Small intestinal bacterial overgrowth in patients with lower gastrointestinal symptoms and a history of previous abdominal surgery.

ABSTRACT

BACKGROUND: The small intestinal bacterial overgrowth (SIBO) breath test has had positive results in 84% of patients with irritable bowel syndrome vs 20% of controls. We hypothesized that SIBO would be more prevalent in patients with symptoms consistent with irritable bowel syndrome who have undergone previous abdominal surgery. OBJECTIVE: To identify causative factors for SIBO. DESIGN: Retrospective review. SETTING: Tertiary colorectal surgery clinic. MAIN OUTCOME MEASURE: Result of SIBO breath test. RESULTS: We identified 77 patients whose differential diagnosis included SIBO from January 1, 2005, to December 31, 2007; 18 were excluded because of noncompliance with testing and 2 because of a decision to treat SIBO without formal testing. Symptoms were chronic abdominal pain in 30 patients (53%), bloating in 25 (44%), constipation in 37 (65%), and diarrhea in 7 (12%). Mean (SD) symptom duration was 45 (22) months. Of the 57 patients enrolled in this study, 45 (79%) tested positive for SIBO and 37 (82%) of those had a history of surgery, whereas 12 (21%) tested negative for SIBO and 9 (75%) of those had a history of surgery. Of the 36 SIBO-positive patients with a history of abdominal surgery (mean number of procedures, 2), the surgery locations were as follows female reproductive organs, 23 (64%); hindgut, 15 (42%); foregut, 8 (22%); and midgut, 6 (17%). Open surgery alone was performed in 32 patients (56%) vs laparoscopic surgery in 7 (12%). Both open and laparoscopic procedures had been performed in 6 patients (11%). Four patients (7%) had a history of small intestinal obstruction. The mean age of SIBO-positive patients was higher than that of SIBO-negative patients (57 vs 44 years; P < .01). Analysis did not reveal any clinically significant independent factor associated with SIBO. CONCLUSION: Physicians should consider SIBO in the differential diagnosis of patients with normal anatomic findings and chronic lower gastrointestinal complaints.