Utility of Hydrogen and Methane Breath Tests in Combination with X-Ray Examination after a Barium Meal in the Diagnosis of Small Bowel Bacterial Overgrowth after Jejuno-Ileal Bypass for Morbid Obesity

To study why the symptoms of abdominal bloating occurring in a number of patients after jejuno-ileal bypass for morbid obesity become resistant to antibiotics, we used a method which combined a hydrogen breath test after lactulose with an X-ray examination of the abdomen after barium. Ten operated patients with bloating symptoms resistant to antibiotics, ten operated patients without symptoms or with pre-existing symptoms, that had remitted after antibiotic treatment and ten non-operated obese controls were investigated. There was a significant correlation between post-surgical symptoms persisting after antibiotics and the exhalation of large amounts of hydrogen of colonic origin (> 100 parts per million) after lactulose. Furthermore, symptomatic patients had high prevalence of colonic motility disorders (slow transit). In these patients, treatment with a prokinetic (cisapride 40 mg/kg/day for 10 days) reduced colonic transit time, colonic hydrogen production and bloating symptoms. Abdominal symptoms in these patients may therefore have other causes than small-bowel bacterial overgrowth alone. All operated patients with persistent abdominal bloating should therefore be investigated before starting empirical treatment with antibiotics.