Exam Cram

• Pathophysiology: bacterial overgrown in small bowel

• Presentation: bloating, diarrhoea, increased flatus; anaemia

• Diagnosis: hydrogen (14-D xylose) breath test, 

• Management: metronidazole 

Outline

Background

• Common in those with GI dysmotility: 

  • Systemic Sclerosis (40%), Marfan's Syndrome 

  • Previous surgery

  • Diabetic gastroparesis (45%)

Assessment

History

•  Abdominal bloating, diarrhoea & increased flatus

Examination

• Abdomen: soft but distended

• Pale conjunctiva

Investigations

• Anaemia, B12 deficiency, Osteomalacia, HypoCalcaemia 

• Breath test: lactulose hydrogen or carbohydrate

• Barium meal: jejunal diverticulae

Diagnosis

Diagnostic criteria: lactulose hydrogen breath test

Differentials: Giardia Gastroenteritis, Irritable Bowel Syndrome, Coeliac Disease

Management

Acute: 

• Metronidazole

Med Reg Notes

Diagnosis

• Exhaled peak of hydrogen > 20ppm within 90 minutes is diagnostic

• In SIBO the lactulose is metabolised much faster due to overgrowth

• Duodenal aspirate gold standard but not routinely required

Management II

Other options after metronidazole:

1. Rifampicin or Tetracycline

2. Jejunal aspiration: grow organism

References and Resources

Written in 2024