Peritoneal Catheter Exit Site and Tunnel Infections

Introduction

Peritoneal dialysis (PD)–related infections, including peritonitis, exit site infections, and tunnel infections, remain an important cause of morbidity and technique failure. While peritonitis is usually the most frequent and morbid event among the infectious complications, exit site and tunnel infections are relevant and concerning complications of PD. This chapter will focus on the risk factors for their occurrence, as well as optimal strategies for their prevention and management.

Definitions

Catheter-related infection is used as the collective term to describe both exit site and tunnel infections. The definition of an exit site infection has evolved over time, and there have been several classifications created to try to improve the consistency in the diagnosis and reporting of exit site infections. In the simplest terms, based on the International Society for Peritoneal Dialysis (ISPD) guidelines, an exit site infection is defined as the presence of purulent discharge, with or without erythema of the skin at the catheter–epidermal interface. While erythema is often present during an exit site infection, the presence of erythema alone in the absence of purulent drainage may reflect inflammation of the skin rather than infection. Furthermore, a positive culture from an exit site in the absence of purulent drainage should be interpreted with caution, as this may simply reflect colonization of the skin.

The PD catheter tunnel is the soft tissue space that the catheter passes through between the exit site and the peritoneal cavity. A tunnel infection is defined as the presence of clinical inflammation (tenderness, edema, induration, or erythema) over the PD catheter tunnel or by the presence of a fluid collection along the catheter tunnel on ultrasound. Since a tunnel infection usually results from migration of organisms from an infected exit site into the adjacent tunnel tract, most tunnel infections occur in the presence of an associated exit site infection with the same organism.