Hydronephrosis

Hydronephrosis is a condition where one or both kidneys become stretched and swollen as the result of a build-up of urine (pee) inside them. It can affect people of any age. It’s sometimes spotted in unborn babies during routine pregnancy ultrasound scans. 

About hydronephrosis

Hydronephrosis doesn't generally cause any long-term problems if it's diagnosed and treated promptly. Babies with the condition may not require any treatment at all.

The condition can increase your chances of getting urinary tract infections (UTIs). In severe cases that are left untreated, the kidney(s) may become scarred, which could lead to loss of kidney function (kidney failure).

Hydronephrosis in babies

Hydronephrosis is increasingly being found in unborn babies during routine ultrasound scans. It's estimated to occur in at least 1 in every 100 pregnancies.

As a parent, it can be worrying to learn your baby has a problem with their kidneys. Most cases of hydronephrosis in babies aren't serious and shouldn't affect the outcome of your pregnancy.

About four out of every five cases will resolve on their own before or within a few months of birth. It will cause no long-term problems for you or your baby.

The remaining cases may require treatment with antibiotics to prevent kidney infections. In some cases surgery may be needed.

Signs and symptoms

Hydronephrosis doesn't always cause symptoms. If it does, these may develop quickly over a few hours or gradually over weeks or months.

Symptoms can include:

  • pain in your back or side – this may be sudden and severe, or may be a dull ache that comes and goes over time; it may get worse after you've drunk a lot
  • symptoms of a UTI, such as a high temperature (fever) of 38C (100.4F) or above, chills and feeling or being sick
  • blood in your urine
  • urinating less often than you used to or with a weak stream
  • in severe cases, noticeably swollen kidneys

When to see your GP

You should see your GP if you:

  • develop severe or persistent pain in your back or side
  • have symptoms of a UTI
  • notice a change in how often you urinate (pee)

Your GP may refer you for an ultrasound scan to assess your kidneys.

Hydronephrosis in babies doesn't usually cause symptoms. But you should seek medical advice as soon as possible if your child develops signs of a possible UTI, such as a high fever without any other obvious cause.

Causes of hydronephrosis

Hydronephrosis diagnosed in pregnancy is usually mild. It is thought to be caused by an increase in the amount of urine your baby produces in the later stages of pregnancy.

In more severe cases, it may be caused by:

  • a blockage in the flow of urine from the kidney(s) to the bladder
  •  backflow of urine from the bladder to the kidney(s)
  • a blockage in the flow of urine out of the bladder

In adults, hydronephrosis is commonly caused by:

Treating hydronephrosis

If you have hydronephrosis, your treatment will depend on what's causing the condition and how severe it is. Pregnant women and babies with the condition may not require any treatment.

In adults, the first stage of treatment is often to drain the urine out of your kidneys. This is done by inserting a tube called a catheter into your bladder or kidney(s). This will help relieve the pressure on your kidneys.

Once the pressure has been relieved, the cause of the build-up of urine may need to be treated. The treatments used will depend on why the condition developed.

The health professional looking after your care will discuss with you the most appropriate treatment options.

For example:

  • kidney stones may be removed during an operation or broken up using sound waves
  • an enlarged prostate can be treated with medication or surgery to remove some of the prostate
  • blockages in the ureters can be treated using surgery to insert a small tube called a stent
  • cancer may be treated using a combination of chemotherapyradiotherapy or surgery to remove the cancerous tissue

The information on this page has been adapted from original content from the NHS website.

For further information see terms and conditions.

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