Lactulose Hydrogen Breath Test In Patients With Diarrhea- Predominant Irritable Bowel Syndrome And The Effects Of Antibiotics

Objective:The relationship between small intestine bacterial overgrowth (SIBO) and irritable bowel syndrome (IBS) remains controversial. This study was aimed to investigate the positive rate of lactulose hydrogen breath test (LHBT) and the effect of short-term administration of antibiotic in patients with diarrhea-predominant irritable bowel syndrome (IBS-D).Methods:The LHBTs and the relationship between LHBT and symptom scores of IBS were detected in 89 cases of patients with IBS-D. Antibiotics(tinidazole or sparfloxacin) were administrated to 16 patients with LHBT-positive IBS-D for one week, and their effects on the symptom scoes of IBS investigated.Results:Among the 89 cases of IBS-D,46 cases (51.7%) are LHBT positive. At the aspects of the degree and the frequency of abdominal pain, and abdominal distention, there exists a significant difference between the LHBT-positive and negative IBS-D patients (P<0.05). After the treatment of antibiotics,10 cases (62.5%) with LHBT-positive turned to LHBT negative and there was a positive correlation between the symptom-improvement rate (Y) and the reduction rate(X) of H2 breath(Y= 31.3+0.34X,r=0.61, P=0.03).Conclusions:These results indicated that 51.7% IBS-D patients had SIBO, which contributed to the symptom of abdominal pain and abdominal distension. A short-term antibiotic treatment improved the symptoms in some LHBT-positive IBS-D patients.