Antenatal diagnosis of pelvic hydronephrosis: assessment of renal function and drainage as a guide to management.

The optimal management of children with antenatally diagnosed unilateral hydronephrotic kidneys is unclear. We have monitored renal function and drainage using 99mTc-DTPA renography in 77 children with such kidneys presenting at 1-14 mo of age with the aims of throwing light on the natural history of the condition and evaluating the response of the kidney to pyeloplasty. Since management was independent of the drainage criteria on renography, the opportunity also was presented to evaluate the efficacy of diuretic renography for diagnosing obstruction in these children. Follow-up ranged between 1 and 6 yr, during which renography was performed between 2 and 6 times in each patient. Thirty-nine patients were treated conservatively, while 30 patients underwent pyeloplasty at varying times after presentation. No overall significant change in function was observed either in the nonoperated children or as a result of surgery. This also applied to sub-groups of children with poor drainage. Function improved significantly, however, in a sub-group of nonoperated children who presented with impaired function in the hydronephrotic kidney. Surgery, although having no overall effect on function, significantly improved drainage. As a means of identifying obstruction, 99mTc-DTPA diuretic renography was unreliable, erroneously indicating obstruction in 24 nonoperated children in whom function of the hydronephrotic kidney never became abnormal and who could not, therefore, have been considered to have obstruction. This retrospective study underlines the importance of performing a randomized prospective study on the value of pyeloplasty in this group of children.