The Treatment of Functional Abdominal Bloating and Distension

M. Schmulson; L. Chang


Aliment Pharmacol Ther. 2011;33(10):1071-1086. 

In This Article

Abstract and Introduction


Background Abdominal bloating and distension are common symptoms in patients with functional gastrointestinal disorders (FGIDs), however, relatively little is known about their treatment.
Aim To review the treatment trials for abdominal bloating and distension.
Methods A literature review in Medline for English-language publications through February 2010 of randomised, controlled treatment trials in adults. Study quality was assessed according to Jadad's score.
Results Of the 89 studies reviewed, 18% evaluated patients with functional dyspepsia, 61% with irritable bowel syndrome (IBS), 10% with chronic constipation and 10% with other FGIDs. No studies were conducted in patients diagnosed with functional abdominal bloating. The majority of trials investigated the efficacy of prokinetics or probiotics, although studies are heterogeneous with respect to diagnostic criteria and outcome measures. In general, bloating and/or distension were evaluated as secondary endpoints or as individual symptoms as part of a composite score rather than as primary endpoints. A greater proportion of IBS patients with constipation reported improvement in bloating with tegaserod vs. placebo (51% vs. 40%, P < 0.0001) and lubiprostone (P < 0.001). A greater proportion of nonconstipating IBS patients reported adequate relief of bloating with rifaximin vs. placebo (40% vs. 30%, P < 0.001). Bloating was significantly reduced with the probiotics, Bifidobacterium infantis 35624 (1 × 108 dose vs. placebo: −.71 vs. −.44, P < 0.05) and B. animalis (live vs. heat-killed: −.56 ± 1.01 vs. −.31 ± 0.87, P = 0.03).
Conclusions Prokinetics, lubiprostone, antibiotics and probiotics demonstrate efficacy for the treatment of bloating and/or distension in certain FGIDs, but other agents have either not been studied adequately or have shown conflicting results.


Bloating is a common symptom that is reported by 6% to 31% of the general population.[1–3] It is usually considered the subjective sensation that is associated with abdominal distension, i.e. the visible increase in abdominal girth,[4,5] which is considered more of an objective sign. In a population-based study in Olmsted County in the United States, the age and gender-adjusted overall prevalence for bloating was 19% and 9% for visible abdominal distension.[6]

Bloating is a common complaint in patients with functional gastrointestinal disorders (FGIDs). In a U.S. study of a mixed population recruited from an academic university clinic and advertisement, of 542 patients with irritable bowel syndrome (IBS), 76% of patients reported abdominal bloating.[7] Moreover, in a cross-sectional study among employees of a Veterans Affairs Health Care Center in the United States, of which 39% were men, bloating was reported by 35% of individuals with nonconstipating IBS, 23% with nondiarrhoea IBS and 42% with non-investigated dyspepsia.[8]

However, studies suggest that while bloating and distension are related, they are two separate symptoms. For example, in the above mentioned study in an academic university clinic, 24% reported having bloating only and 76% had both bloating and visible abdominal distension.[7] IBS patients with bloating and distension had a higher female-to-male ratio, constipation predominance, symptom severity and less diurnal variation compared with those with bloating only. Patients with bloating with and without distension reported that symptoms progressively worsened during the day and were relieved by defecation or gas passage.[7] Approximately 50% of the subjects fulfilling modified Rome II criteria for dyspepsia reported bloating, while almost half of this group also had visible abdominal distension. In addition, subjects with dyspepsia were two times more likely to have bloating alone or distension alone when compared with controls.[6] In another U.S. study, distension defined by the presence of both bloating and visible abdominal distension was more prevalent than bloating alone in IBS and functional dyspepsia (FD), but bloating alone was more common than distension in functional constipation.[6]

Bloating has been considered a secondary criterion for IBS and FD according to the Rome I classification[9] and a supportive symptom for IBS in the Rome II and III diagnostic criteria.[10,11] Despite being a common symptom of several FGIDs,[12] the Rome classification includes Functional Bloating as an independent entity. The name has changed from Functional Abdominal Bloating both in Rome I and II[9,10] to Functional Bloating in Rome III (Table 1).[11] This diagnosis is made in patients with symptoms of bloating who do not meet the diagnostic criteria of IBS, FD or other FGIDs.

The pathophysiological mechanisms associated with abdominal bloating and distension are poorly understood. Bloating and distension together with eructation, aerophagia and flatulence, have been attributed to excessive intestinal gas accumulation.[13,14] Other proposed underlying mechanisms include impaired small intestinal handling of gas,[15] impaired clearance from the proximal colon,[16] psychological factors,[17] fluid retention,[18] food intolerance and carbohydrate malabsorption,[4,19] increase in lumbar lordosis,[5,20] weakness of abdominal wall musculature,[21] altered sensorimotor function,[22] small intestinal bacterial overgrowth and altered gut microflora.[23]

Although bloating and distension are very common symptoms, they are considered challenging to treat in clinical practice. Relatively little is known about the efficacy of treatments for these symptoms. Therefore, we reviewed the literature of treatment interventions for bloating and distension in patients with FGIDs.