Hydronephrosis

Stretching or dilation of the urinary tract may occur because of a blockage to the flow of urine, which causes increased pressure “up stream,” and leads to urine building up above the point of blockage.

Hydronephrosis can also occur due to an abnormal connection between the ureter and bladder that allows urine to flow backward toward the kidney when the bladder contracts to empty. This condition is known as reflux.

Sometimes hydronephrosis can be caused by a blockage that has cleared and left the urinary system stretched but not under any pressure.

How is Hydronephrosis Diagnosed?

Medical advances in prenatal ultrasound examinations have helped identify large numbers of infants with urinary dilation or stretching prior to birth. In diagnosing hydronephrosis, Nemours urologists may recommend a voiding cystourethrogram (VCUG) and a renal (kidney) scan.

The VCUG tells us if the “one-way” valve in the bladder is functioning, while the renal scan reveals how well the kidneys are functioning and assesses how fast the urine drains from the kidney into the bladder to see if a blockage exists. These studies help determine if surgical repair or immediate treatment is needed since hydronephrosis can lead to urinary tract infections (UTIs) and sometimes permanent kidney damage.

Urine Test: Dipstick

What It Is

A urine dipstick test is often done as part of an overall urinalysis, but it can also be done on its own, depending on the doctor's concerns. Once a urine sample is collected, a nurse or technician will place a specially treated chemical strip (dipstick) into your child's urine. Patches on the dipstick will change color to indicate the presence of such things as white blood cells, protein, or glucose.

Why It's Done

The results of a urine dipstick test may point to a diagnosis of urinary tract infection (UTI), kidney disease, diabetes, or a urinary tract injury. If test results are abnormal, other tests will be needed before a definite diagnosis can be made.

Preparation

No preparation other than cleansing the area around the urinary opening is required for the urine dipstick test.

The Procedure

Your child will be asked to urinate into a clean sample cup in the doctor's office. If your child isn't potty trained and can't urinate into a cup, a catheter (a narrow, soft tube) may need to be inserted into the bladder to obtain the urine specimen.

The skin surrounding the urinary opening has to be cleaned and rinsed just before the urine is collected. In this "clean-catch" method, you or your child cleans the skin around the urinary opening with a special towelette. The child then urinates, stops momentarily, and then urinates again into the collection container. Catching the urine in "midstream" is the goal. Be sure to wash your hands and your child's hands after this process.

Once collected, the technician or nurse will then place the dipstick into the urine sample. Collecting the specimen should only take a few minutes.

What to Expect

Because the test involves normal urination; there shouldn't be any discomfort as long as your child can provide a urine specimen. It's important to keep the area around the urinary opening clean before the test and to catch the urine sample midstream.

Getting the Results

The results of the urine dipstick test will be available right away. If abnormalities are found, further urine tests will be needed. Talk to your child's doctor about the meaning of the specific test results.

Risks

No risks are associated with taking a urine dipstick test. If a catheterized specimen is required it may cause temporary discomfort and you can discuss any questions you have about this procedure with your healthcare provider.

Helping Your Child

The urine dipstick test is painless. Explaining how the test will be conducted, and why it's being done, can help ease your child's fear. Make sure your child understands that the urinary opening must be clean and the urine must be collected midstream.

If You Have Questions

If you have questions about the urine dipstick test, speak with your doctor.

Reviewed by: Yamini Durani, MD
Date reviewed: February 2012