What is the treatment approach for infectious colitis?

Treatment Approach for Infectious Colitis

The treatment of infectious colitis must be tailored to the specific pathogen causing the infection, with initial empiric therapy guided by clinical presentation and severity of symptoms.

Diagnosis and Initial Assessment

• Obtain stool samples for:

  • Standard stool culture (for Shigella, Salmonella, Campylobacter)
  • C. difficile toxin testing
  • Inflammatory markers (leukocytes, lactoferrin, calprotectin)
  • Consider multiplex PCR for rapid pathogen identification 1

• Assess severity based on:

  • Vital signs (fever, tachycardia, hypotension)
  • Stool frequency and consistency
  • Presence of blood in stool
  • Abdominal examination findings
  • Laboratory markers (leukocytosis, elevated CRP)

Treatment Algorithm by Pathogen

Clostridium difficile Colitis

C. difficile is a common cause of infectious colitis, particularly in patients with recent antibiotic exposure.

1. First-line treatment:

   • Mild to moderate disease: Oral metronidazole 500 mg three times daily for 10 days 2
   • Severe disease: Oral vancomycin 125 mg four times daily for 10 days 2, 3

2. Severe complicated/fulminant disease:

   • Intravenous metronidazole 500 mg three times daily PLUS
   • Vancomycin 500 mg four times daily via nasogastric tube AND/OR
   • Intracolonic vancomycin 500 mg in 100 mL saline every 4-12 hours 2

3. Recurrent C. difficile infection:

   • First recurrence: Same as initial episode based on severity
   • Second recurrence: Vancomycin 125 mg four times daily for at least 10 days, followed by tapered/pulsed regimen 2
   • Multiple recurrences: Consider fecal microbiota transplantation 2

4. Supportive measures:

   • Discontinue the inciting antibiotic if possible 2
   • Avoid antiperistaltic agents and opiates 2
   • Consider discontinuing proton pump inhibitors 2

Bacterial Enteric Pathogens (non-C. difficile)

For febrile dysenteric diarrhea caused by invasive bacterial pathogens:

1. Empiric therapy (while awaiting culture results):

   • Azithromycin 1000 mg single dose for adults 4

2. Pathogen-specific therapy:

   • Shigella: Ciprofloxacin or azithromycin (based on susceptibility)
   • Salmonella: Generally self-limited; antibiotics only for severe disease or high-risk patients
   • Campylobacter: Azithromycin or ciprofloxacin (based on susceptibility)
   • E. coli (STEC): Avoid antibiotics due to risk of hemolytic uremic syndrome 4

Severe Ulcerative Colitis (Inflammatory Bowel Disease)

While not primarily infectious, ulcerative colitis can present similarly and requires different management:

1. Acute severe colitis:

   • Intravenous corticosteroids (methylprednisolone 60 mg/day or hydrocortisone 100 mg four times daily) 2
   • If no improvement within 3-5 days, consider second-line therapy (infliximab or cyclosporine) or colectomy 2

2. Supportive care:

   • Intravenous fluid and electrolyte replacement
   • Thromboprophylaxis with low-molecular-weight heparin
   • Nutritional support if malnourished 2

Indications for Surgical Intervention

Surgery should be considered in the following scenarios:

1. Toxic megacolon with:

   • Perforation
   • Massive bleeding with hemodynamic instability
   • Clinical deterioration despite medical therapy 2

2. Fulminant colitis unresponsive to medical therapy within 24-72 hours 2

3. Life-threatening complications:

   • Free perforation
   • Generalized peritonitis
   • Uncontrolled hemorrhage 2

Monitoring Response to Treatment

• Daily physical examination to assess abdominal tenderness
• Monitor vital signs and stool frequency/consistency
• Follow laboratory markers (CBC, CRP, electrolytes, albumin)
• Consider repeat imaging if clinical deterioration occurs

Important Caveats

• Never delay treatment while awaiting stool culture results in severely ill patients
• Avoid antiperistaltic agents in infectious colitis as they may worsen disease
• Early surgical consultation is crucial for severe or refractory cases
• Monitor elderly patients closely for complications, especially with vancomycin therapy due to risk of nephrotoxicity 3
• Consider joint gastroenterology and surgical management for severe cases 2

By following this algorithmic approach based on pathogen identification and disease severity, infectious colitis can be effectively managed to minimize morbidity and mortality.