What are the initial treatment recommendations for a patient with inflammatory bowel disease (IBD)?

Initial Treatment of Inflammatory Bowel Disease

Initial treatment of IBD must be stratified by disease type (ulcerative colitis vs. Crohn's disease), anatomical location, and severity, with combination topical and oral mesalazine as first-line for mild-to-moderate UC, while Crohn's disease requires corticosteroids or biologics depending on severity and location. 1

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 initial 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

• Start with oral mesalazine 2-4g daily or balsalazide 6.75g daily. 1
• If inadequate response, escalate to oral prednisolone 40mg daily, reduced gradually over 8 weeks. 1

Severe UC

• Intravenous steroids (hydrocortisone 400mg/day or methylprednisolone 60mg/day) are appropriate. 2
• Concomitant intravenous metronidazole is often advisable to distinguish active disease from septic complications. 2
• Surgery should be considered for disease not responding to intensive medical therapy. 1

Maintenance Therapy for UC

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

Crohn's Disease Treatment Algorithm

Mild Ileocaecal CD

• High-dose mesalazine 4g daily as initial therapy. 1
• 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
• Advanced therapy (biologics or small molecules) as first-line treatment improves long-term disease control and should be strongly considered. 1
• Infliximab 5mg/kg is effective but should be avoided in patients with obstructive symptoms. 2

Alternative First-Line Options for CD

• Elemental or polymeric diets are less effective than corticosteroids but may be used in selected patients with contraindications to steroids or who prefer to avoid them. 2
• Sulphasalazine 4g daily is effective for active colonic disease but has high incidence of side effects and is not first-line. 2

Fistulating and Perianal CD

• Metronidazole 400mg three times daily and/or ciprofloxacin 500mg twice daily are appropriate first-line treatments for simple perianal fistulae. 2
• Azathioprine 1.5-2.5mg/kg/day or mercaptopurine 0.75-1.5mg/kg/day are potentially effective where distal obstruction and abscess have been excluded. 2
• Infliximab (three infusions of 5mg/kg at 0,2, and 6 weeks) should be reserved for refractory fistulae and used as part of a strategy including immunomodulation and surgery. 2

Maintenance Therapy for CD

• Azathioprine 1.5-2.5mg/kg/day or mercaptopurine 0.75-1.5mg/kg/day are effective maintenance options. 1
• All smokers should be strongly advised to stop, as smoking cessation is the most important factor in maintaining remission. 2

Initial Diagnostic Workup

Essential Laboratory Tests

• Full blood count, U&Es, liver function tests, ESR or CRP. 2
• Microbiological testing for infectious diarrhea including Clostridium difficile toxin. 2
• Fecal calprotectin to exclude IBD in patients <45 years with diarrhea. 2

Endoscopic Evaluation

• Rigid or flexible sigmoidoscopy should be performed for all patients presenting with diarrhea. 2
• For mild to moderate disease, colonoscopy is preferable to assess disease extent. 2
• In moderate to severe disease, flexible sigmoidoscopy is safer due to higher perforation risk with colonoscopy. 2
• For suspected CD, colonoscopy to terminal ileum and small bowel barium studies to define extent and site. 2

Imaging

• Abdominal radiography is essential in suspected severe IBD to exclude colonic dilatation and assess disease extent. 2
• MRI is particularly helpful for perianal disease evaluation. 2

Critical Pitfalls to Avoid

• Do not use insoluble fiber (wheat bran) in IBD as it may exacerbate symptoms; only soluble fiber like ispaghula is appropriate. 2
• Avoid infliximab in CD patients with obstructive symptoms. 2
• Do not perform primary anastomosis in the presence of sepsis and malnutrition. 2
• Azathioprine/mercaptopurine have slow onset of action and cannot be used as sole therapy for active disease. 2
• Check FBC within 4 weeks of starting azathioprine/mercaptopurine and every 6-12 weeks thereafter to detect neutropenia. 2

Surgical Considerations

Crohn's Disease

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

Ulcerative Colitis

• Surgery is indicated for disease not responding to intensive medical therapy, dysplasia/carcinoma, or poorly controlled disease. 1
• Subtotal colectomy with long rectal stump is the procedure of choice in acute fulminant UC. 2

Long-Term Monitoring

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