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What Is Hydronephrosis?

Hydronephrosis (pronounced high-dro-nef-row-sis) is a radiology term for swelling or fluid in the kidney. Hydronephrosis is not a disease, but can be a radiographic sign of other kidney or bladder problems or developmental issues. Similar terms for less severe kidney swelling which are used interchangeably are pyelectasis or pelviectasis.

What Symptoms Are Associated with Hydronephrosis?

Most children with prenatal hydronephrosis have no symptoms and experience no pain, although there can be abdominal pain, nausea or vomiting in some children who have severe hydronephrosis. When the hydronephrosis occurs later on and is acute, it is usually accompanied with these symptoms as it represents a sudden obstruction of urine flow and stretching of the kidney.

Sometimes there is swelling of the kidney and the ureter, or urine tube to the bladder, when both the kidney and the ureter are dilated. This is known as hydroureteronephrosis. This can be seen with different kinds of ureteral issues or bladder outlet obstruction where the bladder is not emptying normally. Depending on the etiology of this issue, there can be decreased drainage of the urine on the involved side and increased risk of urine infection

How Is Hydronephrosis Diagnosed?

Hydronephrosis is usually determined on imaging studies such as renal ultrasounds, CT scan or MRIs. Regular X-rays can show the outlines of an enlarged kidney, but hydronephrosis is not typically diagnosed on this type of film.

Much of the hydronephrosis seen in children is diagnosed prior to birth during a prenatal ultrasound of the fetus which checks the organs and development of the baby before birth. This would be called prenatal or congenital hydronephrosis. The majority of these dilated kidneys will improve to a more normal size some time after birth, although this process may take a couple of years.

Acquired hydronephrosis is due to some event or disease process that happens after birth, like a kidney stone blocking flow of urine or some kind of external mass compressing the urine tube.

Most hydronephrosis in children is first diagnosed with a renal ultrasound. Other tests used may include one or more of the following: voiding cystogram, nuclear medicine renal scan, MRI or CT scan. Depending on the severity of hydronephrosis and its cause, additional follow up studies are usually necessary over time to track the improvement or worsening of the kidney swelling.

Is Surgery Required for Hydronephrosis?

If the hydronephrosis is not symptomatic and is improving, then surgical intervention may not be needed.

Surgery can become necessary if the disease associated with the congenital hydronephrosis worsens or the child develops an acute cause of hydronephrosis.

What is Hydroureter?

Hydroureter is when the ureter gets bigger than normal due to a backup of urine (pee). Ureters carry urine from each kidney, to the bladder. Hydroureter can happen with other problems of the urinary tract, but it can also be the only condition present.

What are the Causes of Hydroureter?

Hydroureter is most often caused by a blockage that keeps the bladder from emptying. This can cause fluid to back up into the ureters. There are also some cases with no known cause.

What are the Signs and Symptoms of Hydroureter?

Signs of hydroureter can often be seen on a 20-week ultrasound. They can include:

  • Swelling or bulging of the ureters

  • Hydronephrosis - swollen, enlarged kidneys

  • Oligohydramnios - a low amount of amniotic fluid around the baby

  • Pulmonary Hypoplasia - lungs that are not developed fully

How is Hydroureter Diagnosed?

Hydroureter is usually found at the routine 20-week ultrasound. Your health care provider will do more ultrasounds to see if the condition gets better or worse. Usually, these ultrasounds will be every 4 weeks. They are done to check on the ureters and measure the amount of amniotic fluid.

Sometimes an amniocentesis may be done. This is when the amniotic fluid is taken from the amniotic sac in the mother’s belly and tested for other problems.

After birth, your child may have an ultrasound of the bladder, ureters, and kidneys. This is done to see how urine moves through their urinary system.

How is Hydroureter Treated?

Treatment for hydroureter depends on other conditions. In many cases, it goes away on its own before birth or within the first few months after birth.

If hydroureter is severe after birth, your baby may be sent to the NICU so they can be treated and watched closely.

Treatment may involve surgery. This is usually done in the first year or two of your baby’s life. The type of treatment will depend on what is causing the blockage.

Possible Problems

Low amniotic fluid (oligohydramnios) is a possible problem with hydroureter. This can affect your baby’s lung development. It can also narrow the umbilical cord. This can limit or cut off your baby’s blood, food, and oxygen supply. If your baby has this problem, you will be watched closely during pregnancy and after delivery.

Lifelong Considerations

For children with hydroureter that does not go away on its own, surgery can usually fix the problem. This can keep your child from having kidney damage or urinary tract blockages.

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