Introduction

Hydronephrosis is a condition where one or both kidneys become stretched and swollen as theresult of a build-up of urine inside them.

It can affect people of any age and is sometimes spotted in unborn babies during routine pregnancy ultrasound scans (this is known as antenatal hydronephrosis).

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

However, 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 toloss of kidney function (kidney failure) .

Hydronephrosis in babies

Hydronephrosis is increasingly being found in unborn babies during routine ultrasound scans. This is known as antenatal hydronephrosis. It's estimated to occur in at least1 in every 100 pregnancies.

As a parent, it can be worrying to learn your baby has a problem with their kidneys. However, 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 and will cause no long-term problems for you or your baby. The remaining cases may require treatment with antibiotics to prevent kidney infections, and in some cases surgery may be needed.

If it does, these may develop quickly over a few hours or gradually over weeks or months.

Symptomscan include:

• pain in your back or side this may be suddenand 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 orbeing sick
• blood in your urine
• urinating less often than you used toor with a weak stream
• in severe cases, noticeably swollen kidneys

You should see your GP ifyou develop severeor persistent pain in your back or side, have symptoms of a UTI, or notice a change in how often you urinate. They 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.

It isthought 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), or a blockage in the flow of urine out of the bladder.

In adults, hydronephrosis is commonly caused by:

• kidney stones
• pregnancy
• an enlarged prostate gland in men
• narrowing of the ureters (the tubes that carry urine from the kidneys to the bladder)because ofinjury, infection or surgery
• some types of cancer, including kidney cancer , bladder cancer , prostate cancer or ovarian cancer

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. For example:

• kidney stones may be removed during an operationor 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 inserta small tube called a stent
• cancer may be treated using a combination of chemotherapy , radiotherapy or surgery to remove thecancerous tissue

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