Minimally invasive treatment of renal abscess.

PURPOSE: We critically evaluated the most appropriate management of renal abscesses, and identified the set of patients that most benefits from conservative treatment. MATERIALS AND METHODS: We retrospectively reviewed charts regarding discharge diagnoses, radiological studies, pathological specimens, epidemiology factors and outcomes. Statistical analysis was performed using loglinear and covariant analysis. RESULTS: Nine years of experience (1984 to 1993) at 2 affiliated hospitals (1 public and 1 private) were reviewed. A total of 52 patients with renal abscesses was identified with a followup rate of 98%. In immunocompetent patients 100% of small abscesses (less than 3 cm.) managed by antibiotics and observation alone resolved. Of medium abscesses (3 to 5 cm.) treated with percutaneous abscess drainage alone 92% resolved. Large abscesses (greater than 5 cm.) often required more than 1 percutaneous drainage procedure (33%) or adjunct open surgical intervention (37%). Statistical analysis revealed that no single treatment modality yielded a superior resolution rate or shorter hospitalization for abscesses stratified by size, patient age or treatment instituted early (1984 to 1993) or late (1992 and 1993) in the study period. CONCLUSIONS: Our series suggests that percutaneous drainage is as effective as open surgery for large and medium renal abscesses. Small abscesses may be effectively treated with a course of intravenous antibiotic therapy. A treatment algorithm is reported.