A study on the role of small intestinal bacterial overgrowth in patients with functional dyspepsia

Background: Functional dyspepsia (FD) accounts for majority of dyspepsia. Before labeling them as FD, a bunch of investigations to be done to rule out organic cause. Small intestinal bacterial overgrowth (SIBO) which is one of the cause for dyspepsia is not commonly sought and always neglected among physicians. So we aimed to study the frequency of SIBO in patients with dyspeptic symptoms and whether to include investigations to diagnose SIBO in the algorithm of approach to dyspepsia. Materials and methods: We consecutively enrolled 50 newly diagnosed functional dyspepsia patients based on Rome III criteria and 50 healthy controls in this study. They underwent glucose hydrogen breath test (GHBT) after overnight fasting. Results: In the cases with FD, 6 (12%) subjects were found to have positive GHBT and diagnosed as SIBO, whereas in the controls 2 (4%) had positive GHBT with no statistical significant difference among groups with a P value of 0.140. In the cases with FD, the most common subtype was post prandial distress syndrome (46%), followed by epigastric pain syndrome (36%) and mixed type (18%). Patients with SIBO were treated with rifaximin 1200 mg/day in divided doses for 10 days. GHBT was repeated after 4 weeks and found to be normalized in all cases. Conclusion: SIBO should be considered before making a diagnosis of FD. GHBT is a simple non- invasive method to diagnose SIBO. One could avoid taking unnecessary drugs by timely diagnosis of SIBO in patients with dyspepsia.