Kidney Stones 

in Children 

National Kidney and Urologic Diseases Information Clearinghouse 

U.S. Department 

of Health and 

Human Services 

NATIONAL 

INSTITUTES 

OF HEALTH 

What is a kidney stone? 

A kidney stone is a solid piece of material 

that forms in a kidney when substances that 

are normally found in the urine become 

highly concentrated. A stone may stay in 

the kidney or travel down the urinary tract. 

Kidney stones vary in size. A small stone 

may pass out of the body causing little or no 

pain. A larger stone may get stuck along the 

urinary tract and can block the flow of urine, 

causing severe pain or blood that can be seen 

in the urine. 

What is the urinary tract? 

The urinary tract is the body’s drainage 

system for removing wastes and extra water. 

The urinary tract includes two kidneys, two 

ureters, a bladder, and a urethra. The kidneys are a pair of bean-shaped organs, each 

about the size of a fist and located below the 

ribs, one on each side of the spine, toward 

the middle of the back. Every minute, a person’s kidneys filter about 3 ounces of blood, 

removing wastes and extra water. The wastes 

and extra water make up the 1 to 2 quarts of 

urine an adult produces each day. Children 

produce less urine each day; the amount 

produced depends on their age. The urine 

travels from the kidneys down two narrow 

tubes called the ureters. The urine is then 

stored in a balloonlike organ called the bladder. When the bladder empties, urine flows 

out of the body through a tube called the 

urethra at the bottom of the bladder. 

Kidneys 

Ureters 

Bladder 

The kidneys remove wastes and extra water from the 

blood to form urine. Urine travels from the kidneys 

to the bladder through the ureters. 

Are kidney stones common 

in children? 

No exact information about the incidence 

of kidney stones in children is available, but 

many kidney specialists report seeing more 

children with this condition in recent years. 

While kidney stones are more common in 

adults, they do occur in infants, children, and 

teenagers from all races and ethnicities. 
 

What causes kidney stones 

in children? 

Kidney stones can form when substances 

in the urine—such as calcium, magnesium, 

oxalate, and phosphorous—become highly 

concentrated due to one or more causes: 

•	� Defects in the urinary tract may block 

the flow of urine and create pools of 

urine. In stagnant urine, stone-forming 

substances tend to settle together into 

stones. Up to one-third of children who 

have stones have an anatomic abnormality in their urinary tract. 

•	� Kidney stones may have a genetic cause. 

In other words, the tendency to form 

stones can run in families due to inherited factors. 

•	� An unhealthy lifestyle may make children more likely to have kidney stones. 

For example, drinking too little water or 

drinking the wrong types of fluids, such 

as soft drinks or drinks with caffeine, 

may cause substances in the urine to 

become too concentrated. Similarly, 

too much sodium, or salt, in the diet 

may contribute to more chemicals in the 

urine, causing an increase in stone formation. Some doctors believe increases 

in obesity rates, less active lifestyles, and 

diets higher in salt may be causing more 

children to have kidney stones. 

•	� Sometimes, a urinary tract infection can cause kidney stones to form. 

Some types of bacteria in the urinary 

tract break down urea—a waste product removed from the blood by the 

kidneys—into substances that form 

stones. 

•	� Some children have metabolic disorders 

that lead to kidney stones. Metabolism is the way the body uses digested 

food for energy, including the process 

of breaking down food, using food’s 

nutrients in the body, and removing the 

wastes that remain. The most common 

metabolic disorder that causes kidney 

stones in children is hypercalciuria, 

which causes extra calcium to collect in 

the urine. Other more rare metabolic 

conditions involve problems breaking 

down oxalate, a substance made in the 

body and found in some foods. These 

conditions include hyperoxaluria, too 

much oxalate in the urine, and oxalosis, 

characterized by deposits of oxalate and 

calcium in the body’s tissues. Another 

rare metabolic condition called cystinuria can cause kidney stones. Cystinuria 

is an excess of the amino acid cystine in 

the urine. Amino acids are the building 

blocks of proteins. 

What are the signs and 

symptoms of kidney stones 

in children? 

Children with kidney stones may have pain 

while urinating, see blood in the urine, or 

feel a sharp pain in the back or lower abdomen. The pain may last for a short or long 

time. Children may experience nausea and 

vomiting with the pain. However, children who have small stones that pass easily through the urinary tract may not have 

symptoms at all. 

2	� Kidney Stones in Children 
 

What types of kidney stones 

occur in children? 

