• Diarrhoea (can be bloody and/or chronic)
• Abdominal pain
• Weight loss
• Malaise, anorexia, fever
• Poor growth or delayed puberty in kids
• Mouth ulcers
• Abdominal
  • Abdominal tenderness and distension
  • Palpable masses
  • Anal/perianal skin tags, fissures and fistulas (may be asymptomatic)

• Arthritis
• Conjunctivitis/Uveitis/Episcleritis
• Erythema nodosum
• Pyoderma granulosum (purulent ulcers with blue-black edge)
• Clubbing

Macro:

• Distribution
  • 20% colonic; 30% ileocaecal; 40% small bowel
• Bowel thickened and narrowed.
• Deep fissures and ulcers in mucosa, giving a ‘cobblestone’ appearance.
• Fistulae, abcesses and strictures.
• Fat wrapping around affected bits of bowel
• ‘Skip lesions’ – areas of unaffected bowel between inflamed areas.
• Mouth ulcers and anal/peri-anal disease (ulcers, fissures, fistulae)

Micro:

• Full-thickness (transmural) inflammation
• Increase in chronic inflammatory cells (macrophages)
• Granulomata – not caseating

• Toxic megacolon and perforation
• Stricturing and bowel obstruction
• Fistulae
• Small bowel cancer (if ileal involvement)
  • NB. No overall increased risk of bowel cancer in IBD – only certain subgroups have increased risk (NEJM 2013)
• Iron, folate and B12 deficiencies (terminal ileum disease)
• Osteoporosis from steroid therapy
• Short-bowel syndrome and malabsorption