1% is composed of other odiferous compounds. Food groups associated with intestinal gas include pulses, vegetables, fruits, grains, and, for some individuals, dairy. These foods are rich in non–digestible carbohydrates such as raffinose family oligosaccharides, fructans, polyols, and, for sensitive individuals, lactose. These carbohydrates are fermented by colonic bacteria and produce gases directly or by cross–feeding. Additional research on gas production by the gut microbiota and foods associated with gas may help mitigate the symptoms linked to intestinal gas.
Mechano-Regulation of Gene Expression in the Gut: Implications in Pathophysiology and Therapeutic Approaches in Obstructive, Inflammatory, and Functional Bowel Disorders
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The gastrointestinal (GI) tract is composed of a series of hollow organs, subject to transient or persistent mechanical stress. Recent studies have revealed that persistent mechanical stress is present in obstructive and inflammatory conditions and alters gene transcription in the GI tract. Mechanical stress-induced gene expression (mechano-transcription) of inflammatory molecules, pain mediators, pro-fibrotic and growth factors has been shown to play a critical role in pathogenesis of motility dysfunction, visceral hypersensitivity, inflammation, and fibrosis in the gut. Specifically, mechanical stress-induced cyclo-oxygenase-2 (COX-2) and other pro-inflammatory mediators in gut smooth muscle cells account for motility dysfunction and inflammatory process. Mechano-transcription of nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and other pain mediators may lead to visceral hypersensitivity. Emerging evidence suggests that mechanical stress in the gut also leads to up-regulation of certain pro-fibrotic and proliferative mediators such as connective tissue growth factor (CTGF) and osteopontin (OPN), which may contribute to fibrostenotic Crohn’s disease. In this chapter, we will discuss the pathophysiological significance of mechano-transcription of pro-inflammatory molecules, pain mediators, pro-fibrotic and growth factors in obstructive, inflammatory, and functional bowel disorders. We will also evaluate potential therapeutic targets of mechano-transcription process for the management of these disorders.
Correction of Abdominal Distention by Biofeedback-Guided Control of Abdominothoracic Muscular Activity in a Randomized, Placebo-Controlled Trial
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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.
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.
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).
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.
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: Supported in part by the National Institutes of Health (grant DK57064), the Spanish Ministry of Education (grant BFI 2002-03413), and the Instituto Carlos III (grant C03/02).

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Special reports and reviewsAbdominal Bloating

Section snippets

Aims and Methods

Pathophysiology of Bloating: Putative Factors and Mechanisms

An Integrative Overview

General Clinical Features

Management

Conclusion

Acknowledgment

Am J Gastroenterol

Clin Gastroenterol

Am J Gastroenterol

Am J Gastroenterol

Am J Gastroenterol

Am J Gastroenterol

Gastroenterology

Gastroenterology

Gastroenterology

Am J Gastroenterol

Pain

Gastroenterology

Gastroenterology

Gastroenterology

Gastroenterology

Gastroenterology

Gastroenterology

Lancet

Gastroenterology

Gastroenterology

Gastroenterology

Am J Gastroenterol

Gastroenterology

Am J Gastroenterol

Gastroenterology

Am J Gastroenterol

Am J Med

Gastroenterology

Am J Gastroenterol

Lancet

Gastroenterology

Med Clin North Am

Am J Gastroenterol

Functional gastroduodenal disorders

Functional bowel disorders in functional abdominal pain

Abdominal pain, bloating, and diarrhea in the United Statesprevalence and impact

Dig Dis Sci

A patient questionnaire to identify bowel disease

Ann Intern Med

An irritable bowel syndrome-specific symptom questionnairedevelopment and validation

Scand J Gastroenterol

Irritable bowel-type symptoms in spontaneous and induced constipation

Gut

Treatment of excessive intestinal gas

Curr Treat Opin Gastroenterol

Intestinal gas

Gas in the alimentary canal

Gastrointestinal gas

Visible abdominal distention and gas surfacedescription of an automatic method of evaluation and application to patients with irritable bowel syndrome and dyspepsia

Eur J Gastroenterol Hepatol

Abdominal distension in female patients with irritable bowel syndromeexploration of possible mechanisms

Gut

A prospective study of unexplained visible abdominal bloating

N Z Med J

Effect of rectal distension on abdominal girth

Neurogastroenterol Motil

Ambulatory abdominal inductance plethysmographytowards objective assessment of abdominal distension in irritable bowel syndrome

Gut

Abdominal distension in irritable bowel syndrome (IBS)diurnal variation and its relationship to abdominal bloating

Gut

Relationship of abdominal bloating to physical distension in irritable bowel syndrome (IBS)effect of bowel habit

Neurogastroenterol Motil

Special reports and reviews
Abdominal Bloating