Makindo Medical Notes

Related Subjects: |Colorectal cancer |Colorectal polyps |Ulcerative Colitis |Acute Severe Colitis |Crohn's disease

🌟 Anti-TNF agents (e.g., infliximab, adalimumab) have revolutionised Crohn’s disease care, improving remission rates and quality of life. They are particularly important for severe or fistulating disease.

📖 About

• 🌱 Crohn's disease = chronic, relapsing, granulomatous inflammatory disorder.
• 🌀 Can affect the GI tract anywhere from mouth → anus.
• 📊 UK incidence: ~5–8/100,000/year; prevalence: 50–80/100,000.

🧬 Aetiology

• 👩‍🦳 More common in Caucasian & Jewish populations.
• 🚬 Smoking increases risk ×3–4.
• 🧪 Familial link: NOD2/CARD15 mutations → often ileal disease.
• 🌍 Environmental: Possible antigen triggers, OCP use, urban lifestyle.

🔬 Pathology

• Granulomatous, transmural inflammation.
• Deep fissuring ulcers; “cobblestoning” mucosa.
• “Skip lesions” = patchy disease with normal mucosa in between.
• 🤕 Fistulae may form (entero-vesical, entero-vaginal, entero-enteric).

📍 Disease Location (Skip Lesions)

• Terminal ileum: ~90%.
• Ileocolonic: 40%.
• Small intestine alone: 40%.
• Colitis pattern: 20%.
• Perianal disease: <10% (rectum often spared).

🩺 Clinical Presentation

• Proximal small bowel: Colicky pain, partial obstruction, weight loss, anorexia.
• Terminal ileum: RLQ pain (appendicitis mimic), steatorrhoea, B12 malabsorption, inflammatory mass.
• Colonic: Diarrhoea ± blood/mucus, abdominal pain.
• Perianal: Skin tags, fistulae, abscesses.
• Systemic: Fatigue, anaemia, fever, finger clubbing, aphthous ulcers.

⚠️ Complications

• 👁 Ophthalmic: Uveitis, episcleritis.
• 🦴 MSK: Arthropathy, sacroiliitis, ankylosing spondylitis.
• 🟤 Skin: Erythema nodosum, pyoderma gangrenosum.
• 💎 Renal: Oxalate stones.
• ⬆️ Cancer: Colonic adenocarcinoma (with longstanding colitis).
• 🩸 VTE risk significantly increased.

🔎 Investigations

• 🩸 Bloods: Hb, ferritin, B12/folate, ESR/CRP (activity markers).
• LFTs, bone profile.
• 💩 Stool: Ova/cysts/parasites; faecal calprotectin (marker of inflammation).
• Endoscopy: Ileocolonoscopy + biopsy = gold standard (granulomas if present).
• Imaging:
• AXR: Obstruction.
• Barium follow-through: “String sign of Kantor.”
• CT enterography: Activity + complications.
• MRI pelvis: Best for perianal fistulae.
• Antibodies: ASCA +ve in ~60%.

🔄 Differential Diagnosis

• Tuberculosis enteritis.
• Yersinia infection.
• Other causes of ileitis (vasculitis, lymphoma).

🔍 Comparison: Crohn’s Disease vs Ulcerative Colitis

💡 Teaching Tip: In exams, remember the mnemonic:

• Crohn’s → Cobblestone, Complete wall (transmural), Complications (fistulae/strictures)
• UC → starts in Ulcerated rectum, continuous, mucosal only, curable with colectomy.

💊 Management (Stepwise)

• Mild: Oral/rectal 5-ASA (mesalazine), short prednisolone taper.
• Moderate: Prolonged steroids, budesonide (ileal disease), add azathioprine/methotrexate if steroid-dependent.
• Severe/Acute colitis: Admit, IV methylpred, antibiotics, VTE prophylaxis. If steroid-resistant → Ciclosporin or Anti-TNF (infliximab/adalimumab).
• Fistulating disease: Metronidazole, ciprofloxacin, immunosuppressants, anti-TNF; MRI staging before surgery.
• Surgery: For strictures, abscesses, toxic megacolon. ~2/3 will need surgery during lifetime.

🧰 Additional Therapies

• Azathioprine → steroid-sparing.
• Methotrexate → useful in resistant disease (weekly dosing).
• Biologics: Infliximab, adalimumab (esp. fistulating/Severe Crohn’s).
• Metronidazole → perianal disease.
• Multidisciplinary: Dietitian input (nutrition), IBD nurse specialist support.

📑 Step-Up Medical Therapy

Cases — Crohn’s Disease

• Case 1 (Ileal disease): A 21-year-old man presents with 6 months of intermittent abdominal pain, watery diarrhoea, and weight loss. Examination shows a tender right iliac fossa mass. Bloods reveal microcytic anaemia and raised CRP. Colonoscopy with ileoscopy demonstrates patchy ulceration; biopsy shows granulomas. Management: Induction with oral corticosteroids; azathioprine introduced for maintenance. Nutritional supplementation started. Outcome: Symptoms improve and weight stabilises. Remains well at 12-month follow-up with maintenance immunosuppression.
• Case 2 (Perianal disease): A 28-year-old woman reports recurrent perianal pain and discharge. Exam reveals multiple perianal fistulae and abscesses. MRI pelvis confirms complex fistulating Crohn’s. Colonoscopy shows skip lesions in the colon. Management: Surgical drainage of abscess, seton insertion for fistulae, and biologic therapy (infliximab) commenced. Antibiotics (ciprofloxacin + metronidazole) given short-term. Outcome: Marked reduction in perianal symptoms. Ongoing biologic therapy maintains remission; occasional flares managed promptly.
• Case 3 (Complicated stricturing disease): A 46-year-old man with long-standing Crohn’s presents with recurrent subacute small bowel obstruction (vomiting, colicky pain). He has a history of poor adherence to maintenance therapy. CT enterography shows stricturing in the terminal ileum with proximal dilatation. Management: Bowel rest, IV fluids, and corticosteroids initially. Elective laparoscopic ileocaecal resection performed due to symptomatic stricture. Maintenance therapy re-initiated with adalimumab. Outcome: Post-surgical recovery good, symptoms resolved. Counselling emphasised importance of adherence to long-term therapy to prevent recurrence.

Teaching Commentary 🧑‍⚕️

Crohn’s disease is a chronic, relapsing transmural granulomatous inflammation that can affect any part of the GI tract, classically with “skip lesions.” Presentations vary: • Ileal disease → pain, diarrhoea, weight loss, anaemia. • Perianal disease → fistulae, abscesses, often severe. • Stricturing disease → obstruction from chronic inflammation and fibrosis. Management depends on severity and phenotype: steroids for induction, immunomodulators/biologics for maintenance, and surgery for complications. Unlike ulcerative colitis, Crohn’s often recurs after surgery. Long-term care must also address nutrition, bone health, and cancer surveillance.