ABSTRACT
The widespread use of maternal sonography and the routine radiographic evaluation of children with febrile urinary tract infections have resulted in the increased diagnosis of both antenatal and postnatal hydronephrosis. Hydronephrosis is the most common abnormality detected by prenatal ultrasound (US) and is seen in an estimated 1 in 100 to 1 in 500 pregnancies.1 One of the most important distinctions in the assessment of these children is determining which patients would benefit from surgery and which patients can be safely observed. This distinction is important since unnecessary intervention exposes patients needlessly to the morbidity of surgery, whereas inappropriate observation places patients at risk for infection and renal parenchymal loss.
