Renal and perinephric abscesses: a series of 44 cases

Renal abscesses are infrequent event and may occasionally be fatal. In order to characterize its main clinical features, its diagnosis and evolution, a retrospective-descriptive study was done with cases identified between 1996 and 2006 in a teaching hospital. Forty-four cases were collected (mean age 49.9 years). Diabetes mellitus was present in 38.6%, urinary calculi in 36.4%, and previous urinary tract infection in 11.4% of the studied population. Enterobacteriaceae were the most frequent isolated microorganisms (44.4%), and 33.3% had a poli-microbial culture in abscess samples. S. aureus was rarely identified. Main therapeutic approaches were minimally invasive procedures (pigtails, percutaneous drainage or nephrostomy) in 50% followed by surgical interventions (nephrectomy or surgical debridement) in approximately 30%. Only 20.5% of patients were treated exclusively by antibiotics. Minimally invasive procedures were applied progressively after 2001 (p < 0.005). In this series case-fatality rate was 4.5%; 13.6% (n = 6) developed septic shock. Nephrectomy was performed in 9 cases (20.5%). Patients selected for nephrostomy had a lower risk for ICU admission (Odds Ratio 0.083 IC95 0.008-0.911). Renal abscesses are cause of morbidity but had a low case-fatality ratio; the therapeutic approach has changed in recent years favoring at present minimally invasive procedures.