What is the recommended treatment for peritonitis?

Treatment of Peritonitis

Peritonitis requires immediate emergency surgical intervention combined with broad-spectrum antibiotics and aggressive fluid resuscitation, with surgery performed as soon as possible even while continuing resuscitative measures. 1, 2

Immediate Initial Management

Fluid Resuscitation

• Begin immediate intravenous fluid resuscitation to address volume depletion and enhance visceral perfusion—this is critical as patients with peritonitis are typically severely volume depleted 1, 2

Antibiotic Therapy

• Administer broad-spectrum antibiotics as soon as possible, ideally within 1 hour for patients presenting with septic shock 1, 2
• Empiric therapy must cover Gram-negative bacteria (especially E. coli), Gram-positive organisms, and anaerobes (particularly Bacteroides fragilis) given the polymicrobial nature of peritonitis 1

For non-critically ill, immunocompetent patients with adequate source control: use piperacillin/tazobactam 1

For septic shock or critically ill patients: use meropenem, doripenem, or imipenem/cilastatin 1, 3

• For patients at high risk of ESBL-producing Enterobacterales (particularly those who received broad-spectrum antibiotics between initial intervention and reoperation): use ertapenem or eravacycline 1, 4
• Ensure antimicrobial drug levels are maintained during surgical intervention, which may require additional dosing just before the procedure 2

Antifungal Coverage

• Add antifungal therapy (typically fluconazole) for hospital-acquired infections and in critically ill or severely immunocompromised patients 1

Emergency Surgical Intervention

Timing and Approach

Do not delay surgery for complete physiologic stabilization—proceed to emergency laparotomy immediately while continuing resuscitative measures concurrently 2

• Delayed source control is directly associated with increased morbidity and mortality 2
• The primary surgical goals are: drain infected foci, control ongoing peritoneal contamination, and restore anatomic and physiological function 1, 2

Surgical Technique Based on Etiology

• For perforated diverticulitis with diffuse peritonitis in critically ill patients: Hartmann's procedure is recommended 1, 2
• For perforated peptic ulcer or small bowel perforation: Simple closure with or without omental patch for small perforations; resection with primary anastomosis when appropriate 2
• Perform mechanical cleansing of the peritoneal cavity through debridement and copious irrigation 5

Postoperative Surgical Considerations

• On-demand re-laparotomy (rather than mandatory scheduled re-laparotomy) is recommended for severe peritonitis, as it streamlines resources and reduces costs 1
• Open abdomen may be necessary for physiologically deranged patients with ongoing sepsis to facilitate subsequent exploration and prevent abdominal compartment syndrome 1
• Mandatory re-laparotomy is NOT recommended unless there is intestinal discontinuity, abdominal fascial loss preventing closure, or intra-abdominal hypertension 2

Duration of Antibiotic Therapy

For patients with adequate source control: use a short course of 3-5 days 1

• For immunocompromised or critically ill patients with adequate source control: extend to up to 7 days 1
• This represents a shift toward "less is better" in terms of both number of drugs and duration 6

Diagnostic Imaging

• If secondary bacterial peritonitis is suspected, perform abdominal computed tomography to identify the source 1

Critical Pitfalls to Avoid

• Never delay surgical intervention while attempting complete physiologic stabilization—this increases mortality 2
• Avoid using broad-spectrum antibiotics between initial intervention and reoperation, as this is the primary risk factor for emergence of multidrug-resistant bacteria (OR = 5.1) 4
• Do not fail to maintain adequate antimicrobial coverage during the perioperative period 2
• Do not use Hartmann's procedure inappropriately—reserve it for critically ill patients with perforated diverticulitis, not all causes of peritonitis 2

Meropenem Dosing (When Indicated)

• For intra-abdominal infections including peritonitis: 1 gram IV every 8 hours 3
• Administer as IV infusion over 15-30 minutes, or as IV bolus over 3-5 minutes 3
• Adjust dosing for renal impairment: for creatinine clearance 26-50 mL/min, give recommended dose every 12 hours; for 10-25 mL/min, give half dose every 12 hours; for <10 mL/min, give half dose every 24 hours 3