Definition & Facts of Kidney Stones in Children

What are kidney stones?

Kidney stones are hard, pebble-like pieces of material that form in one or both of a child’s kidneys when high levels of certain minerals occur in urine. Kidney stones rarely cause permanent damage if treated by a health care professional.

Kidney stones vary in size and shape. They may be as small as a grain of sand or as large as a pea. Rarely, some kidney stones are as big as golf balls. Kidney stones may be smooth or jagged and usually are yellow or brown.

A small kidney stone may pass through the urinary tract on its own, causing little or no pain. A larger kidney stone may get stuck along the way. A kidney stone that gets stuck can block the flow of urine, causing severe pain or bleeding. Learn more about the urinary tract and how it works.

A child who has symptoms of kidney stones including severe pain, blood in the urine, or vomiting needs care right away. A health care professional, such as a urologist, can treat any pain and determine how and when to treat the kidney stone. The provider may also prescribe medicine to prevent further problems or treat a urinary tract infection (UTI).

Illustration of a human kidney with several kidney stones blocking the urinary tract.
A small kidney stone may pass through the urinary tract on its own, causing little or no pain. A larger kidney stone may get stuck along the way.

Do kidney stones have another name?

The scientific name for a kidney stone is a renal calculus or nephrolith. You may hear health care professionals call this condition nephrolithiasis or urolithiasis.

What type of kidney stones occur in children?

Children develop one of four main types of kidney stones, listed below. Treatment for kidney stones usually depends on their size, location, and what they are made of.

Calcium stones

Calcium stones, including calcium oxalate stones and calcium phosphate stones, are the most common types of kidney stones in children. Calcium oxalate stones are more common than calcium phosphate stones.

Calcium from food does not increase the chance of having calcium oxalate stones. Normally, calcium that isn’t taken up by a child’s bones and muscles goes to the kidneys and is flushed out with urine. In some children, the kidneys leak extra calcium, which can join with other waste products to form a kidney stone.

Uric acid stones

A uric acid stone may form when a child’s urine contains too much uric acid. Medical conditions or inherited disorders can cause too much uric acid in your child’s urinary tract. Less often, eating fish, shellfish, and meat—especially organ meats—may increase uric acid in urine and lead to kidney stones.

Struvite stones

Struvite stones may form after an infection in the upper urinary tract, where the kidneys are found. These stones can develop suddenly and become large quickly. Struvite stones tend to affect children whose urinary tracts did not develop normally and the flow of urine may be limited or blocked. Simple urinary tract infections (UTIs), such as bladder infections, don’t usually lead to struvite stones.

Cystine stones

Cystine stones result from a disorder called cystinuria that is passed down through families. In cystinuria, the child’s kidneys leak large amounts of cysteine, an amino acid. Cystine crystals can then form in the urine and cause stones.

How common are kidney stones in children?

Kidney stones are not common in children, but the number of children affected has grown steadily larger during the last several years. Changing eating habits may be responsible, especially the rise in the amount of sodium children eat through processed foods and table salt. Learn how changes in a child’s diet may help prevent kidney stones.

The rise in obesity and less active lifestyles may also cause more children to have kidney stones.

Which children are more likely to develop kidney stones?

Children of all ages can develop kidney stones, including infants, but they occur much more often in teens. A family history of kidney stones makes a child more likely to develop them. Children who’ve had kidney stones in the past have a greater chance of developing another kidney stone.

An unhealthy lifestyle and diet can make children more likely to have kidney stones. For example, drinking too little water or drinking the wrong types of liquid, such as sugary soft drinks or drinks with caffeine, may cause substances in the urine to become too concentrated.

Likewise, too much sodium, a part of salt, may force extra minerals into the urine, which can become kidney stones. Unhealthy amounts of sodium are found in many prepared foods, including restaurant meals, chips, sandwich meats, frozen foods, and some sports drinks.

Children with certain conditions

Children are more likely to develop kidney stones if they have certain conditions, including

  • a blockage in or abnormal shape of the urinary tract
  • chronic, or long-lasting, inflammation of the bowel
  • cystic fibrosis
  • cystic kidney diseases, which are disorders that cause fluid-filled sacs to form on the kidneys
  • cystinuria
  • digestive problems or a history of gastrointestinal tract surgery
  • gout, a disorder that causes painful swelling of the joints
  • hypercalciuria, a condition that runs in families in which urine contains unusually large amounts of calcium; this is the most common condition found in people who form calcium stones
  • hyperoxaluria, a condition in which urine contains unusually large amounts of oxalate
  • hyperparathyroidism, a condition in which the parathyroid glands release too much parathyroid hormone, causing extra calcium in the blood
  • hyperuricosuria, a disorder in which too much uric acid is in the urine
  • obesity
  • repeated urinary tract infections (UTIs)
  • renal tubular acidosis, a disease that occurs when the kidneys fail to remove acids into the urine, which causes a person’s blood to remain too acidic

Children who take certain medicines

Children are more likely to develop kidney stones when taking the following medicines or medicinal diets over a long period of time:

  • diuretics, often called water pills, which help rid the body of water
  • calcium-based antacids
  • too much vitamin D
  • indinavir and other protease inhibitors used to treat HIV infection
  • topiramate and zonisamide, medicines used for seizures and migraine headaches
  • A ketogenic diet, which is used for seizure disorders that do not respond to medicine

What are the complications of kidney stones in children?

Complications of kidney stones are rare if a child is treated by a health care professional before problems occur.

If kidney stones are not treated, they can cause

May 2017
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This content is provided as a service of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), part of the National Institutes of Health. The NIDDK translates and disseminates research findings through its clearinghouses and education programs to increase knowledge and understanding about health and disease among patients, health professionals, and the public. Content produced by the NIDDK is carefully reviewed by NIDDK scientists and other experts.

The NIDDK would like to thank:
Michael J.G. Somers, MD; Harvard Medical School; Michelle A. Baum, MD, Harvard Medical School; Jeffrey M. Saland, MD, MSCR, Icahn School of Medicine at Mt. Sinai