ABSTRACT
Clinical presentation Routine use of prenatal ultrasonography has resulted in the diagnosis of large numbers of fetuses with hydronephrosis, which occurs in approximately 1 in 800 pregnancies. Some of these asymptomatic congenitally hydronephrotic kidneys improve spontaneously, whereas others progressively deteriorate unless the obstruction is relieved. Clinical parameters used to evaluate hydronephrosis are not always helpful in differentiating between the two groups. The pediatric urologist is charged with the responsibility of distinguishing between ongoing significant obstruction and innocuous residual dilatation of the collecting system in order to institute the appropriate clinical management.
