What is the initial treatment for peritonitis in a patient?

Initial Treatment for Peritonitis

The initial treatment for peritonitis requires immediate fluid resuscitation, early broad-spectrum antimicrobial therapy, and prompt surgical intervention for source control in patients with diffuse peritonitis. 1

Immediate Stabilization

Fluid Resuscitation

• Begin rapid restoration of intravascular volume immediately upon diagnosis 1
• For patients with septic shock, resuscitation should begin immediately when hypotension is identified 1
• Even patients without evidence of volume depletion should receive IV fluid therapy when peritonitis is suspected 1
• Avoid excessive crystalloid overload which can impair bowel perfusion 1
• Monitor electrolytes and acid-base status, as severe metabolic acidosis and hyperkalemia may be present 1

Antimicrobial Therapy

• Initiate broad-spectrum antibiotics as soon as peritonitis is diagnosed or strongly suspected 1
• For patients with septic shock, antibiotics should be administered as soon as possible 1
• For patients without septic shock, antimicrobial therapy should be started in the emergency department 1
• Recommended regimens for intra-abdominal infections include:
  • For mild-to-moderate severity: Cefazolin, cefuroxime, ceftriaxone, cefotaxime, ciprofloxacin, or levofloxacin, each in combination with metronidazole 1
  • For high-risk or severe infections: Imipenem-cilastatin, meropenem, doripenem, or piperacillin-tazobactam 1, 2
  • Piperacillin-tazobactam is specifically FDA-approved for peritonitis at a dosage of 3.375g IV every 6 hours 2

Source Control

Surgical Intervention

• Patients with diffuse peritonitis should undergo emergency surgical procedure as soon as possible, even if ongoing resuscitation measures need to be continued during the procedure 1
• Further diagnostic imaging is unnecessary in patients with obvious signs of diffuse peritonitis when immediate surgical intervention is planned 1
• An appropriate source control procedure should:
  • Drain infected foci
  • Control ongoing peritoneal contamination by diversion or resection
  • Restore anatomic and physiological function 1

Timing of Surgery

• The timing and adequacy of source control are critical; late or incomplete procedures may have severely adverse consequences, especially in critically ill patients 1
• For hemodynamically stable patients without evidence of acute organ failure, intervention may be delayed for up to 24 hours if appropriate antimicrobial therapy is given and careful clinical monitoring is provided 1

Surgical Approach

• For diffuse peritonitis, the primary objectives of surgical intervention include:
  • Determining the cause of peritonitis
  • Draining fluid collections
  • Controlling the origin of abdominal sepsis 1
• Surgical source control may involve:
  • Resection or suture of perforated viscus
  • Removal of infected organs
  • Debridement of necrotic tissue
  • Resection of ischemic bowel
  • Repair/resection of traumatic perforations 1

Special Considerations

Relaparotomy Strategies

• In patients with severe peritonitis, mandatory or scheduled relaparotomy is not recommended unless there is intestinal discontinuity, abdominal fascial loss, or intra-abdominal hypertension 1
• "On-demand" relaparotomy should be performed only when absolutely necessary and only for patients who would clearly benefit 1

Microbiologic Evaluation

• Blood cultures are not routinely recommended for community-acquired intra-abdominal infections 1
• However, if a patient appears clinically toxic or is immunocompromised, knowledge of bacteremia may help determine antimicrobial therapy duration 1

Pitfalls to Avoid

• Delaying surgical intervention in patients with diffuse peritonitis 1
• Inadequate source control, which is a major determinant of outcome 1
• Inappropriate antibiotic selection not covering anaerobes and Gram-negative bacteria 3, 4
• Underestimating fluid requirements in patients with peritonitis 1
• Overreliance on conservative management for patients with significant peritoneal contamination 3

By following this algorithmic approach with prompt resuscitation, early appropriate antimicrobial therapy, and timely surgical intervention for source control, the morbidity and mortality associated with peritonitis can be significantly reduced.