Kidney stones are small, solid masses that can form in the urinary tract. They happen when salts and minerals in urine (pee) get extra concentrated and then become crystals. Over a few weeks or months, the crystals can build up and become stones.
Kidney stones range in size from a fraction of an inch to several inches. Small kidney stones (0.2 inches or less than 5 mm) can pass through the urinary tract and out of the body with little or no pain. But larger stones can be quite painful, block the flow of pee, and cause blood in the urine and other symptoms.
Kidney stones (also called calculi or nephrolithiasis) mostly affect adults. But but kids and teens can get them. There are different types of kidney stones with many different causes, and they affect boys more often than girls.
Usually, kidney stones don't cause symptoms until they move around in the kidney or pass into the ureter . Small stones might pass through the urinary tract and out of the body with no pain or complications.
Larger stones, though, may block the urinary tract and cause symptoms like:
A stone that's too large to move can sometimes create a backup of pee, causing one or both kidneys to swell (this is called hydronephrosis). Hydronephrosis can cause pain in the side and back. If it's not treated, it may cause long-term kidney damage. Most kidney stones, though, don't cause permanent damage.
Most kids who get kidney stones have a health condition that increases their risk for them. But others get them for no known reason.
Some types of kidney stones run in families, so having a relative with kidney stones can make a person more likely to get them. Kids who have had kidney stones before are more likely to get them again.
Other risk factors include:
The four major types of kidney stones are:
See a doctor as soon as possible if your child has:
Go to an emergency clinic or hospital emergency room right away if your child has:
The doctor will ask about the symptoms and how long they've been going on; your child's diet; things that could be causing dehydration; any family medical history of kidney stones; and any history of diseases or conditions that affect the kidneys or urinary tract.
The doctor will do a physical exam and probably order blood tests, urine tests, or kidney function tests to look for kidney stones. Imaging tests (such as ultrasounds, X-rays, or CT scans) are often used to get a better look at the kidneys. If there is a stone, an imaging test can show its exact size and location, which will help doctors decide on the best treatment.
Treatment depends on the type of kidney stones and their size. Some kids just need to drink a lot of water and take pain medicines to pass a kidney stone. Those with larger stones may need surgery or other treatments to help remove the stones.
To help pass a small stone, give your child plenty of water to drink and medicine to ease the pain. Often, over-the-counter medicines such as ibuprofen and acetaminophen are enough. But sometimes prescription pain medicines are needed.
The doctor might ask you to strain your child's pee for a few days to collect the passed kidney stones. Examining the stones can help the doctor decide if further treatment is needed.
Kidney stones that block the urinary tract or cause severe pain or dehydration may require a hospital visit. In the hospital, a child may be given intravenous (IV) fluids and pain medicine to help stones pass and treat or prevent dehydration.
Large stones rarely pass on their own. To get rid of large stones and stones that are damaging the kidneys, doctors might use:
Doctors will monitor kids who have had kidney stones to prevent new ones from forming. Your child's doctor might have you use a 24-hour urine collection test. This measures the volume of pee within a 24-hour period and checks the substances in it.
Depending on the type of kidney stone your child had, the doctor can prescribe treatments or medicines to reduce the levels of crystal-forming substances in the pee.
It's not always possible to prevent some types of kidney stones. But drinking enough water to avoid dehydration is important. Pee that's almost clear is a sign that a person is getting enough liquids. Cutting back on salt and salty foods also helps lower the risk of kidney stones.
To help prevent new stones, all kids who've had kidney stones should:
If dietary changes don't prevent kidney stones, medicines are available to lower the levels of crystal-forming substances in the pee.
Reviewed by: Robert S. Mathias, MD
Date Reviewed: 01-10-2016