Emphysematous pyelonephritis: classification, management, and prognosis

Abstract

ABSTRACTUrinary tract infections are commonly encountered and managed worldwide, and emphysematous pyelonephritis (EPN) is among the most serious types of urinary tract infections. EPN is an acute necrotizing infection of the kidney, often associated with high rates of renal loss and mortality. The symptoms of EPN infection can be nonspecific, but the clinical triad of fever, flank pain, and nausea represent the most common presentations. The diagnosis and classification are performed with the assistance of computed tomography (CT). The imaging-based classification system created by Huang and Tseng is widely used in clinical assessments. They defined EPN into four different class (1–4), with the higher number the more severe disease. Optimal EPN treatment is controversial, with emergent nephrectomy suggested during early studies, whereas more recent evidence favors more conservative approaches. Escherichia coli, Klebsiella pneumoniae and Proteus mirabilis are most common pathogens. The initial use of broad-spectrum antibiotics such as Third-or fourth-generation cephalosporins and carbapenems are recommended. Diabetes, obstructive uropathy and hypertension are the most common risk factors and often need treatment together. Emergent drainage is indicated with a larger-sized drainage tube to achieve better drainage function. CT guidance has a better success rate than insertion under the guidance of ultrasonography. Nephrectomy should be reserved as the last resort for those who fail to respond to conservative therapy. This review aims to provide comprehensive, evidence-based recommendations for the diagnosis and management of this life-threatening urological infection.