Ultrasonography in the management of exit site infections in peritoneal dialysis patients

To assess the efficacy of using ultrasonography (USG) in monitoring the progress of exit site infection (ESI) in patients undergoing continuous ambulatory peritoneal dialysis (CAPD).

Twenty-two cases of newly diagnosed ESI and 20 cases with normal exit sites as controls were assessed by using USG. The exit sites were reassessed by using USG after finishing a course of antibiotic therapy, and the sonographic findings were correlated with the clinical outcome.

Out of the 22 cases of ESI, 21 cases had definite sonolucent zones around the external cuffs, while one case had normal sonographic findings. Of the 20 control cases of normal exit sites, 16 had normal sonographic findings, and four had sonolucent zones around the external cuffs. Exit site infections correlated with positive sonographic findings as compared to normal exits (P <0.0001). The 21 cases of ultrasonic-positive ESI were re-examined after antibiotic therapy, and 10 of these had a post-treatment sonolucent rim around the distal cuff < or =1 mm thick, while 11 cases were persistently > mm thick. The former group was shown to have a more favourable outcome (P=0.013). And despite variable USG findings, all eight patients with Pseudomonas aeruginosa-related ESI had an unfavourable clinical outcome.

Ultrasonography of the exit sites in CAPD patients is a useful adjunctive tool in the management of ESI. A sonolucent zone around the external cuff >1 mm thick following a course of antibiotic treatment and the involvement of the proximal cuff are associated with poor clinical outcome. In ESI caused by Pseudomonas aeruginosa, the clinical outcome was uniformly poor irrespective of the sonographic findings.