Ulcerative Colitis

Background

UC is a chronic, relapsing-remitting, non-infectious inflammatory disease of the GI tract, involving the rectum and variable lengths of colon.

• Unlike Crohn’s disease, inflammation is usually only superficial, affecting the mucosal layer.
• UC can be broadly classified by the extent of disease
  • Ulcerative proctitis
    • Inflammation of the rectum only
  • Left sided colitis
    • inflammation extends to the sigmoid colon but not beyond the splenic flexure
  • Extensive colitis (pancolitis)
    • inflammation extends beyond the splenic flexure

Aetiology/Risk factors

• The exact cause of UC is unknown
• Genetic
  • Genetically susceptible individuals- abnormally reactive humoral and cell mediated immunity against intestinal bacteria
  • Family history is a strong risk factor
  • HLA-B27 allele is associated with UC, Ankylosing spondylitis, psoriatic arthritis, uveitis and other spondyloarthropathies
• Autoantibodies e.g. perinuclear antineutrophil cytoplasmic antibodies (p-ANCA) may play a role
• Smoking, in contrast to Crohn’s, is protective against UC
• NSAID use may increase the risk of UC and Crohn’s

Presentation

Onset of symptoms is usually (but not always) insidious/slow.

• Bloody diarrhoea for more than 6 weeks is a cardinal feature
  • Urgency and nocturnal diarrhoea also common
  • Tenesmus (persistent painful urge to pass stool even when rectum is empty)
• Abdominal pain
  • Colicky
  • Lower left quadrant
  • May be relieved by bowel movements
• Weight loss, anorexia
• Extraintestinal manifestations (see Crohn’s disease)
  • Psoriasis/psoriatic arthritis and ankylosing spondylitis are more common in patients with UC (HLA B27 allele association)

Investigations

• Initial Blood investigations
  • FBC- anaemia (chronic disease, blood loss); thrombocytopenia
  • U&Es- Hypokalaemia, hyponatraemia, hypomagnesemia
  • LFTs- Hypoalbuminaemia
    • Also check for extraintestinal manifestations e.g. raised Alk Phos/bilirubin (may suggest hepatobiliary disease)
  • Raised CRP (correlates with disease activity)
  • Serology
    • p-ANCA is positive in 60-80% of patients with UC (50% sensitive and 94% specific)
    • ASCA less common in UC (moreso in Crohn’s)
• The gold standard for the diagnosis of UC is colonoscopy with biopsy
  • abnormal erythematous mucosa (superficial ulceration may be present; deep ulceration rare cf Crohns) extending from the rectum to part or all of the colon
    • the inflammation is uniform, without normal mucosa in between (skip lesions are not a feature of UC but of Crohns)
    • histologically, inflammation is limited to the mucosa/submucosa (cf Crohns).  Crypt abscesses/atrophy is classical but not specific.  Infiltration with inflammatory cells (mainly neutrophils (acute activity)/lymphocytes (chronic), plasma cells, mast cells and eosinophils)
• Imaging may be useful in evaluating the extent of disease
  • Contrast enema studies traditionally most useful but CT colonography becoming increasingly popular

Assessing Severity

• Truelove and Witts’ severity index
• 

NB Subacute UC refers to moderate-severely active UC that would be managed in an outpatient setting

Management

• Inducing remission
  • Mild – moderate (/ first presentation)- 1st line
    • Proctitis/proctosigmoiditis
      • offer topical aminosalicylate alone or combined oral and topical aminosalicylate
      • Oral aminosalicylate may be used alone but is not as effective
        • if this is not suitable a topical / oral corticosteroid may be offered
      • Subacute disease may be offered oral prednisolone
    • Left-sided and extensive disease
      • high induction dose of oral aminosalicylate
      • consider a topical aminosalicylate or oral beclometasone diproprionate
        • if these aren’t appropriate, consider oral prednisolone
    • 2nd/3rd line – any extent
      • add oral prednisolone (stop beclometasone treatment prior to this)
      • consider adding oral tacrolimus to prednisolone if this is inadequate
      • NB Infliximab is NOT recommended for mild-moderate disease)
  • Acute Severe disease; all extents
    • Offer IV corticosteroids
      • Where this is not tolerable or contrainidicated- consider IV ciclosporin (or surgery)
    • Assess need for surgery
      • more likely if >8 stools/day; pyrexic; tachycardic; colonic dilation on AXR
• Maintaining remission
  • For 1st time, or after mild-moderate disease
    • Proctitis/proctosigmoiditis
      • Topical +/- oral aminosalicylate (daily or intermittent)
    • Left sided/extensive disease
  • For 2+ flare-ups in 12 months, if remission is not maintained with oral aminosalicylates, or after a severe flare up:
    • consider oral azathioprine/mercaptopurine (see Crohn’s for monitoring)
• Other management issues
  • Screen and monitor for osteopenia/osteoporosis
  • Regular colonoscopy for colorectal cancer screening (as well as disease activity)

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