Overview
Ulcerative Colitis
1. Clinical Overview
Summary
Ulcerative Colitis (UC) is a Chronic Inflammatory Bowel Disease (IBD) characterised by Diffuse, Continuous Mucosal Inflammation of the Colon and Rectum, Starting at the Rectum and extending proximally to a variable extent. UC primarily affects the Large Bowel Only (Unlike Crohn's Disease which can affect any part of the GI tract). The hallmark symptoms are Bloody Diarrhoea, Urgency, and Tenesmus. The inflammation is Superficial, Affecting only the Mucosa and Submucosa. The cause is Unknown but involves a dysregulated immune response to gut microbiota in genetically susceptible individuals, Triggered by environmental factors. The disease course is typically Relapsing-Remitting. Severity is classified using the Truelove and Witts Criteria (Mild, Moderate, Severe). Treatment aims to Induce and Maintain Remission using 5-ASA (Aminosalicylates), Corticosteroids, Immunomodulators (Azathioprine, 6-MP), And Biologics (Anti-TNF, Vedolizumab, Ustekinumab, JAK Inhibitors). Colectomy is curative and may be required for refractory disease, Acute severe colitis, Or dysplasia/Cancer. Patients with extensive, Long-standing UC have an Increased Risk of Colorectal Cancer requiring surveillance colonoscopy. [1,2,3]
Clinical Pearls
"Bloody Diarrhoea + Urgency + Tenesmus = Think UC": Classic triad.
"Rectum Always Involved, Continuous Inflammation": Key distinction from Crohn's.
"5-ASA is Mainstay for Mild-Moderate UC": Both induction and maintenance.
"Colectomy is Curative": Unlike Crohn's. Consider for refractory/Dysplasia.
2. Epidemiology
Demographics
| Factor | Notes |
|---|---|
| Incidence | ~10-20 per 100,000 per year (Developed countries). |
| Prevalence | ~250-500 per 100,000. |
| Age of Onset | Bimodal: Peak 15-30 years (Second peak 50-70 years). |
| Sex | Slightly Male predominance. |
| Geography | More common in Northern Europe, North America. Increasing worldwide. |
Risk Factors
| Risk Factor | Notes |
|---|---|
| Family History | First-degree relative increases risk ~4-10 fold. |
| Genetics | HLA associations. NOD2 gene (More Crohn's). |
| Non-Smoker/Ex-Smoker | Smoking is Protective in UC (Opposite of Crohn's). Stopping smoking can trigger flares. |
| Appendectomy (Before Age 20) | May be protective. |
| Diet / Westernisation | |
| Infection / Dysbiosis |
3. Classification
Extent (Montreal Classification)
| Extent | Description |
|---|---|
| E1: Proctitis | Rectum only (Distal to rectosigmoid junction). |
| E2: Left-Sided (Distal) Colitis | Up to splenic flexure. |
| E3: Extensive / Pancolitis | Beyond splenic flexure. Entire colon. |
Severity (Truelove and Witts Criteria – For Acute Flare)
| Feature | Mild | Moderate | Severe |
|---|---|---|---|
| Bloody Stools/Day | less than 4 | 4-6 | ≥6 |
| Pulse (bpm) | less than 90 | 90-100 | >90 OR |
| Temperature (°C) | Afebrile | ≤37.8 | >37.8 OR |
| Haemoglobin (g/dL) | >11 | 10.5-11 | less than 10.5 OR |
| ESR (mm/hr) | less than 30 | ≤30 | >30 |
| Albumin (g/L) | Normal | less than 30 |
4. Pathophysiology
Mechanism
- Genetic Susceptibility: Polygenic. HLA associations. Genes affecting barrier function, Innate/Adaptive immunity.
- Environmental Triggers: Altered gut microbiome, Diet, Infections, NSAIDs, Stress.
- Dysregulated Immune Response: Th2-mediated cytokine response (IL-5, IL-13) – Predominantly.
- Mucosal Inflammation: Neutrophil infiltration, Crypt abscesses, Goblet cell depletion, Epithelial damage.
- Ulceration: Superficial ulcers. Mucosal/Submucosal only.
- Continuous, Circumferential Involvement: Starting from rectum, Extending proximally without skip lesions.
