prediction of renal cortical involvement using serum and urinary inflammatory markers in children with febrile urinary tract infection

Background: erythrocyte sedimentation rate (esr), serum c-reactive protein (crp), urinary β2 microglobulin, antibody-coated bacteria in the urine sediment, and urinary lactic dehydrogenase (ldh) are more traditional tests used to diagnose true pyelonephritis. acute-phase dimercaptosuccinic acid (dmsa) scan is a sensitive method for diagnosis of true pyelonephritis. objectives: defining predictive values of traditional inflammatory serologic parameters, urine analysis indexes, kidney ultrasonography and fever in children with febrile urinary tract infection for predicting renal cortical involvement. patients and methods: in a prospective study, 20 children admitted due to febrile urinary tract infection were assessed for renal cortical involvement by technetium-99 m-labeled dimercapto succinic acid (tc99-dmsa) scan. body temperature ≥ 39c, white blood cell count ≥ 15000 cell/µl, positive c-reactive protein, erythrocyte sedimentation rate (first hour) ≥ 30 mm/h, presence of proteinuria, severe pyuria or bacteriuria on urine analysis, urine specific gravity ≤ 1010, and renal ultrasonography were used for predicting renal cortical involvement. sensitivity, specificity, positive and negative predictive values of these variables were measured by specific formula. results: the highest measured sensitivity was 100% (erythrocyte sedimentation rate ≥ 30 mm/h). urine specific gravity < 1010 and bacteriuria had the highest (75%) and lowest (20%) specificities respectively. the highest and lowest positive predictive values were 85.7% ( urine specific gravity < 1010) and 57% (proteinuria), whereas the highest and lowest negative predictive values were related to erythrocyte sedimentation rate > 30 mm/h (100%) and proteinuria (11%) respectively. normal sonography had a low sensitivity for predicting absence of renal involvement (23%). conclusions: erythrocyte sedimentation rate ≥ 30 mm/h is a sensitive marker with high negative predictive value for predicting renal involvement in febrile urinary tract infection.