What is the treatment for infectious colitis?

Treatment for Infectious Colitis

The treatment of infectious colitis should be pathogen-specific, with empiric therapy using azithromycin 1000mg as a single dose for adults with febrile dysenteric diarrhea while awaiting culture results. 1

Diagnostic Approach

Before initiating treatment, proper diagnosis is essential:

• Stool testing should include:

  • Standard stool culture for bacterial pathogens (Shigella, Salmonella, Campylobacter)
  • Testing for Clostridioides difficile, especially with recent antibiotic exposure
  • Testing for E. coli O157:H7 and Shiga toxin in cases of acute dysentery with minimal fever 1
  • Multiplex PCR testing is preferred over traditional stool cultures 2, 3

• Laboratory workup should include:

  • Complete blood count (CBC)
  • Comprehensive metabolic panel (CMP)
  • Inflammatory markers (ESR or CRP) 4

Treatment Algorithm Based on Pathogen

1. Clostridioides difficile Colitis

• Mild to moderate disease: Oral vancomycin 125mg four times daily for 10 days 5
• Severe disease: Oral vancomycin 125mg four times daily for 10 days 5, 6
• Alternative for first episode: Fidaxomicin (equally effective with lower relapse rates) 6

2. Bacterial Enteropathogens (Shigella, Salmonella, Campylobacter)

• Empiric therapy: Azithromycin 1000mg single dose for adults with febrile dysenteric diarrhea 1
• Adjust therapy based on culture results and susceptibility testing

3. Staphylococcal Enterocolitis

• Oral vancomycin 500mg to 2g daily in 3-4 divided doses for 7-10 days 5
• For pediatric patients: 40mg/kg/day in 3-4 divided doses (not to exceed 2g daily) 5

Supportive Care

• Fluid and electrolyte replacement to correct and prevent dehydration 4
• Blood transfusion to maintain hemoglobin >10 g/dl if significant bleeding 4
• Nutritional support for malnourished patients 4

Special Considerations

• Acute onset colitis: Treatment should not be delayed while awaiting stool microbiology results 4
• Shiga toxin-producing E. coli (STEC): Antimicrobials should be avoided as they may increase risk of hemolytic uremic syndrome 1
• Immune checkpoint inhibitor-related colitis: Different management approach requiring immunosuppression rather than antimicrobials 4

Monitoring and Follow-up

• Daily physical examination to evaluate abdominal tenderness
• Regular monitoring of vital signs
• Stool chart to record frequency and character of bowel movements
• Laboratory tests every 24-48 hours in severe cases 4
• Abdominal imaging if clinical deterioration or suspicion of complications

Pitfalls to Avoid

1. Delaying treatment while awaiting stool culture results in severe cases
2. Using antimicrobials for STEC infections
3. Failing to distinguish between infectious colitis and inflammatory bowel disease
4. Not considering C. difficile in patients with recent antibiotic exposure
5. Inadequate fluid and electrolyte replacement in severe cases

Early recognition of surgical candidates is essential to decrease mortality in severe cases that fail to respond to medical therapy 6.