Clinical characteristics and risk factors for septic shock in patients receiving emergency drainage for acute pyelonephritis with upper urinary tract calculi

A retrospective study was performed of 98 patients (101 events) requiring emergency drainage at our urology department for obstructive APN associated with upper urinary tract calculi from January 2003 to January 2011. Clinical characteristics were summarized, and risk factors for septic shock were assessed by logistic regression analysis.Objective evidence of sepsis was found in 64 (63.4%) events, and 21 events (20.8%) were categorized as septic shock. Ninety-six patients recovered, but 2 patients died of septic shock. Multivariate analysis revealed that age and the presence of paralysis were independent risk factors for septic shock.APN associated with upper urinary tract calculi is a severe disease that should be treated with caution, particularly when risk factors are present.Acute pyelonephritis (APN) is a common complication of ureteral obstruction caused by urolithiasis, which can be lethal if it progresses to sepsis or septic shock. APN is broadly divided into uncomplicated and complicated cases. Complicated cases are defined to have anatomical or functional abnormality of urinary tract, such as ureteral obstruction caused by urolithiasis. It has been estimated that 41% of patients with complicated APN develop severe sepsis or septic shock [1]. The clinical presentation of APN can vary widely from loin pain and a positive urine culture to fulminant sepsis with a severely ill patient. APN associated with upper urinary tract calculi sometimes requires emergency drainage via a ureteral stent or percutaneous nephrostomy. Previous studies on the clinical characteristics of sepsis associated with upper urinary tract calculi have shown that bacteremia is an indicator of severe APN [1], while old age and poor performance status are risk factors for emergency drainage [2]. Despite intensive management and emergency drainage, the mortality rate remains around 2% [2]. We retrospectively studied the clinical characteristics of patients with septic shock due to APN with u