Hydronephrosis

Just a few decades ago, children born with hydronephrosis may not have been diagnosed until they began to show symptoms, if at all. But advances in ultrasound technology mean that today this highly treatable condition—in which urine trapped in the kidney causes it to swell—is often detected during pregnancy, meaning there are a lot of parents out there who are wrestling with the same questions and concerns as you.

• The urinary system—the kidneys, ureters, bladder and urethra—filters waste from the body and removes it in the form of urine. In hydronephrosis, the outflow of urine is impaired, putting stress on this vital system.
   
• Hydronephrosis isn’t a specific diagnosis. Instead, it’s a finding that shows that urine is overfilling the kidney.
   
• A number of conditions can cause this backup of urine. Identifying the cause of your child’s hydronephrosis will help determine how we will treat it.
   
• The excess urine in your child’s kidney may be caused by a condition that either blocks its flow (obstruction) or allows it to leak backward through the urinary system (reflux).
   
• In many children, the cause is never known.
   
• In more than half of the cases where hydronephrosis shows up on ultrasound, it resolves itself by the time the baby is born or soon after.
   
• In children who have mild or, sometimes, moderate hydronephrosis, kidney function is not harmed.
   
• If surgery is called for, there is a very high success rate.

Regardless of the underlying cause, your doctor will describe your child’s hydronephrosis as being mild, moderate or severe. This is based on how much the kidney is stretched and how much the urinary flow is impaired. Your doctor will also tell you whether it’s unilateral (affecting one kidney) or bilateral (affecting both kidneys).

Children’s Hospital Boston’s approach to hydronephrosis

At Children’s, our physicians and nurses specially trained in  pediatric urology have extensive experience with hydronephrosis; it’s the most common congenital problem (that is, present at birth) that our urological team treats.

Hydronephrosis can take many forms and can show up in children at varying ages. In caring for patients across the full spectrum of this condition, what sets Children’s apart are our innovations in two key areas:

Prenatal care: Founded in 2000, the Advanced Fetal Care Center is one of just a handful of comprehensive fetal care centers in the country. It brings together physicians from more than 20 specialties to provide the finest diagnosis, care and treatment for a woman carrying a baby with a congenital condition, such as hydronephrosis. Read more about our Advanced Fetal Care Center.

Surgical technique: Ever since 2001, when we became the first pediatric hospital to acquire a surgical robot, Children's has been a leader in robotic-assisted surgery for a variety of conditions, including those that cause hydronephrosis. This high-tech approach can offer less pain and scarring, shorter hospital stays and faster recovery.

Condition: Reviewed by Alan Retik, MD, © Children’s Hospital Boston, 2010