[Fungal peritoneal dialysis catheter-related exit-site infection combined with tunnel infection: A case report]

Peritoneal dialysis (PD) catheter-related infection (i.e. exit-site infection and tunnel infection) is one of the main causes of PD-related peritonitis. If it cannot be controlled effectively, it could lead to PD technique failure. Therefore, timely and effective diagnosis and treatment and active prevention so as to reduce PD catheter-related infection is an important treatment goal in PD patients. PD catheter exit-site infection (ESI) and tunnel infection can be caused by a variety of microorganisms, mainly bacteria, while fungi are very rare. Few public data can be used to guide treatment of PD catheter-related fungal infection, and there is no related report in China till now. Once fungal peritonitis occurred, the patient can only withdraw from PD treatment. Here, we report a case of fungal PD catheter ESI combined with tunnel infection which was successfully diagnosed and treated in our PD center. A 71-year-old woman came to clinic because of "PD for 5 years, secretions from exit site for 8 days and aggravation for 1 day". The patient suffered from peritonitis, ESI and tunnel infection for many times in the past 5 years, involving a variety of pathogens. Eight days before, she found white viscous discharge from exit site. The subcutaneous cuff completely came out of it and rubbed its skin. The Schaefer exit-site score was 3 points. Due to the suspected ESI 2 months before, the discharge swab for bacterial culture was positive for Pseudomonas aeruginosa, so the exit site swab for bacterial culture was done again, and gentamicin injection was applied topically once a day for empirical treatment. The exit site was evaluated one day before: The subcutaneous tunnel was significantly swollen and slightly tender at 2.5 cm away from the exit site, and with white medium amount of viscous secretions. The exit-site score increased to 4 points. Routine test of dialysis effluent was (-). The bacterial culture of the exit-site discharge was rechecked twice, and Candida parapsilosis was positive for two times, so the diagnosis of fungal PD catheter ESI combined with tunnel infection was clear. Immediately we searched for the causes of ESI and tunnel infection. We found that the patient had a suspicious history of gray toenail on the foot. The toenail smear was positive for fungi and visible hyphae. She washed feet with hands every day, and washed clothes on a low bench every day, which made the exit-site and tunnel squeezed for a long time. Based on the above causes, we gave her comprehensive treatment as follows: For ESI and tunnel fungal infections, fluco-nazole was used systemically according to the drug sensitivity results, and miconazole cream was applied to the exit-site locally. For the subcutaneous cuff that came out completely, daily iodophor disinfection was given locally. At the same time, local antifungal treatment was given to the foot. We followed up closely during treatment, evaluated the exit-site every 2-3 days, and took photos of the exit-site to dynamically observe the effect. After 14 days of treatment, the exit-site score continued to be 0-1, the bacterial culture of the exit-site was negative, the cuff culture was negative, and the tunnel B-ultrasound was normal. The patient had been followed up regularly once a month for 60 months, no ESI and tunnel infection occurred. Fungal PD catheter ESI and tunnel infection are rare complications of PD. When the standard anti-infection treatment is ineffective, the possibility of fungal infection should be considered, so as to avoid prolonged use of antibiotics, aggravating fungal infection, and even progressing to fungal peritonitis, leading to withdrawal from PD. Accurate exit-site evaluation is helpful for timely diagnosis and early treatment of ESI and tunnel infection. The exit-site discharge culture and drug sensitivity test before treatment are helpful to identify the pathogen and adjust subsequent treatment. At the same time, repeated discharge culture is required in order to exclude positive fungal culture results caused by contamination. Once fungal catheter-related infection is diagnosed, we should search for possible causes actively, subsequent targeted and comprehensive treatment plays a decisive role for the prognosis of patients.