Criteria to Initiate Intraperitoneal Antibiotics for PD Peritonitis
Start empirical intraperitoneal antibiotics immediately when the peritoneal dialysis effluent shows cloudy fluid with an elevated white blood cell count, even before culture results are available, as delays in treatment significantly increase morbidity and mortality. 1, 2
Clinical Presentation Triggering Treatment
Initiate IP antibiotics when a patient on peritoneal dialysis presents with any of the following clinical features:
- Cloudy peritoneal dialysis effluent (the most common and cardinal sign) 2
- Abdominal pain or tenderness 2
- Fever (though absence does not exclude peritonitis) 2
- Nausea or vomiting 2
The presence of cloudy effluent alone is sufficient to warrant immediate empirical treatment while awaiting confirmatory testing. 2
Laboratory Confirmation Criteria
The diagnostic threshold is a peritoneal dialysis effluent white blood cell count >100 cells/μL with >50% polymorphonuclear cells (neutrophils). 2 This is the standard criterion that confirms PD-associated peritonitis and mandates immediate antibiotic therapy.
Key Diagnostic Steps:
- Send PD effluent for cell count with differential immediately upon suspicion 2
- Inoculate at least 10 mL of effluent into blood culture bottles at bedside before starting antibiotics to maximize culture yield 2, 3
- Obtain blood cultures if systemic signs of infection are present 2
- Perform Gram stain of the effluent, though treatment should not be delayed for this result 2
Empirical Antibiotic Regimen
Start empirical IP antibiotics covering both Gram-positive organisms (including Staphylococcus aureus) and Gram-negative organisms (including Pseudomonas aeruginosa) as soon as diagnostic specimens are obtained. 2, 3
The most commonly recommended initial regimen based on recent evidence:
- Vancomycin (for Gram-positive coverage) plus gentamicin or ceftazidime (for Gram-negative coverage) administered intraperitoneally 2, 4, 3
- A meta-analysis showed that glycopeptide (vancomycin) plus ceftazidime achieved an 86% resolution rate, significantly superior to first-generation cephalosporin plus aminoglycoside (66% resolution) 4
Route of Administration:
Intraperitoneal administration is the strongly preferred route over intravenous therapy, as it achieves higher local concentrations at the site of infection and has been associated with better outcomes. 2
Critical Timing Considerations
Do not wait for culture results to initiate treatment. The diagnosis is clinical and based on cell count criteria; empirical therapy must begin immediately upon diagnostic confirmation to prevent progression to technique failure, peritoneal membrane damage, and mortality. 2, 5
- Treatment delays beyond the first few hours of symptom recognition are associated with worse outcomes 5
- Adjust antibiotic therapy once culture and sensitivity results become available (typically 24-48 hours) 2, 4
Additional Prophylactic Measures
Add antifungal prophylaxis (preferably oral nystatin) when starting antibiotics to prevent secondary fungal peritonitis, which carries a particularly poor prognosis and typically requires catheter removal. 2
Common Pitfalls to Avoid
- Never delay antibiotics waiting for clear effluent or culture results if clinical suspicion is high 2
- Do not rely solely on fever or systemic symptoms—many PD peritonitis cases present with only cloudy effluent and mild abdominal discomfort 2
- Do not use narrow-spectrum monotherapy empirically—inadequate initial coverage of either Gram-positive or Gram-negative organisms increases treatment failure rates 2, 4
- Ensure adequate specimen collection—inoculating effluent into blood culture bottles at bedside (rather than sending fluid in a sterile container) increases culture positivity from ~40% to >90% 2
When to Consider Catheter Removal
If peritonitis fails to improve within 5 days of appropriate antibiotic therapy, or if peritonitis is relapsing (recurrence within 4 weeks with the same organism) or fungal, catheter removal is recommended to prevent permanent peritoneal membrane damage and mortality. 2, 5