What are the symptoms and treatment of peritonitis?

Peritonitis: Symptoms and Treatment

Clinical Presentation

Peritonitis presents with abdominal pain and tenderness in 74-95% of patients, typically accompanied by rebound tenderness and guarding, which are the hallmark physical examination findings. 1

Key Symptoms

• Abdominal rigidity strongly suggests peritonitis and is a critical diagnostic finding 1
• Tachycardia occurs in 62.5% of patients 1
• Fever greater than 38.5°C is present in 38% of cases 1
• Decreased or absent bowel sounds are commonly observed 1
• Ileus symptoms including vomiting and absence of defecation may develop 1
• Hemodynamic instability and shock can occur, particularly in diffuse peritonitis 1
• Abdominal distension is seen in 6.6% of patients 1
• Rectal bleeding occurs in 15% of cases 1

Laboratory Findings

• Leukocytosis with left shift (band neutrophils >20%) is characteristic 1
• Elevated C-reactive protein (CRP) levels 1
• Increased serum lactate levels indicate ongoing sepsis 1
• Elevated serum creatinine (>50% above baseline) may be present 1
• For spontaneous bacterial peritonitis (SBP): ascitic fluid neutrophil count >250/mm³ is diagnostic 1
• For secondary peritonitis: low ascitic fluid glucose (<50 mg/dL) and multiple organisms on culture suggest gastrointestinal perforation 1, 2

Imaging Findings

• CT scan is the imaging modality of choice for stable patients not requiring immediate surgery, showing free fluid and air, bowel wall thickening, and pericolic inflammation 3, 1
• Free air on plain abdominal radiograph indicates perforation but has lower sensitivity 1
• Ultrasound can identify free fluid in resource-limited settings 1

Treatment Approach

Immediate Resuscitation

Patients with peritonitis require rapid restoration of intravascular volume and physiological stability, with resuscitation beginning immediately upon diagnosis. 3

• For septic shock: fluid resuscitation must begin immediately when hypotension is identified 3
• For stable patients: intravenous fluid therapy should begin when intra-abdominal infection is first suspected 3

Antimicrobial Therapy

Antimicrobial therapy should be initiated once peritonitis is diagnosed or strongly suspected, with antibiotics administered as soon as possible in patients with septic shock. 3

Empiric Antibiotic Regimens

For community-acquired peritonitis (mild-to-moderate severity):

• Single agents: Ertapenem, moxifloxacin, tigecycline, or ticarcillin-clavulanate 3
• Combination therapy: Cefazolin, cefuroxime, ceftriaxone, cefotaxime, ciprofloxacin, or levofloxacin, each combined with metronidazole 3

For high-risk or severe peritonitis:

• Single agents: Imipenem-cilastatin, meropenem, doripenem, or piperacillin-tazobactam 3
• Combination therapy: Cefepime, ceftazidime, ciprofloxacin, or levofloxacin, each combined with metronidazole 3

For spontaneous bacterial peritonitis:

• Third-generation cephalosporins (cefotaxime 2g IV every 8 hours) are first-line 1, 4
• Albumin infusion (1.5 g/kg at diagnosis, 1 g/kg on day 3) reduces renal failure and mortality 4

Piperacillin-tazobactam is FDA-approved for peritonitis caused by beta-lactamase producing E. coli or Bacteroides fragilis group at 3.375 grams every 6 hours for 7-10 days 5

Source Control

Patients with diffuse peritonitis should undergo emergency surgical intervention as soon as possible, even if resuscitation measures need to be continued during the procedure. 3

Surgical Approach

• Emergency surgery is required for diffuse peritonitis with signs of generalized contamination 3
• Source control procedures include drainage of infected foci, control of ongoing contamination, resection or repair of perforated viscus, and debridement of necrotic tissue 1
• Percutaneous drainage is preferable to surgical drainage for well-localized abscesses when feasible 3
• For hemodynamically stable patients without acute organ failure, intervention may be delayed up to 24 hours if appropriate antibiotics are given and close monitoring is provided 3

Critical Timing Considerations

Delay in diagnosis and treatment significantly increases mortality rates—each minute counts in peritonitis management. 1, 6, 7

• Delayed source control beyond 24 hours results in higher mortality 3, 6
• Inadequate source control is associated with intolerably high mortality rates 3, 1
• Early re-laparotomy appears most effective for postoperative peritonitis 3

Special Populations

For highly selected patients with minimal physiological derangement and well-circumscribed infection (periappendiceal or pericolonic phlegmon), antimicrobial therapy alone may be considered with very close clinical follow-up 3

For postoperative peritonitis: prompt surgical source control should be performed following diagnosis, as this population shows particularly high mortality due to nonspecific symptoms 3, 7

Duration of Treatment

• Community-acquired peritonitis: 7-10 days of antibiotic therapy 5
• Nosocomial peritonitis: 7-14 days of treatment 5
• Tuberculous peritonitis: 6-month regimen with first-line anti-tuberculous agents if suspected 4

Common Pitfalls

• Do not delay surgery in patients with diffuse peritonitis for additional imaging—obvious signs of peritonitis warrant immediate intervention 3
• Do not obtain routine blood cultures for community-acquired peritonitis unless the patient appears clinically toxic or is immunocompromised 3
• Consider tuberculous peritonitis in patients with lymphocytic-predominant ascites, particularly in endemic areas or immunocompromised patients (ADA >32-40 U/L has 100% sensitivity) 4, 2
• Multiple organisms on ascitic fluid culture suggest secondary rather than primary peritonitis and require surgical evaluation 1, 2