Inflammatory Bowel Disease — Written Clinical Reasoning

SAQ 1 — Acute Severe UC Flare Management (20 marks, 30 minutes)

Prompt: Outline your integrated management plan for this patient, including immediate treatment, day-3 assessment strategy, rescue therapy options, maintenance escalation, and surveillance planning. Justify each decision with evidence. [1]

Model Answer

Problem list (4 marks):

1. Acute severe ulcerative colitis — Truelove-Witts severe (more than 6 bloody stools, HR 98, temp 38.0, Hb 101, ESR not yet available but CRP 48 consistent)
2. Steroid-refractory risk — she is already on azathioprine 2 mg/kg, suggesting immunomodulator-refractory disease
3. Anaemia of chronic disease with active inflammation
4. VTE risk — acute severe colitis is a prothrombotic state
5. Colitis surveillance overdue (7 years extensive colitis — surveillance should start at 8 years)
6. Extraintestinal manifestations likely to flare with bowel activity (erythema nodosum, episcleritis are activity-related) [1]

Immediate management (5 marks): [1]

1. Admit to hospital — acute severe UC is a medical emergency requiring inpatient management.
2. IV corticosteroids — hydrocortisone 100 mg QID or methylprednisolone 60 mg daily. This is first-line induction for severe disease.
3. Stool studies — culture and C. difficile toxin (already sent); exclude CMV colitis with tissue biopsies if steroid-refractory (CMV reactivation is common in immunosuppressed colitis).
4. IV fluids and electrolyte correction (potassium, magnesium).
5. DVT prophylaxis — enoxaparin 40 mg SC daily. Acute severe colitis carries a VTE risk comparable to post-surgical patients; pharmacological prophylaxis is mandatory unless contraindicated.
6. Flexible sigmoidoscopy (unprepared, limited) — to assess endoscopic severity (Mayo endoscopic subscore), confirm diagnosis, and obtain biopsies for CMV and histology.
7. Surgical review — involve colorectal surgery from admission. Early surgical involvement is associated with better outcomes. [1]

Day-3 assessment strategy (3 marks): [1]

Assess at 72 hours using the Oxford criteria:

• Stool frequency more than 8/day on day 3 → predicts colectomy in 85 per cent — proceed to rescue therapy
• CRP more than 45 mg/L AND stool frequency 3 to 8/day on day 3 → also predicts colectomy in 85 per cent — proceed to rescue therapy
• Fewer than 3 stools/day with normal CRP → continue IV steroids, expectant management [1]

Rescue therapy options (3 marks): [1]

If steroid-refractory (no response by day 3 to 5):

• Infliximab 5 mg/kg single dose — the Järnerot study demonstrated reduced 3-month colectomy compared to placebo [1]. Preferred in most ANZ units for simplicity of administration.
• Ciclosporin 2 mg/kg/day IV continuous infusion for 24 hours — requires monitoring of levels, renal function, magnesium, and blood pressure. Equally effective to infliximab (CYSIF trial showed no significant difference in treatment failure between ciclosporin 60 per cent and infliximab 54 per cent) [2].
• If rescue therapy fails → colectomy. Do not delay — early colectomy in deteriorating patients reduces mortality.

Maintenance escalation plan (3 marks): [1]

Given she is already on azathioprine 2 mg/kg and still flaring severely:

• If she responds to IV steroids or rescue therapy, escalate maintenance to a biologic:
  • Infliximab 5 mg/kg at weeks 0, 2, 6, then every 8 weeks (if used as rescue, continue as maintenance)
  • Vedolizumab 300 mg IV at weeks 0, 2, 6, then every 8 weeks (gut-selective, lower systemic risk)
  • Tofacitinib 10 mg BID for 8 weeks then 5 mg BID (oral, rapid onset)
• The choice depends on her comorbidities, preference, funding, and infectious screen (HBV, HCV, HIV, TB quantiferon before biologics). [1]

