ABSTRACT
With the exception of strictures, urethral obstruction in childhood is congenital in origin and of the various causes of urethral obstruction only posterior urethral valves commonly give rise to secondary changes in the upper renal tracts – sometimes with devastating consequences. There is increasing evidence to indicate that the consequences of outflow obstruction are due as much to secondary effects upon bladder function as to the underlying obstruction itself. Moreover, the earlier the obstruction develops the worse the impact on the upper tracts, to the extent that obstruction dating from early fetal life is commonly complicated by renal dysplasia.
