Intermittent hydronephrosis: the occult ureteropelvic obstruction.

Occult ureteropelvic obstruction was found in 3 children and 7 adults with painful intermittent obstruction of urographically normal or nearly normal upper urinary tracts. These patients constituted 3.4 per cent of those who underwent pyeloplasty during a 10-year period. The occult obstruction was demonstrated dramatically by infusion excretory urography with furosemide stimulation in all 10 patients. The urographic lateralization was of even more value in 4 patients whose renal pelves were equally generous bilaterally and in 8 whose pain also was reproduced as a result of massive diuresis, which is characteristic of this technique alone. The manifestations and various other techniques for accurate diagnosis of this frequently elusive condition are discussed.