Congenital Ureteropelvic Junction Obstruction

Abstract

Primitive or congenital hydronephrosis is a dilation of renal pelvis and intrarenal calyces mostly due to an abnormality of the ureteropelvic junction (UPJ), which results in an inadequate drainage of urine from the pelvis into the ureter. Increased intrapelvic pressure and urinary stasis in the collecting ducts cause progressive damage to the kidney.