Abdominal Bloating and Distension in Functional GI Disorders
Abdominal Bloating and Distension in Functional GI Disorders
Background: A sensation of abdominal bloating, sometimes accompanied by an increase in girth (distension), is one of the most common and most intrusive features of functional bowel disorders.
Aim: To conduct a systematic, evidence-based review of the epidemiology and pathophysiology of abdominal bloating and its relationship to distension.
Methods: The terms bloating, distension, functional bowel, irritable bowel syndrome, constipation and diarrhoea were searched on MEDLINE up to 2006. References from selected articles and relevant abstracts were also included.
Results: Approximately 50% of irritable bowel syndrome patients with bloating also experience an increase in abdominal girth and this is more pronounced with constipation than diarrhoea. Bloating appears to be more frequently associated with visceral hypersensitivity, whereas distension is more often related to hyposensitivity and delayed transit. Although there is little evidence for excessive gas as a cause of bloating, gas infusion studies suggest that handling of gas may be impaired in irritable bowel syndrome and there may also be abnormal relaxation of the anterior abdominal musculature in these patients.
Conclusions: There is unlikely to be a single cause for bloating and distension, which probably have different, but overlapping, pathophysiological mechanisms. Relieving constipation might help distension, but the treatment of bloating may need more complex approaches involving sensory modulation.
Abdominal bloating and distension occur extremely commonly in the functional gastrointestinal disorders with many patients ranking them as particularly intrusive symptoms. Characteristically, the problem is exacerbated by meals, fluctuates in intensity, is worse at the end of the day and settles overnight. When these symptoms follow this pattern, they are almost pathognomonic of a functional gastrointestinal disorder and it is somewhat surprising that their diagnostic utility has not been harnessed more often. This is in part because these features do not appear to be so common in men, but to some extent, this is because men describe the problem differently often referring to it as a 'hardness' or 'tightness' of the abdomen. Probably the best way to view these features is that when they are present, they make the possibility of a functional bowel disorder almost certain but when absent, they don't exclude the diagnosis.
Until recently, research into bloating and distension has been sparse and largely empirical as well as being based on the assumption that the two descriptors were describing the same phenomenon. Thus, interpreting the data from older studies is difficult and even today, patients and their physicians often use the terms synonymously. However, with the development of more objective ways of assessing it such as the gas challenge technique or abdominal inductance plethysmography (AIP), there is increasing evidence that bloating and distension may have different pathophysiological mechanisms.
Background: A sensation of abdominal bloating, sometimes accompanied by an increase in girth (distension), is one of the most common and most intrusive features of functional bowel disorders.
Aim: To conduct a systematic, evidence-based review of the epidemiology and pathophysiology of abdominal bloating and its relationship to distension.
Methods: The terms bloating, distension, functional bowel, irritable bowel syndrome, constipation and diarrhoea were searched on MEDLINE up to 2006. References from selected articles and relevant abstracts were also included.
Results: Approximately 50% of irritable bowel syndrome patients with bloating also experience an increase in abdominal girth and this is more pronounced with constipation than diarrhoea. Bloating appears to be more frequently associated with visceral hypersensitivity, whereas distension is more often related to hyposensitivity and delayed transit. Although there is little evidence for excessive gas as a cause of bloating, gas infusion studies suggest that handling of gas may be impaired in irritable bowel syndrome and there may also be abnormal relaxation of the anterior abdominal musculature in these patients.
Conclusions: There is unlikely to be a single cause for bloating and distension, which probably have different, but overlapping, pathophysiological mechanisms. Relieving constipation might help distension, but the treatment of bloating may need more complex approaches involving sensory modulation.
Abdominal bloating and distension occur extremely commonly in the functional gastrointestinal disorders with many patients ranking them as particularly intrusive symptoms. Characteristically, the problem is exacerbated by meals, fluctuates in intensity, is worse at the end of the day and settles overnight. When these symptoms follow this pattern, they are almost pathognomonic of a functional gastrointestinal disorder and it is somewhat surprising that their diagnostic utility has not been harnessed more often. This is in part because these features do not appear to be so common in men, but to some extent, this is because men describe the problem differently often referring to it as a 'hardness' or 'tightness' of the abdomen. Probably the best way to view these features is that when they are present, they make the possibility of a functional bowel disorder almost certain but when absent, they don't exclude the diagnosis.
Until recently, research into bloating and distension has been sparse and largely empirical as well as being based on the assumption that the two descriptors were describing the same phenomenon. Thus, interpreting the data from older studies is difficult and even today, patients and their physicians often use the terms synonymously. However, with the development of more objective ways of assessing it such as the gas challenge technique or abdominal inductance plethysmography (AIP), there is increasing evidence that bloating and distension may have different pathophysiological mechanisms.
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