Diagnosis and Classification of IBD

Establishing the Diagnosis

1. Biopsy
   1. UC -- crypt hyperplasia, abscesses
   2. Crohn's -- granulomatous
2. Endoscopically
   1. Disease location: skip lesions bum to gum vs contiguous from rectum
   2. Visually: Cobblestone (Crohn's). Both can have deep ulcerations.
3. Imaging
   1. CT/MR enterography
   2. Ultrasound
   3. Abdominal XR
4. Serological
   1. p-ANCA (Crohn's > UC)
   2. ASCA (UC > Crohn's)

Affected Sites

• Crohn's: terminal ileal > ileocolonic. Tends to be deeper inflammation.
• Ulcerative Colitis: proctitis > left-sided > pancolitis. Tends to be superficial inflammation.

Classification of IBD

• Crohn's
  • Fistulizing disease: more aggressive. Indication for biologics.
  • Stricturing disease: slower, longer duration of inflammation.

Management

Pharmacotherapies

1. Systemic Steroids (methylprednisolone/prednisone)
2. Topical/Luminal Steroids (budesonide). Mild to moderate.
3. 5-ASA - typically for UC or joint manifestation. For mild to moderate disease.
4. Antimetabolites (AZA, 6-MP) and immunomodulators (MTX, cyclosporine),
5. Biologics
   1. Anti-TNFs (infliximab -- Remicade, adalimumab -- Humira)
   2. JAK inhibitor (tofacitinib - for UC only)
   3. Anti-integrins (vedolizumab -- Entyvio)
   4. Ustekinumab

Crohn's Disease

Mild to Moderate Disease

Moderate to Severe Disease

Ulcerative Colitis

Mild to Moderate Disease

Moderate to Severe Disease

References

1. AGA Clinical Practice Guidelines on the Medical Management of Moderate to Severe Luminal and Perianal Fistulizing Crohn’s Disease - Gastroenterology
2. Canadian Association of Gastroenterology Clinical Practice Guideline for the Management of Luminal Crohn’s Disease | Journal of the Canadian Association of Gastroenterology | Oxford Academic
3. https://www.cag-acg.org/images/cddw/ulcerative-colitis_overview-of-guidelines_marshall.pdf