Clinical Management

Abstract

Idiopathic hydronephrosis is primarily a radiographic diagnosis made by recognition on the intiavenous urogram (IVU) of an enlarged pelvicalyceal system. Successful management depends not only on diagnosis, but also on determining the aetiology and significance of the dilatation and then instituting appropriate therapy. Until recently, the demonstration of hydronephrosis was usually considered presumptive evidence for pelviureteric junction obstruction and diagnosis was followed by corrective surgery. This approach was predicated on the assumption that hydronephrosis was due to obstruction and was invariably progressive throughout life (Roberts and Slade 1964). Such a supposition, however, has never been proven and recent evidence suggests that it may not be true for a significant number of patients. Firstly, it is now well appreciated that hydronephrosis does not necessarily equate with obstruction because a variety of congenital, acquired and postoperative conditions have been observed to produce pelvicalyceal dilatation and to simulate obstruction in its absence (Whitaker 1978). Further, the changes of hydronephrosis on the IVP are merely a chronicle of prior morphologic alterations which have affected the kidney but do not define obstruction or indicate the likelihood for progressive renal deterioration (Djurhuus et al. 1976; Wax and McDonald 1966). Secondly, as assessed by renography, clearance techniques and urinary concentrating ability, many patients with genuine hydronephrosis have no measurable reduction in renal parenchymal function (Bratt et al. 1977; Nilsson et al. 1979). Thirdly, conservative (non-operative) management of selected patients with hydronephrosis has resulted neither in diminution of renal function nor in progressive urinary tract dilatation (Bratt et al. 1977). Finally, the reported results of corrective pelviureteric surgery with respect to IVP appearances and renal function, although varying considerably from series to series, have been often less than ideal with up to 40% of patients showing no measurable postoperative improvement (Drake et al. 1978; Johnston et al. 1977; Hendren et al. 1980; Williams and Kenaw 1976).