Ultrasound as a tool in the diagnosis and management of exit-site infections in patients undergoing continuous ambulatory peritoneal dialysis.

Ultrasonographic examination of the subcutaneous course and exit site of the Tenckhoff catheter in patients undergoing continuous ambulatory peritoneal dialysis (CAPD) was performed to evaluate catheter-related infections. Real-time ultrasound studies were performed in 24 patients with initial exit-site infections; clinically suspected tunnel infections were excluded from analysis. A peri-catheter sonolucent fluid collection, considered a positive study, was demonstrated in 13 ultrasound examinations and tended to be organism-specific; eight of 12 Staphylococcus aureus exit-site infections and three of four gram-negative exit-site infections had positive studies. Only two of seven Staphylococcus epidermidis exit-site infections were initially positive on ultrasound examination. Nine of 13 patients with positive ultrasound studies ultimately lost their catheters to infection despite weeks of parenteral antibiotic therapy and local incision and drainage. There were 11 negative ultrasound studies. Only one of these patients' catheters was lost because of infection. In some episodes of CAPD-associated exit-site infections, especially those caused by S aureus and gram-negative organisms, ultrasound examination of the catheter course may be useful to diagnose unsuspected tunnel infections, direct early therapy, and confirm resolution or persistence of the infections.