Elevated Methane Levels in Small Intestinal Bacterial Overgrowth Suggests Delayed Small Bowel and Colonic Transit

Abstract

Limited research exists regarding the relationship between small intestinal bacterial overgrowth (SIBO), small bowel transit (SBT), and colonic transit (CT). Furthermore, symptom analysis is limited between the subtypes of SIBO: hydrogen producing (H-SIBO) and methane producing (M-SIBO). The primary aims of this study are to: compare the SBT and CT in patients with a positive lactulose breath test (LBT) to those with a normal study; compare the SBT and CT among patients with H-SIBO or M-SIBO; compare the severity of symptoms in patients with a positive LBT to those with a normal study; compare the severity of symptoms among patients with H-SIBO or M-SIBO.A retrospective review was performed for 89 patients who underwent a LBT and whole gut transit scintigraphy (WGTS) between 2014 and 2016. Seventy-eight patients were included. WGTS evaluated gastric emptying, SBT (normal ≥40% radiotracer bolus accumulated at the ileocecal valve at 6 hours), and CT (normal geometric center of colonic activity = 1.6-7.0 at 24 hours, 4.0-7.0 at 48 hours, 6.2-7.0 at 72 hours; elevated geometric center indicates increased transit). We also had patients complete a pretest symptom survey to evaluate nausea, bloating, constipation, diarrhea, belching, and flatulence.A total of 78 patients (69 females, 9 males, mean age of 48 years, mean BMI of 25.9) were evaluated. Forty-seven patients had a positive LBT (H-SIBO 66%, M-SIBO 34%). Comparison of SBT among patients with a positive LBT to normal LBT revealed no significant difference (62.1% vs 58.6%, P = .63). The mean accumulated radiotracer was higher for H-SIBO compared to M-SIBO (71.5% vs 44.1%; P < .05). For CT, all SIBO patients had no significant difference in geometric centers of colonic activity at 24, 48, and 72 hours when compared to the normal group. When subtyping, H-SIBO had significantly higher geometric centers compared to the M-SIBO group at 24 hours (4.4 vs 3.1, P < .001), 48 hours (5.2 vs 3.8, P = .002), and at 72 hours (5.6 vs 4.3, P = .006). The symptom severity scores did not differ between the positive and normal LBT groups. A higher level of nausea was present in the H-SIBO group when compared to the M-SIBO group.Overall, the presence of SIBO does not affect SBT or CT at 24, 48, and 72 hours. However, when analyzing the subtypes, M-SIBO has significantly more delayed SBT and CT when compared to H-SIBO. These results suggest the presence of delayed motility in patients with high methane levels on LBT.Abbreviations: BMI = body mass index, CT = colonic transit, H-SIBO = hydrogen type small intestinal bacterial overgrowth, IBD = inflammatory bowel disease, IBS = irritable bowel syndrome, LBT = lactulose breath test, M-SIBO = methane type small intestinal bacterial overgrowth, PAGI-SYM = Patient Assessment of Gastrointestinal Disorders Symptom Severity Index, PPM = parts per million, SBT = small bowel transit, SIBO = small intestinal bacterial overgrowth, WGTS = whole gut transit scintigraphy, WMC = wireless motility capsule.

The effectiveness of rotating versus single course antibiotics for small intestinal bacterial overgrowth

“…Indeed, delayed small bowel transit and colonic transit have been described in methane-producing SIBO. 26 Female gender was overrepresented in our patients as described previously in SIBO 14 but was not associated with clinical evolution.…”

“…Although GBT is not the gold standard for the diagnosis of methanogenic flora, 25 the relief of bloating symptoms may result from a greater decrease in methane‐producing gut flora in patients treated with rotating antibiotics. Indeed, delayed small bowel transit and colonic transit have been described in methane‐producing SIBO 26 …”

Small Intestinal Bacterial Overgrowth and Irritable Bowel Syndrome – An Update

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Oral Iron Supplementation—Gastrointestinal Side Effects and the Impact on the Gut Microbiota

“…Methane has been linked with the slowing of intestinal transit [56]. Oro-caecal and whole gut transit time significantly decrease in methane producers compared to nonmethane producers [56] and methane attenuates peristaltic movement in the intestines by promoting the contraction of non-propagating circular muscles [57,64]. Whilst there is an association between methane and constipation, it is uncertain whether methane is a cause or consequence of constipation [58].…”