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

Richard Lea, MD; Peter J. Whorwell, MD

In This Article

How to Manage Patients With Bloating

The majority of patients complaining of bloating are ultimately diagnosed as suffering from one of the functional gastrointestinal disorders. However, it is important to exclude organic explanations when indicated. When extreme, distension can cause concern that conditions such as ascites or subacute obstruction are being overlooked, but it is usually possible to distinguish these conditions from bloating clinically, especially if the characteristic diurnal pattern associated with functional distension is present. Approaches to the diagnosis of functional gastrointestinal disorders have been reviewed in detail elsewhere and will not be discussed at length here.[47] Whether tests for bacterial overgrowth or carbohydrate malabsorption should be routinely undertaken in patients with bloating is controversial, although these are unlikely to harm the patient and may sometimes be useful for symptomatic management. The possibility of celiac disease also needs to be considered, especially in high prevalence areas, and serologic testing, which is now widely available, has made screening for this condition much easier. Very rarely, specific tests for other forms of malabsorption, such as pancreatic insufficiency, may be necessary, although overinvestigation should be avoided.

There is no completely satisfactory treatment for bloating in patients with functional gastrointestinal disorders, although in most cases, some improvement in this symptom can be achieved. Patients seen in hospital practice have often been advised to take a high-fiber diet that is frequently detrimental,[48] and consequently, we routinely recommend a trial of wheat-fiber withdrawal which seems to reduce bloating and distension in a good proportion of cases. Other dietary modifications may also help -- for example, limitation of fat intake, avoiding carbonated drinks, and excluding artificial sweeteners. A discussion of dietary treatments for IBS can be found elsewhere.[49] It is not known whether exercises to strengthen the anterior abdominal musculature would be helpful despite evidence that these muscles may be weak in patients with IBS.[12]

A number of medications aimed at limiting intestinal gas volumes have been suggested for use in patients with bloating, although experience with these agents has largely been disappointing. Simethicone, an antisurfactant is frequently used by patients, but there appears to be little objective evidence of benefit over placebo.[50] Beano, which is an alpha-galactosidase preparation capable of digesting complex sugars, has been shown to reduce flatus volume and frequency, but not bloating.[51] Activated charcoal is frequently recommended for gas-related complaints, but evidence for any beneficial effect has largely been conflicting.[52,53] Rifaximin, which is a nonabsorbable antibiotic, has been shown to reduce gas production, flatus events, and abdominal distension, although, paradoxically, no improvement in bloating was reported in this study.[33] In another study from the Barcelona group which is of potential therapeutic importance, it was reported that intravenous neostigmine was capable of reversing both gas retention and symptoms following the gas challenge test.[54]

Antispasmodics warrant a trial, although there is little evidence that they have particular utility in reducing bloating.[55] Treating constipation can be helpful, but it is important to note that some laxatives such as lactulose and fermentable fiber preparations may actually worsen bloating and gas-related symptoms. Approximately one third of patients with functional gastrointestinal disorders improve with antidepressants, yet again, no studies have specifically addressed the effect of this class of drug on bloating.[56] Various psychological therapies have also been found to be helpful in improving IBS symptomatology and there is evidence that hypnotherapy can improve bloating.[57,58] However, these treatments vary considerably in their local availability and by their very nature can only be offered to restricted numbers of patients with more severe symptoms.

Finally, it is of considerable interest that tegaserod, a new 5-HT4 receptor partial agonist, has been shown to improve the symptom of bloating. Several large randomized, controlled trials have consistently demonstrated an improvement in bloating with this drug in patients with IBS,[59,60,61] and pooled data from a number of trials have confirmed this effect, suggesting that tegaserod may have specific utility for this indication.[62]


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