What is the treatment approach for inflammatory bowel disease (IBD)?

Treatment of Inflammatory Bowel Disease

Treatment of IBD must be stratified by disease type (ulcerative colitis vs. Crohn's disease), anatomic location, and severity, with combination topical and oral mesalazine as first-line for UC and corticosteroids or advanced biologics for moderate-to-severe CD. 1, 2

Ulcerative Colitis Treatment Algorithm

Mild to Moderate Distal/Left-Sided UC

• Combination therapy with topical mesalazine ≥1g/day PLUS oral mesalazine ≥2.4g/day is superior to either agent alone and should be the first-line approach. 1
• Topical mesalazine is more effective than topical corticosteroids and should be preferred. 1
• Once-daily dosing is as effective as divided doses and improves adherence. 1

Mild to Moderate Extensive UC

• Oral mesalazine 2-4g daily or balsalazide 6.75g daily as first-line therapy. 1, 2
• If inadequate response after 2-4 weeks, escalate to oral prednisolone 40mg daily with gradual taper over 8 weeks. 1, 3

Severe UC

• Requires hospital admission with joint management by gastroenterologist and colorectal surgeon from the outset. 4, 2
• Intravenous corticosteroids: hydrocortisone 400mg/day or methylprednisolone 60mg/day. 4
• Subcutaneous low-molecular-weight heparin for thromboprophylaxis. 4
• Never continue IV corticosteroids beyond 7-10 days without escalating to rescue therapy (infliximab or cyclosporine) or surgery. 4
• Never delay corticosteroids while awaiting stool cultures in suspected severe UC. 4
• Never use anti-diarrheal medications in severe colitis. 4

Fulminant UC with Complications

• Emergency surgery indicated for hemodynamic instability, free perforation, toxic megacolon, or massive hemorrhage. 4
• Subtotal colectomy with ileostomy is the procedure of choice. 4, 3

Crohn's Disease Treatment Algorithm

Mild Ileocaecal CD

• High-dose mesalazine 4g daily as initial therapy. 1, 2
• Budesonide 9mg daily is appropriate for isolated ileocaecal disease with moderate activity, though marginally less effective than prednisolone. 1

Moderate to Severe Active CD

• Oral prednisolone 40mg daily, reduced gradually over 8 weeks. 1, 2, 3
• Advanced therapy (biologics such as infliximab or small molecules) as first-line treatment for moderate to severe CD improves long-term disease control and should be strongly considered. 1
• Infliximab 5mg/kg at weeks 0,2, and 6 is effective for induction, but avoid in patients with obstructive symptoms. 3, 5

Chronic Active/Steroid-Dependent CD

• Azathioprine 1.5-2.5mg/kg/day or mercaptopurine 0.75-1.5mg/kg/day as adjunctive therapy and steroid-sparing agents. 3, 2
• Methotrexate IM 25mg weekly for up to 16 weeks followed by 15mg weekly is effective; oral dosing works for many patients. 3
• Monitor complete blood count within 4 weeks of starting azathioprine/mercaptopurine and every 6-12 weeks thereafter to detect neutropenia. 3

Fistulating and Perianal CD

• Metronidazole 400mg three times daily and/or ciprofloxacin 500mg twice daily as first-line for simple perianal fistulae. 3
• Azathioprine 1.5-2.5mg/kg/day or mercaptopurine 0.75-1.5mg/kg/day for simple perianal or enterocutaneous fistulae after excluding distal obstruction and abscess. 3
• Infliximab (5mg/kg at weeks 0,2, and 6) reserved for refractory fistulae as part of a strategy including immunomodulation and surgery. 3, 5
• Seton drainage, fistulectomy, and advancement flaps appropriate for persistent or complex fistulae in combination with medical treatment. 3

Maintenance Therapy

Ulcerative Colitis

• Lifelong maintenance therapy is generally recommended, especially for left-sided or extensive disease. 1, 2
• Aminosalicylates as first-line maintenance. 1, 2
• Azathioprine 1.5-2.5mg/kg/day or mercaptopurine 0.75-1.5mg/kg/day as second-line options. 1
• Maintenance therapy may reduce colorectal cancer risk by up to 75% in extensive UC. 1

Crohn's Disease

• Smoking cessation is crucial. 2
• Mesalazine has limited benefit for maintenance in CD. 2
• Azathioprine 1.5-2.5mg/kg/day or mercaptopurine 0.75-1.5mg/kg/day are effective second-line maintenance options. 1, 2
• Infliximab maintenance (5mg/kg every 8 weeks) significantly prolongs time to loss of response compared to placebo. 5

Surgical Considerations

Crohn's Disease

• Surgery should be limited to symptomatic disease only, not asymptomatic radiologically identified disease. 3, 1
• Resections should be conservative, limited to macroscopic disease. 3, 1, 2
• May be appropriate as primary therapy for limited ileal or ileocaecal disease. 3, 1

Ulcerative Colitis

• Surgery indicated for disease not responding to intensive medical therapy, dysplasia/carcinoma, or poorly controlled disease. 1, 2
• Subtotal colectomy leaving a long rectal stump is the procedure of choice in acute fulminant UC. 3
• Patients requiring elective surgery should be counselled regarding all surgical options, including ileo-anal pouch where appropriate. 3

Cancer Surveillance

• Colonoscopy after 8-10 years to re-evaluate disease extent, particularly for extensive or left-sided disease. 1, 2
• Surveillance decisions should be individualized based on patient risk factors. 1, 2

Critical Safety Considerations

• Sulfasalazine 4g daily is effective for active colonic CD but not recommended as first-line due to high incidence of side effects. 3, 6
• Metronidazole 10-20mg/kg/day, though effective, carries long-term risk of peripheral neuropathy and is not usually first-line. 3, 6
• Corticosteroids have numerous adverse events including opportunistic infections, diabetes, hypertension, glaucoma, cataracts, psychiatric complications, and increased fracture risk, particularly with high doses and prolonged treatment. 7
• Methotrexate is contraindicated in pregnancy. 6