What is the appropriate treatment for enteritis based on its etiology?

Treatment of Enteritis Based on Etiology

The treatment of enteritis should be tailored to the specific causative agent, with rehydration as the cornerstone of management for all types, and antimicrobial therapy reserved for specific bacterial and parasitic etiologies. 1

Initial Assessment and Management

Rehydration Therapy

• First-line treatment for all forms of enteritis is fluid and electrolyte replacement
  • Mild to moderate dehydration: Reduced osmolarity oral rehydration solution (ORS) 1
  • Severe dehydration: Isotonic intravenous fluids (lactated Ringer's or normal saline) until pulse, perfusion, and mental status normalize 1
  • Nasogastric ORS may be considered for those unable to tolerate oral intake 1

Diagnostic Approach

• Stool samples should be obtained for culture, C. difficile testing, and other pathogens before starting antibiotics 2
• Complete blood count and electrolyte profile to assess dehydration severity 2
• Consider multiplex antimicrobial testing for persistent or severe symptoms 3

Treatment Based on Specific Etiologies

Viral Enteritis (Most Common Cause)

• Supportive care with rehydration therapy
• Antimicrobial therapy is not indicated 1
• Consider ondansetron for significant vomiting that hinders oral rehydration 4

Bacterial Enteritis

Indications for Empiric Antimicrobial Therapy 1

• Infants < 3 months with suspected bacterial etiology
• Immunocompetent patients with fever, abdominal pain, bloody diarrhea, and bacillary dysentery presumptively due to Shigella
• Recent international travel with temperature ≥38.5°C and/or signs of sepsis
• Immunocompromised patients with severe illness and bloody diarrhea

Antimicrobial Selection

1. Adults: Fluoroquinolone (e.g., ciprofloxacin) or azithromycin based on local susceptibility patterns 1
2. Children:
   • Infants < 3 months: Third-generation cephalosporin
   • Others: Azithromycin based on local susceptibility patterns 1
3. Specific Pathogens:
   • Shigella/Campylobacter/Salmonella (invasive): Azithromycin or ciprofloxacin 2, 5
   • E. coli (enterotoxigenic): Ciprofloxacin 5
   • C. difficile: Vancomycin or fidaxomicin 2
   • Complicated intra-abdominal infections: Ciprofloxacin plus metronidazole 5

Important Cautions

• Avoid antibiotics for STEC O157 and other Shiga toxin 2-producing E. coli as they may increase risk of hemolytic uremic syndrome 1
• Modify or discontinue antimicrobial therapy when a specific organism is identified 1

Neutropenic Enteritis/Typhlitis

• Requires prompt broad-spectrum antibiotic therapy (anti-pseudomonal β-lactam agent, carbapenem, or piperacillin-tazobactam) 1
• Bowel rest, nasogastric decompression, and serial abdominal examinations 2
• Surgery only for perforation or ischemia 1

Sexually Transmitted Enteritis 1

• Proctitis: Ceftriaxone 250 mg IM single dose PLUS doxycycline 100 mg orally twice daily for 7 days
• Proctocolitis/Enteritis: Treatment based on identified pathogen (Campylobacter, Shigella, E. histolytica, etc.)

Duration of Therapy

• Antimicrobial therapy for established infection should be limited to 4-7 days 1
• For acute stomach and proximal jejunum perforations with source control within 24 hours: 24-hour prophylactic therapy 1
• Bowel injuries from trauma repaired within 12 hours: 24-hour antibiotic coverage 1

Special Considerations

Inflammatory Bowel Disease with Enteritis

• Antibiotics should not be routinely administered unless superinfection is suspected or intra-abdominal abscess is present 1
• For superinfection or abscesses: Prompt antimicrobial therapy against gram-negative/aerobic and facultative bacilli, gram-positive streptococci, and obligate anaerobic bacilli 1

Monitoring and Reassessment

• Track stool frequency and consistency
• Monitor vital signs, fluid balance, weight, and serum electrolytes
• Reassess if no improvement after 48-72 hours 2

Common Pitfalls to Avoid

1. Overuse of antimicrobials for viral or self-limiting enteritis
2. Administering antibiotics for STEC infections (may worsen outcomes)
3. Inadequate rehydration therapy (the cornerstone of management)
4. Failing to modify antimicrobial therapy when culture results become available
5. Neglecting to consider C. difficile in patients with recent antibiotic exposure

Remember that while antimicrobial therapy is important for specific bacterial causes, the mainstay of treatment for all forms of enteritis is appropriate rehydration therapy to prevent complications from dehydration.