CAPD Catheter Exit-Site and Tunnel Infection with Fungal Etiology—Treatment and Catheter Reinsertion for an Extremely Rare Complication

Case Report

A 54-year-old non-diabetic female patient with chronic kidney disease (CKD) on CAPD (Tenckhoff double-cuff catheter) for 10 months presented with pus discharge at the CAPD catheter exit site. She has severe kyphoscoliosis, amputation above the left knee (due to a soft tissue tumor in childhood and stump squamous cell carcinoma 14 years previously), uses an artificial limb and requires a crutch to walk. There is no prior history of catheter infection, CAPD peritonitis, or use of antibiotics. She was performing daily exit-site dressing with mupirocin ointment and was not on intranasal mupirocin. There was no history of fever, cloudy effluent, or abdominal pain. Local examination revealed pus discharge from the exit site but no tenderness or erythema.

Lab investigations showed a normal hemogram, with no evidence of leukocytosis; fasting and postprandial blood sugars were in the normal range and the exit-site pus culture was sent for evaluation.

Treatment with amoxicillin-clavulanic acid and ciprofloxacin was initiated empirically, in keeping with the microbiological spectrum of exit-site infections (ESIs). An ultrasound of the catheter tunnel showed evidence of fine internal echoes, with a volume of 1 to 2 mL involving the external cuff and tracking down to approximately 2 cm, with no involvement of the internal cuff. There was no evidence of CAPD peritonitis (cytology nil and culture-negative); the pus culture from the exit site grew Candida albicans. A diagnosis of exit site with tunnel infection due to Candida albicans was made. She was started on caspofungin, the CAPD catheter was removed after 2 days of positive culture report, and in the interim period she was managed on hemodialysis via right internal jugular vein access. Caspofungin was given for 7 days and later changed to oral voriconazole for 2 weeks. Repeat ultrasound of the tunnel did not show any evidence of subcutaneous infection. The CAPD catheter was re-inserted 4 weeks after removal, and she was reinitiated on CAPD 2 weeks after reinsertion. She is currently doing well on CAPD with peritoneal equilibration test (PET) revealing a high-average transport status(weekly Kt/V of 2.08, dialysate Kt/V of 1.77, renal Kt/V of 0.31 and creatinine clearance of 42.30 L/week with dialysate creatinine clearance of 34.38 L/week).

Discussion

As per the International Society for Peritoneal Dialysis (ISPD) 2010 update, the presence of purulent discharge is considered ESI with or without skin erythema (1). Tunnel infection may be occult or can present as tenderness, edema, or erythema. Occult tunnel infection can be detected by ultra-sonographic study (2), which is a useful method for diagnosing tunnel infection (3). Our patient had pus discharge at the exit site, with no clinical evidence of tunnel infection; ultrasonography of the tunnel revealed internal echoes suggestive of tunnel infection.

The decision to revise the tunnel, replace the catheter, or continue antibiotic therapy alone is made depending on the extent of infection as seen on the ultrasound (4). Poor outcomes are associated with a 1-mm thick sonolucent zone around the external cuff following a course of antibiotic treatment and involvement of the internal cuff (1).

Our patient had collection near the external cuff tracking down to 2 cm and the exit-site culture grew Candida albicans. A review of the literature revealed fungal infection to be a rare cause of exit-site and tunnel infection, with no guidelines available regarding removal of the CAPD catheter. However, in view of an underlying fungal ESI, tunnel infection with sonolucent zone tracking down to 2 cm, a decision was taken to remove the CAPD catheter.

The majority of ESIs are caused by S. aureus and P. aeruginosa. However, other rare organisms include nonfermenting bacteria, streptococci, diphtheroids, nontuberculous mycobacteria, anaerobic organisms, Legionella, and fungi (1). Keeping in mind the above microbiological spectrum for ESI, our patient was started empirically on broad-spectrum antibiotics. The pus culture from the exit site in our patient grew Candida albicans. Fungal ESI is an extremely rare entity. In a study done by Freitas et al., a total of 76 ESIs were documented with fungal etiology being the least common, seen in only 1 patient. The overall rate of ESI in 137 patients over 240.41 dialysis years at risk was 0.31 episodes per year at risk. The episode/patient year was least amongst fungal ESI, being 0.004 (5).

Our patient had severe kyphoscoliosis, amputation above the knee requiring an artificial limb and crutch to walk, with the exit site positioned in the skin fold resulting in difficulty maintaining proper exit-site hygiene, which may have contributed to the fungal ESI in this patient.

There are no guidelines regarding treatment of fungal exit-site and tunnel infection (antifungal drug to be used, dosage, duration of treatment, time of CAPD catheter removal and reinsertion if possible). We started this patient on antifungal therapy and removed the CAPD catheter once there was evidence of fungal infection and tunnel infection to prevent fungal peritonitis. After an initial 7 days of intravenous (IV) caspofungin, this patient was discharged on oral voriconazole for 2 weeks. A repeat ultrasound did not reveal any evidence of subcutaneous infection. The catheter was reinserted 1 week after completion of antifungal therapy, and the patient was reinitiated on CAPD with retraining and stress on sterility. She is currently doing well on CAPD with good ultrafiltration and solute clearance and the PET done is suggestive of high-average transport status.

Conclusions

Fungal exit-site and tunnel infection of the CAPD catheter is a rare entity with no clear guidelines regarding management. Improper exit-site hygiene is an important risk factor for fungal ESI. It is imperative to determine pre-operatively the ideal exit site for a patient's particular clinical profile. It is especially important to closely involve microbiologists when looking for fungal infections to help in accurate diagnosis. Appropriate antifungal therapy with early removal of the CAPD catheter can salvage the peritoneal membrane and help reinitiation of CAPD after completion of antifungal therapy with good results. However, more data are required regarding the choice of antifungal drug, dosage, and time of catheter removal, and reinsertion.