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Dr. Andrea Pinto Lopez

Sep 19, 20227 min read

What Is Hydronephrosis? Causes, Symptoms, and Treatment

The information provided herein does not constitute an expert or medical advice, nor intended to replace such advice.


Your kidneys are two organs located in the lower part of your abdomen. They are constantly working to filter your blood of any waste, and they also get rid of excess fluid. As a result, your kidneys are responsible for producing urine. However, there are many diseases that can affect your kidneys and potentially cause complications if left untreated. Hydronephrosis is one of those conditions.

Learn more about hydronephrosis, its causes, symptoms, diagnosis, and treatment by reading the article below.

Hydronephrosis definition

According to the National Kidney Foundation, hydronephrosis is a condition characterized by kidney swelling caused by a buildup of urine. Hydronephrosis can affect one or both kidneys at the same time. 

Human beings typically have two kidneys, which are part of the urinary system. The urinary system is composed of the kidneys, ureters, bladder, and urethra. The ureters are two small tubes that carry urine from the kidneys to the bladder, and the urethra is a narrow tube that carries urine from the bladder to the outside of the body.

The kidneys are responsible for producing urine in order to remove waste and fluid from the body. To do this, specific blood vessels carry blood to the kidneys in order to be filtered. When someone gets hydronephrosis, it leads to swelling and pressure inside the kidneys that make it harder for them to work properly, which leads to a variety of symptoms.

Hydronephrosis causes

As we mentioned above, your kidneys are responsible for filtering blood and producing urine. According to the Cleveland Clinic, hydronephrosis happens when there is an incomplete emptying of the urinary tract, which leads to urine backing up into the kidney.

If you only get hydronephrosis in one kidney, the condition is called unilateral hydronephrosis. But if both kidneys are swollen, it’s called bilateral hydronephrosis. The condition is known as hydroureteronephrosis when it also affects the ureters.

Anyone can get hydronephrosis, regardless of their age, gender, or ethnicity. 

According to the NHS, it’s not always clear why babies get hydronephrosis. Unborn babies can develop a condition known as antenatal hydronephrosis, which usually improves by itself within a few months after delivery. 

Dilated kidneys in adults can be caused by a wide range of conditions. Some of the causes of enlarged kidneys can include:

  • Kidney stones
  • Scarring from previous trauma or surgeries
  • Blood clots
  • Tumors or growths
  • Urinary tract infections (UTIs)
  • An enlarged prostate
  • Pregnancy

Hydroureteronephrosis symptoms

In some cases, hydronephrosis and hydroureteronephrosis can be asymptomatic. But according to the Mayo Clinic, when these conditions do cause symptoms, they can include:

  • Pain in the sides of the abdomen, back, lower abdomen, and groin
  • Painful urination
  • Frequent urge to urinate
  • Fever
  • Nausea and vomiting
  • Failure to thrive in infants and children

The symptoms of hydronephrosis can be confused for a UTI, so it’s very important to avoid self-medication. Instead, you should seek medical assistance in order to get the right diagnosis and start treatment. 

Hydronephrosis diagnosis

If you have signs of hydronephrosis, your doctor will usually perform a thorough physical examination, ask about your medical history, and order certain tests.

In addition to confirming a hydronephrosis diagnosis, your healthcare provider will also be able to rule out other conditions that could be causing your symptoms.

For example, an anatomical variation called extrarenal pelvis can be confused for hydronephrosis in some cases. Bilateral extrarenal pelvis is usually asymptomatic, but in some cases, it can cause symptoms that mimic hydronephrosis.

Fluid around the kidneys can be seen in an ultrasound; other imaging tests that can be used include X-rays, CT scans, or MRI scans. Your doctor could also order blood and urine tests. In some cases, a test called a cystoscopy can be used to get a better view of your bladder.

Will hydronephrosis go away?

Some cases of hydronephrosis can go away on their own, but you shouldn’t skip getting medical assistance. If left untreated, hydronephrosis can lead to serious health issues. Your doctor will be able to determine whether you need immediate treatment, and monitor your symptoms and condition until you get better.

In order to treat hydronephrosis, the underlying cause of the problem needs to be solved. This can include:

  • Removing kidney stones
  • Fixing anatomical defects in the kidney
  • Inserting a small tube to drain excess urine
  • Taking medications to clear infections
  • Removing part of the kidney

According to MedlinePlus, hydronephrosis complications can cause permanent damage to one or both kidneys if left untreated. Loss of your kidney function can lead to kidney failure, especially in people who only have one working kidney.

This is a rare complication, but it can happen in some cases. Kidney failure is an extremely serious medical condition, and you should get treatment for hydronephrosis as quickly as possible to avoid kidney damage.

Visit STDWatch.com now to learn more about many other health conditions.


Hydronephrosis - kidney.org

Hydronephrosis - my.clevelandclinic.org

Hydronephrosis - mayoclinic.org

Causes - Hydronephrosis - nhs.uk

Hydronephrosis of one kidney - medlineplus.gov

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