This content created by Halil Tuğtepe, Prof. Dr. with attribution to scientific articles.


What Is Hydronephrosis?

Hydronephrosis means the kidneys are abnormally large or overfilled with urine and can be seen in both kidneys. Hydronephrosis occurs in about 1 in every 100 babies.

Most hydronephrosis detected by ultrasound in the mother's womb is temporary. However, it may also be caused by a blockage in a part of the urinary tract or the reflux of urine (reflux of urine from the bladder). It may also be due to abnormal development or formation of the kidney in the absence of obstruction or reflux.

There are three main categories of hydronephrosis:

  1. Idiopathic hydronephrosis with no apparent cause and usually resolves spontaneously before or after birth.
  2. Vesicoureteral reflux is the urine to flow back to the ureter (the channel connecting the kidneys to the bladder) abnormally in the bladder, instead of the urine flows smoothly from the kidneys to the bladder.
  3. Congestion in four possible locations;
  • Where the kidney meets the ureter (ureteropelvic junction-UPJ)
  • Where the ureter meets the bladder (ureterovesical junction-UVJ)
  • Inside the urethra (the tube that carries urine from the body to the bladder, which occurs only in men) (posterior urethral valves-PUV)
  • Incorrect connection of the ureter to the bladder (ectopic ureter or ureterocele)

Newborns and infants with hydronephrosis usually show few or no symptoms. Older children with moderate to severe cases may experience abdominal and flank pain and blood in the urine. Urinary tract infection (UTI) can sometimes be the only symptom in all patients with hydronephrosis. Therefore, it is a good example of why it should be investigated in infants or children with urinary tract infections.

There are four main options for treatment depending on the severity of hydronephrosis in your baby:

  1. Close observation with ultrasound before and after birth for mild or moderate cases.
  2. After the baby is born, using antibiotics to prevent infection, when the infection may be more likely to occur.
  3. Surgical treatment to recover any urinary tract obstruction in more severe cases.
  4. Fetal surgery to place a drainage tube in your baby's bladder in the most severe cases.

About half of the patients diagnosed with hydronephrosis recover the health on its own.

Patients should be observed according to their degrees or with an appropriate treatment method. Hydronephrosis, which is severe or does not recover too long and if untreated can cause serious damage, such as the loss of a kidney or both kidneys. Because kidney functions are injured and kidneys cannot function. Therefore, severe hydronephrosis should be researched and treated immediately.


Frequently Asked Questions

What are the advanced tests required for diagnosis and treatment?

Some tests may be required to diagnose the disease. These tests include a complete urine test, ultrasound, scintigraphy, MRI, and cystoscopy tests.

In the disease that is diagnosed early, blockages or reflux are treated and the person is restored to his health. Being late in diagnosis and treatment causes permanent damage to the kidneys.

How is hydronephrosis treated after childbirth?

Treatment depends on the number of kidneys affected and how severe the condition was before birth.

If hydronephrosis disappears before birth, your baby will not need any tests or treatments after birth.

If hydronephrosis has not disappeared, your baby will need various tests after birth and treatment may be required.

If the condition involves only one kidney or is mild, an ultrasound will be done after your baby is 1 week old. Depending on these results, it may need other tests. Your doctor may prescribe an antibiotic medication to help prevent your baby from getting a kidney infection.

If the condition involves both kidneys or is severe, your baby will have an ultrasound within the first few days after birth. Your doctor will likely prescribe an antibiotic medication to help prevent your baby from getting a kidney infection. Other tests may be needed to check your baby's urinary tract.

​​​​​​​Will I need more tests?

Yeah. If your baby has hydronephrosis, your doctor will want to see the baby's health. You will need to have one or more ultrasounds to follow up during pregnancy.

When your doctor does an ultrasound;

  • Presence of hydronephrosis in one or both kidneys,
  • How critical the situation is,
  • It checks your amniotic fluid (Amniotic fluid is the uterine fluid that surrounds the baby. It consists of the baby's urine. If any problem prevents the kidneys from producing enough urine, the amount of amniotic fluid will below.).

If the follow-up ultrasound shows the hydronephrosis is gone, you probably won't need any more tests.

If the follow-up ultrasound shows that hydronephrosis is not going away or is getting worse, you will need more tests. These may include more ultrasound or different tests to evaluate other conditions.

How is prenatal hydronephrosis treated during pregnancy?

Doctors will monitor the disease with tests, but they usually don't treat it. There is usually no need for premature birth.

How can I understand if my baby has prenatal hydronephrosis?

Doctors can diagnose hydronephrosis when they perform a routine imaging test called ultrasound to check the baby's health during pregnancy. Ultrasound gives an image of the baby in the womb.

Is hydronephrosis important?

70% of hydronephrosis disappears after a certain period from birth. This period can take up to two years. This condition is not serious and does not cause any long-term problems.

If hydronephrosis does not disappear, it may be caused by a serious problem in the urinary tract. For example, there may be a blockage in the urinary tract or urine flowing backwards from the bladder to the kidney (Urinary reflux).

For this reason, babies with hydronephrosis should be researched and proved that there is no underlying cause, and then they should be closely monitored.

What is prenatal hydronephrosis?

"Prenatal" attributes to the condition in which the baby is in the mother's womb, it includes situations that occur during pregnancy.

Prenatal hydronephrosis is called swelling of the kidney and being larger than normal and is a condition affecting one or both of the baby's kidneys.

Published: 02 Şubat 2021
Updated: 25 Şubat 2021

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