What are the symptoms and treatment of peritonitis?

Symptoms and Treatment of Peritonitis

Peritonitis requires prompt diagnosis and treatment with antibiotics and source control procedures to reduce mortality and morbidity. 1, 2

Clinical Features and Symptoms

Common Symptoms

• Abdominal pain and tenderness occur in 74-95% of patients, often accompanied by rebound tenderness and guarding 2
• Tachycardia is observed in 62.5% of patients 2
• Fever greater than 38.5°C is present in 38% of patients 2
• Decreased bowel sounds are a common finding 2
• Abdominal rigidity strongly suggests the presence of peritonitis 2
• Rectal bleeding is observed in 15% of patients 2
• Isolated abdominal distension is seen in 6.6% of patients 2
• Ileus symptoms, such as vomiting and absence of defecation, may be present 2
• Hemodynamic instability and shock can occur in severe cases 2

Laboratory Findings

• Leukocytosis with a left shift (band neutrophils >20%) is common 2
• Elevated C-reactive protein (CRP) levels 2
• Increased serum creatinine levels (more than 50% above baseline) in some patients 2
• Elevated serum lactate levels, indicating tissue hypoperfusion 2
• Ascitic fluid analysis showing neutrophil count >250/mm³ is diagnostic for spontaneous bacterial peritonitis 2, 3

Imaging Findings

• Free air on plain abdominal radiograph indicates perforation 2
• Ultrasonography may show free fluid in the abdomen 2
• CT scan has the highest sensitivity and specificity for detecting peritonitis 2
• CT findings include free fluid and air, bowel wall thickening, and pericolic fat inflammation 2

Types of Peritonitis

Primary Peritonitis (Spontaneous Bacterial Peritonitis)

• Diffuse bacterial infection without loss of integrity of the gastrointestinal tract 1, 4
• Typically occurs in patients with cirrhosis and ascites 4, 3
• Usually monomicrobial, most commonly caused by gram-negative aerobic bacteria like E. coli 3
• Diagnosed when ascitic fluid neutrophil count is >250/mm³ 3

Secondary Peritonitis

• Most common form of peritonitis 1, 4
• Results from loss of integrity of the gastrointestinal tract (perforation) 1, 4
• Usually polymicrobial with multiple organisms isolated from cultures 4
• Common causes include perforated duodenal ulcer, typhoid ileal perforation, and ruptured appendix 5

Tertiary Peritonitis

• Recurrent infection of the peritoneal cavity following primary or secondary peritonitis 1
• May be termed "ongoing peritonitis" or "persistent peritonitis" 1
• Often associated with multidrug-resistant organisms 4

Treatment Approach

Source Control

• Source control is essential for secondary and tertiary peritonitis 1
• Primary objectives include determining the cause of peritonitis, draining fluid collections, and controlling the origin of abdominal sepsis 1
• Surgical source control includes resection or suture of perforated viscus, removal of infected organ, debridement of necrotic tissue, and repair of traumatic perforations 1
• Percutaneous drainage of abscesses may be appropriate in selected patients 1
• Delay in source control significantly increases mortality rates 2

Antibiotic Therapy

For Primary (Spontaneous) Peritonitis

• Third-generation cephalosporins (e.g., cefotaxime 2g every 8 hours) are first-line treatment 2, 3
• Albumin infusion may reduce renal failure and mortality risk 2

For Secondary Peritonitis

• Antibiotics must cover both aerobic and anaerobic bacteria 6
• Treatment options based on severity 6:
  • Less severe cases: cefoxitin or amoxicillin/clavulanate plus gentamicin 6
  • More severe cases: piperacillin/tazobactam or ertapenem 6
  • Metronidazole is indicated for treatment of anaerobic infections including peritonitis caused by Bacteroides species 7
• For complicated intra-abdominal infections, cefepime (2g every 12 hours) plus metronidazole (500mg every 6 hours) is effective 8

For Tertiary/Nosocomial Peritonitis

• Broader antimicrobial coverage for resistant organisms 4
• Imipenem plus amikacin is considered reference treatment 6
• Antifungal treatment (fluconazole) may be necessary until culture results are available 6

Duration of Treatment

• Less severe forms: as short as 48 hours 6
• More severe forms: up to 14 days 6

Common Pitfalls to Avoid

• Delaying diagnosis and treatment, which significantly increases mortality rates 2
• Inadequate source control, associated with elevated mortality rates 2
• Not considering secondary peritonitis when multiple organisms are isolated from ascitic fluid 3
• Using quinolones empirically in patients already on quinolone prophylaxis 3
• Delaying antibiotic treatment while waiting for culture results 3