Aspergillus is a rare cause of peritonitis, potentially fatal (Burkart, 2000), in patients on CAPD with clinical manifestations similar to bacterial and candidal peritonitis. It is a “locally-invasive” form of infection due to the obvious disruption of the anatomical barrier and the evidence of impaired function of peritoneal macrophages in patients on CAPD. Clues to the diagnosis include eosinophilic exudate, negative bacterial cultures and persistence of symptoms despite antibiotics. Aspergillus antigen may be detectable in dialysate or serum. Preparing fungal cultures by passing dialysate through a filter and then plating on appropriate media may increase sensitivity. Preferably repeated positive cultures are required to establish the diagnosis, since Aspergillus can occur as a laboratory contaminant (Geiss, 1995). PCR has not been used in diagnosis yet, but may be useful.
However, since repeated cultures and slow growth of Aspergillus on standard media may delay the diagnosis, and delayed treatment is associated with increased mortality, prompt initiation of treatment should be advised in cases of “refractory bacterial peritonitis” with presumed fungal origin while awaiting for culture results.
Identification of Aspergillus species was possible in 17 of the 20 totally reported cases ofAspergillus peritonitis: A. niger in nine cases, A. fumigatus in five cases and one each for A. flavus and A. terreus. An additional case of A. thermomutatus peritonitis in a pediatric peritoneal dialysis patient has recently published (Matsumoto, 2002).
Important risk factors include previous treatment with broad-spectrum antibiotics, neutropenia, recent bacterial peritonitis, recurrent peritonitis, steroids treatment (Tanis, 1995, Kitiyara, 1996, Basok, 2000), although none have beeen subjected to formal multivariate analysis.
Although the optimal kind and duration of treatment is not well defined due to few reports and inability to conduct controlled studies, the majority of studies suggest the early removal of peritoneal catheter, as soon as possible, and the introduction of intravenous amphotericin and/or azole antifungals (Perez-Fontan, 1991, Basok, 2000, Matsumoto, 2002).
From the total reported cases of Aspergillus peritonitis, 3 of the 4 patients in whom the catheter remained in situ died, while of the 16 patients in whom the catheter was removed, only 3 died. In cases where culture-negative peritonitis persists it is crucial to remove and culture the catheter (Stein, 1991).
Local therapy through the catheter with amphotericin B is of no value and delays catheter removal. Intravenous amphotericin B remains the drug of choice; lipid-based formulations were as effective as conventional amphotericin and showed less acute infusion-related toxicity and could be used successfully in this form of invasive aspergillosis (Matsumoto, 2002).
Although itraconazole has poor water solubility and is not detected in the peritoneal fluid following oral administration, there is evidence that is a useful regimen in persistentAspergillus peritonitis, following amphotericin B treatment (Matsumoto, 2002, Kitiyakara, 1996). Ascites is not drained successfully in some instances due to formation of multiple loculated fluid collections (Matsumoto, 2002)
A return to CAPD is possible after successful therapy (Prewitt, 1989, Miles, 1995), although in a recent report, 2 of 3 Aspergillus peritonitis cases successfully treated, returned temporarily to CAPD, but consequently transferred to hemodialysis due to membrane failure. Moreover in reviewing cases conducted by Tanis (1995), only 4 of the 13 subsequently returned to CAPD.
Prepared by:
Dr Helen Sambatakou
Senior Registrar in the Infectious Diseases Unit
The General Hospital “G Gennimatas”
Athens, Greece
David W. Denning FRCP FRCPath FIDSA FMedSci
Professor of Medicine and Medical Mycology
Director, National Aspergillosis Centre
Education and Research Centre
University Hospital of South Manchester (Wythenshawe Hospital)
Southmoor Road
Manchester M23 9LT UK
References:
Case histories: