Hydronephrosis

The first step in treating your child is forming an accurate and complete diagnosis. Unlike hemophilia or strep throat, hydronephrosis isn’t a specific diagnosis of disease. Instead, it’s a finding that shows there’s an impairment in your child’s urinary flow that’s making the kidney swell. In diagnosing hydronephrosis, your doctor will search for what is causing that impairment in order to determine the best treatment for your child.

You may hear your child’s hydronephrosis described as “prenatal” or “antenatal,” and “neonatal” or “post-natal.” These terms refer to when the diagnosis occurred—either in the womb or after birth—and not to different conditions.

Prenatal testing

Signs of hydronephrosis may first show up on a routine prenatal ultrasound (sonography). The test transmits high-frequency sound waves into the uterus; the echoes that bounce back are recorded and transformed into an image of your baby. It will show the size and shape of your child’s kidneys, as well as the amount of amniotic fluid; it can also help reveal obstructions in the urinary system.

However, doctors usually can’t make a precise diagnosis of hydronephrosis right away. This is partly due to the fact that fetal tissue is very stretchy, so a swelling in the kidney may look worse than the condition really is.

If an ultrasound indicates your child may have hydronephrosis, your obstetrician will monitor your pregnancy more closely and may perform more frequent ultrasound testing to check for any changes over time. While your child is being monitored, your caregivers will take precise measurements of your child and his kidneys, and the level of amniotic fluid surrounding him.

Post-natal testing

For newborns and older children, doctors will use some or all of the following tests to help determine the cause and severity of the hydronephrosis:

• Renal ultrasound (RUS): By focusing on the kidneys, this ultrasound gives a good picture of how serious the hydronephrosis is. This is the first post-natal test your doctor will perform, and will help determine whether further tests are needed.
   
• Voiding cystourethrogram (VCUG): This special kind of x-ray is used to check for reflux, a common cause of hydronephrosis; it also can show if there is an obstruction in the urethra. Using a small tube called a catheter, doctors will fill your child’s bladder with a liquid containing iodine. As the bladder fills and your child urinates, the flow of the liquid will be visible on video x-ray images.
   
• Renal scan (MAG 3): This is a type of nuclear scanning test that helps measure the difference in function between the two kidneys and also estimate the degree of blockage in the urinary system. After a tiny amount of radioactive material (radioisotope) is injected into your child’s bloodstream, a special camera called a gamma camera is used to take pictures of the kidneys as the radioactive material moves through them, showing how well they are filtering and draining.

After we complete all necessary tests, our experts meet to review and discuss what they have learned about your child's condition. Then we will meet with you and your family to discuss the results and outline the best treatment options.