What is the treatment approach for a patient with colitis, considering their overall health, medical history, and potential complications?

Treatment of Colitis

Treatment of colitis is guided primarily by the type of colitis (ulcerative colitis vs. Crohn's colitis vs. infectious), disease location, and severity, with 5-aminosalicylates (5-ASA) as first-line therapy for mild-to-moderate ulcerative colitis and corticosteroids reserved for moderate-to-severe disease or inadequate response to 5-ASA. 1

Initial Diagnostic Considerations

Before initiating treatment, you must exclude infectious causes through stool testing for bacterial pathogens, C. difficile, and parasites, as treatment should not be delayed while awaiting results in severe presentations 1. Endoscopic confirmation with biopsies establishes the diagnosis, assesses disease extent and severity, and guides therapeutic decisions 2.

Treatment Algorithm for Ulcerative Colitis

Ulcerative Proctitis (Rectum Only)

• Start with topical mesalamine suppositories 1g daily as first-line therapy 1
• If inadequate response or intolerance occurs, add oral 5-ASA (2-3g daily) or substitute topical corticosteroids 1
• Refractory proctitis may require oral corticosteroids, topical tacrolimus, JAK inhibitors, S1P agonists, or biologic therapy 1

Mild-to-Moderate Extensive or Left-Sided Disease

Initiate combination therapy with oral mesalamine 2-4g daily PLUS topical mesalamine 1g daily, as this achieves superior remission rates compared to monotherapy 1, 2. The evidence strongly supports:

• Standard-dose oral mesalamine (2-3g/day) over low-dose formulations 1
• Once-daily dosing rather than multiple daily doses for improved adherence 1, 2
• If suboptimal response after 2-4 weeks, escalate to high-dose oral mesalamine (>3g/day) with continued rectal therapy 1

If no response within 2-4 weeks of optimized 5-ASA therapy, initiate oral corticosteroids (prednisolone 40mg daily) 1. Do not delay corticosteroid initiation beyond this timeframe, as this risks disease progression 1.

Moderate-to-Severe Disease

Start prednisolone 40mg daily combined with 5-ASA therapy immediately 1. The 2025 British Society of Gastroenterology guidelines demonstrate that 40mg/day is more effective than 20mg/day, with no additional benefit from doses exceeding 40-60mg/day 1. Taper gradually over 8 weeks to prevent early relapse 1.

If inadequate response to oral corticosteroids within 2 weeks, if corticosteroid taper fails, or to avoid repeated corticosteroid courses, escalate to advanced therapy (biologics or small molecule drugs) 1. This represents a critical decision point where delaying biologic initiation increases colectomy risk.

Severe/Acute Ulcerative Colitis Requiring Hospitalization

Patients meeting Truelove and Witts criteria or failing maximal oral therapy require:

• Intravenous hydrocortisone 400mg/day or methylprednisolone 60mg/day (methylprednisolone preferred due to less mineralocorticoid effect) 1, 2
• Daily monitoring: vital signs four times daily, stool frequency chart, complete blood count, CRP, albumin, electrolytes every 24-48 hours 1, 2
• Abdominal radiography if colonic dilatation suspected (transverse colon >5.5cm) 1
• IV fluid/electrolyte replacement with potassium supplementation ≥60mmol/day 2
• Subcutaneous heparin for thromboprophylaxis (rectal bleeding is NOT a contraindication) 1, 2
• Blood transfusion to maintain hemoglobin >10g/dL 1

Assess response after 3-5 days of IV corticosteroids 2. Approximately 67% respond to IV corticosteroids alone 2. If inadequate response by day 3-5, initiate rescue therapy with infliximab 5mg/kg or ciclosporin 2mg/kg/day 2, 3. Do not continue IV corticosteroids beyond 7-10 days maximum, as prolonged courses increase toxicity without additional benefit 2.

Joint medical-surgical management is mandatory, as 20-29% require colectomy during the same admission 1, 2. Patients should be informed of the 25-30% colectomy risk 1.

Treatment Algorithm for Crohn's Colitis

Mild Ileocolonic Disease

• High-dose mesalazine 4g daily may be sufficient as initial therapy 1
• If inadequate response, escalate to prednisolone 40mg daily 1

Moderate-to-Severe Crohn's Disease

• Prednisolone 40mg daily is appropriate for moderate-to-severe disease or failure of mesalazine 1
• Budesonide 9mg daily is an alternative for isolated ileo-caecal disease with moderate activity, though marginally less effective than prednisolone 1
• For severe disease, use IV hydrocortisone 400mg/day or methylprednisolone 60mg/day, often with concomitant IV metronidazole to distinguish active disease from septic complications 1

Maintenance Therapy

Lifelong maintenance therapy is generally recommended for all patients, especially those with left-sided or extensive disease 1. The treatment goal has shifted from clinical response to achieving biochemical, endoscopic, and histologic remission 1.

• Continue the agent successful in achieving induction, with the critical exception that corticosteroids are NOT recommended for long-term maintenance 1
• Oral 5-ASA at least 2g/day for ulcerative colitis maintenance reduces relapse risk and potentially reduces colorectal cancer risk 1, 2
• Azathioprine or mercaptopurine can be used for maintenance, though they typically require induction with another agent 1
• When combining TNF antagonists with immunomodulators in corticosteroid-free remission ≥6 months, do not withdraw the TNF antagonist 2

Advanced Therapy Selection

For moderate-to-severe disease requiring biologics or small molecules, options include infliximab, vedolizumab, ustekinumab, tofacitinib, and upadacitinib 1, 2. Combine TNF antagonists with thiopurines or methotrexate rather than using TNF antagonist monotherapy, as combination therapy is superior for inducing remission 2. JAK inhibitors should be reserved for patients with prior failure or intolerance to TNF antagonists 2.

Critical Pitfalls to Avoid

• Do not use probiotics, curcumin, or fecal microbiota transplantation in mild-moderate UC, as these lack evidence and risk delaying proven effective therapy 1
• Do not switch between different oral 5-ASA formulations if initial therapy fails, as this is ineffective 2
• Avoid anti-diarrheal medications in severe colitis to prevent toxic megacolon 2
• Do not delay infectious workup, but do not withhold corticosteroids while awaiting stool culture results in severe presentations 1
• Recognize that bulk-forming laxatives like psyllium are contraindicated if stercoral colitis is present 4