Kimberly Low

The Degree of Breath Methane Production in IBS Correlates With the Severity of Constipation

BACKGROUND:Recent work has demonstrated that among irritable bowel syndrome (IBS) subjects, methane on lactulose breath test (LBT) is nearly universally associated with constipation predominance. This work has been based on subjective constipation outcomes. In this study, methane is compared to constipation in another population of IBS subjects with constipation being determined both subjectively and objectively.METHODS:A nested study was conducted in subjects enrolled in a double-blind randomized placebo-controlled study. After consent, subjects were asked to complete a stool diary for 7 days. This included logging of all bowel movements that week as well as documenting the stool consistency for each during the same period using the Bristol Stool Score. After 7 days, subjects were asked to rate their symptoms on a visual analogue scale (VAS) score (0–100 mm) for diarrhea and constipation. They then had an LBT to evaluate both methane and hydrogen profiles over 180 min. Subjects with methane were compared to those without methane for Bristol Stool Score, stool frequency, as well as VAS scores for diarrhea and constipation. The degree of constipation was then compared to the quantity of methane production on LBT based on area under the curve.RESULTS:Among 87 subjects, 20 (23.8%) produced methane. IBS subjects with methane had a mean constipation severity of 66.1 ± 36.7 compared to 36.2 ± 30.8 for nonmethane producers (P < 0.001). The opposite was noted for diarrhea (P < 0.01). On LBT, the quantity of methane seen on breath test was directly proportional to the degree of constipation reported (r = 0.60, P < 0.01). In addition, greater methane production correlated with a lower stool frequency (r = −0.70, P < 0.001) and Bristol Stool Score (r = −0.58, P < 0.01).CONCLUSION:Methane on LBT is associated with constipation both subjectively and objectively. The degree of methane production on breath test appears related to the degree of constipation.

Efficacy of the glucagon‐like peptide‐1 agonist exenatide in the treatment of short bowel syndrome

Background  Short bowel syndrome (SBS) is a serious clinical disorder characterized by diarrhea and nutritional deprivation. Glucagon‐like peptide‐1 (GLP‐1) is a key hormone, produced by L‐cells in the ileum, that regulates proximal gut transit. When extensive ileal resection occurrs, as in SBS, GLP‐1 levels may be deficient. In this study, we test whether the use of GLP‐1 agonist exenatide can improve the nutritional state and intestinal symptoms of patients with SBS.

A Combination of Rifaximin and Neomycin Is Most Effective in Treating Irritable Bowel Syndrome Patients With Methane on Lactulose Breath Test

There is a growing interest in methane and its association with constipation in functional bowel disease. Neomycin-based treatment of methane-positive subjects has resulted in improvement of constipation. Rifaximin, although superior for the treatment of irritable bowel syndrome compared with other antibiotics, seems less effective in methane-positive subjects. In this study, we evaluate 3 different antibiotic treatments in patients who have a methane-positive breath test: rifaximin only, neomycin only, and the combination of neomycin and rifaximin. Methods A retrospective chart review was conducted on patients with methane on their lactulose breath test (≥3 ppm of methane) who received one of the following antibiotic treatments: 500 mg b.i.d. for 10 days of neomycin alone, 400 mg t.i.d. for 10 days of rifaximin alone, or a combination of both rifaximin and neomycin for 10 days. All patients must have received antibiotic treatment after their initial consultation at the medical center and, in addition, had at least 1 follow-up to evaluate the effects of the treatment. After inclusion/exclusion criteria were met, all charts were evaluated to determine if the subject was a responder to the antibiotic therapy. This included clinical symptom improvement and eradication of methane on their breath test. Results Of the subjects receiving the treatment of rifaximin and neomycin (n=27), 85% had a clinical response, compared with 63% of subjects in the neomycin only group (n=8) (P=0.15) and 56% of subjects in the rifaximin only group (n=39) (P=0.01). When comparing the neomycin group with the rifaximin group, the difference was nonsignificant. When evaluating methane eradication results, 87% of subjects taking the rifaximin and neomycin combination eradicated the methane on their breath test. This is compared with 33% of subjects in the neomycin group that eradicated the methane (P=0.001), and only 28% of subjects in the rifaximin group (P=0.001). Of the patients who did not eliminate the methane with only rifaximin treatment, 66% of those who subsequently used the rifaximin and neomycin treatment were able to normalize their breath test. Conclusions The combination of rifaximin and neomycin is more effective in treating methane-producing subjects—in both clinical response and methane elimination.

