Pilot Study on Gas Patterns of Irritable Bowel Syndrome and Small Intestinal Bacterial Overgrowth Following Ingestion of Lactulose

Abstract

Background & Aims: Fermentation site and increasing time of symptomatic gas would be different between irritable bowel syndrome (IBS) and small intestine bacterial overgrowth (SIBO). The aim of this study was to determine the time for increase in abdominal gas following ingestion of lactulose and the possibility of differential diagnosis of SIBO and IBS. Methods: A prospective study was conducted on a series of IBS patients (n = 14) who were referred to the Oroku-Hospital (Okinawa, Japan) from June 6, 2014 to December 30, 2014. Imaging was first performed in early morning after fasting. After ingestion of lactulose, 1 -4 plain abdominal radiographs were taken for investigation of increased gas during the indicated timeframe. Regions of interest of the gas areas were highlighted on the images obtained. Gas images were divided into three areas, the stomach, small intestine, and large intestine, and each total area was calculated. Results: At a dose of 10 g lactulose and an observation time of two hours, patients displayed no symptoms, and the gas volume was only slightly increased. However, when the dose of lactulose was increased (13 g/50 kg), and the observation time for the lactulose challenge was extended to 240 -300 minutes, the results clearly demonstrated an increase in the gas produced in IBS patients. Conclusions: An increased dose of lactulose coupled with an extended observation time for the lactulose challenge clearly demonstrated an increase in the gas produced in IBS patients. Alterations in diet rather than antibiotics might reduce IBS symptoms.

Logical hypothesis: Low FODMAP diet to prevent diverticulitis

“…Since this study measured the lactulose-induced increase of gas indirectly, with the hydrogen breath test, a more recent study of the FODMAP diet obtained a direct confirmation of the increasing intestinal gas by abdominal X-ray[68]; these findings, thus, support the theory that the FODMAP diet increases the intraluminal volume of gas and fluid.…”

“…Jang et al[69] performed a breath test in patients with right DD at 180 min following ingestion of 10 g of lactulose and determined that methane gas was increased but hydrogen gas was decreased in these individuals as compared to controls. It is important to note here, though, that gas volume is known to significantly increase in response to lactulose ingestion at time points greater than the 180 min used in that study, specifically at 240 to 300 min after the ingestion[68]. Therefore, to more accurately investigate the influence of colon gas on clinical symptoms, it is necessary that the study design allow for adequate time for fermentation to occur in the large intestine.…”