Clinical Gastroenterology and Hepatology
Volume 7, Issue 1 , Pages 7-8, January 2009

Impact of Bloating and Distention in Irritable Bowel Syndrome: Have We Wandered too far From the Manning Creed?

published online 16 October 2008.

Article Outline

 

Bloating, distention, and various other symptoms rightly or wrongly attributed to excessive accumulation or emission of gas are undoubtedly common among irritable bowel syndrome (IBS) patients. Indeed, many clinicians would regard complaints such as “I get so bloated when I eat,” “I feel six months pregnant by evening time,” or “I suffer terribly from trapped wind” as virtually pathognomonic of IBS.1 Furthermore, of the many symptoms that assail the IBS sufferer, bloating and distention are among those most recalcitrant to therapy, some accolade in a syndrome scarcely renowned for its susceptibility to cure! Thus distention is included in one of the first diagnostic schemes in IBS, the Manning criteria.2 Later studies of the prevalence of bloating and related symptoms among IBS patients attending a physician attested not only to the high prevalence of these symptoms but also to their frequent contribution to patient distress and impairment of quality of life.3, 4 In this month's issue of Clinical Gastroenterology and Hepatology, Ringel et al5 provided further evidence of the impact of these symptoms in their study of bloating among a large community sample by illustrating in a U.S. population, as Hungin et al6 had in Europe, just how common and distressful bloating is in IBS. Yet, these very symptoms are notable by their absence among the criteria most commonly used nowadays for the definition and classification of IBS for clinical trials, Rome I through III.7, 8, 9 If bloating and distention are so common and important to the IBS patient, why are they so ignored by the cognoscenti?

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I Bloat: Therefore I'm not! 

Valid objections to the inclusion of bloating and distention amid the Rome canon have been mounted and include the relatively high prevalence of bloating in the general population; the difficulties that many face in attempting to describe, never mind define, the symptoms and, in so doing, differentiate on a consistent basis between bloating distention, flatulence, and gas; and the challenges that the translation of these symptoms into other languages and across differing cultures presents.

The fact that bloating, or a complaint akin to it, is common in the general population10 is certainly an issue that the epidemiologist and clinical investigator should be aware of, although the growing evidence that bloating in IBS is a source of much distress and a contributor to an impaired quality of life, as again evidenced by Ringel et al,5 should surely allow the clinician and the clinical researcher alike to differentiate that which might well be “normal” in the general population from that which is pathologic and a very significant component of the IBS constellation. Here we can draw on an analogy from the upper gastrointestinal tract; no one would argue that the occasional episode of heartburn, such as any individual might suffer from in relation to dietary excess or indiscretion, implies that all have a disease, gastroesophageal reflux disease (GERD).11 This moniker is reserved for those who not only have frequent or severe heartburn, but who have incurred impairment in quality of life as a consequence. To dismiss bloating in IBS because it is common would be equivalent to discarding heartburn, a cardinal symptom of GERD, as valueless in its assessment. Bloating is a most common and troubling symptom for the IBS patient; it is our duty not to ignore it but to seek to understand it better within the context of the syndrome.

The clinical differentiation of bloating from distention reflects, for the most part, clinical sloppiness on our behalf and a failure to listen to the patient and understand what they actually mean by these symptoms. Peter Whorwell, a contributor of novel and important ideas to this literature, is quite clear on this issue; bloating refers “to a sensation of increased abdominal pressure,” whereas “distent should only be used when there is an actual change in abdominal circumference.”1 A considerable body of clinical and research evidence supports the veracity of these concepts; although bloating and distention often occur together, they are different. Distention in IBS is real; the idea that it was imagined or represented some sort of patient trick or artifice provides yet another example of the paternalistic approach that was often taken to IBS patients and their symptoms in the past.12, 13, 14 Not only can changes in abdominal girth be detected in both control subjects and IBS patients, but just as our patients have been telling us for years, distention does indeed progress through the day and is exacerbated by meals.12 Furthermore, bloating is not a consistent accompaniment of measured changes in girth.14, 15, 16 The pathogenesis of these symptoms is complex and includes contributions from gas trapping,17 enhanced sensitivity to luminal distention,18 dysfunctional abdominal wall and diaphragmatic responses to intra-abdominal pressure,19, 20 and perhaps very localized changes in gas content. The observation, in the study herein, by Ringel et al5 that bloating is especially common among those whose predominant bowel habit is constipation, thereby confirming an observation made by others,3 also speaks to the relevance of distinct motor or sensory factors in its pathogenesis. Most interesting in this regard is the suggestion by Agarwal et al14 that bloating might result from relative visceral hypersensitivity, whereas those who distend are relatively hyposensitive. The differentiation of bloating from distention has now, therefore, transcended mere semantics and has even made the transition from concept to evidence.

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What We Need to Know? 

Bloating and distention should be accepted as valid components of the IBS spectrum and no longer dismissed as unworthy to be seen in the company of their supposedly illustrious fellow travelers, pain and bowel dysfunction.21 Indeed, for many patients, bloating and distention are the issue; especially because our limited therapeutic arsenal can have some impact on pain, constipation, and diarrhea, yet leave bloating and distention unscathed to linger unabashed and distress the sufferer. It is time to listen to the patient, strive to understand what they mean, and follow the lead of those researchers who have strived to bring science to bear on these challenging clinical issues.

When it comes to bloating and distention count me in with the Manning crowd (with due apology to Thomas Hardy)!

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References 

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  2. Manning AP, Thompson W, Heaton KW, et al. Toward positive diagnosis of irritable bowel. Br Med J. 1978;2:653–654
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PII: S1542-3565(08)01039-2

doi:10.1016/j.cgh.2008.10.010

Clinical Gastroenterology and Hepatology
Volume 7, Issue 1 , Pages 7-8, January 2009