Diagnosis of Kidney Stones in Children

How do health care professionals diagnose kidney stones in children?

To diagnose kidney stones health care professionals use a child’s

• a medical history
• physical exam
• lab and imaging tests

In addition, a health care provider will ask questions about

• symptoms
• family history of kidney stones
• typical foods and drinks.

What tests do health care professionals use to diagnose kidney stones in children?

Health care professionals may use lab or imaging tests to diagnose kidney stones.

Lab tests

Urine tests can show whether there are high levels of minerals that could form kidney stones. Urine and blood tests can also help determine which type of kidney stone is causing a child’s symptoms.

Urinalysis. A child collects a urine sample at a medical clinic or lab, and a health care professional tests the sample. For an infant or young toddler, a parent may need to use a special urine collection bag. Urinalysis can find blood in the urine and minerals that can form kidney stones. White blood cells and bacteria in the urine can be signs of a urinary tract infection.

24-hour urine collection. This test measures how much urine a child produces, minerals that can form stones, substances that may help prevent stones, and the pH level of the urine. Parents will need to use a urine collection bag for an infant or young toddler. Older children will use a special container.

Blood tests. A health care professional may take a blood sample and send it to a lab to test. The blood test can show high blood levels of certain minerals that can lead to kidney stones in children.

Imaging tests

Imaging tests can help find kidney stones. The tests may also show problems that caused a kidney stone to form, such as a birth defect or blockage in the urinary tract. Children usually do not need anesthesia for imaging tests.

Ultrasound. An ultrasound is often the first choice when a child needs an imaging test to find a kidney stone. An ultrasound uses specialized sound waves to look at structures inside the body without exposing a child to radiation. During an ultrasound test, a child lies on a table while a technician moves a wand called a transducer over the child’s body. Ultrasound can create images of a child’s entire urinary tract. No anesthesia is needed.

Abdominal x-ray. An abdominal x-ray is a picture of the abdomen that uses low levels of radiation and is recorded on film or on a computer. A technician takes an abdominal x-ray at a hospital or outpatient center, and a radiologist reads the images. During the x-ray, a child lies on a table or stands up and the technician positions the machine close to the abdomen. The technician may ask for different positions for additional pictures. Abdominal x-rays can show the location of kidney stones in the urinary tract but not all stones are visible on abdominal x-ray.

Computed tomography (CT) scans. CT scans use a combination of x-rays and computer technology to create images of a child’s urinary tract. CT scans expose children to more radiation than other imaging methods, but they may provide more information. A hospital or radiology center that works with children will know how to adjust a CT scan to use the lowest possible amount of radiation. Your child will lie on a table that slides into a tunnel-shaped device that takes the x-rays. CT scans can show the size and location of a kidney stone, whether the stone is blocking the urinary tract, and conditions that may have caused the kidney stone to form.

CT scans can sometimes be done with a contrast medium, but this is not usually needed to see kidney stones. Contrast medium is a dye or other substance that makes structures inside your body easier to see during imaging tests. If needed, a health care professional may give your child a shot of contrast medium before the CT scan and should explain why the contrast is being given.