Outcome of hydronephrosis diagnosed antenatally.

We evaluated 23 neonates with prenatally diagnosed dilatation of the renal pelvis involving 33 renal units. The dilatation was graded from 0 to 4 by ultrasonography. Diuresis renography was used to evaluate differential renal function. The patterns of the excretory curve following administration of furosemide were analyzed. Antegrade pyelography and pressure flow studies were done in selected patients. The mean follow-up was 34 weeks. The single most important prognostic indicator in this group of patients was the degree of dilatation on ultrasonography. Six of 7 renal units with grade I hydronephrosis improved and 1 remained stable on follow-up. Four of the 12 renal units with grade II hydronephrosis improved spontaneously; 1 remained stable. Three of 11 renal units with grade III hydronephrosis either improved or remained stable. The measurement of differential renal functions on DTPA renography did not correlate well with the degree of dilatation when renal size and parenchymal thickness were adequate. The excretory curves after lasix administration were not helpful to determine treatment in the neonatal period. Seventeen renal units (7 grade II, 9 grade III, 1 grade IV) were treated surgically due to persistent dilatation, evidence of obstruction on either DTPA renography or the Whitaker test, or because of impaired renal function. Sixteen of the 33 renal units diagnosed prenatally improved with observation. Of all the parameters studied only the degree of dilatation on ultrasonography correlated well with the prognosis.(ABSTRACT TRUNCATED AT 250 WORDS)