Four major types of kidney stones occur in 

children: 

•	� Calcium stones are the most common 

type of kidney stone and occur in two 

major forms: calcium oxalate and 

calcium phosphate. Calcium oxalate 

stones are more common. Calcium oxalate stone formation has various causes, 

which may include high calcium excretion, high oxalate excretion, or acidic 

urine. Calcium phosphate stones are 

caused by alkaline urine. 

•	� Uric acid stones form when the urine 

is persistently acidic. A diet rich in 

purines—substances found in animal proteins such as meats, fish, and 

shellfish—may cause uric acid. If uric 

acid becomes concentrated in the urine, 

it can settle and form a stone by itself or 

along with calcium. 

•	� Struvite stones result from kidney infections. Eliminating infected stones from 

the urinary tract and staying infectionfree can prevent more struvite stones. 

•	� Cystine stones result from a genetic 

disorder that causes cystine to leak 

through the kidneys and into the urine 

in high concentration, forming crystals 

that tend to accumulate into stones. 

How are kidney stones in 

children diagnosed? 

The process of diagnosing any illness begins 

with consideration of the symptoms. Pain 

or bloody urine may be the first symptom. 

Urine, blood, and imaging tests will help 

determine whether symptoms are caused by 

a stone. Urine tests can be used to check 

for infection and for substances that form 

stones. Blood tests can be used to check for 

biochemical problems that can lead to kidney 

stones. Various imaging techniques can be 

used to locate the stone: 

•	� Ultrasound uses a device, called a 

transducer, that bounces safe, painless 

sound waves off organs to create an 

image of their structure. An abdominal ultrasound can create images of 

the entire urinary tract. The procedure is performed in a health care 

provider’s office, outpatient center, or 

hospital by a specially trained technician, and the images are interpreted 

by a radiologist—a doctor who specializes in medical imaging; anesthesia is 

not needed. The images can show the 

location of any stones. This test does 

not expose children to radiation, unlike 

some other imaging tests. Although 

other tests are more useful in detecting 

very small stones or stones in the lower 

portion of the ureter, ultrasound is 

considered by many health care providers to be the best screening test to look 

for stones. 

•	� Computerized tomography (CT) 

scans use a combination of x rays and 

computer technology to create threedimensional (3-D) images. A CT scan 

may include the injection of a special 

dye, called contrast medium. CT scans 

require the child to lie on a table that 

slides into a tunnel-shaped device where 

the x rays are taken. The procedure is 

performed in an outpatient center or 

hospital by an x-ray technician, and the 

images are interpreted by a radiologist; 

anesthesia is not needed. CT scans may 

be required to get an accurate stone 

count when children are being considered for urologic surgery. Because CT 

scans expose children to a moderate 

amount of radiation, health care providers try to reduce radiation exposure in 

3	� Kidney Stones in Children 
 

 

children by avoiding repeated CT scans, 

restricting the area scanned as much 

as possible, and using the lowest radiation dose that will provide the needed 

diagnostic information. 

• X-ray machines use radiation to create 

images of the child’s urinary tract. The 

images can be taken at an outpatient 

center or hospital by an x-ray technician, and the images are interpreted by 

a radiologist; anesthesia is not needed. 

The x rays are used to locate many kinds 

of stones. A conventional x ray is generally less informative than an ultrasound 

or CT scan, but it is less expensive and 

can be done more quickly than other 

imaging procedures. 

How are kidney stones in 

children treated? 

The treatment for a kidney stone usually 

depends on its size and what it is made of, 

as well as whether it is causing symptoms of 

pain or obstructing the urinary tract. Small 

stones usually pass through the urinary tract 

without treatment. Still, children will often 

require pain control and encouragement to 

drink lots of fluids to help move the stone 

along. Pain control may consist of oral or 

intravenous (IV) medication, depending 

on the duration and severity of the pain. 

IV fluids may be needed if the child becomes 

dehydrated from vomiting or an inability to 

drink. A child with a larger stone, or one 

that blocks urine flow and causes great pain, 

may need to be hospitalized for more urgent 

treatment. Hospital treatments may include 

the following: 

• Shock wave lithotripsy (SWL). A 

machine called a lithotripter is used by 

the doctor to crush the kidney stone. In 

SWL, the child lies on a table or, less 

commonly, in a tub of water above the 

lithotripter. The lithotripter generates shock waves that pass through the 

child’s body to break the kidney stone 

into smaller particles to pass more readily through the urinary tract. Children 

younger than age 12 may receive general anesthesia during the procedure. 

