What is the initial treatment regimen for patients with colitis?

Initial Treatment Regimen for Colitis

For mild to moderate ulcerative colitis, the initial treatment should consist of aminosalicylates (5-ASA) with a combination of oral mesalamine ≥2.4 g/day and topical mesalamine enemas ≥1 g/day. 1

Treatment Based on Disease Extent and Severity

Mild to Moderate Disease

1. First-line therapy:

   • Oral mesalamine: 2.4-4 g/day (once-daily dosing is as effective as divided doses) 1, 2
   • Plus topical mesalamine: Enemas 1 g/day for left-sided or extensive disease 1

2. If no response within 10-14 days or incomplete relief after 40 days:

   • Add oral corticosteroids 1

Moderate to Severe Disease or Non-responders to Mesalamine

1. Systemic corticosteroids:

   • Methylprednisolone 60 mg/day IV or
   • Hydrocortisone 100 mg four times daily IV 1

2. For severe disease requiring hospitalization:

   • Intravenous corticosteroids
   • IV fluid and electrolyte replacement
   • Thromboprophylaxis with low-molecular-weight heparin 1

3. If no improvement within 48-72 hours:

   • Consider biologic therapy (e.g., infliximab) 1, 3
   • Infliximab dosing: 5 mg/kg at weeks 0,2, and 6, then every 8 weeks 3
   • Urgent surgical consultation 1

Diagnostic Workup for Acute Colitis

• Stool cultures and Clostridium difficile toxin assay
• Unprepared flexible sigmoidoscopy and biopsy (if possible)
• Complete blood count, inflammatory markers (CRP), electrolytes, liver function tests
• Fecal calprotectin (>150 mg/g indicates active inflammation) 1

Supportive Care Measures

• IV fluid resuscitation to correct and prevent dehydration
• Electrolyte replacement, especially potassium (at least 60 mmol/day)
• Thromboprophylaxis with low-molecular-weight heparin
• Nutritional support if malnourished (enteral preferred over parenteral) 1

Medications to Avoid

• Anticholinergics
• Anti-diarrheals
• Non-steroidal anti-inflammatory drugs
• Opioids
• Antimotility agents (can precipitate toxic megacolon) 1

Maintenance Therapy After Remission

• Oral mesalamine ≥2.4 g/day (once-daily dosing) 1, 2
• For patients who have frequent relapses or steroid-dependent disease:
  • Consider immunomodulators (azathioprine) 1

Special Considerations

• Pediatric patients weighing ≥24 kg: Weight-based dosing of mesalamine 2
• Pregnancy: Most IBD medications are safe; active disease poses greater risk than treatment 1
• Before immunosuppressive therapy: Test for C. difficile and other pathogens 1

Common Pitfalls to Avoid

1. Delaying thromboprophylaxis in hospitalized patients with colitis
2. Missing C. difficile infection which can worsen the condition
3. Inadequate potassium replacement which can worsen colonic dilatation
4. Prolonged ineffective steroid therapy leading to unnecessary delays in treatment
5. Using antimotility agents which can precipitate toxic megacolon 1

The treatment approach should be guided by the extent of inflammation, disease severity, and response to initial therapy, with the goal of achieving complete remission defined as durable symptomatic and endoscopic remission without corticosteroid therapy.