Recent advances in functional bowel disorders

Shino Shimura et al. Small Intestinal Bacterial Overgrowth in Patients with Refractory Functional Gastrointestinal Disorders. J Neurogastroenterol Motil 2016;22:60-68. Functional gastrointestinal disorders (FGID) are common; however, despite their prevalence the underlying pathophysiology is not well understood. The interest in the microbiome of the gut, and the differences in fermentation seen in patients with irritable bowel syndrome (IBS)and functional dyspepsia (FD) have led some researchers to suggest that small intestinal bacterial overgrowth (SIBO) may play a role. Standard therapy for FGDI in the form of antidepressants, prokinetics and antacids is likely to have a limited role in symptom of SIBO sufferers. In this study, the authors examined the frequency of SIBO in patients with refractory FGDI using Glucose Hydrogen Breath Testing (GHBT). The authors defined FGDI as failure of afore mentioned pharmacological therapies for 4 weeks or more, fulfilling Rome III criteria, without alternative organic cause to explain symptoms and effort was taken to exclude confounding variables. Enrolled patients testing positive for SIBO (2/38) were treated with Levofloxacin for 7 days. 1 patient had IBS and one had FD, both were female and negative for Helicobacter Pylori. Following antibiotic treatment GHBT was redone and both participants showed normal patterns. Patients were assessed before and after treatment using the Izumo Scale (a self-assessment of abdominal symptoms effect on quality of life). Post treatment assessment showed a reduction in symptoms of fullness though little other changes in symptoms. The authors comment that the Japanese study cohort may have lower SIBO than the literature has suggested in other populations (ranging from 2-84% in IBS sufferers), and likely reflects variations in SIBO diagnostic tests, diet and geographic variations in small intestinal microbiome. The authors concede that their cohort is unlikely to be generalizable due to the low rates of SIBO in Japan that their cohort was sourced from a tertiary centre. However they stress that SIBO is an important differential in hard to treat patients with IBS or FD.