Peritonitis in PTS Undergoing CAPD

Pathogenesis: In a phenomenon similar to that seen in intravascular device-related infections, organisms migrate along the catheter, a foreign body that serves as an entry point.
Microbiology: CAPD-associated peritonitis usually involves skin organisms, with Staphylococcus spp. such as coagulase-negative staphylococci and Staphylococcus aureus accounting for ~45% of cases; gram-negative bacilli and fungi (e.g., Candida) are occasionally identified. A polymicrobial infection should prompt evaluation for secondary peritonitis.
Clinical manifestations: CAPD-associated peritonitis presents similarly to secondary peritonitis, in that diffuse pain and peritoneal signs are common.
Diagnosis: Several hundred milliliters of removed dialysis fluid should be centrifuged and sent for culture.
- - Use of blood culture bottles improves the diagnostic yield.
- - The dialysate is usually cloudy and contains >100 WBCs/µL, with >50% neutrophils; the percentage of neutrophils is more important than the absolute WBC count.

Treatment: Peritonitis in PTS Undergoing CAPD

Empirical therapy should be directed against staphylococcal species and gram-negative bacilli (e.g., cefazolin plus a fluoroquinolone or a third-generation cephalosporin such as ceftazidime). Vancomycin should be used instead of cefazolin if methicillin resistance is prevalent, if the pt has an overt exit-site infection, or if the pt appears toxic.
- - Antibiotics are given by the IP route either continuously (e.g., with each exchange) or intermittently (e.g., once daily, with the dose allowed to remain in the peritoneal cavity for 6 h). Severely ill pts should be given the same regimen by the IV route.
- - Catheter removal should be considered in fungal infection, for pts with exit-site or tunnel infection, or if the pt's condition does not improve within 48-96 h.
- - Uncomplicated CAPD-associated peritonitis should be treated for 14 days; up to 21 days may be necessary in pts with exit-site or tunnel infection.