Diagnosis: Peritonitis in Peritoneal Dialysis (PD)
Case Summary: Well done! This patient has peritonitis in the setting of peritoneal dialysis, one of the potential complications of PD. This young woman has had, until now, an uncomplicated 2 years on PD and is now presenting with abdominal pain worsening over 1 day. Just like with any non-PD patient, abdominal pain has a wide differential diagnosis, and we should be cautious not to anchor too quickly on peritonitis or other PD complications.
Small or large bowel obstruction
Nephrolithiasis (kidney stone)
Encapsulating peritoneal sclerosis
While keeping our eyes out for non-PD related pathology, it is important to act quickly with any suspicion for peritonitis. Looking at the PD fluid itself can also be helpful in making a diagnosis. PD fluid should be sent immediately for cell count with differential, gram stain, and culture.
Intraperitoneal disease (appendicitis, cholecystitis, bowel ischemia)
Retroperitoneal disease (pancreatitis, renal cell carcinoma)
Drugs (vancomycin, amphotericin B)
Allergic reaction (increased eosinophils)
Drugs (calcium channel blockers)
Ovarian cyst rupture
The fluid cell count and differential should come back relatively quickly. An elevated dialysate white blood cell (WBC) count >100 cells/microL and/or greater than 50% polymorphonuclear leukocytes (PMNs) would be consistent with bacterial peritonitis. Both gram-positive (predominantly coagulase negative Staphylococcus or S. aureus) and gram-negative organisms (mainly gastrointestinal pathogens) can cause peritonitis.
Empiric antibiotic coverage is crucial. Intraperitoneal antibiotics should be initiated as soon as possible; if unavailable, systemic IV antibiotics should be given.
Antibiotic therapy should be narrowed as culture data allows. Up to 20-40% of cases, however, will be culture negative. These patients should continue empiric therapy and undergo repeat fluid testing in 3 days. Failure to improve should prompt further evaluation.
The majority of patients improve with antibiotic therapy, though some conditions require peritoneal dialysis catheter removal. Infection with Pseudomonas, fungi, vancomycin-resistant enterobacter (VRE), or Mycobacterium should prompt removal. In addition, concomitant exit-site or tunnel-site abscess, failure of therapy after five days of antibiotics, or a relapsed episode of peritonitis with the same organism are indications for catheter removal. The main goal is to act quickly to provide the best chance for resolution!
For more on peritonitis and peritoneal dialysis in general, take a look below:
- Li PK-T, Szeto CC, Piraino B, Arteaga J de, Fan S, Figueiredo AE, Fish DN, Goffin E, Kim Y-L, Salzer W, Struijk DG, Teitelbaum I, Johnson DW: ISPD Peritonitis Recommendations: 2016 Update on Prevention and Treatment. Perit. Dial. Int. 36: 481–508, 2016
- Mujais S: Microbiology and outcomes of peritonitis in North America. Kidney Int. Suppl. S55-62, 2006
- Nessim SJ: Prevention of peritoneal dialysis-related infections. Semin. Nephrol. 31: 199–212, 2011