Overview
Small intestinal bacterial overgrowth (SIBO) describes excessive bacterial growth in the small bowel. Unlike the colon, the small bowel has significantly fewer bacteria present. Inflammation due to invasive strains of bacteria leads to clinical symptoms.
Epidemiology
- SIBO is more common in women
- The incidence of SIBO increases with age
Risk Factors
Risk factors typically include disorders of abnormal gastrointestinal (GI) motility:
- Irritable bowel syndrome (IBS)
- Opioid misuse
- Hypothyroidism
- Diabetes mellitus
- Scleroderma
Presentation
Patients present with features similar to IBS:
- Abdominal pain
- Bloating
- Flatulence
- Diarrhoea
Investigations
- Hydrogen breath test – the test of choice:
- The patient fasts and is fed glucose, which is metabolised by bacteria-producing hydrogen. Increased levels suggest SIBO.
Management
Treatment involves managing the underlying disorder with gastric motility. Rifaximin may be considered.