Histology (Key Features)
| Feature | Notes |
|---|---|
| Mucosal / Submucosal Inflammation | Superficial. Does NOT extend beyond submucosa (Unlike Crohn's – Transmural). |
| Crypt Abscesses | Neutrophils in crypts. |
| Crypt Distortion / Atrophy | Architectural changes. |
| Goblet Cell Depletion | Loss of mucus-secreting cells. |
| Pseudopolyps | Regenerating mucosa. Chronic UC. |
| NO Granulomas | (Granulomas suggest Crohn's). |
5. Clinical Presentation
Symptoms
| Symptom | Notes |
|---|---|
| Bloody Diarrhoea | Hallmark. Blood and mucus in stool. |
| Urgency | Pressing need to defaecate. |
| Tenesmus | Feeling of incomplete evacuation. Rectal involvement. |
| Increased Stool Frequency | Can be >10/day in severe. |
| Abdominal Cramping | Lower abdominal pain. |
| Nocturnal Symptoms | |
| Systemic Symptoms (Severe) | Fever, Weight loss, Fatigue, Malaise. |
Extraintestinal Manifestations (~25%)
| System | Manifestation |
|---|---|
| Musculoskeletal | Peripheral arthritis (Pauciarticular, Correlates with bowel activity). Axial spondyloarthropathy (Ankylosing spondylitis – HLA-B27, Does NOT correlate). |
| Skin | Erythema Nodosum (Correlates). Pyoderma Gangrenosum (Does NOT correlate). |
| Eyes | Episcleritis (Correlates). Uveitis (Does NOT correlate). |
| Hepatobiliary | Primary Sclerosing Cholangitis (PSC) – Strong association. Does NOT correlate with UC activity. |
| Other | Aphthous ulcers. VTE (Increased risk). Anaemia. |
6. Investigations
Laboratory
| Test | Findings |
|---|---|
| FBC | Anaemia (Iron deficiency, Chronic disease). Leucocytosis, Thrombocytosis (Inflammation). |
| CRP, ESR | Elevated (Inflammation). |
| Albumin | Low (Protein loss, Malnutrition, Inflammation). |
| U&Es, LFTs | ALP raised if PSC. |
| Stool Tests | Faecal Calprotectin (Elevated – Correlates with inflammation. Useful for monitoring). Stool MC&S (Exclude infective colitis – Campylobacter, Salmonella, Shigella, E. coli O157). C. difficile toxin. |
| p-ANCA | Positive in ~60-70% UC (Vs 10-20% Crohn's). |
| ASCA | Usually negative in UC (Positive in Crohn's). |
Colonoscopy with Biopsies (Gold Standard)
| Finding | Notes |
|---|---|
| Erythema, Oedema, Granularity | |
| Loss of Vascular Pattern | |
| Friability / Bleeding on Contact | |
| Ulceration (Superficial) | |
| Pseudopolyps (Chronic) | |
| Continuous Inflammation from Rectum | |
| Biopsies: Crypt abscesses, Architectural distortion, No granulomas. |
Imaging
| Modality | Notes |
|---|---|
| Plain Abdominal X-Ray | In acute severe colitis. Exclude Toxic Megacolon (Transverse colon >6cm). |
| CT Abdomen | Mucosal thickening. Rule out perforation, Abscess. |
7. Management
Management Algorithm
ULCERATIVE COLITIS DIAGNOSED
(Colonoscopy + Histology)
↓
ASSESS EXTENT AND SEVERITY
- Extent: Proctitis / Left-sided / Extensive
- Severity: Mild / Moderate / Severe (Truelove & Witts)
↓
TREATMENT BY SEVERITY AND EXTENT
┌────────────────┬────────────────┬────────────────┐
MILD-MODERATE MODERATE-SEVERE ACUTE SEVERE
(Outpatient) (May need admit) COLITIS (ASUC)
(ADMIT – Emergency)
↓ ↓ ↓
MILD-MODERATE UC
┌──────────────────────────────────────────────────────────┐
│ **PROCTITIS (E1)** │
│ - Topical 5-ASA (Mesalazine suppositories 1g OD) │
│ (First-line) │
│ - Add Oral 5-ASA if inadequate │
│ - Topical steroids (Prednisolone foam/Enema) if needed │
│ │
│ **LEFT-SIDED (E2) / EXTENSIVE (E3) – MILD-MODERATE** │
│ - **Oral 5-ASA** (Mesalazine ≥2-4g/day) + │
│ - **Topical 5-ASA** (Enema/Foam – Improves efficacy) │
│ - Combination oral + topical more effective than either │
│ alone. │
│ - If no response: Add oral steroids (Prednisolone) │
└──────────────────────────────────────────────────────────┘
↓
MODERATE-SEVERE UC (May Need Hospitalisation)
┌──────────────────────────────────────────────────────────┐
│ - Oral Prednisolone (40mg OD, Taper over 6-8 weeks) │
│ - If steroid-dependent/Refractory: │
