# ddw 2005 SIBO



## eric (Jul 8, 1999)

Digestive Disease Week 2005Functional Bowel Disorders -- Clinical Highlights CMESmall Intestinal Bacterial Overgrowth in IBSSmall Intestinal Bacterial Overgrowth in IBSRecurrent abdominal pain associated with bloating and altered bowel function is the typical composite for the pathology described as IBS. However, the symptoms associated with IBS are similar to those associated with small intestinal bacterial overgrowth. Data from one study[10] have suggested a high prevalence of small intestinal bacterial overgrowth in patients with IBS. This study was criticized because of the low accuracy of the lactulose breath test, which was used to define small intestinal bacterial overgrowth. Glucose has become the preferred substrate for hydrogen breath testing. Additional work aimed at clarifying the potential association between small intestinal bacterial overgrowth and IBS was presented during this year's DDW meeting.In this setting, Lupascu and colleagues[11] assessed the prevalence of small intestinal bacterial overgrowth by glucose breath testing in IBS patients vs healthy controls. The study involved patients with IBS as defined by Rome II criteria; an appropriately matched group without IBS served as the control population. The study authors found a significantly increased (P < .05) proportion of patients with small intestinal bacterial overgrowth among patients in the IBS group: 20 of 65 (30.7%) compared with 4 of 102 (3.9%) controls. These findings are consistent with an increasing awareness of a postinfectious IBS syndrome.McCallum and colleagues[12] presented additional evidence on the association of small intestinal bacterial overgrowth with IBS. They evaluated only patients with IBS with diarrhea using the glucose breath test, assessing both H2 and CH4 production as criteria for a positive test. They defined a prevalence rate of small intestinal bacterial overgrowth of 38.5% in their population of 143 patients with IBS with diarrhea. For the breath-test analysis, 74.5% of patients were positive only by H2 analysis, and 23.6% were positive only by the CH4 analysis. These investigators suggest that both the H2 and CH4 analysis should be performed to optimize the interpretation of these breath tests in this population of patients.CommentaryBoth of these studies are provocative in suggesting a high prevalence of small intestinal bacterial overgrowth in IBS. However, there are limitations before these data can be extrapolated to the "world" of IBS. The study by Lupascu and colleagues did not separate patients by subtype of IBS (eg, IBS with diarrhea vs IBS with constipation). There is an emerging body of evidence regarding postinfectious IBS. In these patients, there is a clearly defined start date (ie, symptoms) and the condition is typically more homogeneous (ie, generally IBS with diarrhea). Clearly, we will need prospective randomized controlled trials with identification of the specific patient IBS subtypes to further explore the potential of this association.http://www.medscape.com/viewarticle/506599


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