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Ulcerative colitis

SNOMED: 275129008910 words•Updated 03/03/2026
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Exam Tips

  • Classic UC pattern is continuous inflammation beginning at the rectum; absence of skip lesions helps distinguish from Crohn disease.
  • In acute severe UC, think emergency: frequent bloody stools plus systemic toxicity; request AXR early to exclude toxic megacolon.
  • Do not use steroids for maintenance; use 5-ASA and/or steroid-sparing agents for long-term control.
  • Always exclude infection (especially C. difficile) in an apparent flare before escalating immunosuppression.
  • Remember high-yield extra-intestinal associations for OSCE/vivas: uveitis, erythema nodosum, pyoderma gangrenosum, and PSC.
  • Image recall point: review a colonoscopy image showing diffuse, friable, continuous rectum-to-proximal colitis and an AXR example of transverse colonic dilatation in toxic megacolon.

Definition

Ulcerative colitis is a chronic inflammatory bowel disease with a relapsing-remitting course, characterized by continuous superficial inflammation of the colonic mucosa that almost always starts in the rectum and extends proximally for a variable distance. Disease extent is classified as proctitis, left-sided colitis, or extensive/pancolitis, and extra-intestinal inflammation (for example eye, skin, joint, and hepatobiliary disease) is common.

Pathophysiology

UC arises from immune dysregulation in a genetically susceptible host, with impaired epithelial barrier function and an abnormal mucosal response to gut microbiota/environmental triggers. Inflammation is typically limited to the mucosa and submucosa (unlike Crohn disease), producing diffuse continuous erythema, friability, and ulceration from the rectum proximally without skip lesions. Histology classically shows crypt architectural distortion, cryptitis/crypt abscesses, and chronic inflammatory infiltrate; severe inflammation can cause systemic toxicity, colonic dilatation, and perforation.

Risk Factors

  • Family history of ulcerative colitis (highest risk in first-degree relatives)
  • Genetic susceptibility to immune-mediated intestinal inflammation
  • Non-smoking status and recent smoking cessation (risk increases after quitting)
  • No appendicectomy in childhood (appendicectomy appears protective)
  • Possible flare trigger: non-selective NSAID exposure
  • Peak diagnosis age 20-40 years, with a second smaller peak around 60 years

Clinical Features

Symptoms

  • Bloody diarrhoea lasting more than 6 weeks
  • Rectal bleeding, urgency, tenesmus, and mucus
  • Crampy lower abdominal pain (often left-sided) and increased stool frequency
  • Nocturnal stooling during active disease
  • Fatigue, weight loss, reduced appetite, and malaise
  • Extra-intestinal symptoms: painful red eye/photophobia, joint pain/swelling, mouth ulcers, tender nodules on shins

Signs

  • Abdominal tenderness (commonly left lower quadrant)
  • Tachycardia, fever, dehydration in moderate-severe flare
  • Pallor from anaemia
  • Blood and mucus on digital rectal examination
  • Peripheral arthritis or enthesitis
  • Erythema nodosum, pyoderma gangrenosum, episcleritis/uveitis signs

Investigations

FBC, CRP/ESR, U&E, LFT, albumin:Anaemia, raised inflammatory markers, thrombocytosis, hypoalbuminaemia; electrolyte disturbance (including low potassium/magnesium) in severe disease
Stool tests (MCS and Clostridioides difficile assay):Exclude infectious colitis and C. difficile-triggered flare
Faecal calprotectin:Raised, supporting intestinal inflammation rather than functional bowel disorder
Flexible sigmoidoscopy/colonoscopy with biopsies:Continuous mucosal inflammation from rectum proximally, erythema/friability/ulceration; histology with chronic active colitis and crypt abscesses
Abdominal X-ray in acute severe colitis:Colonic dilatation (especially transverse colon) suggesting toxic megacolon; helps assess perforation risk
Cancer surveillance colonoscopy in longstanding/extensive disease:Detect dysplasia/colorectal neoplasia risk progression

Management

Lifestyle Modifications

  • Provide IBD specialist nurse support, flare action plan, and shared decision-making
  • Nutritional assessment and correction of iron, folate, B12, and vitamin D deficiencies
  • Avoid non-selective NSAIDs where possible because they may worsen flares
  • Do not advise smoking to treat UC despite epidemiological association; promote standard smoking cessation for overall health
  • Psychological support for anxiety/depression and bowel urgency-related quality-of-life impact
  • VTE risk assessment during flares/hospital admissions and prophylaxis when indicated

Pharmacological Treatment

Aminosalicylates (5-ASA) for mild-moderate disease

  • Mesalazine suppository 1 g rectally at night (ulcerative proctitis)
  • Mesalazine enema 1-4 g rectally once daily (distal/left-sided disease)
  • Oral mesalazine 2.4-4.8 g daily for induction, then 1.2-2.4 g daily for maintenance

Combine oral plus rectal 5-ASA for better remission rates in distal disease; monitor renal function before and during mesalazine therapy.

Corticosteroids for induction (not maintenance)

  • Prednisolone 40 mg orally once daily, then taper over about 6-8 weeks
  • Budesonide MMX 9 mg orally once daily for up to 8 weeks
  • Hydrocortisone 100 mg IV four times daily in acute severe colitis

Use shortest effective course; monitor glucose, blood pressure, mood, infection risk, and bone health. Avoid repeated steroid courses where possible.