│ - **Thiopurines** (Azathioprine, 6-MP) for │
│ maintenance │
│ - **Biologics** (Anti-TNF: Infliximab, Adalimumab, │
│ Golimumab. Anti-Integrin: Vedolizumab. Anti-IL-12/ │
│ 23: Ustekinumab. JAK Inhibitors: Tofacitinib, │
│ Filgotinib) │
└──────────────────────────────────────────────────────────┘
↓
ACUTE SEVERE ULCERATIVE COLITIS (ASUC) – EMERGENCY
┌──────────────────────────────────────────────────────────┐
│ **ADMIT TO HOSPITAL** (Joint medical-surgical care) │
│ │
│ **INITIAL MANAGEMENT** │
│ - IV Hydrocortisone (100mg QDS) OR IV │
│ Methylprednisolone (60mg OD) │
│ - IV Fluids, Electrolyte correction │
│ - VTE Prophylaxis (LMWH) │
│ - Avoid NSAIDs, Opioids, Anticholinergics │
│ - Stool chart, Daily bloods (FBC, CRP, U&Es) │
│ - AXR Day 0 (Assess dilatation, Mucosal islands) │
│ - Stool C. diff / CMV (Exclude superinfection) │
│ - Flexible sigmoidoscopy (Confirm diagnosis, Severity) │
│ │
│ **DAY 3 ASSESSMENT (Travis Criteria)** │
│ - Stool frequency >8/day OR │
│ - CRP >45 AND Stool >3-8/day │
│ → HIGH RISK OF COLECTOMY (~85%) → Rescue therapy │
│ or Surgery │
│ │
│ **RESCUE THERAPY (If No Response to IV Steroids)** │
│ - **Infliximab** (5mg/kg) OR **Ciclosporin** IV │
│ - Discuss Surgery as alternative │
│ │
│ **SURGERY (Colectomy)** │
│ - If not responding to rescue therapy │
│ - Toxic megacolon, Perforation, Massive haemorrhage │
│ - Subtotal Colectomy + Ileostomy (Emergency) │
│ - Elective: Restorative Proctocolectomy + Ileal Pouch- │
│ Anal Anastomosis (IPAA / J-Pouch) │
└──────────────────────────────────────────────────────────┘
↓
MAINTENANCE THERAPY
┌──────────────────────────────────────────────────────────┐
│ - **5-ASA (Oral ± Topical)**: Mainstay for mild- │
│ moderate. Reduces relapse. Reduces CRC risk. │
│ - **Thiopurines (Azathioprine, 6-MP)**: For steroid- │
│ dependent or frequent relapses. TPMT testing before. │
│ - **Biologics / JAK Inhibitors**: For moderate-severe │
│ refractory. Continue if induced remission. │
└──────────────────────────────────────────────────────────┘
↓
COLORECTAL CANCER SURVEILLANCE
┌──────────────────────────────────────────────────────────┐
│ - Increased CRC risk if: Extensive disease, Long │
│ duration (>8-10 years), PSC, Family history CRC. │
│ - **Surveillance Colonoscopy** starting 8-10 years │
│ from symptom onset. │
│ - Chromoendoscopy or HD colonoscopy with targeted │
│ biopsies. │
│ - Interval: Annual (High risk) to 5-yearly (Low risk). │
│ - Dysplasia → Colectomy. │
└──────────────────────────────────────────────────────────┘
8. Complications
| Complication | Notes |
|---|---|
| Acute Severe Colitis | Medical emergency. ~15% of patients. |
| Toxic Megacolon | Colonic dilation >6cm. Sepsis. Risk of perforation. Emergency colectomy. |
| Perforation | |
| Massive Haemorrhage | |
| Colorectal Cancer | Increased risk with extensive, Longstanding disease. Surveillance. |
| Stricture | Less common than Crohn's. Consider carcinoma if present. |
| Anaemia, Malnutrition | |
| VTE | Increased risk. Thromboprophylaxis inpatient. |
| PSC | Liver complication. Independent of UC activity. |
9. Prognosis and Outcomes
| Factor | Notes |
|---|---|
| Disease Course | Relapsing-remitting in most. ~10-15% have chronic continuous symptoms. |
| Colectomy Rate | ~20-30% lifetime. |
| CRC Risk | Approximately 2% at 10 years, 8% at 20 years, 18% at 30 years (Varies). Reduced with surveillance and 5-ASA. |
| Mortality | Slightly increased, Especially in first year and with severe disease. |
| IPAA (J-Pouch) | Good functional outcomes. Avoids permanent stoma. Risk of pouchitis (~50%). |
10. Evidence and Guidelines
Key Guidelines
| Guideline | Organisation | Key Recommendations |
|---|---|---|
| Ulcerative Colitis | BSG 2019, ECCO | 5-ASA first-line. IV steroids for ASUC. Rescue therapy (Infliximab/Ciclosporin). Colectomy if refractory. CRC surveillance. |
11. Patient and Layperson Explanation
What is Ulcerative Colitis?
