What is the treatment approach for infective colitis?

Treatment Approach for Infective Colitis

For infective colitis, the treatment should be based on the specific pathogen identified, with metronidazole as first-line therapy for mild to moderate Clostridioides difficile infection and oral vancomycin for severe cases. 1

Diagnostic Approach

• Obtain stool cultures to identify the causative pathogen
• Look for inflammatory markers in stool (leukocytes, lactoferrin, calprotectin)
• Consider specialized testing based on epidemiologic factors:
  • Prior international travel
  • Shellfish consumption
  • Living in parasite-endemic regions
• For suspected Shiga toxin-producing E. coli (STEC), request specific testing for E. coli O157:H7 and Shiga toxin

Treatment Algorithm Based on Pathogen

Clostridioides difficile Infection (CDI)

1. Mild to Moderate CDI:

   • Metronidazole 500 mg orally three times daily for 10 days 1
   • If clearly antibiotic-induced, consider stopping the inducing antibiotic and monitoring closely 1

2. Severe CDI (determined by leukocytosis >15,000 cells/μL, serum creatinine >1.5 mg/dL, or signs of severe colitis):

   • Vancomycin 125 mg orally four times daily for 10 days 1, 2
   • For patients unable to take oral medications:
     • Metronidazole 500 mg IV three times daily 1
     • Consider intracolonic vancomycin 500 mg in 100 mL normal saline every 4-12 hours 1

3. Recurrent CDI:

   • First recurrence: Same as initial episode treatment 1
   • Second or later recurrences: Vancomycin 125 mg four times daily for at least 10 days, followed by tapering/pulsed regimen 1
   • Consider fecal microbiota transplantation for multiple recurrences 1

Bacterial Pathogens (non-C. difficile)

• Shigella, Salmonella, Campylobacter:
  • Azithromycin 1000 mg as a single dose for empiric treatment of febrile dysenteric diarrhea 3
  • Adjust therapy based on culture and sensitivity results

Cytomegalovirus (CMV) Colitis

• Intravenous ganciclovir 5 mg/kg twice daily for 3-5 days 1
• Transition to oral valganciclovir 900 mg twice daily to complete 2-3 week course 1
• Consider broad-spectrum antibiotics for secondary bacterial infections

Supportive Care Measures

• Intravenous fluid resuscitation and electrolyte replacement
• Venous thromboembolism prophylaxis with low-molecular-weight heparin
• Nutritional support for severely undernourished patients
• Avoid antiperistaltic agents and opiates 1
• Discontinue proton pump inhibitors if possible 1

Indications for Surgical Consultation

• Perforation of the colon
• Systemic inflammation not responding to antibiotic therapy
• Toxic megacolon
• Severe ileus
• Rising serum lactate (>5.0 mmol/L) 1

Surgical Options

• Total colectomy for fulminant colitis 1
• Diverting loop ileostomy with colonic lavage as an alternative to total colectomy 1

Important Considerations

• Antibiotic Stewardship: Use the narrowest spectrum antibiotic effective against the identified pathogen 1
• Monitoring: For patients with severe disease, monitor vital signs, abdominal examination, and laboratory values (WBC, lactate) frequently
• Pitfall: Failing to distinguish between infectious colitis and inflammatory bowel disease flare, which require different management approaches
• Caution: In patients with STEC infection, antibiotics may increase the risk of hemolytic uremic syndrome and should be avoided 3

Remember that prompt identification of the causative pathogen and early appropriate antimicrobial therapy are crucial for improving outcomes in infective colitis.