Duplex Collecting System

Also known as: duplicated ureter, duplex kidney, ureteral duplication.

What is duplex collecting system?

In a normal urinary tract, the ureters are two thin tubes in the abdomen, one each connecting a kidney to the bladder. These enable the removal of urine from the body. When a duplex collecting system is present, two ureters (one draining the upper part of a kidney-the other draining the lower half) connect each kidney to the bladder. Often a ballooning of the ureter (ureterocele) occurs in the ureter draining the top half of the kidney, close to the bladder which with its lower bladder position may cause urinary reflux (backflow of urine from the bladder towards the kidney-vesicoureteral reflux-VUR,  and hydronephrosis-swelling of the kidney). This common abnormality can occur in one or both kidneys.

What causes duplex collecting system?

The cause of urethral duplication is unknown, however girls tend to get it more often than boys and though it can run in families, it’s genetic basis is not clear.

What are the signs/symptoms of duplex collecting system? 

A duplex collecting system often causes no symptoms and may only be noticed during pregnancy when routine ultrasound examination shows fetal hydronephrosis. After birth, urinary tract infections and/or day/nighttime wetting, or flank pain may be presenting signs/symptoms.

What are duplex collecting system care options?

 In many cases, a duplex collecting system does not require treatment. If however vesicoureteral reflux or other complication is present, these might require antibiotics and/or surgical correction.


Reviewed by: Jack Wolfsdorf, MD, FAAP

This page was last updated on: 3/30/2018 8:08:34 AM

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