Inflammatory bowel disease (summary)

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This is a basic article for medical students and other non-radiologists

Inflammatory bowel disease is a generic term used to describe diseases of the GI tract that have an inflammatory cause. Crohn disease (CD) and ulcerative colitis (UC) are the commonest causes of inflammatory bowel disease.

Reference article

This is a summary article; read more in our article on inflammatory bowel disease.

Summary

  • epidemiology
    • young adults
      • CD: 15-25 years, M=F
      • UC: 15-40 years, M>F
  • presentation
    • chronic diarrhea (may be bloody)
    • abdominal pain
    • Crohns may present with extra-intestinal features
  • pathophysiology
    • CD: any part of the bowel may be affected
      • skip lesions, fistulation
    • US: only the colon is affected
  • investigation
    • blood tests: raised inflammatory markers, e.g. CRP, ESR
    • colonoscopy: visualize abnormal areas and allow biopsy
    • ultrasound: thickened bowel wall
    • CT: used in the acutely unwell patient to identify complications
    • MRI: assessment of small bowel or perianal fistula (Crohn)
  • treatment
    • disease-modifying drugs
      • steroids
      • immunomodulation, e.g. azathioprine, cyclosporine, methotrexate
      • biological agents, e.g. infliximab
    • surgical treatment
      • strictures, fistulae, abscess, perforation
      • non-responding bowel disease, e.g. colectomy

Role of imaging

Radiology can be useful for diagnosis and follow-up.

  • identify abnormal bowel
  • determine response to therapy
  • identify complications

Radiographic features

Ultrasound

Bowel ultrasound allows assessment of the whole bowel. It is a relatively simple technique but requires a practitioner who has appropriate experience. It requires patient preparation and cooperation and may take up to 30 minutes.

  • bowel wall thickening
  • loss of normal bowel wall architecture
  • increased vascularity

Ultrasound may also detect complications:

  • localized perforation
  • interloop abscess
  • fistulation

Ultrasound is used in the assessment of rectal disease (endorectal ultrasound) and of liver disease (abdominal ultrasound).

CT

CT with both IV and luminal contrast can be used to assess small and large bowel.

  • bowel wall thickening
  • ulceration
  • strictures
  • fistulae (CD)
  • abscess formation and perforation
MRI

MRI is particularly useful in Crohn disease:

  • assessment of small bowel disease
  • assessment of perianal fistulae
Medical student radiology curriculum