🩺 Hydronephrosis (Kidney Swelling) Explained

Hydronephrosis is swelling of the kidney caused by a blockage or backup of urine. Learn causes, symptoms, testing, and treatment in simple terms. 

🩺 Hydronephrosis (Kidney Swelling) Explained 

What Is Hydronephrosis? 

How Does Hydronephrosis Happen? 

Normally, urine flows like this:

Kidneys → ureters → bladder → out of the body

If something blocks that pathway, urine can build up inside the kidney.

Over time this pressure can:

• Stretch the kidney
  
  

• Reduce blood flow
  
  

• Damage kidney tissue
  
  

• Lower kidney function

What Causes Hydronephrosis? 

There are many possible causes.

Common Causes Include:

• Kidney stones
  
  

• Enlarged prostate
  
  

• Tumors
  
  

• Scar tissue
  
  

• Birth defects of the urinary tract
  
  

• Pregnancy (temporary pressure on the ureters)
  
  

• Blood clots
  
  

• Severe urinary tract infections
  
  

Anything that blocks urine flow can lead to hydronephrosis.

What Are the Symptoms? 

Symptoms depend on how severe the swelling is.

Common symptoms may include:

• Pain in the side or back
  
  

• Abdominal pain
  
  

• Nausea or vomiting
  
  

• Trouble urinating
  
  

• Frequent urination
  
  

• Blood in the urine
  
  

• Fever (if infection is present)
  
  

Mild hydronephrosis may cause no symptoms at all.

How Is Hydronephrosis Diagnosed? 

Other Tests

• Urinalysis
  
  

• Blood tests for kidney function
  
  

• Creatinine and eGFR

How Is Hydronephrosis Treated? 

Treatment focuses on fixing the underlying cause.

Possible treatments include:

1. Removing a Blockage

• Passing a kidney stone
  
  

• Surgery to remove stones
  
  

• Procedures to open narrowed areas
  
  

2. Treating Infections

• Antibiotics if infection is present
  
  

3. Relieving Pressure

• Temporary stents
  
  

• Drainage tubes
  
  

• Catheters
  
  

Once the blockage is fixed, the swelling often improves.

Can Hydronephrosis Cause Permanent Damage? 

Is Hydronephrosis Serious? 

It can be.

Mild cases may resolve quickly.
Severe cases can become emergencies.

Urgent treatment is needed if there is:

• Infection
  
  

• Complete blockage
  
  

• Severe pain
  
  

• Sudden loss of kidney function

When Should You See a Doctor? 

Seek medical care if you have:

• Severe flank or back pain
  
  

• Blood in your urine
  
  

• Fever with urinary symptoms
  
  

• Difficulty urinating
  
  

• Abnormal kidney test results
  
  

These can be warning signs of hydronephrosis.

Important Takeaway 

Hydronephrosis is a warning sign that something is blocking normal urine flow.

Finding and treating the cause early can protect the kidneys from permanent harm. 

Related Pages

• Kidney Ultrasound Results Explained
  
  

• Kidney Stones Explained
  
  

• Kidney Infection (Pyelonephritis)
  
  

• Creatinine Blood Test
  
  

• Chronic Kidney Disease Explained