Aetiology, diagnosis and management of small intestinal bacterial overgrowth

Abstract

Small intestinal bacterial overgrowth is a small bowel disorder characterised by excessive amounts of bacteria populating the small intestine leading to symptoms of abdominal pain, bloating and change in bowel habit. This creates some degree of diagnostic uncertainty due to the overlap of these symptoms with numerous other gastrointestinal conditions. Quantitative culture of jejunal aspirates is the gold standard diagnostic test but has largely been replaced by glucose and lactulose breath tests due to their relative ease and accessibility. The approach to treatment centres around reducing bacterial numbers through antibiotic therapy and managing any predisposing factors. Further research is required in order to define the optimum antibiotic choice and duration of therapy as well as the potential diagnostic utility of home breath testing and capsule-based technology.

Keywords: ANTIBIOTIC THERAPY; BACTERIAL OVERGROWTH; NUTRITION; SMALL BOWEL.

Figure 1

Breath test in a healthy patient versus a patient with small bowel intestinal overgrowth (SIBO) showing an earlier rise in hydrogen.

Figure 2

Breath test in a patient with Small Bowel Intestinal Overgrowth with double peak representing the early rise seen in the small intestine followed by a short duration fall in hydrogen before the expected rise in hydrogen in the large bowel.