Sunday, 5 January 2014

Inflammatory Bowel Disease

IBD (not to be confused with IBS) is made up of Ulcerative Colitis and Crohn's Disease.

Ulcerative Colitis
- Young adults (15-40 years old)
- More common in males
- Environmental and genetic factors play a part, but mostly idiopathic
- Incidence: 10-20/100 000
- Prevalence: 100-200/100 00


Symptoms
- Chronic bloody diarrhoea with tenesmus, pain and fever
- Colicky abdominal pain, urgency


Categories

Distal disease is confined to the rectum (proctum) and sigmoid colon (proctosigmoiditis).
Extensive disease includes left sided colitis (up to the splenic flexure)
Extensive colitis is up to the hepatic flexure
Pancolitis affects the whole colon



Mild:
  • The patient produces fewer than four stools daily with or without blood
  • There is no systemic disturbance
  • The patient has a normal ESR or CRP test.
Moderate:
  • Produces four to six stools a day
  • Has minimal systemic disturbance.
Severe:
  • Produces more than six stools a day with blood
  • Has evidence of systemic disturbance (any of fever, tachycardia, anaemia, or hypoalbuminaemia).

Pathology
- Limited to the mucosa
- UC - needs macroscopic findings on sigmoidoscopy

Crohn's Disease

Incidence: 5-10/100 000
Prevalence: 50-100/ 100 000
Incidence increasing

Symptoms and Diagnosis
Abdominal pain, diarrhoea and weight loss
Systemic fever or malaise, anorexia or fever
May cause intestinal obstruction
Anaemia in Crohn's disease around 30% but ranges from 10% to 70%



Pathology
- Elevated malignancy risk
- Transmural disease ie. patchy inflammation
- 3 different patterns of disease - inflammatory, fistulating or stricturing-  Focal inflammation seen on histology



Treatment of Inflammatory Bowel Disease
  • Aminosalicylates
    • Mesalazine
      • 2-4g daily
    • Sulphasalazine main group. Newer modules have come out that are better tolerated. 
    • Pentasa has a time controlled release.
    • Sulphasalazine - causes side effects in 10 - 45%  of patients.
      • Headache
      • Epigastric pain
      • Diarrhoea
      • Steven-Johnson Syndrome
  • Steroids
    • Combination of oral and rectal steroids better than either alone
    • 40mg prednisolone optimal
    • Needs slow dose reduction
  • Thiopurines
    • Azathioprine, mercaptopurine
    • Need for two or more corticosteroid courses in a calendar year
    • Relapse of disease when the dose of prednisolone is <15 mg
    • Relapse within six weeks of stopping steroids
  • Methotrexate
    • Teratogenic
    • Can cause early toxicity - primarily GI
    • Toxicity reduced by co-administration of folic acid
  • Ciclosporin
    • Prevents clonal expansion of T-cell subsets
    • For severe, steroid refractory treatments
  • Infliximab
    • Chimeric anti-TNF monoclonal antibody with potent anti-inflammatory effects. 
  • Institution of a cinnamon and benzoate free diet has been shown to provide improvement in 54-78% of patients.


ED Management
  • Vital signs
  • Clinical examination
  • Low threshold for AXR 
  • FBC, U&E, ESR or CRP
  • s/c heparin
  • Intravenous corticosteroids (hydrocortisone 400 mg/day or methylprednisolone 60 mg/day. 
  • Withdrawal of anticholinergic, antidiarrhoeal agents, NSAID and opioid drugs, which risk precipitating colonic dilatation
  • IV antibiotics if infection considered 
  • Immediate surgical referral if there is evidence of toxic megacolon (diameter >5.5 cm, or caecum >9 cm).
  • Stool cultures -50% of relapses in patients with ulcerative colitis are associated with pathogens.
Fistulating and perianal disease
  • Metronidazole 400 mg tds and/or ciprofloxacin 500mg bd (grade B) are appropriate first line treatments for simple perianal fistulae.
  • Azathioprine 1.5–2.5 mg/kg/day or mercaptopurine 0.75–1.5mg/kg/day are potentially effective for simple perianal fistula
  • Infliximab (three infusions of 5 mg/kg at 0, 2, and 6 weeks) for refractory illness only. 

http://learning.bmj.com/learning/module-intro/ulcerative-colitis.html?moduleId=5003315&searchTerm=%E2%80%9Canal%E2%80%9D&page=1&locale=en_GB
http://www.bmj.com/content/346/bmj.f432?sso=
http://radiopaedia.org/articles/crohns-disease-vs-ulcerative-colitis
http://www.bmj.com/content/335/7632/1260
http://gut.bmj.com/content/53/suppl_5/v1.full
http://learning.bmj.com/learning/module-intro/crohn%E2%80%99s-disease.html?moduleId=10014189&searchTerm=%E2%80%9Canal%E2%80%9D&page=1&locale=en_GB

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