Steroid-sparing maintenance immunomodulation

  • Azathioprine 2-2.5 mg/kg orally daily
  • Mercaptopurine 1-1.5 mg/kg orally daily

Check TPMT activity before thiopurines; monitor FBC/LFT regularly. Counsel regarding myelosuppression, hepatotoxicity, pancreatitis, and infection risk.

Advanced therapy for moderate-severe or refractory UC

  • Infliximab 5 mg/kg IV at weeks 0, 2, and 6 then every 8 weeks
  • Vedolizumab 300 mg IV at weeks 0, 2, and 6 then every 8 weeks
  • Ustekinumab 6 mg/kg IV induction then 90 mg SC every 8-12 weeks
  • Tofacitinib 10 mg orally twice daily induction then 5 mg twice daily maintenance

Before biologic/JAK therapy: screen for TB and viral hepatitis, assess vaccination status, and exclude active sepsis. With tofacitinib, assess VTE/MACE risk carefully.

Acute severe colitis rescue therapy

  • Infliximab 5 mg/kg IV rescue dose
  • Ciclosporin 2 mg/kg/day IV (specialist-led)

Hospital specialist management only; avoid antidiarrhoeals/opioids due to toxic megacolon risk; early surgical review if no response.

Surgical / Interventional

  • Subtotal colectomy with end ileostomy for fulminant/refractory acute severe colitis, perforation, uncontrolled haemorrhage, or toxic megacolon
  • Restorative proctocolectomy with ileal pouch-anal anastomosis (IPAA) for selected patients with chronic refractory disease or dysplasia/cancer
  • Total proctocolectomy with permanent ileostomy when pouch is unsuitable

Complications

  • Toxic megacolon (life-threatening colonic dilatation with systemic toxicity)
  • Bowel perforation, especially in acute severe colitis or delayed surgery
  • Severe haemorrhage and anaemia (iron deficiency, chronic disease, or drug-related)
  • Bowel obstruction/stricture (stricture in longstanding disease raises concern for colorectal cancer)
  • Colorectal cancer risk increased with long disease duration, childhood onset, PSC, and strong family history
  • Venous thromboembolism risk at least doubled, highest during active disease
  • Extra-intestinal disease: arthritis, episcleritis/uveitis, erythema nodosum, pyoderma gangrenosum, hepatobiliary disease including PSC
  • Growth failure, delayed puberty, and malnutrition in paediatric disease
  • Pouchitis after colectomy with IPAA

Prognosis

UC is lifelong with relapse-remission cycling; up to 90% relapse after first presentation. Around 15-25% require admission for acute severe flare at some stage, and modern-era mortality in acute severe colitis is below 1% with prompt specialist treatment. Poorer outcomes are associated with severe initial presentation, early frequent relapse, extensive colitis, persistently raised inflammatory markers, younger age at onset (especially childhood), and poor adherence.

Sources & References

💊BNF Drug References(34)

✅NICE Guidelines(1)

📖Textbook References(20)

  • David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 704)[context]
  • David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 257, 258)[context]
  • David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 703, 704)[context]
  • David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 706)[context]
  • David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 256)[context]
  • David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 255)[context]
  • David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1802)[context]
  • David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1143)[context]
  • David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 698)[context]
  • David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 257, 258)[context]
  • David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1833)[context]
  • David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1844)[context]
  • Oxford Handbook of Clinical Diagnosis (Huw Llewelyn, Hock Aun Ang, Keir Lewis etc.) (Z-Library).pdf(pp. 445, 446)[context]
  • Oxford Handbook of Clinical Diagnosis (Huw Llewelyn, Hock Aun Ang, Keir Lewis etc.) (Z-Library).pdf(pp. 358, 359)[context]
  • [Oxford Medical Handbooks] Ian Wilkinson, Tim Raine, Kate Wiles, Anna Goodhart, Catriona Ha - Oxford Handbook of Clinical Medicine (2017, Oxford University Press) - libgen.li.pdf(pp. 905)[context]
  • [Williams, Bailey and Love's Short Practice of Surgery] Norman Williams, Christopher Bulstrode, P Ronan O'Connell - Bailey & Love's Short Practice of Surgery 26E (2013, CRC Press) - libgen.li.pdf(pp. 1163)[context]
  • [Williams, Bailey and Love's Short Practice of Surgery] Norman Williams, Christopher Bulstrode, P Ronan O'Connell - Bailey & Love's Short Practice of Surgery 26E (2013, CRC Press) - libgen.li.pdf(pp. 1239)[context]
  • [Williams, Bailey and Love's Short Practice of Surgery] Norman Williams, Christopher Bulstrode, P Ronan O'Connell - Bailey & Love's Short Practice of Surgery 26E (2013, CRC Press) - libgen.li.pdf(pp. 1131, 1132)[context]
  • [Williams, Bailey and Love's Short Practice of Surgery] Norman Williams, Christopher Bulstrode, P Ronan O'Connell - Bailey & Love's Short Practice of Surgery 26E (2013, CRC Press) - libgen.li.pdf(pp. 1163, 1164)[context]
  • [Williams, Bailey and Love's Short Practice of Surgery] Norman Williams, Christopher Bulstrode, P Ronan O'Connell - Bailey & Love's Short Practice of Surgery 26E (2013, CRC Press) - libgen.li.pdf(pp. 1239)[context]

Sources

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