Role of Cytolethal Distending Toxin in Altered Stool Form and Bowel Phenotypes in a Rat Model of Post-infectious Irritable Bowel Syndrome

Background/Aims Campylobacter jejuni infection is a leading cause of acute gastroenteritis, which is a trigger for post-infectious irritable bowel syndrome (PI-IBS). Cytolethal distending toxin (CDT) is expressed by enteric pathogens that cause PI-IBS. We used a rat model of PI-IBS to investigate the role of CDT in long-term altered stool form and bowel phenotypes. Methods Adult Sprague-Dawley rats were gavaged with wildtype C. jejuni (C+), a C. jejuni cdtB knockout (CDT-) or saline vehicle (controls). Four months after gavage, stool from 3 consecutive days was assessed for stool form and percent wet weight. Rectal tissue was analyzed for intraepithelial lymphocytes, and small intestinal tissue was stained with anti-c-kit for deep muscular plexus interstitial cells of Cajal (DMP-ICC). Results All 3 groups showed similar colonization and clearance parameters. Average 3-day stool dry weights were similar in all 3 groups, but day-to-day variability in stool form and stool dry weight were significantly different in the C+ group vs both controls (P < 0.01) and the CDT- roup (P < 0.01), but were not different in the CDT- vs controls. Similarly, rectal lymphocytes were significantly higher after C. jejuni (C+) infection vs both controls (P < 0.01) and CDT-exposed rats (P < 0.05). The counts in the latter 2 groups were not significantly different. Finally, c-kit staining revealed that DMP-ICC were reduced only in rats exposed to wildtype C. jejuni. Conclusions In this rat model of PI-IBS, CDT appears to play a role in the development of chronic altered bowel patterns, mild chronic rectal inflammation and reduction in DMP-ICC.

Factor analysis demonstrates a symptom cluster related to methane and non-methane production in irritable bowel syndrome.

Introduction Irritable bowel syndrome (IBS) is a chronic disorder often subdivided into constipation-predominant and diarrhea-predominant forms. Earlier studies have shown that IBS patients with methane detected on lactulose breath test (LBT) are more likely to have constipation. The goal of this study was to conduct a factor analysis to determine whether there is a cluster of symptoms associated with methane production. Methods Patients with IBS referred for a LBT completed a questionnaire assessing 31 symptoms. The degree of each symptom was graded on a visual analog scale of 0 to 5. Exploratory factor analysis was carried out separately in methane and nonmethane patients. A score was determined for each symptom cluster by summing across the related variables. The cluster scores were compared between the 2 groups by the Wilcoxon rank-sum test. Results A total of 459 IBS patients (72 with methane, 387 with nonmethane) were evaluated. On the basis of factor analysis results, 3 symptom clusters (bloating weighted, pain weighted, and constipation weighted) were created in methane-producing patients. Two symptom clusters (bloating weighted and diarrhea weighted) were created in the nonmethane group. The groups did not differ significantly on the methane-derived bloating score (P=0.24) or the pain score (P=0.15). However, the methane-derived constipation score was significantly higher in the methane group, 15.3±4.9 versus 13.4±4.9, P=0.002. The constipation-weighted cluster included the following symptoms: constipation, lack of milk intolerance, lack of weight loss, small bowel movements, and straining. The diarrhea cluster score was significantly higher in the nonmethane group, 14.2±8.0 versus 11.3±6.5, P=0.005. The diarrhea cluster included the following symptoms: diarrhea, pain with bowel movements, pain after bowel movements, foul-smelling bowel movements, and large bowel movements. The groups did not differ significantly on the nonmethane-derived bloating cluster, P=0.11. Conclusions Methane-producing IBS patients have a unique cluster of symptoms related to constipation.

T1832 Methanobrevibacter Smithii is Prominent in Stool of Subjects With Constipation Predominant IBS and Methane on Lactulose Breath Test

G A A b st ra ct s disease with hepatocellular carcinoma (HCC). Microsporidial infection was positive on wet preparation in 8(2.7%), in 11(3.7%) on Trichrome staining and in 13(4.3%) on PCR. Microsporidia was diagnosed with PCR in 8(61%) (p= 0.002) with IBS-D, 4(31%) with HCC and 1(8%) with functional dyspepsia. Conclusion: Microsporidial infection may be associated with IBS-D. PCR for microsporidia has a better yield than examination of a wet preparation or Trichrome staining