IBD

• Inflammatory Bowel Disease (IBD)


  Includes Ulcerative Colitis and Crohn's Disease
• The prevalence of Crohn's Disease is around 27-106 per 100,000
• The prevalence of Ulcerative Colitis is around 80-150 per 100,000 and the highest prevalence is seen in Northern Europe and North America

  
• Etiology of IBD


  Unknown, but there is a Th1 cell type inflammatory response seen in the gut for both conditions
• Factors associated with the development of IBD


  • Familial
  • Environmental (good domestic hygiene, nutrition, smoking, NSAIDs)
  • Stress
• Hygiene Hypothesis


  Decrease in childhood infections due to improved hygiene practices in developed countries might be linked to an increase in autoimmune diseases like Crohn's disease
• Pathogenesis of IBD


  1. Defective mucosal immune response, producing an inappropriate response to luminal antigens

  2. Bacteria in the microflora stimulate an inflammatory response via dendritic cells, producing a predominantly Th1 helper T cell response

  3. Macrophages are also stimulated

  4. Result is severe tissue damage and attraction of more inflammatory cells
• Ulcerative Colitis (UC)


  Inflammatory disorder that affects the rectum and extends proximally, in continuity, to affect a variable extent of the colon

  
• Ulcerative Colitis


  • High incidence in the US, UK and northern Europe
  • Presents in young adults, more commonly in females
  • Presents with rectal bleeding, diarrhoea and abdominal pain

  
• Crohn's Disease (CD)


  Chronic inflammatory condition that can affect any part of the GI tract from mouth to anus, with a particular tendency to affect the terminal ileum and the ascending colon

  
• Crohn's Disease


  • Disease can affect one area or multiple areas with relatively normal bowel seen in-between (skip lesions)
  • Two peaks in incidence, 1st at 15-30 years and 2nd at 60 years
  • Mucosa dominated by Th1 (T-helper) cells, which produce Interferon Gamma (IFN-g) and IL-2
• Investigations for IBD


  • Colonoscopy
  • Biopsies of involved mucosa
  • Stool analysis (parasites, Clostridium difficile toxin, culture)
  • Barium radiographs
  • CT scan
  • Capsule endoscopy
  • Plain X-Ray if bowel obstruction or perforation suspected
  • C-reactive protein (CRP)

  
• 1. reactive protein (CRP)


  Protein produced by the liver in response to inflammation in the body
• Macroscopic changes in Crohn's Disease


  • Thickened and narrowed involved small bowel, leading to stenosis
  • Transmural inflammation extending through all layers of the bowel, with deep ulcers and fissures producing a 'cobblestone' appearance
  • Apthoid ulceration developing into deeper ulcers
  • Fistulae developing between bowel and other structures

  
• Macroscopic changes in Ulcerative Colitis


  • Reddened, inflamed and bleeding mucosa
  • Extensive ulceration with inflammatory (pseudo) polyps

  
• Extra-gastrointestinal manifestations of IBD


  • Joint complications
  • Eye problems
  • Skin problems
  • Liver problems
  • Venous thrombosis

  
• Microscopic changes in Crohn's Disease


  • Transmural inflammation
  • Increase in chronic inflammatory cells
  • Lymphoid hyperplasia
  • Granulomas (50%)
• Microscopic changes in Ulcerative Colitis


  • Superficial inflammation
  • Chronic inflammatory cell infiltrate in the lamina propria
  • Crypt abscesses
  • Goblet cell depletion

  
• Differences between Ulcerative Colitis and Crohn's Disease


  • Depth of inflammation (mucosal vs transmural)
  • Pattern of disease (continuous vs skip areas)
  • Location (colorectum vs mouth to anus)
  • Rectal involvement (usual vs less common)
  • Ileal disease (backwash ileitis vs common)
  • Fistulas (rare vs common)
  • Perianal disease (rare vs common)
  • Granulomas (unlikely vs 50-60% of patients)
  • Overt bleeding (usual vs less common)
  • Malnutrition (unlikely vs more common)
  • Cancer risk (colorectal cancer vs colorectal and small bowel cancer)
  • Tobacco use (protective vs harmful)

  
• Diagnostic difficulties in separating UC and CD


  • Distinction has major implications for treatment, prognosis, and disease course
  • Occasionally not possible to distinguish, particularly in acute phase
  • Patients considered to have Colitis of Undetermined Type and Etiology (CUTE) or Indeterminate colitis (IC)
  • Serological testing for ANCA and ASCA may be of value
  • Exact diagnosis sometimes only possible after examining surgical colectomy specimen
• Presentation of Crohn's Disease


  • Upper GI involvement (nausea, vomiting, low grade fever, dyspepsia, small bowel obstruction, anorexia, weight loss, loose stools)
  • Colonic Disease (diarrhoea, steatorrhea, passage of blood)

  
• Investigations for suspected Crohn's Disease


  • Radiological and imaging (barium enema, CT scan, colonoscopy)
  • Stool sample
  • Blood tests (anaemia, raised CRP, hypoalbuminaemia)
• Investigations for Ulcerative Colitis


  • Colonoscopy and biopsy
  • Imaging (plain abdominal X-Ray)
  • Stool sample
  • Blood tests (anaemia, raised CRP, positive pANCA)

  
• Treatment for Crohn's Disease


  • Induction of remission (oral/IV glucocorticosteroids, enteral nutrition, anti-TNF antibodies)
  • Maintenance of remission (methotrexate, azathioprine, anti-TNF antibodies)
  • Perianal disease (ciprofloxacin, metronidazole, azathioprine, anti-TNF antibodies)
• Surgical Management of Crohn's Disease


  • Failure of therapy with acute or chronic symptoms
  • Complications (dilation, obstruction, perforation, abscesses)
  • Failure to grow in children despite treatment
  • Colectomy and ileorectal anastomosis
• Treatment for Ulcerative Colitis


  • Distal disease (topical/suppository corticosteroids)
  • Left-sided colitis (topical corticosteroid enema)
  • Extensive colitis (oral corticosteroids, infliximab)

  
• Surgical Management of Ulcerative Colitis


  • Patients with complications or corticosteroid dependence
  • In acute disease, subtotal colectomy with end ileostomy and preservation of the rectum

  
• Patients with UC will develop either more proximal disease in a third of cases, relapses in a third of cases, or only have the single attack in a third of cases
• Patients with IBD have an increased risk of developing colon cancer, and CD patients have increased risk of small bowel cancer as well. Screening is regularly needed.