Rapid diagnosis of peritonitis in peritoneal dialysis patients
Peter Rutherford
Senior Lecturer in Nephrology
University of Wales College of Medicine
Wrexham, UK
Introduction
- Peritonitis is the major complication of peritoneal dialysis with acute morbidity and resource implications.
- Lab tests
- Drugs
- In-patient days
- In the longer term, episodes of peritonitis are associated with higher risk of peritoneal membrane failure and the need for eventual dialysis modality change
Declining residual function
- All patients commencing APD in a single UK centre
- UK Renal Association targets were used and times/volumes/exchanges increased accordingly
- RRF and dialysis adequacy were measured monthly - 24 hr urine and PD collection
- weekly creatinine clearance and kt/v (Adequest™)
Clinical and resource issues with peritonitis
- Audit of all episodes of peritonitis in patients receiving PD in a single centre over 5 years.
- Overall rate of peritonitis was approximately 1 in 35 patient month
Peritonitis audit results
- 62 episodes in 40 patients
- Presenting symptoms
- 29 abdominal pain
- 19 cloudy dialysate
- 14 general symptoms eg malaise
- 25 needed admission with a median duration of 9 days (range 1-56)
Diagnosis of peritonitis
- Based on a combination of symptoms and lab findings
- symptoms of peritoneal inflammation
- cloudy dialysate with leucocyte count (>100) with a preponderance of neutrophils (>50%)
- demonstration of organisms in dialysate
- Can be confused by +/- symptoms, +/- cloudy and cloudy fluid due to fibrin/blood
Peritoneal fluid
- contains macrophages, monocytes and less commonly lymphocytes
- neutrophil leucocytes rarely exceed 15% of the total
Rapid diagnosis of peritonitis
- Rapid diagnosis of peritonitis would allow early commencement of antibiotics with potential benefits in terms of
- reduced need for in-patient care
- reduced chance of dialysis modality change
- Diagnosis could occur at “point of care” and eliminate confusion and allow early treatment
Aim of the Study
- To examine the utility of a rapid peritonitis method in PD patients in a single UK centre
- Patients would be managed according to standard protocols concerning;
- diagnosis
- antibiotic treatment
Patients and samples
- All PD patients receiving dialysis in a single UK centre
- Samples were obtained -
- where there was a clinical suspicion of peritonitis
- where exclusion of peritonitis was required
- follow up samples where peritonitis confirmed
Methods
- PD sample obtained and sent for
- white cell count (including differential)
- culture and determination of sensitivities
- Clinical decisions were made on the basis of these results
- >100 leucocytes/µ l with > 50% neutrophils
- Standard antibiotic therapy - Vancomycin and gentamicin (ceftazadime from 2/1)
- Sample also analysed using rapid diagnosis strip
Periscreen™ rapid diagnosis strip
- A semi-quantitative indication of level of leucocytes in PD fluid
- Indicator pad contains all of the components needed to measure leucocyte esterase
- Peritoneal leucocyte esterase is elevated and associated with increased neutrophil counts in PD peritonitis
- Grades as - Negative, Trace, Small and Large
- Trace = > 50 ul neutrophils
VA Study
- Examined utility of the Periscreen™ strip in a VA dialysis centre
- Results
- Sensitivity = 100%
- Specificity = 96%
Results
- The strips are easy to use and interpret by nursing and medical staff
- All 17 episodes of peritonitis as defined by above criteria were detected by the Periscreen strip
- Overall
- Sensitivity = 100%
- Specificity = 96%
 | Below trace | Trace or more |
|---|
| <50 neutrophilis | 57 | 1 |
| >50 neutrophilis | 0 | 22 |
| Total | 57 | 23 |
Evidence base vs experience base
Case history
- NP, 24 yr old female, ESRF secondary to CPN
- PD commenced 1/2001
- 31/1 Abdo pain, fluid clear
- 31/1 - Periscreen Trace, WCC = 147 (30 = neutrophils)
- No treatment
- 1/2 - Periscreen Negative, WCC = 120 (10 = neutrophils
- Pain settled
- 8/3 - Abdo pain, constipation, fluid clear
- 8/3 = Periscreen Negative, WCC = 220 (neutrophils = 16)
- No treatment
- 9/3 = Periscreen Negative, WCC = 90 (neutrophils = 10)
- 11/3 = Periscreen Negative, WCC = 40 (no neutrophils)
- Pain settled, fluid clear
Conclusions
- The Periscreen ™ strip is useful in the diagnosis of PD peritonitis and can be applied at the “point of care”
- It is sensitive and specific and differentiates between high PD neutrophil counts and raised white cell count due to other cell types
- The Periscreen ™ strip is a useful additional tool with a role in the management of PD peritonitis
