IBD

Question 1

Differentiate Crohn’s vs UC:

• Affected GIT parts
• Rectal involvement
• Pattern
• Strictures

Answer 1

Crohn’s:

• Ileum +/- colon
• Sometimes - rectal sparing can occur
• Segmental - skip lesions
  
  • Can see cobblestoning in late Crohn’s
• Strictures

UC:

• Colon only
• Always - rectum first → extend proximally
• Diffuse patterns
• Strictures rare

Question 2

Differentiate Crohn’s vs UC:

• Inflamed layers
• Pseudopolyps = areas of regenerative scar tissue developing from granulation tissue
• Ulcers (perforations)
• Fibrosis
• Serositis
• Granulomas
• Fistulae/sinuses

Answer 2

Crohn’s:

• Transmural inflammation
• Mod pseudopolyps
• Deep ulcers
• Lots of fibrosis and serosis
• 50% granulomas only
• Fistulae/sinuses

UC:

• Superficial inflammation (mucosa/submucosa only)
• Lots pseudopolyps
• Superficial ulcers
• Little to none fibrosis/serositis/granulomas/fistulae/sinuses

Question 3

Differentiate Crohn’s vs UC:

• Diarrhoea
• Pain
• Perianal fistula
• Malabsorption
• Malignant potential
• Recurrence after surgery
• Toxic megacolon

Answer 3

Crohn’s:

• Can be bloody, but mucous-y more common
• Pain more common in Crohn’s, because of strictures
• Perianal fistulae - with colonic disease
• Malabs present
• Malignant potential with colonic involvement
• Recurrence after surgery common
• no TMC

UC:

• Bloody diarrhoea - mucosa lining of colon affected
• Pain less common
• No perianal fistula/malabs/recurrence after surgery
• Malignant potential
• Yes TMC

Question 4

What is TMC defined as? Mx?

Answer 4

• = Dilated colon on AXR (transverse colon > 6cm)
  
  • ‘Toxic’ owing to fever, tachycardia, leukocytosis, anaemia
• EMERGENCY surgery - indication for colectomy

Question 5

What are some extra-intestinal manifestations of IBD?

Answer 5

• Eyes: episcleritis, uveitis
• Joints: arthritis
• Skin: erythema nodosum, pyoderma gangrenosum
• Mouth: ulcers, stomatitis
• Kidneys: stones, UTI

Question 6

What stool studies should you include for IBD?

Answer 6

• Exclude infection
  
  • Microscopy and culture
  • Ova, cysts and parasites
  • Clostridium difficile toxin
• Faecal calprotectin
  
  • More specific marker of intestinal inflammation
  • Protein released by gut inflammatory cells

Question 7

Compare (adult) maintenance therapy for Crohn’s vs UC.

Answer 7

Crohn’s:
1. Azathioprine/mercaptopurine 1st, or if not tolerated/ineffective, MTX + folic acid

2. Biologics
   
   • Anti-TNFα Abs:
     
     1. Infliximab (Remicade), adalimumab (Humira)
     2. Anti-integrin Abs: Vedolizumab

UC:

1. 5-ASA oral + rectal mesalazine if respond to it well
2. Azathioprine/mercaptopurine 1st, MTX + folate
3. Infliximab or vedolizumab

Question 8

Name some toxic effects of MTX

Answer 8

• Teratogenic
• Hepatotoxicity
• Renal impairment
• Immunosuppression - pancytopaenia
• Pneumonitis and pulmonary fibrosis