Clinical Value of Acute Pyelonephritis Grade Based on Computed Tomography in Predicting Severity and Course of Acute Pyelonephritis

Abstract

This study aimed to evaluate the efficacy of computed tomography (CT)-based acute pyelonephritis (APN) grades for predicting clinical severity and disease course. This study involved the analysis of the data of 204 consecutive patients with APN who underwent a CT examination at admission. Patients who had undergone prior treatment and those with ureteral calculi or an abscess by CT were excluded. Computed tomographic findings were divided into 4 grades according to renal parenchymal involvement, as follows: no renal parenchyma involvement (grade 1), less than 25% involvement (grade 2), 25% to 50% involvement (grade 3), and greater than 50% (grade 4). Patients with these grades were compared with respect to APN severity index (highest body temperature, initial C-reactive protein, and leukocytosis) and recovery index (hospital stay, fever duration, and leukocytosis duration). A total of 204 patients of mean age 39.3 years were included. Acute pyelonephritis severity indices and recovery indices increased with APN grade. Mean highest body temperature values were 38.3°C and 38.9°C in grades 1 and 4, respectively (P = 0.002). Mean hospital stay increased from 5.7 days for grade 1 to 7.6 days for grade 4 (P < 0.001). Initial C-reactive protein, initial leukocytosis, fever duration, and leukocytosis duration also increased with APN grade. This study suggests that APN grades, as determined by CT examination, valuably predict the clinical course of APN.