What is the initial treatment for a patient with colitis?

Initial Treatment for Colitis

For newly diagnosed ulcerative colitis, start with combination therapy of topical mesalamine (≥1 g/day suppository for proctitis) plus oral mesalamine (≥2.4 g/day), which is superior to either therapy alone. 1

Treatment Based on Disease Location and Severity

Mild Distal Disease (Proctitis)

• Mesalamine 1 g suppository once daily is the preferred first-line treatment, as it delivers medication more effectively to the rectum than foam or enemas and demonstrates better tolerability 1
• Topical mesalamine demonstrates superior efficacy compared to topical corticosteroids for proctitis 1
• Add oral mesalamine ≥2.4 g/day to the suppository regimen, as combination therapy enhances effectiveness over monotherapy 1

Mild to Moderate Extensive Disease (Left-Sided or Pancolitis)

• Initiate oral mesalamine 2.4-4.8 g/day as first-line therapy 1, 2
• For ulcerative colitis, oral aminosalicylates are effective in both distal and extensive disease, though remission rates are lower than topical therapy for distal disease 3

Moderate to Severe Disease

• Add oral prednisolone 40 mg daily if inadequate response to optimized mesalamine after 10-14 days or if symptoms worsen 1
• Taper prednisolone gradually over 6-8 weeks to prevent early relapse; rapid reduction is associated with treatment failure 4, 1
• If symptoms persist after 40 days of optimized mesalamine, escalate to corticosteroid therapy 1

Severe/Hospitalized Disease

• Administer intravenous methylprednisolone 60 mg/24 hours or hydrocortisone 100 mg four times daily 4
• Higher doses provide no additional benefit, and treatment beyond 7-10 days carries no advantage 4
• Provide IV fluid and electrolyte replacement with potassium supplementation of at least 60 mmol/day, as hypokalaemia can promote toxic dilatation 4
• Administer subcutaneous prophylactic low-molecular-weight heparin for thromboembolism prevention 4
• Perform unprepared flexible sigmoidoscopy with biopsy to confirm diagnosis and exclude cytomegalovirus infection 4
• Test stool for Clostridium difficile toxin, which is more prevalent in severe UC and associated with increased mortality 4

Treatment Escalation for Steroid-Refractory Disease

Second-Line Medical Therapy (Day 3 of Steroid Therapy)

• Consider infliximab or vedolizumab early (on or around Day 3) if inadequate response to intravenous steroids 4
• Infliximab 5 mg/kg is effective for moderate to severe disease 4
• Ciclosporin 2 mg/kg/day IV is an alternative, particularly for patients who should avoid steroids (steroid psychosis, osteoporosis, poorly controlled diabetes) 4
• Patients remaining on ineffective corticosteroid therapy suffer high morbidity from delayed surgery 4

Crohn's Disease-Specific Treatment

Mild Ileocolonic Crohn's Disease

• High-dose mesalazine 4 g/daily may be sufficient as initial therapy 4
• Budesonide 9 mg daily is appropriate for isolated ileo-caecal disease with moderate activity, though marginally less effective than prednisolone 4

Moderate to Severe Crohn's Disease

• Oral prednisolone 40 mg daily is appropriate for patients with moderate to severe disease or those who failed oral mesalazine 4
• Azathioprine 1.5-2.5 mg/kg/day or mercaptopurine 0.75-1.5 mg/kg/day may be used as adjunctive therapy and steroid-sparing agents, though slow onset precludes use as sole therapy 4
• Infliximab 5 mg/kg is effective but should be avoided in patients with obstructive symptoms 4

Maintenance Therapy

• Continue lifelong maintenance therapy with mesalamine after achieving remission to prevent relapse 1
• Maintenance therapy may reduce colorectal cancer risk, especially in left-sided or extensive disease 1
• Monitor renal function by checking eGFR before starting mesalamine, after 2-3 months, and then annually 1

Critical Monitoring Parameters

• Perform initial screening colonoscopy 8 years after pancolitis onset and 12-15 years after left-sided disease onset, with follow-up every 2-3 years 5
• Monitor for extraintestinal manifestations, which occur in up to 25% of ulcerative colitis patients 5
• Joint management by gastroenterologist and colorectal surgeon is essential for severe disease 4