Older children usually receive an IV 

sedative and pain medication. 

• Removal of the stone with a ureteroscope. A ureteroscope is a long, tubelike instrument used to visualize the 

urinary tract. After the child receives a 

sedative, the doctor inserts the ureteroscope into the child’s urethra and slides 

the scope through the bladder and into 

the ureter. Through the ureteroscope, 

which has a small basket attached to the 

end, the doctor may be able to see and 

remove the stone in the ureter. 

Ureter 

Stone 

Ureteroscope 

Bladder 

Stone 

Kidney 

Ureter 

Ureteroscope 

Eye piece 

4 Kidney Stones in Children 

Ureteroscopic stone removal 
5 Kidney Stones in Children 

• Lithotripsy with a ureteroscope. 

Another way to treat a kidney stone 

through a ureteroscope is to extend a 

flexible fiber through the scope up to 

the stone. The fiber is attached to a 

laser generator. Instead of shock waves, 

the fiber delivers a laser beam to break 

the stone into smaller pieces that can 

pass out of the body in the urine. The 

child may receive general anesthesia or 

IV sedation. 

• Percutaneous nephrolithotomy. In this 

procedure, a tube is inserted directly 

into the kidney through an incision in 

the child’s back. Using a wire-thin viewing instrument called a nephroscope, 

the doctor locates and removes the 

stone. For large stones, an ultrasonic 

probe that acts as a lithotripter may 

be needed to deliver shock waves that 

break the stone into small pieces that 

can be removed more easily. Children 

receive general anesthesia for percutaneous nephrolithotomy. Often, children 

stay in the hospital for several days after 

the procedure and may have a small 

tube called a nephrostomy tube inserted 

through the skin into the kidney. The 

nephrostomy tube drains urine and 

any residual stone fragments from the 

kidney into a urine collection bag. The 

tube usually is left in the kidney for 

2 or 3 days while the child remains in 

the hospital. 

Nephroscope 

Ultrasonic probe 

Percutaneous nephrolithotomy 

Kidney 

Urine 

collection 

bag 

Nephrostomy 

tube 

Nephrostomy tube 
 

How are kidney stones in 

children prevented? 

To prevent kidney stones, health care providers and their patients must understand what 

is causing the stones to form. Especially in 

children with suspected metabolic abnormalities or with recurrent stones, a 24-hour 

urine collection is obtained to measure daily 

urine volume and to determine if any underlying mineral abnormality is making a child 

more likely to form stones. Based on the 

analysis of the collected urine, the treatment 

can be individualized to address a metabolic 

problem. 

In all circumstances, children should drink 

plenty of fluids to keep the urine diluted and 

flush away substances that could form kidney 

stones. Urine should be almost clear. 

Eating, Diet, and Nutrition 

Families may benefit from meeting with a 

dietitian to learn how dietary management 

can help in preventing stones. Depending on 

the underlying cause of the stone formation, 

medications may be necessary to prevent 

recurrent stones. Dietary changes and medications may be required for a long term or, 

quite often, for life. Some common changes 

include the following: 

•	� Children who tend to make calcium 

oxalate stones or have hypercalciuria 

should eat a regular amount of dietary 

calcium and limit salt intake. A thiazide 

diuretic medication may be given to 

some children to reduce the amount of 

calcium leaking into the urine. 

•	� Children who have large amounts of 

oxalate in the urine may need to limit 

foods high in oxalate, such as chocolate, 

peanut butter, and dark-colored soft 

drinks. 

•	� Children who form uric acid or cystine 

stones may need extra potassium citrate 

or potassium carbonate in the form of 

a pill or liquid medication. Avoiding 

foods high in purines—such as meat, 

fish, and shellfish—may also help prevent uric acid stones. 

6	� Kidney Stones in Children 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Points to Remember 

•	� A kidney stone is a solid piece of 

material that forms in a kidney when 

some substances that are normally 

found in the urine become highly 

concentrated. 

•	� Kidney stones occur in infants, children, and teenagers from all races 

and ethnicities. 

•	� Kidney stones in children are diagnosed using a combination of urine, 

blood, and imaging tests. 

•	� The treatment for a kidney stone 

usually depends on its size and composition as well as whether it is causing symptoms of pain or obstructing 

the urinary tract. 

•	� Small stones usually pass through the 

urinary tract without treatment. Still, 

children will often require pain control and encouragement to drink lots 

of fluids to help move the stone along. 

