PassFinals
Gastroenterology & Nutrition

Ulcerative Colitis

A chronic inflammatory colitis that usually begins in the rectum and extends continuously proximally, producing bloody diarrhoea and urgency; severity determines whether the pathway is outpatient induction, specialist escalation or acute severe colitis admission.

In a nutshell

Ulcerative colitis usually causes continuous rectal-to-proximal colonic inflammation with bloody diarrhoea, urgency and tenesmus. Confirm extent and exclude infection, induce remission without chronic steroids, recognise acute severe colitis early, escalate with an IBD MDT and follow risk-based cancer surveillance.

Classic presentation

Relapsing bloody diarrhoea with mucus, urgency and tenesmus, sometimes accompanied by anaemia, fatigue, extraintestinal inflammation or systemic toxicity.

Key points

  • Use extent and severity together: proctitis, left-sided and extensive disease have different topical and oral aminosalicylate pathways.
  • Acute severe colitis is an inpatient emergency; involve gastroenterology and colorectal surgery, assess daily and discuss colectomy early.
  • Exclude stool infection, especially C. difficile, before escalating immunosuppression.
  • Aminosalicylates induce or maintain mild-to-moderate disease; corticosteroids are time-limited and not maintenance therapy.
  • If intravenous steroid response is inadequate after the guideline review point or the patient worsens, use specialist rescue or surgery without delay.
  • Current NICE options for moderate-to-severe disease include biologic and targeted medicines under the relevant technology appraisals; reassess ongoing treatment at least annually.
  • Colorectal surveillance is risk-based; current BSG specialist guidance uses an earlier first risk-assessment point than NICE CG118.

First-line investigation

Stool microbiology and inflammatory bloods with faecal calprotectin where appropriate, followed by ileocolonoscopy and biopsies; use limited endoscopy and acute-severe assessment in hospitalised patients.

Management

Recognise acute severe colitis

  • Admit for frequent bloody stools with systemic toxicity, dehydration, severe anaemia, abdominal distension, peritonism or suspected toxic megacolon; involve gastroenterology and colorectal surgery together and give inpatient supportive care.1,2,4

Confirm activity and exclude infection

  • Use stool microbiology including C. difficile, inflammatory and safety bloods, faecal calprotectin where appropriate, and ileocolonoscopy with biopsies; in acute severe disease use limited endoscopy and abdominal imaging according to safety.1,3,2

Induce remission by extent

  • Use topical aminosalicylate first-line for proctitis and proctosigmoiditis; combine topical and oral aminosalicylates for extensive disease, adding a time-limited corticosteroid when remission is not achieved.1,5,6

Use steroid-sparing and advanced treatment

  • For recurrent, steroid-dependent or moderate-to-severe UC, use thiopurine, biologic or targeted specialist pathways under current NICE technology appraisals; match treatment to prior exposure, safety, pregnancy, preference and the least-expensive suitable option.1,13,12,11,14,15,16,2

Rescue acute severe disease and involve surgery

  • Give intravenous corticosteroids for acute severe colitis and assess surgery daily; if there is little or no improvement within 72 hours or deterioration at any time, consider intravenous ciclosporin or colectomy, using infliximab when ciclosporin is contraindicated or clinically inappropriate.1,17,18,2
  • Discuss colectomy for refractory disease, dysplasia, cancer, perforation, toxic megacolon or failed rescue therapy; provide balanced information about emergency and restorative surgical options.1,2,7

Maintain remission and surveil cancer risk

  • Use extent-appropriate maintenance aminosalicylate or specialist steroid-sparing treatment, monitor treatment toxicity and objective inflammation, and do not use corticosteroids as maintenance.1,3,5,10
  • Use the current BSG colorectal-surveillance pathway with risk assessment around 8 years after symptoms or at PSC diagnosis, while recording NICE CG118's 10-year threshold as a labelled divergence.8,7,1

Exam traps

  • Do not diagnose UC from bloody diarrhoea alone: infection and Crohn's colitis must be considered and tested for.
  • Do not use a full colonoscopy as the default acute severe colitis procedure when limited assessment is safer.
  • Do not leave a patient with steroid dependence on repeated courses without steroid-sparing or advanced-therapy review.
  • Normal inflammatory markers do not overrule severe stool frequency, bleeding, dehydration or abdominal findings.
  • Do not present smoking as treatment: cessation remains appropriate despite the historical exam association with UC.
  • Do not confuse the newer BSG colorectal-surveillance starting point with the still-current NICE CG118 alternative; teach the chosen source line and label the divergence.

Illustrations

Continuous ulcerative colitis in a colectomy specimenOpened colectomy specimen showing confluent mucosal inflammation with a sharp transition to less affected mucosa, illustrating the continuous colonic distribution of ulcerative colitis.Mikael Häggström, M.D., Wikimedia Commons · CC0
Toxic megacolon on abdominal radiographyPlain abdominal radiograph showing marked colonic dilatation in acute severe colitis, a finding that requires urgent inpatient assessment.Hellerhoff, Wikimedia Commons · CC-BY-SA-3.0

Key sources

  1. NICE NG130, Ulcerative colitis: managementUpdated 18 Mar 2026
  2. British Society of Gastroenterology, guidelines on inflammatory bowel disease in adults: 2025Updated 1 Jun 2025
  3. NICE CKS, ulcerative colitis
  4. NHS, inflammatory bowel diseaseUpdated 5 May 2023
  5. BNF, mesalazine
  6. BNF, prednisolone
  7. NICE CG118, colorectal cancer prevention: colonoscopic surveillance in adults with ulcerative colitis, Crohn's disease or adenomasUpdated 24 Feb 2026
  8. British Society of Gastroenterology, guidelines on colorectal surveillance in inflammatory bowel diseaseUpdated 12 Mar 2025
  9. NICE NG12, Suspected cancer: recognition and referralUpdated 15 Apr 2026
  10. BNF, azathioprine
  11. NICE TA956, etrasimod for moderately to severely active ulcerative colitisUpdated 11 Mar 2024
  12. NICE TA856, upadacitinib for moderately to severely active ulcerative colitisUpdated 11 Jan 2023
  13. NICE TA329, infliximab, adalimumab and golimumab for moderately to severely active ulcerative colitisUpdated 25 Feb 2015
  14. NICE TA998, risankizumab for moderately to severely active ulcerative colitisUpdated 22 Aug 2024
  15. NICE TA1094, guselkumab for moderately to severely active ulcerative colitisUpdated 28 Aug 2025
  16. NICE TA925, mirikizumab for moderately to severely active ulcerative colitisUpdated 25 Oct 2023
  17. NICE TA163, infliximab for acute exacerbations of severely active ulcerative colitisUpdated 23 Jul 2008
  18. BNF, ciclosporin

This page is exam revision material, not medical advice, and must not be used for patient care. Always check drug doses against the BNF and current guidance. Full disclaimer.