Confused About Abdominal Bloating? – No More!

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adominalMichael Ash BSc(Hons).DO. ND. FDipION reviews the current understanding behind bloating and distension.

The unpleasant symptoms of bloating and abdominal distension are common and bothersome, affecting up to 96% of patients with functional gastrointestinal disorders (such as IBS) and an estimated 30% of the general population. Clear pathophysiologic explanations have been lacking and available treatment options can appear contradictory and ineffective. Treatments will be explored in a follow up review.

Bloating refers to the subjective sensation of abdominal swelling, whereas visible abdominal distension refers to an actual increase in abdominal girth.[1] For a long time, these have been poorly understood symptoms, but recent studies, have shed some light on the different mechanisms involved in the generation of these symptoms and summarised in this review.[2],[3]

Specialised measuring devices called abdominal inductance plethysmography (a test used to measure changes in blood flow or air volume in different parts of the body) and computed tomography ((CT) A diagnostic technique in which x-rays are taken in many different directions. A computer synthesises the x-rays to generate cross-sectional and other images of the body) have convincingly demonstrated that distension of the abdomen is a real event with some patients exhibiting as much as a 12cm increase in abdominal girth.[4]

However, bloating and distension are not always present at the same time. In IBS studies only half of ‘bloated patients’ also have visible distension.[5] This sub group of ‘bloated and distended’ patients tend to present with constipation and visceral hyposensitivity, whereas the simply ‘bloated’ group present more frequently with diahorrea and visceral hypersensitivity.

The more severe the bloating the greater the change in rectal perception[6] (The lower threshold for pain or discomfort in response to distension).[7] It may well be that bloating and distension have a mix of common and uncommon causes.

Click on the image below to see an enlarged model of possible causes and exacerbating factors in the development of bloating and distension. This diagram was extracted from: Gastroenterology. Volume 136, Issue 5, May 2009, Pages 1487-1490