What is the management of peritonitis, particularly in patients with a history of intra-abdominal infection or liver disease?

Management of Peritonitis

Prompt surgical source control combined with broad-spectrum antibiotics started immediately is the cornerstone of peritonitis management, with delays in either intervention significantly increasing mortality. 1

Immediate Resuscitation and Diagnostic Workup

• Start aggressive fluid resuscitation and hemodynamic stabilization immediately upon suspicion of peritonitis, before definitive diagnosis 2, 3
• Obtain blood cultures and ascitic fluid analysis (if present) before initiating antibiotics 1
• CT scan is the most sensitive and specific imaging modality for detecting peritonitis and should be obtained in stable patients to characterize the source 2
• Ascitic fluid neutrophil count >250/mm³ is diagnostic for spontaneous bacterial peritonitis (SBP) in cirrhotic patients 2
• Multiple organisms on ascitic fluid culture, low glucose (<50 mg/dL), and elevated protein suggest secondary peritonitis requiring surgical intervention 4, 2

Antibiotic Therapy

Community-Acquired Peritonitis

• Initiate narrow-spectrum empiric antibiotics immediately covering E. coli, Klebsiella, Streptococcus species, and anaerobes 1
• Acceptable regimens include:
  • Piperacillin-tazobactam 3.375-4.5g IV every 6-8 hours for complicated intra-abdominal infections including appendicitis and peritonitis 5
  • Meropenem 1g IV every 8 hours for complicated intra-abdominal infections 6
• Administer antibiotics within the first hour in critically ill patients to ensure timely coverage 1

Hospital-Acquired/Healthcare-Associated Peritonitis

• Use broader-spectrum antibiotics with anti-ESBL and anti-Pseudomonal coverage due to higher risk of multidrug-resistant organisms 1, 3
• Consider meropenem 1g IV every 8 hours as first-line for nosocomial peritonitis 6
• Obtain intra-operative cultures in all hospital-acquired cases to guide de-escalation 1

Special Populations

Spontaneous Bacterial Peritonitis (Cirrhotic Patients):

• Third-generation cephalosporin (cefotaxime 2g IV every 8 hours) is first-line 2
• Add albumin infusion (1.5 g/kg on day 1, then 1 g/kg on day 3) to reduce renal failure and mortality 2

Peritoneal Dialysis-Associated Peritonitis:

• Administer intraperitoneal antibiotics covering both Gram-positive and Gram-negative organisms including Pseudomonas 7
• Remove catheter for refractory, recurrent, or fungal peritonitis 7

Duration of Antibiotic Therapy

• Limit antibiotics to 3-5 days post-operatively in patients with adequate source control 1
• No post-operative antibiotics are needed for uncomplicated appendicitis or cholecystitis with definitive source control 1
• Investigate for ongoing infection if signs of peritonitis persist beyond 5-7 days of treatment 1

Surgical Source Control

Timing and Approach

• Perform surgical source control immediately upon diagnosis of secondary peritonitis—delays beyond 24 hours significantly increase mortality 1, 2
• Operating room latency ≥60 hours is an independent predictor of need for relaparotomy and death 1

Surgical Techniques

• Source control includes: 1, 8

  • Resection or suture of perforated viscus
  • Removal of infected organs (appendix, gallbladder)
  • Debridement of necrotic tissue
  • Drainage of abscesses and fluid collections
  • Repair of traumatic perforations with primary anastomosis or diversion

• Consider damage control surgery in physiologically deranged patients with ongoing sepsis, preventing abdominal compartment syndrome 1

• Open abdomen may be necessary for unstable patients with diffuse contamination 1

Re-laparotomy Strategy

• On-demand re-laparotomy is preferred over planned re-laparotomy as it reduces healthcare costs and prevents unnecessary procedures 1
• Indications for re-exploration include persistent sepsis, clinical deterioration, or inadequate initial source control 1

Non-Operative Management (Highly Selected Cases Only)

The following patients MAY be managed non-operatively if hemodynamically stable and responding to antibiotics: 1

• Perforated diverticulitis with abscess <4 cm diameter 1
• Peri-appendiceal phlegmon or small abscess 1
• Small perforated peptic ulcer with minimal contamination 1
• CT findings of pericolic air only without diffuse peritonitis or distant free air 1

Critical caveat: Distant free air, hemodynamic instability, or diffuse peritonitis mandates immediate surgical intervention 1

Antifungal Coverage

• Empirical antifungal therapy is recommended for hospital-acquired peritonitis due to high risk of Candida species 1
• Echinocandins are preferred in critically ill patients with suspected Candida peritonitis 9

Common Pitfalls to Avoid

• Do not delay surgery for additional imaging in unstable patients with clinical peritonitis 2
• Do not continue antibiotics beyond 5 days without investigating for inadequate source control 1
• Do not use narrow-spectrum antibiotics in hospital-acquired peritonitis—resistance patterns demand broader coverage 1
• Do not forget albumin in cirrhotic patients with SBP—it significantly reduces mortality 2
• Adjust antibiotic dosing based on renal function and pharmacokinetic parameters in critically ill patients 1, 6