ABSTRACT
Characteristically, urinary tract obstruction is associated with progressive hydronephrosis, parenchymal atrophy and impairment of renal functions. Hydronephrosis is common in paediatric urology, occurring in as many as 1.4% of fetuses and it may persist after birth.1 However, hydronephrosis is not equivalent with obstruction and in the asymptomatic infant who has been diagnosed prenatally with hydronephrosis dilatation only persists in approximately 25% of the cases, consistent with a high degree of spontaneous resolution. This observation has therefore created a clinical enigma since a dilatation without progression and complications is clinically unimportant, whereas in an unpredictable minority of the dilatations it is important to detect obstruction to prevent renal function deterioration. At present there are no golden standard methods which in a satisfactory manner can establish or rule out whether a dilated kidney is obstructed. Moreover, there is no consensus on when a dilated kidney should be operated on and uniform criteria for when intervention is required are still lacking.
