|

Ulcerative Colitis

Last updated:

Overview

Ulcerative colitis (UC) is a type of inflammatory bowel disease (IBD) that characteristically starts at the rectum and extends proximally, affecting variable lengths of the colon. It does not extend past the ileocaecal valve. Its pathophysiology is not fully understood, however, genetic and environmental factors are implicated.

Unlike Crohn’s disease (CD), its inflammation is continuous (no skip lesions are present) and is superficial, not typically extending beyond the submucosa.

For more regarding differentiating between CD and UC, see Inflammatory Bowel Disease.

Epidemiology

  • UC is the most common cause of IBD and its incidence and prevalence are increasing globally
  • Its prevalence in the UK is around 243 per 100,000
  • Its onset peaks between late adolescence and 30s, and a second peak in the 60s 

Risk Factors

  • Family history
  • HLA-B27
  • Infection
  • NSAID use

Unlike CD, the incidence of UC is decreased in people who smoke.

Presentation

  • The main feature of UC is bloody diarrhoea, generally persisting for more than 6 weeks. Other features:
    • Rectal bleeding
    • Faecal urgency
    • Faecal incontinence
    • Tenesmus
    • Abdominal pain:
      • Generally in the lower left quadrant
    • Non-specific symptoms:
    • Fever may be seen – suggesting a more serious disease
    • Features of complications may be seen, and may even precede symptoms of IBD:

Investigations

  • Full blood count:
    • May show anaemia which can be due to chronic inflammation, blood loss, or iron/B12/folate malabsorption
    • Increased white cells suggest acute or chronic inflammation
    • Increased platelets suggest active inflammation
  • Iron studies:
    • To identify iron deficiency
  • Haematinics:
    • To assess serum B12 and folate:
  • Liver function tests:
  • C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR):
    • Elevated in inflammation and correlates with disease activity
  • Stool testing:
    • To rule out an infection such as Clostridium difficile
  • Faecal calprotectin:
    • A non-specific marker released from neutrophils in gastrointestinal tract inflammation
    • Can help with differentiating IBD from irritable bowel syndrome (IBS)
  • Colonoscopy with biopsies:
    • The diagnostic test
    • In some patients, flexible sigmoidoscopy may be considered, particularly those with severe disease due to the risk of perforation
    • A biopsy may show superficial inflammation not extending beyond the submucosa, pseudopolyps, crypt abscesses, Goblet cell and mucin depletion, and absent granulomas

Classification

NICE classification of severity

NICE has categorised UC into mild, moderate, and severe. This stratification guides management:

  • Mild:
    • <4 stools per day
    • Small amounts of blood
  • Moderate:
    • 4-6 stools per day
    • Varying amounts of blood
    • No features of systemic upset (e.g. fever >37.8°C, raised CRP/ESR >30 mm/hr, anaemia, tachycardia >90 bpm) 
  • Severe:
    • >6 stools per day
    • Visible blood
    • Features of systemic upset

Management

Inducing remission

Treatment is initiated by a specialist in secondary care. Inducing remission depends on the site and severity of UC.

In mild-moderate UC:

  • Proctitis (UC affecting the rectum):
    • 1st-line: topical (rectal) aminosalicylate (e.g. mesalazine and sulfasalazine)
    • If no remission within 4 weeks: add oral aminosalicylate
    • If remission is still not attained: a time-limited course (4-8 weeks) of topical or oral corticosteroid
  • Proctosigmoiditis and left-sided UC:
    • 1st-line: topical aminosalicylate
    • If no remission within 4 weeks: add high-dose oral aminosalicylate or switch to high-dose oral aminosalicylate + topical corticosteroid
    • If remission is still not attained: stop topical treatment and give oral aminosalicylate and oral corticosteroid
  • Extensive disease:
    • 1st-line: topical aminosalicylate + high-dose oral aminosalicylate
    • If no remission within 4 weeks: stop topical treatment and give oral aminosalicylate and oral corticosteroid

In severe UC:

  • Patients with severe UC should be admitted to hospital
    • 1st-line: IV corticosteroids
    • If contraindicated, IV ciclosporin may be used
    • If complications such as toxic megacolon, perforation, haemorrhage, or shock occur, surgery is indicated

Maintaining remission

  • Maintaining remission depends on the site and severity of UC:
  • Proctitis and proctosigmoiditis:
    • Topical aminosalicylate daily/intermittent or
    • Topical aminosalicylate daily/intermittent + oral aminosalicylate or
    • Oral aminosalicylate only
  • Left-sided and extensive UC:
    • Low maintenance dose of oral aminosalicylate
  • After a severe relapse or ≥2 flare-ups in the last year:
    • Oral azathioprine or oral mercaptopurine
      • Check thiopurine methyltransferase (TPMT) activity before giving these

Patient Advice

  • Despite smoking being associated with a decreased likelihood of a UC flare, the research is mixed. The risks associated with smoking such as COPD, heart disease, and cancer outweigh the benefits significantly regarding smoking and UC. Other treatments for UC are much safer than continuing smoking.
  • NSAIDs and the combined oral contraceptive pill (COCP) should be avoided as they have been associated with worse outcomes in CD
  • Patients with any recurrence of symptoms should seek medical help urgently
  • Patients taking immunosuppressants with fevers, malaise, chills, sore throat, bruising, or mouth ulcers should seek medical help as they may be indicators of serious drug side effects (e.g. myelosuppression)

Complications

See Inflammatory Bowel Disease: Complications for more.

Prognosis

  • UC is a lifelong condition characterised by periods of relapse and remission
  • The lifetime risk for surgery in UC is around 20-30%

Author