Expert Commentary -- Bloating, Distension, and the Irritable Bowel Syndrome

Richard Lea, MD; Peter J. Whorwell, MD

In This Article

The Relationship Between Bloating and Distension

Chang and colleagues[4] recently conducted a questionnaire study investigating the relationship between bloating and distension and found that three quarters of patients with IBS with bloating also described physical abdominal distension, whereas only one quarter had bloating alone. Several factors were reported to influence this relationship: for example, bloating and distension were more frequently associated with constipation and female sex. Furthermore, although bloating without distension was rarely described as an intrusive symptom, bloating with distension was frequently ranked as one of the most bothersome symptoms of IBS.

Several studies have attempted to objectively determine whether bloating is actually associated with abdominal distension. In one of these investigations, Sullivan[12] showed that in patients with bloating, abdominal girth during symptomatic episodes was greater than that measured in controls. In another study, Maxton and colleagues[21] also demonstrated increased abdominal distension in patients with IBS. However, both of these studies used tape measures and could have been unintentionally influenced either by the patient or investigator. Abdominal inductance plethysmography is a technique that overcomes these problems by allowing objective, continuous measurement of girth in ambulatory patients -- if necessary, over prolonged time periods. The technique was validated by Lewis and colleagues[22,23] in healthy volunteers and showed a high correlation with girth measurements made with tape measures, being accurate to within 1 mm. Additional studies using this technique have objectively demonstrated that abdominal distension is indeed increased in patients with IBS compared with controls, and furthermore, that the symptom of bloating correlates with the degree of abdominal distension.[24] Another technique that has recently been validated in healthy volunteers is an extensometer based on ultrasound, although this is not currently capable of measuring girth in ambulatory patients.[25]


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