What is the treatment for pseudomembranous colitis?

Treatment of Pseudomembranous Colitis

Oral vancomycin 125 mg four times daily for 10 days is the preferred first-line treatment for pseudomembranous colitis, with clinical success rates of approximately 80% and superior efficacy compared to metronidazole in severe disease. 1

Immediate Management Steps

Discontinue the inciting antibiotic immediately upon suspicion of C. difficile infection, as continued use significantly increases recurrence risk. 2 If ongoing antibiotic therapy is essential for another infection, switch to agents less commonly associated with CDI such as parenteral aminoglycosides, sulfonamides, macrolides, vancomycin, or tetracycline/tigecycline. 2

First-Line Antibiotic Therapy

Oral Vancomycin (Preferred)

• Dosing: 125 mg orally four times daily for 10 days 1
• Efficacy: Clinical success rates of 81-81.3% in randomized controlled trials 1
• Median time to diarrhea resolution: 4-5 days 1
• Advantages: Superior efficacy in severe disease, particularly in patients with ≥10 unformed bowel movements per day or WBC ≥15,000/mm³ 2, 1
• Important caveat: Must be given orally; parenteral vancomycin is not effective for pseudomembranous colitis 1

Oral Metronidazole (Alternative)

• Indication: Effective for mild-to-moderate disease 2
• Advantages: Lower cost and reduced selection pressure for vancomycin-resistant enterococci 2
• Comparative efficacy: Equivalent to vancomycin in non-severe cases with 97% cure rates, though inferior in severe disease 3

Management of Severe-Complicated Disease

Urgent surgical consultation is mandatory for patients showing signs of systemic toxicity, peritonitis, or worsening despite medical therapy. 2 Surgical intervention should be considered when patients develop organ failure, worsening CT findings, or signs of peritonitis. 4

Surgical Approach

• Procedure of choice: Subtotal colectomy with mortality rate of 14% 4
• Avoid: Left hemicolectomy, which carries 100% mortality rate 4
• Critical pitfall: The external appearance of the colon is often deceptively normal at laparotomy and should not influence the decision to perform subtotal colectomy 4

Recurrent Disease Management

After First Recurrence

• Consider extended/pulsed vancomycin or fidaxomicin before considering fecal microbiota transplantation 3
• Fidaxomicin and bezlotoxumab significantly reduce recurrence rates compared to standard vancomycin 3, 2
• Pulsed/tapered dosing of vancomycin results in fewer recurrences than standard dosing 3

After Multiple Recurrences (≥2 episodes)

• Fecal microbiota transplantation (FMT) should be considered after failure of three courses of antibiotics 3
• FMT shows 92% clinical resolution across studies, with lower GI delivery (95%) superior to upper GI delivery (88%) 3
• For FMT failure in pseudomembranous colitis specifically: Repeat FMT every 3 days until resolution of pseudomembranes has been successful 3
• Alternative protocol: Restart 5 days of vancomycin if FMT fails, before offering another FMT 3

Monitoring and Follow-Up

Renal Function Monitoring

• Monitor renal function during and after treatment in patients >65 years of age, including those with normal baseline renal function, as nephrotoxicity risk is increased 1
• Serum vancomycin concentration monitoring may be appropriate in patients with renal insufficiency, colitis, or those receiving concomitant aminoglycosides 1

Ototoxicity Surveillance

• Serial auditory function tests may be helpful, particularly in patients with underlying hearing loss or receiving concomitant ototoxic agents 1

Critical Pitfalls to Avoid

• Do not perform "test of cure" after treatment, as 56% of successfully treated patients asymptomatically shed C. difficile spores for up to 6 weeks 3
• Do not repeat testing after initiating treatment unless there are clear clinical changes, as test positivity does not correlate with treatment failure 2
• Do not treat asymptomatic carriage with C. difficile 3
• Distinguish recurrent CDI from post-infectious irritable bowel syndrome, which can cause symptoms in up to 35% of patients during the first 2 weeks and 4.3% beyond 3 months 3
• Discontinue vancomycin immediately if signs of severe dermatologic reactions (TEN, SJS, DRESS, AGEP, or LABD) appear 1

Expected Outcomes

• Recurrence rates after successful initial treatment: 18-25% within 4 weeks 1
• Overall mortality with appropriate medical management: <2% 5
• Surgical mortality with subtotal colectomy: 14% (versus 38% overall surgical mortality when inappropriate procedures performed) 4