Types of Congenital Kidney & Urinary Tract Problems

Specialists at Hassenfeld Children’s Hospital at NYU Langone identify and treat children who have a congenital problem affecting the formation and function of the kidneys and other organs of the urinary system. Many of these problems are diagnosed before a child is born.

If not recognized early, many congenital kidney and urinary tract problems can cause recurrent urinary tract infections and scarring in the kidneys, further compromising kidney function. Over time, these conditions may lead to chronic kidney disease and hypertension, which can affect a child’s growth and development.

Our kidney specialists perform a variety of diagnostic tests to evaluate your child’s kidney and urinary function. Our doctors use information from these tests to recommend individualized treatments aimed at protecting the urinary tract system and allowing your child to grow and develop normally.

Some of the more common congenital kidney and urinary tract problems include the following:


Hydronephrosis refers to swelling in one or both kidneys. This condition is often due to an obstruction between the kidneys and bladder, resulting in a buildup of urine in the kidneys.

Vesicoureteral Reflux

Vesicoureteral reflux, also known as urinary reflux, is a backflow of urine from the bladder into the kidneys. It occurs when one or both of the ureters—the tubes that drain urine from the kidneys to the bladder—are not positioned properly or have poor muscle attachments to the bladder.

Early intervention with antibiotics may prevent kidney damage since antibiotics have recently been shown to reduce the risk of future infections.

Ureteropelvic Junction Obstruction

Ureteropelvic junction obstruction is a blockage in the area where the renal pelvis—a balloon-like structure in the kidney that collects urine before it flows into the ureters—meets the ureters.

Ureterovesical Junction Obstruction

Ureterovesical junction obstruction is a blockage in the area where the ureter meets the bladder.

Multicystic Dysplastic Kidney

In multicystic dysplastic kidney, fluid-filled sacs or cysts that appear as a grape-like mass replace normal kidney tissue. These cysts have poor blood flow and no function. This condition usually occurs in only one kidney. The cysts often disappear by the time a child is around age five.


A ureterocele is a blockage in one or more of the ureters, preventing the normal flow of urine. A ureterocele appears as a balloon-like structure at the end of the ureter that opens into the bladder. Ureteroceles often occur in children who are born with a duplex or “double-decker” kidney. A duplex kidney is divided into an upper and lower portion, each with its own drainage tube or ureter.

Renal Agenesis

Renal agenesis is the absence of a kidney. This condition usually affects only one of the kidneys. Most people lead normal, healthy lives with one functioning kidney.

Renal Hypoplasia

In renal hypoplasia, one or both kidneys are abnormally small. In some children with renal hypoplasia, the affected kidney is not fully functional.

Posterior Urethral Valves

Posterior urethral valves are leaflets, or extra flaps of tissue, that develop in the urethra—the tube through which urine flows out of the bladder—of boys. Depending on the severity of the condition, it may slow the flow of urine from the kidneys into the bladder and prevent the bladder from emptying completely.

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