Small intestine bacterial overgrowth is frequent in cystic fibrosis: combined hydrogen and methane measurements are required for its detection

摘要

Hydrogen breath test (BT) is commonly used as a diagnostic tool for the detec-tion of small intestine bacterial overgrowth (SIBO). It was reported that colonic methane pro-duction is far more frequent in cystic fibrosis (CF) patients than in other subjects. Therefore,measuring exclusively hydrogen in the diagnostic breath test for diagnosing SIBO might be oflimited value. We aimed to assess the usefulness of combined measurement of hydrogen andmethane expiration for the diagnosis of SIBO in CF. Material and Methods: The study com-prised 62 CF patients aged 5 to 18 years. Three-hundred-ninety subjects assessed due to gas-trointestinal symptoms for the presence of SIBO served as a comparative group. In all subjectshydrogen/methane BT using glucose was performed. A positive BT was defined as fasting hy-drogen ≥20 ppm or fasting methane ≥10 ppm or a rise of ≥12 ppm hydrogen or i6 ppm meth-ane over baseline during the test. Results: In 23 (37.1%) CF patients and in 52 (13.3%) subjectsfrom the comparative group abnormal BT results were found. In seven (11.3%) CF patients and29 (7.4%) of the other subjects studied methane measurement allowed diagnosis of SIBO. Con-clusions: Small intestine bacterial overgrowth is frequent in cystic fibrosis. For its detection incystic fibrosis and other gastrointestinal patients, combined hydrogen and methane measure-ment instead of hydrogen breath test should be applied. Without the additional measurementof methane a significant percentage of SIBO will be missed.