Hydronephrosis (Kidney Swelling)

From the kidney, urine normally passes through the ureter and drains into the bladder before being flushed out of the body. However, when a blockage occurs at any part of the urinary tract or when there is urine reflux, the kidneys may swell.

The causes of hydronephrosis include:

• Blockages
  Often, urinary tract blockages form where the kidney meets the ureter. However, blockages may occur in other parts of the urinary tract – where the ureter meets the bladder, within the urethra. Blockage may also occur when the ureter is incorrectly attached to the bladder.
• Backflow of urine into the kidneys
  Vesicoureteral reflux takes place when, instead of flowing naturally from the kidneys to the bladder, the urine incorrectly flows from the bladder back up into the kidney. This deprives the kidney to empty, causing the kidney to swell.
• Genetic causes which can occur with other conditions in the infant
• Unknown reasons (idiopathic hydronephrosis)

Infants with hydronephrosis may display few or no symptoms. Children with moderate to severe hydronephrosis may experience the following:

• Pain in the abdomen
• Back and side pains
• Blood in the urine
• Persistent urge to urinate
• Fever
• Vomiting

Your child needs a complete and accurate diagnosis in order to receive the appropriate treatment. To establish the nature and cause of a child’s condition, the doctor will recommend that your child undergo the following tests:

Ultrasound

The first test that your child will undergo will likely be a renal ultrasound. Through the images taken, the doctor can closely examine your child’s kidneys. The findings from the ultrasound will help determine if further tests are needed.

Voiding cystourethrogram

This x-ray imaging procedure takes a close look at the bladder to examine as it empties. This helps determine if there is urine reflux, which is one of the common causes of hydronephrosis. This can also check if there is blockage in the urethra. Using a catheter, the child’s bladder will be filled with a liquid dye that contains iodine. The x-ray images will show the flow of the liquid dye as the bladder fills and the child urinates.

Renal scan

Your child may also be required to undergo a renal or kidney scan to check the kidneys and examine any blockage in the urinary tract. In a renal scan, a small amount of radioactive material will be injected into the bloodstream. With the help of a special camera, the doctor will check how the kidneys function as the radioactive material moves through them.

Prenatal testing

Through a routine prenatal ultrasound, hydronephrosis may be detected even while before your child’s birth. A prenatal ultrasound will show the shape and size of your baby’s kidneys and the amount of amniotic fluid. It also can help reveal obstructions in the urinary system.

Hydronephrosis in babies is examined using kidney ultrasound and kidney function scans. The results will allow the doctor to find the location of the blockage and suggest a suitable treatment option for the baby:

• No action may be required in some cases, as the baby’s kidney can get better over time
• Surgery may be needed if the upper end of the ureter is partially blocked to relieve the pressure on the kidney

Speak to a doctor to learn more about hydronephrosis and its treatment options for your child.

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Typically, hydronephrosis in children resolve early in life. Even in cases where hydronephrosis does not resolve early, the child can still lead a normal life. However, there are some cases of hydronephrosis in children that are severe and may lead to complications and other diseases if left untreated.  These complications include:

• Urinary tract infection (UTI) – When a child has moderate to severe hydronephrosis, there is higher risk of developing UTI.
• Scarring of the kidney – Untreated kidney swelling can negatively affect the child’s kidneys. In the long run, it can cause kidney scarring or permanent kidney damage.
• High blood pressure –  If left untreated, hydronephrosis can lead to hypertension.
• Kidney failure – In some cases, untreated hydronephrosis can lead to kidney failure, which means the kidneys can no longer function.