Peritonitis Follow-Up Guidelines

Laboratory Tests and Interpretation

• In patients with infected ascites, follow-up paracentesis should be performed if the clinical setting, symptoms, organism(s), or response to treatment are atypical to distinguish between spontaneous bacterial peritonitis (SBP) and secondary peritonitis, as recommended by the American Association for the Study of Liver Diseases 1, 2
• Routine follow-up paracentesis is not necessary in all patients with infected ascites who show typical presentation and good clinical response to treatment, according to the American Association for the Study of Liver Diseases 1, 2
• The American Association for the Study of Liver Diseases recommends follow-up paracentesis in patients with atypical clinical presentation or setting, atypical ascitic fluid analysis results, unusual or multiple organisms on culture, or poor clinical response to appropriate antibiotic therapy 1, 2, 3
• The presence of total protein >1 g/dL, lactate dehydrogenase (LDH) > upper limit of normal, or glucose <50 mg/dL in ascitic fluid may suggest secondary peritonitis, as indicated by the American Association for the Study of Liver Diseases 1, 4
• Carcinoembryonic antigen (CEA) >5 ng/mL or alkaline phosphatase >240 U/L may indicate gut perforation, with 92% sensitivity and 88% specificity, according to the American Association for the Study of Liver Diseases 4, 2
• The American Association for the Study of Liver Diseases recommends monitoring serum electrolytes, creatinine, and complete blood count during the initial assessment of peritonitis follow-up 1, 2
• The 48-hour polymorphonuclear leukocyte (PMN) count should decrease from pretreatment value in SBP with appropriate antibiotic therapy, as recommended by the American Association for the Study of Liver Diseases 3
• Rising PMN count despite treatment suggests nonperforation secondary peritonitis, according to the American Association for the Study of Liver Diseases 3, 5

Monitoring Algorithm

• The American Association for the Study of Liver Diseases recommends evaluating clinical response, monitoring serum electrolytes, creatinine, and complete blood count, and performing follow-up paracentesis with complete fluid analysis if necessary, during the initial assessment of peritonitis follow-up 1, 2, 3
• The American Association for the Study of Liver Diseases suggests considering surgical evaluation and adding anaerobic coverage to antibiotics in cases of suspected secondary peritonitis 3, 5

Common Pitfalls and Caveats

• Waiting too long to perform follow-up paracentesis in patients with poor clinical response can delay diagnosis of secondary peritonitis, as warned by the American Association for the Study of Liver Diseases 1, 3
• The classic criteria for secondary peritonitis (protein, LDH, glucose) have 100% sensitivity but only 45% specificity for perforation, according to the American Association for the Study of Liver Diseases 4, 3
• The total protein, LDH, and glucose criteria are only 50% sensitive in detecting nonperforation secondary peritonitis; follow-up PMN count is more valuable, as indicated by the American Association for the Study of Liver Diseases 3, 5