Pain intensity and imaging at the initial phase of acute pyelonephritis

To identify predictive factors of urological complication on imaging findings in women with pyelonephritis aged 18 to 65 years.

We performed an observational, retrospective, single-center study. The medical charts of women diagnosed with pyelonephritis at the emergency department from 2010 to 2015 were reviewed. Only patients who underwent an imaging study at the emergency department and with microbiologically confirmed pyelonephritis were included for analysis. The primary endpoint was the presence of urological complications on imaging findings. The secondary endpoint was treatment changes after imaging diagnosis.

Of the 193 women enrolled, 88 (45.6%) had urological complication(s) on imaging findings. The multivariate analysis revealed that history of urolithiasis (OR=2.41; P=0.01) and pain requiring morphine use (OR=5.29; P=0.009) were predictive of urological complications on imaging findings. Of the 120 women with uncomplicated pyelonephritis who underwent imaging studies, 45% had urological complication, resulting in a treatment change in 36.7% of patients. The multivariate analysis revealed that age>40 years (OR=4.58; P=0.02) and pain requiring morphine use (OR=3.78; P=0.02) were predictive of urological complication(s) on imaging findings and of treatment change based on imaging findings (OR=6.76; P=0.005 and OR=4.19; P=0.01 respectively) in this subgroup.

Pain requiring morphine use, age, and history of urolithiasis are independent predictors of urological complications on imaging findings in patients with acute pyelonephritis.