Ulcerative Colitis (UC) is a long-term condition where the lining of the large bowel (Colon) and rectum becomes inflamed and develops tiny sores (Ulcers). It is one of the main types of Inflammatory Bowel Disease (IBD).
What are the symptoms?
- Diarrhoea with blood and mucus.
- Urgency (Needing to rush to the toilet).
- Abdominal cramping.
- Tiredness.
- Weight loss.
- Symptoms come and go (Flares and remission).
What causes it?
The exact cause is unknown. It involves the immune system mistakenly attacking the lining of the bowel. Genes, Environment, And gut bacteria play a role.
How is it treated?
- Mild disease: Tablets or suppositories containing 5-ASA (Mesalazine).
- Moderate/Severe disease: Steroids (Short-term). Immunosuppressants. Biologic medications (Infliximab, Vedolizumab, Etc.).
- Surgery: Removing the colon cures UC. Sometimes needed if medications don't work or for cancer prevention.
What about bowel cancer risk?
People with long-standing UC affecting most of the colon have an increased risk of bowel cancer. Regular colonoscopies (Surveillance) are recommended to detect early changes.
12. References
Primary Sources
- Lamb CA, et al. British Society of Gastroenterology consensus guidelines on the management of inflammatory bowel disease in adults. Gut. 2019;68(Suppl 3):s1-s106. PMID: 31562236.
- Magro F, et al. Third European Evidence-based Consensus on Diagnosis and Management of Ulcerative Colitis (ECCO). J Crohns Colitis. 2017;11(6):649-670.
- Travis SPL, et al. Predicting outcome in severe ulcerative colitis (Travis Criteria). Gut. 1996;38(6):905-910.
13. Examination Focus
Common Exam Questions
- Key Distinction from Crohn's: "What features distinguish Ulcerative Colitis from Crohn's Disease?"
- Answer: UC: Rectum always involved, Continuous inflammation, Large bowel only, Mucosal/Submucosal (Superficial), No granulomas, Bloody diarrhoea predominant. Crohn's: Skip lesions, Transmural, Any part of GI, Granulomas, Fistulae, Strictures.
- Severity Assessment (Acute): "What are the Truelove and Witts criteria for assessing UC severity?"
- Answer: Based on: Stool frequency, Pulse, Temperature, Haemoglobin, ESR (See table above).
- First-Line Treatment (Mild-Moderate): "What is the first-line treatment for mild-moderate UC?"
- Answer: 5-ASA (Mesalazine) – Oral and/or Topical.
- Rescue Therapy (ASUC): "What rescue therapies are used if IV steroids fail in Acute Severe UC?"
- Answer: Infliximab OR Ciclosporin.
Viva Points
- Travis Criteria Day 3: Stool >8/day OR CRP >45 + Stool 3-8 → High colectomy risk.
- Smoking Protective in UC: Opposite in Crohn's.
- PSC Association: UC strongly linked. Increases CRC risk further.
- Colectomy is Curative: Unlike Crohn's.
Medical Disclaimer: MedVellum content is for educational purposes and clinical reference. Clinical decisions should account for individual patient circumstances. Always consult appropriate specialists.