What is the initial treatment for acute colitis?

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Initial Treatment for Acute Colitis

For acute severe ulcerative colitis, immediately initiate intravenous corticosteroids (hydrocortisone 100 mg four times daily OR methylprednisolone 40-60 mg daily) along with aggressive supportive care, without waiting for stool culture results. 1, 2

Severity Assessment and Classification

First, classify disease severity using Truelove and Witts' criteria, which defines severe disease as bloody stool frequency ≥6/day plus at least one of the following: 1

  • Tachycardia >90/min
  • Temperature >37.8°C
  • Hemoglobin <10.5 g/dL
  • ESR >30 mm/h (or CRP >30 mg/L)

Perform unprepared flexible sigmoidoscopy with biopsies to confirm diagnosis, assess severity, and exclude cytomegalovirus infection. 1, 2

Treatment Algorithm by Severity

Mild to Moderate Distal Colitis (Proctitis or Left-Sided)

First-line therapy: Topical mesalamine 1 g daily combined with oral mesalamine 2-4 g daily. 1 For proctitis specifically, mesalamine 1g suppository once daily is the preferred initial treatment. 1

If no improvement: Escalate to oral prednisolone 40 mg daily with continued topical agents as adjunctive therapy. 1

Acute Severe Ulcerative Colitis

Immediate IV corticosteroid therapy is mandatory and should not be delayed for screening test results: 1, 2

  • Hydrocortisone 100 mg four times daily, OR
  • Methylprednisolone 40-60 mg daily

Critical supportive measures include: 2

  • IV fluid and electrolyte replacement with potassium supplementation of at least 60 mmol/day to prevent hypokalaemia and toxic dilatation
  • Subcutaneous low-molecular-weight heparin for thromboprophylaxis (rectal bleeding is NOT a contraindication)
  • Blood transfusion to maintain hemoglobin above 8-10 g/dL
  • Withdraw anticholinergic, anti-diarrheal, NSAID, and opioid drugs which may precipitate colonic dilatation

Treatment duration: Limit IV corticosteroids to 7-10 days maximum, as extending beyond this carries no additional benefit. 1, 2

Expected Response and Decision Points

Approximately 67% of patients respond to IV corticosteroids, while 33% require colectomy. 1, 2 Formal assessment of response is required on day 3 to identify patients needing rescue therapy. 2

Monitor closely for signs of progressive deterioration including worsening pain or tenderness, progressive leukocytosis, fever, tachycardia, or hypotension. 3

Rescue Therapy (Days 3-5)

For patients not responding to IV corticosteroids after 3-5 days, two equally effective rescue options exist: 1

  • Infliximab 5 mg/kg IV, OR
  • Cyclosporine 2 mg/kg IV

The decision for rescue therapy versus surgery should be made by a multidisciplinary team including both gastroenterologist and surgeon. 3

Absolute Surgical Indications

Surgery is mandatory for: 1, 2

  • Free perforation with generalized peritonitis
  • Life-threatening hemorrhage with hemodynamic instability despite resuscitation
  • Toxic megacolon complicated by perforation, massive bleeding, clinical deterioration, or signs of shock

Urgent surgery is indicated for: 2

  • No improvement with second-line therapy after 4-7 days
  • Toxic megacolon with no clinical improvement after 24-48 hours of medical treatment

Critical Pitfalls to Avoid

Do not delay corticosteroid treatment while waiting for stool microbiology results. 1 While stool cultures and Clostridium difficile testing should be obtained (as C. diff is more prevalent in severe UC and associated with increased morbidity), treatment must begin immediately. 2

Do not extend IV corticosteroids beyond 7-10 days without escalating to rescue therapy or surgery. 1 Prolonged intravenous immunosuppressive therapy is associated with increased morbidity and mortality following subsequent surgery. 3

Do not delay surgery in critically ill patients with toxic megacolon, as this increases risk of perforation with high mortality. 1 Post-operative morbidity is higher after emergency surgery compared with elective surgery, but delay in surgery carries even greater risks. 3

Multidisciplinary Management

Joint care by gastroenterologist and colorectal surgeon from admission is essential, with early surgical consultation preventing delayed surgery and associated high morbidity. 1, 2 Patients should be informed of a 25-30% chance of needing colectomy. 1

Overall mortality of acute severe ulcerative colitis is 1%, but significantly higher in patients >60 years with comorbidities. 1, 2

References

Guideline

Treatment of Acute Onset Ulcerative Colitis

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Guideline

Acute Severe Ulcerative Colitis Management

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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