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Ulcerative Colitis (UC)

NICE guideline [NG130] Ulcerative colitis: management. Published: May 2019. NICE CKS Ulcerative colitis. Last revised: Mar 2024.

Guidelines

NICE CKS recommends the following tests when UC is suspected. There are 2 main purposes of the following tests: 1) support diagnosis of inflammatory bowel disease and 2) exclude differential diagnoses.
 
Category Test Purpose / Interpretation
Blood tests FBC
  • Anaemia is common at diagnosis, supports malabsorption, malnutrition, GI bleed
  • ↑ Platelet count suggests inflammation
U&E  
LFT, including albumin
  • ↓ Albumin may indicate inflammation and malnutrition, or possible protein-losing enteropathy
Serum ferritin, vitamin B12, folate, vitamin D
  • Detect nutritional deficiencies due to malabsorption
Inflammatory markers (CRP and ESR)
  • ↑ Inflammatory markers suggests inflammation
Coeliac serology
  • Exclude coeliac disease
Stool tests Stool microscopy and culture (including C. difficle toxin)
  • Exclude infective gastroenteritis or pseudomembranous colitis (C. difficle infection)
Note that presence of infection does not exclude Crohn's
Faecal calprotectin
  • ↑ Faecal calprotectin suggests inflammation

Some other tests:
  • TFT - hyperthyroidism can cause diarrhoea
  • Serology (note that it has limited role in diagnosing inflammatory bowel diseases but is common in exam)
    • ↑ pANCA
    • ↑ ASCAAnti-Saccharomyces cerevisiae antibodies

Ileocolonoscopy with biopsy of involved and uninvolved mucosa is the gold standard diagnostic test.

 

Note that ileocolonoscopy should NOT be performed in acute flares or severe disease due to increased risk of perforation. 

In such cases, sigmoidoscopy can be used as an alternative in the acute phase.

 
Category Ulcerative Colitis Crohn's Disease
Macroscopic Findings Distribution / location:
  • Continuous inflammation
  • Rectal involvement almost always present
  • Rarely extend proximal to the ileum

Appearance:
  • Friable mucosa with bleeding on contact
  • Pseudopolyps (raised areas of normal mucosa from repeat ulceration and healing)
 Distribution / location:
  • Skip lesions - discontinuous pattern of involvement
  • Ileum involvement almost always present
  • Rectal sparing is common

Appearance:
  • Shallow ulcers (aphthous ulcers)
  • Cobblestone appearance (inflamed sections interspread with deep ulcerations that resemble cobblestones)
  • Strictures
Histology Findings
  • Mucosal / submucosal inflammation
  • Crypt abscesses
  • Absence of granulomas
  • Reduce in goblet cells
  • Transmural inflammation (full-thickness involvement)
  • Non-caseating granulomas (specific but not always present)
  • Increase in goblet cells

Imaging is used less extensively in UC compared to Crohn's disease, as UC primarily affects the colon and rarely affects the small bowel.

Unlike in Crohn's disease, it affects any part of the GI tract, especially small bowel therefore imaging is essential in diagnosing Crohn's disease.

The severity of UC guides management. NICE recommends using the Trulove and Witts' criteria
 
Component Mild Moderate Severe

Bowel movements (number per day)

<4

4 to 6

≥6 plus at least 1 of the features of systemic upset (marked with*)

Blood in stools

No more than small amounts of blood

Between mild and severe

Visible blood

Pyrexia (temperature >37.8°C)*

No

No

Yes

Pulse >90 bpm*

No

No

Yes

Anaemia*

No

No

Yes

Erythrocyte sedimentation rate (mm/hour)*

30 or below

30 or below

Above 30

In children, NICE recommends using the Paediatric Ulcerative Colitis Activity Index (PUCAI)
 

Approach:
  • If there is severe disease, all managed the same
  • But if its mild or moderate, it depends on the extend of the disease
 

Step Treatment
Step 1 (all patietns) IV corticosteroid
Step 2 If there is little or no improvement within 72 hours of starting steroids, or symptoms worsen at any time despite steroids:
  • Add IV ciclosporin, or
  • Consider surgery

If ciclosporin is not appropriate → consider infliximab

Surgery is generally indicated if:
  • Failed medical therapy
  • Urgent surgery if there is perforation / toxic megacolon / massive haemorrhage
  • Elective surgery if there is chronic refractory UC / dysplastic changes / colorectal cancer

Management depends on the extension of UC
 
Extend of disease Induction treatment
Proctitis only
  • 1st line: topical aminosalicylate (e.g. mesalazine)
  • 2nd line (if no remission after 4 weeks): add oral aminosalicylate
  • 3rd line: add topical / oral steroid for 4-8 weeks
Proctosigmoiditis and left-sided UC
  • 1st line: topical aminosalicylate (e.g. mesalazine)
  • 2nd line: 
    • Stop topical treatment, and 
    • Offer oral aminosalicylate + oral steroid 
Extensive disease (i.e. beyond left-sided UC)
  • 1st line: topical + oral aminosalicylate (e.g. mesalazine)
  • 2nd line (if no remission after 4 weeks):
    • Stop topical treatment, and
    • Continue oral aminosalicylate, and
    • Add oral steroid
 

1st line:
 
Extend of disease Maintenance treatment
Proctitis and proctosigmoiditis Offer either the following:
  • Topical aminosalicylate, or
  • Oral aminosalicylate + topical aminosalicylate, or
  • Oral aminosalicylate (but not as effective as the first 2 options)
Left sided and extensive UC Oral aminosalicylate (e.g. mesalazine)

2nd line: consider oral azathioprine / mercaptopurine if:
  • ≥2 exacerbations in 1 year requiring steroids, or
  • Remission not maintained by aminosalicylates, or
  • After a single episode of acute severe UC

 

Assess TPMT activity before starting azathioprine / mercaptopurine.

  • Do not offer the drug if there is TPMT activity deficiency
  • Offer lower dose if TPMT activity is below normal but not deficient


TPMT is the enzyme that metabolises the drug and its metabolites, converting them into inactive form. If azathioprine / mercaptopurine is given to those with TPMT deficiency, the drug could accumulate and cause myelosuppression.

UC patients are at increased risk of colorectal cancer:
  • Perform a baseline colonoscopy with chromoscopy and biopsy of any abnormal areas to assess risk of developing colorectal cancer.
  • Then, offer colonoscopic surveillance based on the risk (high risk after 1 year, intermediate risk after 3 years, low risk after 5 years)

References

Author: Avana Patel, Adams Lau
Reviewer:
Last edited: 04/08/25