The Significance of Renal Imaging Studies in the Diagnosis of Acute Pyelonephritis

ABSTRACT

PURPOSE: It is difficult to diagnose acute pyelonephritis(APN) in young children, because of their nonspecific symptoms. The younger the age, the higher the risk of renal scars after APN, which can be prevented by early diagnosis and treatment. We compare the significance of renal imaging studies by age for diagnosis of APN in febrile urinary tract infection(UTI) in children. METHODS: Fifty-three hospitalized children(34 patients under age 2 and 19 patients over age 2) with febrile UTI and who had undergone dimercaptosuccinic acid(DMSA) scan, renal ultrasonography(RUS) and voiding cystourethrography(VCUG) during the acute stage were reviewed. We compared the renal imaging studies between the different age groups. RESULTS: The DMSA scan showed cortical defects in 23.5% of patients under age 2, which was significantly lower than 63.2% of patents over age 2(P<0.05). The renal cortical defects on DMSA scan were associated only with a high peripheral leukocyte count, but not with fever duration, erythrocyte sedimentation rate(ESR), and C-reactive protein(CRP). And there was no correlation between the DMSA scan, VCUG or RUS findings. CONCLUSIONS: The DMSA scan is not sensitive for diagnosis of APN in children less than 2 years of age and the findings cannot predict the presence of vesicoureteral reflux(VUR). VCUG may be necessary for proper management in this age group.