Duplicated ureter or duplex collecting system is a congenital condition in which the ureteric bud, the embryological origin of the ureter, splits (or arises twice), resulting in two ureters draining a single kidney. It is the most common renal abnormality, occurring in approximately 1% of the population.

Pathophysiology

Ureteral development begins in the human fetus around the 4th week of embryonic development. A ureteric bud, arising from the mesonephric (or Wolffian) duct, gives rise to the ureter, as well as other parts of the collective system. In the case of a duplicated ureter, the ureteric bud either splits or arises twice. In most cases, the kidney is divided into two parts, an upper and lower lobe, with some overlap due to intermingling of collecting tubules. However, in some cases the division is so complete as to give rise to two separate parts, each with its own renal pelvis and ureter.

Diagnosis

Prenatally diagnosed hydronephrosis (fluid-filled kidneys) suggest post-natal follow-up examination. The strongest neo-natal presentation is urinary tract infection. A hydronephrotic kidney may present as a palpable abdominal mass in the newborn, and may suggest an ectopic ureter or ureterocele. In older children, ureteral duplication may present as:

Classification

Ureteral duplication is either of:

Prevalence

Duplicated ureter is the most common renal abnormality, occurring in approximately 1% of the population. It occurs in about 0.7% of healthy adults and in 2% to 4% of people with urinary tract issues.

Complications

A duplicated ureter increased the risk of: