Gastrointestinal System >
Inflammatory Bowel Disease (IBD)
“A group of inflammatory disorders of the colon and small intestine, principally Ulcerative Colitis (UC) and Crohn’s Disease (CD)”
Risk Factors
- Infective agents (e.g Mycobacteria, rotavirus, measles virus, chlamydia)
- IBD in 1st-degree relative
- Good hygiene
- Smoking ( risk of CD; ¯ risk in UC)
- Immunosuppression
Aetiology
Not entirely understood but relies on the interaction between environmental triggers (nutrition and hygiene), genetic susceptibility, immune response and gut microflora
Pathophysiology
Altered gut microflora/overzealous immune response/genetic defect → bacterial colonisation → bacteria adhere to and compromise mucosal barrier → mucosal invasion → inflammation of GI mucosa
Crohn’s Disease | Ulcerative Colitis | |
---|---|---|
Distribution | Whole GI Tract | Colon only |
Continuity | Skip lesions | Continous (procitis spreads backwards) |
Inflammation | Transmural | Superficial |
Pathology | Cobblestoning | Goblet cell loss, crypt abcesses |
Granulomas | Yes | No |
Smoking | Worsens disease | Protective |
Clinical Presentation
- Crohn’s Disease – Diarrhoea (80%), abdo pain, weight loss. 2o symptoms: malaise, fever, lethargy, N/V
- Ulcerative Colitis – Diarrhoea with blood/mucous, mouth ulceration, relapsing/remitting condition
Investigations
- FBC – anaemia common, ESR, CRP, WCC (UC: pANCA +, CD: usually pANCA -ve)
- Stool culture – faecal calprotectin, rule out infective colitis
- Colonoscopy – superficial lesion, deep ulceration, “skip lesions”
- Abdo XR in acute exacerbations; Abdo USS determine extent of pathology
Management
- Crohn’s Disease:
- Medical:
- Aminosalicylates (e.g mesalazine)
- Abx in adults with infective component (e.g metronidazole)
- Corticosteroids (e.g prednisolone)
- Immunomodulators (e.g azathioprine, methotrexate, 6-MP) or Biologics (Anti-TNFα: infliximab, adlimumab, certolizumab)
- Oxygen controlled via Venturi mask
- Ventilation
- Surgical:
- in ~80% CD patients
- Minimal bowel resections only. Recurrence risk of 15%/year.
- Medical:
- Ulerative Colitis:
- Medical:
- 1st Line – Aminosalicylates for disease remission (+rectal steroids if rectal involvement)
- UC attack/total colitis – IV hydrocortisone (+ azathioprine in recurrent disease).
- Surgery/Rescue therapy – IV hydrocortisone + a) IV cyclosporine or b) Anti-TNFα then switch to oral prednisolone + aminosalicylate for remission
- Medical:
Complications
- UC Attacks
- GI Obstruction
- Toxic Megacolon
- Adhesions
- Bowel Perforation
- Non-GI complications (rheumatoid diseases, skin change, HPB complications common: sclerosing cholangitis, cholelithiasis, Fatty Liver disease)