Prevalence and clinical features of the hydrogen-and-methane variant of the course of the small intestinal bacterial overgrowth syndrome in children with functional dyspepsia

Abstract

Prevalence of small intestinal bacterial overgrowth (SIBO) syndrome, improved diagnostic accuracy and therapeutic approaches require further study. The purpose of this research was to evaluate the effect of hydrogen dominant or hydrogen-producing SIBO (H-SIBO) and methane dominant or methane-producing SIBO (M-SIBO) types on the severity of clinical manifestations in children with functional dyspepsia (FD). Materials and methods used: a single-center cross-sectional study of 90 pediatric patients: 41 (45.6%) aged 11.0 [9.0:13.0] y/o with FD, of which 20 (48.8%) girls/21 (51.2%) boys, and 49 (54.4%) evaluatively healthy children (“control group”) aged 12.0 [9.5:13.6] y/o, of whom 27 (55.1%) girls/22 (44.9%) boys. The SIBO was determined with the domestically-produced “Lactophan” hydrogen breathing test by AMA Co., Ltd. (Saint Petersburg, Russia) and the “GastroCH4ECK Gastrolyzer” CH4 & H2 monitor by Bedfont Scientific Ltd. (Harrietsham, Maidstone, Kent, England, UK). Results: SIBO (41/100% and 28/57.1%, p<0.001) and H-SIBO (29/70.7% and 18/36.7%, p=0.045) were statistically significantly more often detected in children with FD than in the control group. The M-SIBO incidence (12/29.3% and 10/20.4%, p=0.467) did not differ statistically significantly between the groups. The methane output at the 60th to 90th minutes of the breathing test was 1.7 to 1.8 times higher in FD patients. The hydrogen threshold values at the 60th minute of the breathing test in FD patients for predicting of complaints were as follows: above 35 ppm (ROC-AUC=0.88, 95% CI=0.61-1.00, SE 87.5%, SP 97.2%) for “Sour taste in the mouth,” and above 33 ppm (ROC-AUC=0.80, 95% CI=0.53-1.00, SE 80.6%, SP 75.0%) for “Diarrhea.” The hydrogen threshold value at the 90th minute of the breathing test for “Flatulence” symptom was 44 ppm (ROC-AUC=0.71, 95% CI=0.36-0.88, SE 60.9%, SP 75.0%). Conclusion: testing for methane had increased the accuracy of SIBO diagnosis by 29.3% in patients with FD, i.e. from 70.7% to 100%! The relationship between the hydrogen and the methane concentrations coupled with the presence of dyspeptic symptoms may require the correction of SIBO in patients with FD.