Hydronephrosis is the most frequent abnormality, found in 45% of neonates with UTI [9]. Postnatal US prior to 2 months of age is typically performed even if the prenatal US was normal. The NICE guidelines for UTI recommend US in evaluation of UTI in children <6 months of age within 6 weeks of the UTI if typical infection or during the acute infection if an atypical infection [16]. As discussed earlier, the main limitations of US are the detection of pyelonephritis, scarring, and VUR. In a study by Chang et al [22] for evaluation of young infants (<3 months of age) with bacteremic UTI, US kidneys and bladder and fluoroscopic VCUG abnormalities were common, and the authors did not refer to any special imaging considerations for bacteremia in imaging decisions for otherwise well-appearing young infants with UTI. Sensitivity of US for the detection of high-grade VUR is markedly improved when uroepithelial thickening is considered [24]. The main limitation of US is the low sensitivity (76.5%) for detecting VUR and renal scarring [25-31]. Variant 3: Child. 2 months to 6 years of age. First febrile urinary tract infection with appropriate response to medical management. Initial imaging. Prospective studies in children between the ages of 2 months and 6 years with UTIs were done to evaluate the effect of therapy [6,43,44]. There is limited evidence to support routine imaging of uncomplicated UTIs, and optimal imaging is controversial [2,5,43,45]. Currently there are 2 main methods for evaluating children with UTIs: the bottom-up approach [2], which focuses on detection of VUR, and the top-down approach [2,5,16], which focuses on the diagnosis of acute pyelonephritis and renal scarring [2,5]. DMSA followed by cystourethrography if DMSA renal scan suggests pyelonephritis is the top-down approach. The potential benefit of this approach is a decrease in the number of cystourethrography studies.
Urinary Tract Infection Child. Hydronephrosis is the most frequent abnormality, found in 45% of neonates with UTI [9]. Postnatal US prior to 2 months of age is typically performed even if the prenatal US was normal. The NICE guidelines for UTI recommend US in evaluation of UTI in children <6 months of age within 6 weeks of the UTI if typical infection or during the acute infection if an atypical infection [16]. As discussed earlier, the main limitations of US are the detection of pyelonephritis, scarring, and VUR. In a study by Chang et al [22] for evaluation of young infants (<3 months of age) with bacteremic UTI, US kidneys and bladder and fluoroscopic VCUG abnormalities were common, and the authors did not refer to any special imaging considerations for bacteremia in imaging decisions for otherwise well-appearing young infants with UTI. Sensitivity of US for the detection of high-grade VUR is markedly improved when uroepithelial thickening is considered [24]. The main limitation of US is the low sensitivity (76.5%) for detecting VUR and renal scarring [25-31]. Variant 3: Child. 2 months to 6 years of age. First febrile urinary tract infection with appropriate response to medical management. Initial imaging. Prospective studies in children between the ages of 2 months and 6 years with UTIs were done to evaluate the effect of therapy [6,43,44]. There is limited evidence to support routine imaging of uncomplicated UTIs, and optimal imaging is controversial [2,5,43,45]. Currently there are 2 main methods for evaluating children with UTIs: the bottom-up approach [2], which focuses on detection of VUR, and the top-down approach [2,5,16], which focuses on the diagnosis of acute pyelonephritis and renal scarring [2,5]. DMSA followed by cystourethrography if DMSA renal scan suggests pyelonephritis is the top-down approach. The potential benefit of this approach is a decrease in the number of cystourethrography studies.