Children's Hospital Colorado

Duplex Collecting

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.

What are the signs and symptoms of ureteral duplication?

Often a duplex kidney is noticed during pregnancy, when an ultrasound scan may show swelling (hydronephrosis) of the fetus's kidney. However, a duplex kidney may not be recognized until after birth, when it can cause a urinary tract infection and/or day and nighttime wetting for a child.

What tests are used to diagnose ureteral duplication?

A duplex kidney is most commonly diagnosed by using an ultrasound scan. This is a simple test that looks at the kidney and it is not painful. Sometimes it is necessary to do additional tests, which can include a voiding cystourethrogram (VCUG), where a catheter is placed into the bladder and X-rays are taken as the bladder is filled. Another test used to diagnose this condition is a renogram, where the function of the kidney is evaluated.

If your child is diagnosed upon prenatal ultrasound scan, you can visit a urologist before and/or after the child is born. If your child has multiple recurrent urinary tract infections, it is important to visit a urologist to figure out why the infections continue to come back. It is always important to visit your primary care physician first.

How do doctors at Children's Hospital Colorado make a diagnosis?

The diagnosis is made by imaging studies, such as X-rays and ultrasounds by the Urology Department.

How is ureteral duplication treated?

Treatment depends on the child's age, overall health, extent of the condition and medical history. Each child is different and the physician will determine the most appropriate treatment for your child. Treatment could include surgical correction, following the condition with regular radiology testing or nothing.

Why choose Children's Colorado for your child's ureteral duplication?

Children's Colorado has expertise in pediatric urology, pediatric radiology, pediatric anesthesiology and a fetal medicine center. We are therefore able to provide all the areas of care that are necessary to ensure the best outcome for children who are born with duplex kidneys.

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