Culture-negative peritonitis associated with the use of icodextrin-containing dialysate in twelve patients treated with peritoneal dialysis.

Background: In the first half of the year 2001, an unusually large number of culture-negative peritonitis episodes occurred in Center A. One patient noticed that his culture-negative antibiotic-resistant peritonitis promptly cleared after inadvertently stopping the use of icodextrin-containing dialysate, but recurred immediately after using icodextrin again. This observation led to the recognition of eight contemporaneous cases of icodextrin-induced culture-negative peritonitis in Center A, and identification of three additional cases in Center B.

Design: Case studies in 12 patients.

Setting: Peritoneal dialysis unit of a university hospital and an affiliated unit (Center A), and a second university hospital (Center B).

Patients: 12 patients on peritoneal dialysis presenting with culture-negative peritonitis.

Results: At presentation, abdominal pain was absent or mild and dialysate leukocyte counts were moderately elevated (approximately 100-1,500 cells/mm3). Differentiation of the dialysate leukocytes showed a low fraction of neutrophils (approximately 35%). In eight cases, the evidence that the peritonitis was caused by icodextrin was very strong (the clinical picture and laboratory results mentioned above, unresponsiveness to antibiotic therapy, cure after withdrawal of icodextrin, relapse after rechallenge); in 3 patients, the evidence was strong (as in the cases mentioned above, but no rechallenge was performed). Stopping icodextrin promptly relieved the symptoms and normalized the dialysate leukocyte counts. After rechallenge, a relapse invariably occurred, usually within a few days. In one case, the evidence was circumstantial.

Conclusion: Our findings are compatible with icodextrin-induced peritonitis. This entity is characterized by mild abdominal pain at presentation, a moderate dialysate leukocytosis with a low fraction of neutrophils in the differential count, and resistance to antibiotic treatment. Speculations about the pathogenesis of this type of peritonitis include chemical peritonitis due to a contaminating substance or hypersensitivity to icodextrin.