What is a duplex kidney?
In a normal urinary tract, each kidney is connected to one ureter (a tube that drains urine into the bladder).
Children with a duplex kidney (also called a duplicated collecting system) have two ureters coming from a single kidney. These two ureters can drain independently into the bladder or connect and drain as a single ureter into the bladder. Duplex kidneys can occur in one or both kidneys.
![Duplex Kidney Illustration](/sites/default/files/styles/original_320x_2x/public/duplex-kidney-illustration.png?itok=YUs-kd-1)
Duplex kidneys are a normal variant, meaning that they occur commonly enough in healthy children to be considered normal. They occur in 1 percent of the population, and most cause no medical problems and will require no treatment.
Other duplex kidneys can be associated with the following:
Testing and diagnosis
Many duplex kidneys are found incidentally during imaging studies.
Treatment
Since most duplex kidneys are a normal finding, no treatment is necessary. If a duplicated kidney is associated with VUR, an ectopic ureter or a ureterocele, experts in the Division of Urology will follow the treatment plan for those diagnoses.
Reviewed by: Division of Urology
Date: May 2011
Resources to help
Division of Urology Resources
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