Disseminated cryptococcal disease presenting as peritonitis in a patient on automated peritoneal dialysis: Could it have been prevented?

Fungal peritonitis is an uncommon complication of peritoneal dialysis (PD). Cryptococcus neoformans is a very rare cause of fungal PD peritonitis. At our regional dialysis centre, we diagnosed a case of disseminated cryptococcal disease presenting as peritonitis in an 82-year old male receiving automated PD. The main risk factors in this patient were long-term steroid prescription for bullous pemphigoid and repeated episodes of bacterial PD peritonitis requiring multiple courses of antibiotics. A sample of PD fluid was sent to the microbiology facility for microscopy and culture. On receipt of the sample, initial Gram stain revealed yeast cells and white cell count was 19. India Ink was also positive. Small clear mucoid colonies grew after 48 h on blood and Sabouraud agar. MALDI-TOF mass spectrometry identified the organism as C. neoformans. Reference laboratory sensitivity testing confirmed full sensitivity to amphotericin, minimum inhibitory concentration (MIC 1⁄4 0.5), fluconazole (MIC 1⁄4 2) and intermediate to flucytosine (MIC 1⁄4 8). Serum cryptococcal antigen (CrAg) at the start of treatment was strongly positive at 1:800 via latex agglutination test. CrAg of cerebrospinal fluid (CSF) was also positive at 1:32. Ultimately, this patient had evidence of abdominal, central nervous system and lung involvement. This patient received 4 weeks of intravenous liposomal amphotericin B and 2 weeks of high dose fluconazole. Unfortunately, this patient showed deterioration despite aggressive dual antifungal therapy. After careful consideration, active treatment was ceased and the patient died at home with palliative care. In non-HIV patients, one of the main risk factors for cryptococcosis is immunosuppressive drugs, such as corticosteroids, as demonstrated here. In non-HIV nontransplant patients, disseminated disease is very rare. Higher mortality has been observed in this patient cohort, possibly related to late diagnosis compared to the HIV or transplant group. Disseminated cryptococcal infection presenting as peritonitis is extremely uncommon. One case series of cryptococcosis in HIV-negative patients on renal dialysis found only 2 out of 10 cryptococcal PD cases over a 16-year period involved both abdominal ascites and CSF. Antifungal prophylaxis with fluconazole has been shown to reduce the incidence of fungal peritonitis in PD patients when used with treatment for bacterial PD peritonitis. However, there is significant variation in practice across PD providers in the United Kingdom. At the time of this patient’s management, it was not standardised practice at our centre. Further studies are required in this patient subgroup to evaluate whether antifungal prophylaxis may prevent cases of fungal peritonitis in patients with a history of bacterial peritonitis. It has also not been studied in patients who are at risk of invasive fungal disease due to immunocompromise. If C. neoformans is detected, investigating for disseminated cryptococcal disease is important as unfortunately this carries a very high mortality.