DIURETIC RENOGRAPHY IN THE EVALUATION OF NEONATAL HYDRONEPHROSIS - ISIT RELIABLE

Arguments against the use of diuretic renography in the assessment of newborn hydronephrosis include immature function of neonatal kidneys, previously reported poor diuretic response and nonreproducible drainag e patterns. To address these concerns we reviewed the initial and foll owup renal scans of 17 neonates with hydronephrosis without ureterecta sis diagnosed by perinatal ultrasonography. All patients were evaluate d with an initial diuretic renal scan up to the age of 28 days, and al l had normal cystograms. A total of 19 dilated kidneys was studied of which 13 ultimately required pyeloplasty and 6 were managed nonsurgica lly. Patient study parameters included age and weight at the time of e ach renal scan, side of hydronephrosis, differential function of each kidney, pre-diuretic and post-diuretic urine output, and drainage half -time of each kidney. The diuretic renal scans followed a standardized protocol. There was no statistically significant difference between n eonatal and followup differential function (p >0.05), and the correlat ion coefficient was highly significant (r = 0.968). Comparison of resp onse to diuretic stimulation (ml./kg. per minute) revealed no statisti cally significant difference as the patients aged with brisk urine out put 3 to 5 times greater than previously reported. The distribution an d mean drainage half-times for normal nonhydronephrotic kidneys were s imilar when comparing those performed as neonates and at followup. Hyd ronephrotic kidneys managed nonsurgically maintained almost identical patterns. Those repaired surgically demonstrated appropriate improveme nt in drainage but function remained unchanged. These results refute e ach of the criticisms against the use of diuretic renography to evalua te neonatal hydronephrosis and demonstrate its reliability in neonates .