What are the treatment guidelines for inflammatory bowel disease (IBD)?

Treatment Guidelines for Inflammatory Bowel Disease

Disease-Specific Treatment Approaches

Treatment of IBD must be stratified by disease type (Crohn's disease vs. ulcerative colitis), location, and severity, with ulcerative colitis requiring combination topical and oral mesalazine as first-line therapy, while Crohn's disease requires corticosteroids or advanced biologics depending on severity. 1, 2, 3

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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 the most effective first-line approach and superior to either agent alone. 1, 3
• 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. 2, 3
• If inadequate response, escalate to oral prednisolone 40mg daily. 1, 3
• Budesonide MMX 9mg/day may be an alternative to conventional steroids in left-sided disease with inadequate 5-ASA response. 1

Severe UC

• Hospitalization is mandatory with intravenous steroids (hydrocortisone 400mg/day or methylprednisolone 60mg/day), fluid/electrolyte replacement, and close monitoring. 4, 1
• Joint management by gastroenterologist and colorectal surgeon is essential. 1, 2
• Patients should be informed of a 25-30% chance of needing colectomy. 1

Maintenance Therapy for UC

• Lifelong maintenance therapy is generally recommended, especially for left-sided or extensive disease, using aminosalicylates, azathioprine 1.5-2.5mg/kg/day, or mercaptopurine 0.75-1.5mg/kg/day. 2, 3
• Maintenance therapy may reduce colorectal cancer risk by up to 75% in extensive UC. 3

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Crohn's Disease Treatment Algorithm

Mild Ileocaecal CD

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

Moderate to Severe Active CD

• Oral prednisolone 40mg daily is appropriate, reduced gradually over 8 weeks (more rapid reduction causes early relapse). 4, 2
• Advanced therapy (biologics or small molecules) as first-line treatment for moderate to severe CD improves long-term disease control. 3
• Intravenous steroids (hydrocortisone 400mg/day or methylprednisolone 60mg/day) for severe disease, often with concomitant IV metronidazole to exclude septic complications. 4

Steroid-Dependent or Chronic Active CD

• Azathioprine 1.5-2.5mg/kg/day or mercaptopurine 0.75-1.5mg/kg/day are first-line immunomodulators, though slow onset precludes use as sole therapy for active disease. 4, 2, 3
• Corticosteroids should not exceed 8 weeks duration and are NOT recommended for maintenance. 3
• Budesonide maximum duration is 12 weeks. 3

Refractory CD

• Infliximab 5mg/kg (at weeks 0,2, and 6) is effective for active CD, with 81% achieving clinical response and 48% achieving remission at week 4. 4, 5
• Avoid infliximab in patients with obstructive symptoms. 4
• Surgery should be considered for failed medical therapy or may be primary therapy for limited ileal/ileocaecal disease. 4, 2

Fistulizing and Perianal CD

• Metronidazole 400mg three times daily and/or ciprofloxacin 500mg twice daily are first-line treatments for simple perianal fistulae. 4
• Azathioprine 1.5-2.5mg/kg/day or mercaptopurine 0.75-1.5mg/kg/day are effective after excluding distal obstruction and abscess. 4
• Infliximab (three infusions of 5mg/kg at weeks 0,2, and 6) is reserved for refractory fistulae and should be part of a strategy including immunomodulation and surgery. 4, 5
• Seton drainage, fistulectomy, and advancement flaps are appropriate for persistent/complex fistulae in combination with medical treatment. 4

Maintenance Therapy for CD

• Smoking cessation is crucial. 2
• Mesalazine has limited benefit for maintenance. 2
• Azathioprine 1.5-2.5mg/kg/day or mercaptopurine 0.75-1.5mg/kg/day are effective second-line maintenance options. 2, 3

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Critical Safety Considerations

Infection Exclusion

• Always exclude infectious causes before attributing symptoms to IBD flare. 1
• This is particularly important before initiating or escalating immunosuppression.

Immunomodulator Monitoring

• Monitor CBC for myelosuppression with azathioprine/mercaptopurine; consider TPMT or NUDT15 testing for severe or repeated myelosuppression. 6
• Monitor liver function tests weekly initially, then monthly, as mercaptopurine is hepatotoxic. 6
• Hepatosplenic T-cell lymphoma has been reported with mercaptopurine in IBD (though this is an unapproved use). 6

Corticosteroid Pitfalls

• Avoid steroids for perianal CD, when sepsis is present, or for maintenance therapy. 7
• Long-term steroid use should be avoided; rapid tapering causes early relapse. 1

Infliximab Considerations

• Avoid in obstructive symptoms or fibrostenotic strictures. 4, 7
• Do not use when sepsis is present. 7
• Among patients achieving fistula response, 68% maintained response with continued infliximab maintenance versus placebo. 5

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Adjunctive and Alternative Therapies

Nutritional Support

• Elemental or polymeric diets are less effective than corticosteroids but may be used in selected patients with contraindications to steroids or patient preference. 4
• Total parenteral nutrition is appropriate adjunctive therapy in complex fistulating disease. 4

Surgical Considerations for CD

• Surgery should be limited to symptomatic disease with conservative resections of macroscopic disease only. 2
• May be appropriate as primary therapy for limited ileal/ileocaecal disease. 4

Surgical Considerations for UC

• Surgery indicated for disease not responding to intensive medical therapy, dysplasia/carcinoma, or poorly controlled disease. 2
• Colectomy can be curative in UC. 8

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Cancer Surveillance

• Colonoscopy after 8-10 years to re-evaluate disease extent, with surveillance decisions individualized based on patient risk factors. 2, 3
• This is particularly important for extensive or left-sided disease. 2

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Emerging Considerations

• JAK inhibitors provide rapid symptom improvement in moderate-severe UC but are recommended as second-line therapy due to safety concerns. 9
• Anti-TNF remains a time-tested option effective in both UC and CD, though newer biologics (anti-integrins, anti-IL12/23, selective anti-IL23) are expanding treatment options. 9
• The perception that newer biologics have slower onset of action is likely overestimated. 9