Accelerated obstruction at the ureteropelvic junction in adults.

Accelerated obstruction at the initially normal or minimally abnormal ureteropelvic junction was seen in 5 kidneys in 4 women after intervals of 2 to 15 years. Three kidneys had to be removed although the patients had been under observation. Hydronephrosis from ureteropelvic junction obstruction does not always progress gradually from the prenatal period but may rapidly increase in the adult without adequate warning.