Duplex Collecting System: Overview

What is a duplex collecting system

A normal urinary tract includes two kidneys, each with a ureter that drains urine into the bladder. In a duplex system, one or both of the kidneys have two ureters connected to one kidney, draining into the bladder.

A duplex system (ureteral duplication) is often associated with an ureterocele, which causes a back-up of urine in the kidney (hydronephrosis). It is common that the ureter with the ureterocele drains the top of the kidney into the lower part of the bladder and the other ureter drains the lower half of the kidney and inserts in the bladder above the first ureter.

What causes ureteral duplication?

The cause of ureteral duplication is unknown.

Who gets ureteral duplication?

Ureteral duplication is more common in females; however, males can have it as well. Duplex kidneys are known to run in families so there is a hereditary component, but the exact genetic mechanisms are not always known.