Ulcerative Colitis (UC)
NICE guideline [NG130] Ulcerative colitis: management. Published: May 2019.
NICE CKS Ulcerative colitis. Last revised: Mar 2024.
NICE Clinical guideline [CG118] Colorectal cancer prevention: colonoscopic surveillance in adults with ulcerative colitis, Crohn’s disease or adenomas. Last updated: Sep 2022.
Background information added accordingly.
Date: 25/11/25
Background Information
Definition
UC is a chronic, relapsing-remitting, non-infectious inflammatory disease of the GI tract:
- Characterised by continuous mucosal inflammation limited to the colon
- Beginning in the rectum and extending proximally in a continuous pattern
Risk Factors
- Family history
- HLA-B27 association
Smoking is notably protective against developing UC. However, smoking increases the risk of Crohn’s disease.
Clinical Manifestation
UC typically present as a chronic intermittent course, with episodic acute flares and periods of remission.
| GI manifestations |
|
| Extra-GI manifestations | PSC is classically associated with UC (although rare for patients with UC to develop PSC, but ~90% of patients with PSC has UC) – see the Primary Sclerosing Cholangitis (PSC) article for more information
~30% patients with UC have extra-GI manifestations, and may be the 1st presentation
|
| Complications |
Features also seen in Crohn’s disease, but not as common and prominent in UC:
|
In clinical practice, Crohn’s disease and ulcerative colitis overlaps a lot more than how it is described in textbooks. But note the following high-yield exam contrats:
| Crohn’s disease | Ulcerative colitis |
Features mentioned in the ulcerative colitis column may still be present, but classically less common |
Features mentioned in the Crohn’s disease column may still be present, but classically less common |
Extra-GI manifestations that ARE related to disease activity:
- Pauci-articular arthritis
- Erythema nodosum
- Aphthous mouth ulcers
- Episcleritis
- Metabolic bone disease
Others are NOT related to disease activity
Prognosis
Crohn’s disease is a lifelong condition that can significantly impair quality of life:
- Up to 90% of people will experience a relapse following the first presentation
- 15–25% of people will require hospitalisation for an acute severe disease flare at some point in the natural history of their illness, often as the index presentation
- The rate of colectomy in people experiencing acute severe ulcerative colitis in the biologic era is ~23%
- The mortality rate during an acute severe disease flare in the modern treatment era is <1%
Poor prognostic factors:
- Severe symptoms at presentation
- Early relapse or active disease in the first 2 years following initial presentation
- Extensive disease
- Raised inflammatory markers
- <50 y/o, and particularly childhood-onset disease
- Poor compliance with drug treatment
Diagnosis
Work Up
NICE CKS recommends the following tests when UC is suspected. There are 2 main purposes of the following tests: 1) support diagnosis of IBD and 2) exclude differential diagnoses.
| Category | Test | Purpose / Interpretation |
|---|---|---|
| Blood tests | FBC |
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| U&E |
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| LFT, including albumin |
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| Serum ferritin, vitamin B12, folate, vitamin D |
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| Inflammatory markers (CRP and ESR) |
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| Coeliac serology |
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| Stool tests | Stool microscopy and culture (including C. difficle toxin) |
Note that presence of infection does not exclude Crohn’s |
| Faecal calprotectin |
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Some other tests:
- TFT – hyperthyroidism can cause diarrhoea
- Serology (note that it has limited role in diagnosing inflammatory bowel diseases, but is common in exams)
- ↑ pANCA
- ↑ ASCA
Ileocolonoscopy
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.
Ileocolonoscopy with biopsy of involved and uninvolved mucosa is the gold standard diagnostic test for UC
| Category | Ulcerative Colitis | Crohn’s Disease |
|---|---|---|
| Macroscopic Findings | Distribution / location:
Appearance:
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Distribution / location:
Appearance:
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| Histology Findings |
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Imaging
Imaging is used less extensively in UC compared to Crohn’s disease, as UC primarily affects the colon and rarely affects the small bowel.
Crohn’s disease can affect any part of the GI tract, especially the small bowel, therefore imaging is essential in its diagnosis.
Management
Inducing Remission
NICE recommends using the Trulove and Witts’ criteria in adults to guide induction management
- In children, NICE recommends using the Paediatric Ulcerative Colitis Activity Index (PUCAI)
| 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 | ≤30 | >30 |
Approach:
- If there is severe disease, all are managed the same
- But if its mild or moderate, it depends on the extend of the disease
Severe Disease
| Step | Treatment |
|---|---|
| Step 1 (all patients) |
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| Step 2 | If there is little or no improvement within 72 hours of starting steroids, or symptoms worsen at any time despite steroids:
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
Apart from immunosuppressive therapy, active UC disease is associated with a high risk of VTE thus it is important to also give anticoagulation (usually LMWH).
Mild / Moderate Disease
Management depends on the extension of UC:
| Extent of disease | Induction treatment |
|---|---|
| Proctitis only |
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| Proctosigmoiditis and left-sided UC |
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| Extensive disease (i.e. beyond left-sided UC) |
|
Apart from immunosuppressive therapy, active UC disease is associated with a high risk of VTE thus it is important to also give anticoagulation (usually LMWH).
Maintaining Remission
1st line:
| Extent of disease | Maintenance treatment |
|---|---|
| Proctitis and proctosigmoiditis | Offer either the following:
|
| 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.
Colonoscopic Surveillance
Perform a baseline colonoscopy with chromoscopy and biopsy of any abnormal areas to assess risk of developing colorectal cancer
Colonoscopic surveillance is indicated in most patients with UC (exception: those with isolated proctitis)
- Frequency of surveillance is based on the risk (high risk after 1 year, intermediate risk after 3 years, low risk after 5 years)
Overall speaking, risk of colorectal cancer is higher in ulcerative colitis, than in Crohn’s disease.
High-risk features of developing colorectal cancer in IBD (applies to both Crohn’s disease and ulcerative colitis):
- Moderate / severe active inflammation (confirmed on endoscopy or histology)
- Primary sclerosing cholangitis
- Colonic stricture
- Any grade of dysplasia
- Family history of colorectal cancer in a 1st degree relative <50 y/o
References