Hydronephrosis: Definition, Symptoms, Causes, Diagnosis and Treatments

It is a condition that usually occurs when a kidney swells because urine does not correctly drain from the kidney to the bladder.

Hydronephrosis is not a primary disease. It is a secondary condition that results from some other underlying disease. It is structural and results from a blockage or blockage in the urinary tract.

It is believed that hydronephrosis affects approximately 1 in 100 babies.

Symptoms of hydronephrosis

Normally, urine flows through the urinary tract with minimal pressure. Pressure can build up if there is a blockage in the urinary tract. After the urine accumulates for a prolonged period, your kidney may become enlarged.

Your kidney can be so full of urine that it starts to press on nearby organs. If left untreated for too long, this pressure can permanently cause the kidneys to lose function.

Mild symptoms of hydronephrosis include urinating more frequently and a more excellent need to urinate. Other potentially severe symptoms that you may experience are:

  • Pain in the abdomen or flank.
  • Nausea.
  • Vomiting
  • Pain when urinating.
  • Incomplete emptying or emptying of the bladder.
  • Fever.

Interrupting urine flow increases getting a urinary tract infection (UTI). This is why this type of infection is one of the most common complications of hydronephrosis.


Some signs of a urinary tract infection include:

  • Cloudy urine.
  • Pain when urinating.
  • Burning when urinating.
  • A stream of weak urine.
  • Back pain.
  • Bladder pain.
  • Fever.
  • Cold.

If you see signs of hydronephrosis, schedule an appointment with your doctor to talk about your symptoms.


Hydronephrosis may be due to internal and external conditions that affect the kidney and the urinary collecting system.

One of the most common causes of hydronephrosis is acute unilateral obstructive uropathy. This is a sudden development of an obstruction in one of your ureters, the tubes connecting the kidneys to the bladder. The most common cause of this blockage is a kidney stone.

A blocked ureter can cause urine to return to the kidney, causing swelling. This reflux of urine is known as vesicoureteral reflux (VUR).

Other possible causes of a block include:

  • A fold in the ureteropelvic junction is where the ureter meets the pelvis of the kidney.
  • An enlarged prostate in men may be due to benign prostatic hyperplasia (BPH) or prostatitis.
  • Pregnancy causes compression due to the growth of the fetus.
  • Tumors in or near the ureter
  • A narrowing of the ureter from a lesion or congenital disability.

Diagnóstico de hidronefrosis

Getting a diagnosis as soon as possible is extremely important. Your kidneys may be permanently damaged if your condition is not treated for too long.

Your doctor will probably start by getting a general assessment of your health status and then concentrate on the urinary symptoms you may have. You can also feel your enlarged kidney by gently massaging the abdomen and flank area.

Your doctor may use a catheter to drain part of the urine from your bladder. If you can not release a large amount of urine in this way, it could mean that your blockage is in your bladder or your urethra. The urethra is a tube that carries urine from the bladder to the outside of your body.

Your doctor may also want to perform a renal ultrasound or a CT scan to closely monitor the extent of the swelling and possibly locate the blockage area.

Both procedures allow your doctor to see an image of the inside of your body, but renal ultrasound is generally considered the gold standard for the diagnosis of hydronephrosis. It allows your doctor to monitor your kidney closely.


The treatment for hydronephrosis mainly focuses on getting rid of whatever is blocking urine flow. The treatment option that your doctor chooses will depend on the cause of your obstruction.

If a blocked ureter is causing your condition, your doctor may need to do any of the following:

  • Insert a ureteral stent, a tube that allows the ureter to drain into the bladder.
  • Insert a nephrostomy tube, allowing blocked urine to drain through the back.
  • Prescribe antibiotics to control the infection.

Your doctor may have to remove the blockage with surgery. If something like scar tissue or a blood clot is causing the blockage, your doctor may remove the affected area. They can then reconnect the healthy ends of the ureter to restore normal urine flow.

If the cause of your hydronephrosis is a kidney stone, you may need surgery to remove it. Your doctor may perform endoscopic surgery, which involves using tiny instruments to perform the procedure. This allows your surgeon to make smaller incisions, speeding recovery.

Your doctor may also prescribe antibiotics. This will help ensure that you do not develop a kidney infection.