Clinical value of acute pyelonephritis grade based on computed tomography in predicting severity and course of acute pyelonephritis.

Purpose: This study aimed to evaluate the efficacy of computed tomography (CT)-based acute pyelonephritis (APN) grades for predicting clinical severity and disease course.

Materials And Methods: 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).

Results: 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.

Conclusions: This study suggests that APN grades, as determined by CT examination, valuably predict the clinical course of APN.