•	� Children with larger stones, or stones 

that block urine flow and cause great 

pain, may need to be hospitalized for 

more urgent treatment. 

•	� Hospital treatments may include 

shock wave lithotripsy (SWL), 

removal of the stone with a ureteroscope, lithotripsy with a 

ureteroscope, or percutaneous 

nephrolithotomy.
�

•	� To prevent recurrent kidney stones, 

health care providers and their 

patients must understand what is 

causing the stones to form. 

•	�In all circumstances, children should 

drink plenty of fluids to keep the 

urine diluted and flush away substances that could form kidney stones. 

Urine should be almost clear. 

Hope through Research 

The National Institute of Diabetes and 

Digestive and Kidney Diseases (NIDDK), 

one of the National Institutes of Health, supports research aimed at better understanding 

and preventing kidney stones in children. 

Researchers supported by the NIDDK have 

identified three proteins that inhibit the 

formation of calcium oxalate stones. Conventional urine tests do not provide information about the presence or absence of 

these proteins. Developing a test for these 

proteins that can be used in the clinical setting will help health care providers identify 

children at risk for stone formation so they 

can manage that risk. 

Participants in clinical trials can play a more 

active role in their own health care, gain 

access to new research treatments before 

they are widely available, and help others 

by contributing to medical research. For 

information about current studies, visit 

www.ClinicalTrials.gov. 

You may also find additional information about this 

topic by visiting MedlinePlus at www.medlineplus.gov. 

This publication may contain information about 

medications. When prepared, this publication 

included the most current information available. 

For updates or for questions about any medications, 

contact the U.S. Food and Drug Administration tollfree at 1–888–INFO–FDA (1–888–463–6332) or visit 

www.fda.gov. Consult your health care provider for 

more information. 

7	� Kidney Stones in Children 
 

 

 

 

 

For More Information 

American Society of Pediatric Nephrology 

3400 Research Forest Drive, Suite B–7 

The Woodlands, TX 77381 

Phone: 281–419–0052 

Fax: 281–419–0082 

Email: info@aspneph.com 

Internet: www.aspneph.com 

American Kidney Fund 

6110 Executive Boulevard, Suite 1010 

Rockville, MD 20852 

Phone: 1–800–638–8299 or 1–866–300–2900 

Fax: 301–881–0898 

Email: helpline@kidneyfund.org 

Internet: www.kidneyfund.org 

National Kidney Foundation 

30 East 33rd Street 

New York, NY 10016 

Phone: 1–800–622–9010 or 212–889–2210 

Fax: 212–689–9261 

Internet: www.kidney.org 

Acknowledgments 

Publications produced by the Clearinghouse 

are carefully reviewed by both NIDDK scientists and outside experts. This publication 

was reviewed by the following members of 

the American Society of Pediatric Nephrology Clinical Affairs Committee: Michael 

Somers, M.D., Children’s Hospital Boston; 

Deepa Chand, M.D., M.H.S.A., Akron Children’s Hospital; John Foreman, M.D., Duke 

University; Jeffrey Fadrowski, M.D., M.H.S., 

The Johns Hopkins University; Kevin Meyers, M.D., Children’s Hospital of Philadelphia; Greg Nelsen, M.S.S.W., University of 

Virginia Health System; Michelle Baum, 

M.D., Children’s Hospital Boston; and Ann 

Guillot, M.D., University of Vermont. 

National Kidney and 

Urologic Diseases 

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Fax: 703–738–4929 

Email: nkudic@info.niddk.nih.gov 

Internet: www.kidney.niddk.nih.gov 

The National Kidney and Urologic Diseases 

Information Clearinghouse (NKUDIC) 

is a service of the National Institute of 

Diabetes and Digestive and Kidney Diseases 

(NIDDK). The NIDDK is part of the 

National Institutes of Health of the U.S. 

Department of Health and Human Services. 

Established in 1987, the Clearinghouse 

provides information about diseases of the 

kidneys and urologic system to people with 

kidney and urologic disorders and to their 

families, health care professionals, and the 

public. The NKUDIC answers inquiries, 

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works closely with professional and patient 

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This publication is not copyrighted. The Clearinghouse encourages users of this publication to duplicate and distribute as many copies as desired. 

This publication is available at 

www.kidney.niddk.nih.gov. 

U.S. DEPARTMENT OF HEALTH 

AND HUMAN SERVICES 

National Institutes of Health 

NIH Publication No. 11–7383 

September 2011 

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