Aim: The aim of this study was to evaluate the role of different techniques in the diagnostic workup of children with negative prenatal ultrasonogram, referred for urinary tract infection (UTI) within the first 24 months.
Methods: One-hundred and forty-seven patients, 71 males/76 females were studied. All patients were submitted to renal ultrasonogram (RUS) and to micturating cystourethrogram (MCU) independently from the results of RUS. In a small group (48 children) DMSA scan was performed independently from the results of RUS and MCU. Sensitivity and predictive value of RUS for vesicoureteric reflux (VUR) were estimated. Multiple regression analysis was performed on a selected number of signs to evaluate their predictive value. The group investigated by DMSA scan was analysed to evaluate how the presence of VUR on MCU anticipated renal damage.
Results: Nineteen (21%) patients with normal RUS, had VUR. Predictive value of RUS (0.21) was influenced by the grade of the VUR but more than 30% of high grade refluxing renal units appeared normal at initial ultrasonography. DMSA scan was abnormal in 27% of 48 patients; its result was independent from the presence of VUR of whatever grade.
Conclusions: The increasing number of renal abnormalities detected before birth reduces the possibility of late abnormal RUS findings. It makes RUS screening for abnormalities, after a first episode of UTI, scarcely useful. VUR may be easily missed when RUS resulted normal and MCU is omitted. Negative MCU cannot exclude renal damage in presence of UTI. Renal defects at DMSA scan may be unrelated to a demonstrable VUR and could have a different pathogenesis.