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.
A urine calcium test is done to determine how much of the mineral calcium is being excreted in the urine by the kidneys.
Why It's Done
A urine test for calcium is often done to:
help determine the cause of kidney stones and other kidney diseases
detect overactivity or underactivity in the parathyroid glands (glands in the neck that produce hormones that help control the level of calcium in the blood)
monitor disorders of the kidney and diseases of calcium metabolism
Results may also point to digestive disorders that interfere with the small intestine's ability to absorb nutrients. The urine calcium test is usually used in combination with other tests to make a specific diagnosis.
The doctor might prescribe a special diet with high or low levels of calcium for a few days before the test. Your child might need to temporarily stop taking specific drugs, such as antacids, that affect calcium levels in the urine.
Collecting the specimen should only take a few minutes. 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 small catheter may need to be inserted into the bladder to obtain the urine specimen.
Alternatively, a urine collection bag with adhesive tape on one end may be used to collect a sample from an infant. You'll clean your baby's genital area and then arrange the bag around the urinary opening. Once the bag is in place, secure it with the attached tape. You can then put a diaper on your baby. Check your baby's collection bag and remove it after your child has urinated, usually within an hour.
After you bring the sample to the lab, technicians will analyze it for calcium content.
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.
Getting the Results
The results of the urine calcium test are usually available in 1-2 days. Your doctor will go over the results with you and explain what they mean. If abnormalities are found, your doctor may may want to do further tests to make a specific diagnosis.
Infants may occasionally experience skin irritation from the adhesive tape on the collection bag. If a catheter is used to obtain the urine, it may cause temporary discomfort. If you have any questions or concerns about this procedure, talk to your doctor.
Helping Your Child
Urine collections are usually painless. Explaining how the test will be conducted and why it's being done can help ease any fear. Make sure your child understands that there should be no foreign matter, such as toilet paper or hair, in the sample.
If You Have Questions
If you have questions about the urine calcium test, speak with your doctor.