What is the initial treatment approach for a patient with inflammatory bowel disease (IBD)?

Initial Treatment of Inflammatory Bowel Disease

For ulcerative colitis, start with aminosalicylates (mesalamine 4 g/daily for mild-moderate disease), while for Crohn's disease, use high-dose mesalamine (4 g/daily) for mild ileocolonic disease or prednisolone 40 mg daily for moderate-severe disease. 1, 2

Ulcerative Colitis Initial Treatment

Mild to Moderate Disease

• Mesalamine 2.4-4.8 g/daily is first-line therapy, with doses above 2.4 g/day achieving significantly higher rates of clinical and endoscopic remission 3, 4
• Both 2.4 g and 4.8 g once-daily dosing demonstrated superiority over placebo, with 34-41% achieving remission at 8 weeks 3
• Combined topical and oral aminosalicylate therapy is more effective than either alone for distal disease 1

Severe Disease

• Severe ulcerative colitis requires joint management by gastroenterology and colorectal surgery, with patients informed of a 25-30% chance of needing colectomy 1
• Intravenous corticosteroids (hydrocortisone 400 mg/day or methylprednisolone 60 mg/day) are appropriate for severe presentations 1, 2

Maintenance Therapy

• Patients should normally receive maintenance therapy with aminosalicylates to reduce relapse risk and potentially decrease colorectal cancer risk 1
• Mesalamine 2.4 g once daily maintained remission in 84% of patients at 6 months 3

Crohn's Disease Initial Treatment

Disease Severity-Based Approach

Mild Ileocolonic Disease:

• High-dose mesalamine 4 g/daily is sufficient initial therapy 1, 5, 6, 2
• This represents first-line treatment for mild disease with grade A evidence 1

Moderate to Severe Disease:

• Oral prednisolone 40 mg daily is appropriate for moderate-severe disease or mild-moderate disease failing mesalamine 1, 6, 2
• Taper prednisolone gradually over 8 weeks to prevent early relapse; more rapid reduction increases relapse risk 1, 2
• Budesonide 9 mg daily is an alternative for isolated ileo-caecal disease with moderate activity, though marginally less effective than prednisolone 1, 2

Severe Disease:

• Intravenous steroids (hydrocortisone 400 mg/day or methylprednisolone 60 mg/day) with concomitant IV metronidazole to distinguish active disease from septic complications 1, 2

Location-Specific Considerations

Colonic Crohn's Disease:

• Sulphasalazine 4 g daily is effective but not first-line due to high side effect incidence 1
• Topical mesalazine may be effective for left-sided colonic disease of mild-moderate activity 1

Fistulating/Perianal Disease:

• Metronidazole 400 mg three times daily and/or ciprofloxacin 500 mg twice daily are first-line for simple perianal fistulae 1
• Initial aim is treating active disease and sepsis; MRI and examination under anesthesia help define anatomy 1

Adjunctive and Steroid-Sparing Agents

• Azathioprine 1.5-2.5 mg/kg/day or mercaptopurine 0.75-1.5 mg/kg/day serve as adjunctive therapy and steroid-sparing agents 1, 5, 6, 2
• These agents have slow onset of action, precluding use as sole therapy 1
• Particularly useful for patients requiring repeated steroid courses 1

Alternative Therapies for Specific Situations

Nutritional Therapy:

• Elemental or polymeric diets are less effective than corticosteroids but appropriate for patients with contraindications to steroids or those preferring to avoid them 1, 2
• Total parenteral nutrition is adjunctive therapy in complex fistulating disease 1

Biological Therapy:

• Infliximab 5 mg/kg is effective but should be avoided in patients with obstructive symptoms 1, 5, 2
• Reserved for refractory disease as part of a comprehensive strategy 1

Critical Pitfalls to Avoid

• Never rapidly reduce corticosteroids, as this associates with early relapse 1, 2
• Always consider alternative explanations for symptoms beyond active disease: bacterial overgrowth, bile salt malabsorption, fibrotic strictures, dysmotility 1, 2
• Nonadherence to mesalamine is common despite excellent safety profile; once-daily dosing improves compliance 3, 4
• Distinguish between ulcerative colitis with backwash ileitis and Crohn's disease using additional small bowel imaging, as backwash ileitis indicates more refractory disease 2

Surgical Considerations

• Surgery should be considered for medical therapy failure and may be appropriate as primary therapy for limited ileal or ileo-caecal Crohn's disease 1, 5, 2
• In severe cases requiring surgery, staged procedures are recommended, especially in patients on ≥20 mg prednisolone daily for >6 weeks or on anti-TNF agents 2