Hydronephrosis is swelling of the kidneys, and it occurs in about one percent of all infants. Through today’s precise ultrasound technology, infants can be diagnosed with hydronephrosis while they are still in the uterus (prenatal). If your baby is diagnosed with hydronephrosis while you are pregnant, chances are good that the condition will go away on its own before or shortly after delivery (post-natal).
Boys have hydronephrosis four to five times more often than girls, but so far, no other risk factors have been found. This means there is nothing you can do to protect your unborn child from hydronephrosis because it is not a hereditary condition.
What Causes Hydronephrosis?
For unknown reasons, hydronephrosis sometimes happens through normal physiologic development. At least half the time, it is benign and causes no issues. The most common causes for moderate to severe hydronephrosis are:
- An obstruction between the kidneys and the urethra that prevents urine from draining properly from the kidneys. Blockages occur for several reasons, including: 1) posterior urethral valves (PUV), a condition in boys with tissue around the urethra that blocks outflow from the bladder 2) ureterocele, which is swelling in the ureter where it enters the bladder that blocks urine flow 3) ureterovesical junction obstruction (UVJ), a blockage where the ureter and the bladder join and 4) ureteropelvic obstruction (UPJ), a blockage where the kidney and the ureter join.
- Anatomical differences such as: 1) vesicoureteral reflux (VUR), a condition which makes urine flow backwards into the kidneys or 2) ectopic ureter, a condition where the connection between the ureter and the bladder is not in the right place.
- An injury or illness such as kidney stones.
As one of the nation’s top-ranked pediatric urology programs, Riley at IU Health has physicians and nurses who are expertly qualified to diagnose and treat hydronephrosis.
Your child’s symptoms may vary based on the severity of his or her condition.
Hydronephrosis can be categorized as mild, moderate or severe, depending on the degree of swelling in the kidneys and how well urine flows. Infants seldom show symptoms of hydronephrosis, regardless of severity. Similarly, older children may not have symptoms if they are only mildly affected.
Children who have moderate to severe hydronephrosis may have:
- Abdominal pain
- Side pain
- Blood in their urine
- Frequent urinary tract infection or fever
It is important to follow up with a physician if your child has any of these symptoms.
Diagnosis of Hydronephrosis
When hydronephrosis is diagnosed after birth (post-natal), it is usually found after repeated urinary tract infections (UTIs) and/or fevers. If your child has this history, an evaluation by one of our pediatric urologists can determine whether the cause is an obstruction or an underlying difference in his or her anatomy.
We may use one or more tests to diagnose children and decide whether treatment is appropriate. Here are the tests we use most frequently:
- Renal bladder ultrasound
- Voiding system cystourethrogram (VCUG), which examines bladder and urethra anatomy for signs of vesicoureteral reflux
- Nuclear scan to check kidney function and the ability of the kidneys to drain
Some tests are more invasive than others and may require your child to have a catheter and an IV. Child life specialists at Riley at IU Health can help your child cope with these procedures, using calming techniques, toys and other diversions.
It is very rare for an unborn child to need treatment for hydronephrosis. If your baby is diagnosed with hydronephrosis during your pregnancy, you will be monitored closely to make sure your baby has enough amniotic fluid, which is important for growth and development. Your baby’s hydronephrosis is unlikely to affect your pregnancy or delivery.
Within the first few weeks of life, some physicians may start your child on a small dose of antibiotic before a more thorough evaluation. Children with hydronephrosis caused by an underlying anatomy or obstruction may need surgery and/or lifelong follow-up care to protect kidney function.
These corrective surgeries are well-established procedures with good track records of success. Most children who have surgical treatment for hydronephrosis lead normal, healthy lives.
Key Points to Remember
Key Points to Remember
- Hydronephrosis happens in one out of every 100 infants and often resolves without treatment.
- Treatment is usually only needed in moderate to severe cases of hydronephrosis.
- Hydronephrosis is sometimes detected in children after a series of urinary tract infections or fevers.
- Boys have hydronephrosis more often than girls.
- Surgical treatment may be required if your child has an obstruction or a structure that causes hydronephrosis, especially when it is associated with pain.
Support Services & Resources
Support Services & Resources
Riley at IU Health offers a broad range of supportive services to make life better for families who choose us for their children's care.
This organization focuses on awareness, prevention and treatment of kidney disease. Their website includes information about hydronephrosis in children.
This institute is part of the U.S. Department of Health and Human Services and supports medical research through universities and medical institutions in the U.S. It also provides health information about diabetes, digestive and kidney disease.