Predictors of failure of conservative treatment among patients with emphysematous pyelonephritis

Background: Emphysematous pyelonephritis (EPN) is a severe necrotizing infection of the renal parenchyma and perirenal tissues that is caused by gas-producing bacterial pathogens. Percutaneous drainage is now the gold standard of definitive management. The aim of this study is to analyze the predictors associated with failure of conservative treatment among patients with EPN and offer the recommendation of appropriate empirical antibiotic regimen. Methods: From January 2001 to December 2013, 44 consecutive patients were diagnosed with EPN. The demographic characteristics, clinical presentations, management strategies, and final outcomes were analyzed retrospectively. Results: The overall survival rate was 88.6% (39/44). Need for emergency hemodialysis, shock on initial presentation, altered mental status, severe hypoalbuminemia, inappropriate empirical antibiotic treatment and polymicrobial infections were significantly more common in the patients who died compared with the survivors. The overall failure rate of conservative treatment was 32.6% (14/43). Severe hypoalbuminemia (p = 0.003), need for emergency hemodialysis (p = 0.03), and polymicrobial infections (p = 0.04) were significantly associated with failure of conservative treatment. Severe hypoalbuminemia was independently associated with conservative management failure (p = 0.02). Even in the patients treated with percutaneous drainage plus effective antibiotics, failure was still associated with severe hypoalbuminemia (p = 0.01). According to the in vitro susceptibility data, third-generation cephalosporins is recommended as the empirical antibiotic regimen. Conclusions: Both appropriate empirical antibiotic and percutaneous drainage were essential for patients with EPN. Patients with severe hypoalbuminemia had a higher risk of conservative treatment failure, and additional management may be required.