Surveillance and long-term planning (2 marks):

• She is at 7 years with extensive colitis — surveillance colonoscopy is due at 8 years from diagnosis (1 year from now).
• Use dye-spray chromoendoscopy with targeted biopsies.
• DEXA scan and calcium/vitamin D supplementation if prolonged steroid exposure.
• Iron studies — IV ferric carboxymaltose for deficiency (oral iron poorly tolerated in active colitis). [1]

SAQ 2 — Crohn's Disease Phenotype and Treatment Selection

Prompt: A 28-year-old man presents with a 4-month history of right iliac fossa pain, weight loss (5 kg), and non-bloody diarrhoea. Colonoscopy shows ileocolonic Crohn's disease (Montreal L3) with inflammatory (B1) behaviour. He has a palpable right iliac fossa mass. CRP is 35 mg/L. He is naive to immunomodulators and biologics. Outline your management approach and discuss the role of combination therapy based on the SONIC evidence. [1]

Model Answer

Diagnostic and staging workup (3 marks):

1. MR enterography — to assess the right iliac fossa mass (phlegmon versus abscess versus fibrotic stricture). This distinction is critical: an abscess requires drainage and antibiotics before any biologic; a stricture may require surgery; a phlegmon responds to medical therapy.
2. Exclude TB — quantiferon-Gold, chest X-ray before biologic therapy (anti-TNF reactivates latent TB).
3. Nutritional assessment — BMI, iron studies, B12 (terminal ileal involvement), vitamin D.
4. Exclude perianal disease — pelvic examination, consider pelvic MRI if any perianal symptoms. [1]

Induction strategy (4 marks):

• If no abscess and disease is inflammatory (B1): oral prednisone 40 mg daily, taper over 8 to 12 weeks (or budesonide 9 mg daily for milder ileocaecal disease).
• If abscess present: drain first (radiologically or surgically), antibiotics (ciprofloxacin plus metronidazole), and defer biologic until sepsis controlled.
• The palpable mass requires imaging before starting steroids or biologics — do not blindly start immunosuppression in the setting of a potential abscess. [1]

Maintenance strategy — combination therapy (6 marks): [1]

Based on the SONIC trial, for this immunomodulator-naive patient with active ileocolonic Crohn's and high-risk features (young age, weight loss, elevated CRP, extensive L3 disease), combination therapy with infliximab plus azathioprine is preferred: [1]

• SONIC demonstrated steroid-free remission at week 26: 56.8 per cent combination vs 44.4 per cent infliximab alone vs 30.0 per cent azathioprine alone [3].
• Mucosal healing: 43.9 per cent combination vs 30.1 per cent infliximab vs 16.5 per cent azathioprine.
• The top-down strategy (early aggressive combination therapy) is preferred for patients with high-risk features likely to have aggressive disease course.

Alternatives if anti-TNF contraindicated (3 marks):

• Ustekinumab (anti-IL-12/23) — weight-based IV induction then 90 mg SC every 8 to 12 weeks. Favorable safety profile.
• Vedolizumab (gut-selective anti-integrin) — slower onset but no systemic immunosuppression.
• These would be preferred if latent TB, recent malignancy, or heart failure contraindicate anti-TNF. [1]

Monitoring and treat-to-target (2 marks):

• Assess clinical response, CRP and faecal calprotectin at 3 months.
• Assess mucosal healing by colonoscopy or intestinal ultrasound at 6 to 9 months.
• Target: endoscopic healing (absence of ulceration) per STRIDE-II framework. [1]

Surgery (2 marks):

• Not indicated at presentation for B1 disease.
• Reserve surgery for stricturing (B2) disease causing obstruction, fistulising (B3) disease refractory to medical therapy, or failure of optimized medical therapy.
• If surgery is needed (e.g., ileocaecal resection), start anti-TNF or immunomodulator early post-operatively to prevent recurrence in high-risk patients. [1]