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Although kidney stones are not common in children, they have been on the rise in recent years. The reasons for this increase in kidney stones is not completely understood. But diet is thought to play a role. For example, the amount of sodium (the main ingredient in salt) children eat through processed foods may contribute. 

Other factors that make your child more likely to form kidney stones include not having enough citric acid in the urine. Citric acid comes from fruits like oranges and lemons. Also, having too much calcium in the urine can put some children at greater risk for forming kidney stones. 

Kidney stones can be as small as a grain of sand or a pea. In rare cases, kidney stones can be as big as a golf ball. Some kidney stones are smooth, while others are jagged. Most kidney stones are brown or yellow. A small kidney stone may pass through the urinary tract on its own and cause little pain to your child. But a larger kidney stone can get stuck in the urinary tract. When this happens, the stone can block the flow of urine.

Common symptoms of kidney stones in children include pain in the back, side and lower stomach. Kidney stones can also cause blood in the urine (hematuria) or nausea and vomiting. The good news is that kidney stones rarely cause permanent damage if they are treated right away by a health care professional.

There are different types of kidney stones. Calcium stones, including calcium oxalate stones and calcium phosphate stones, are the most common kidney stones in children. About 85 to 90 percent of kidney stones in children are calcium-based. 

A uric acid stone may form when a child’s urine contains too much uric acid. Too much uric acid in your child’s urinary tract can come from medical conditions or inherited disorders. Eating fish, shellfish and organ meats such as livers and hearts can also increase uric acid in urine. But this happens less often. 

Struvite stones are another type of kidney stone that may affect a child whose urinary tract did not develop normally. 

Cystine stones can result from a disorder called cystinuria. This disorder is passed down through families. When a child has cystinuria, the kidneys leak large amounts of cysteine, a type of amino acid (the building blocks of proteins). From there, cystine crystals can form in the urine and cause kidney stones.

To diagnose kidney stones in children, a health care professional will review the child’s medical history and perform a physical exam. Certain lab tests like a urinalysis (urine test) or 24-hour urine collection may be recommended. A urinalysis can find blood in the urine and minerals that form kidney stones. The 24-hour urine collection test measures how much urine a child produces, minerals that can form stones and the pH level of the urine. 

Depending on your child’s situation, your health care professional may also order a blood test. This shows if there are high blood levels of certain minerals that can lead to kidney stones. Imaging tests such as ultrasound or an abdominal x-ray may also be ordered. These tests can help doctors find the location of your child’s kidney stone.

How a kidney stone is treated depends on the type of stone it is, its location and size. A small kidney stone may pass through the urinary tract without treatment. In this case, your child will need to urinate through a strainer for a few days to catch the kidney stone. After the stone is collected, your health care professional will send the stone to a lab to find out what type it is. 

If the kidney stone needs to be removed by a health care provider, a urologist can remove it or break it into small pieces. Pediatric urologists are are surgeons who can diagnose, treat and care for your child’s urinary problems. This includes kidney stones.

There a few ways a urologist can break up kidney stones. Shock wave lithotripsy works by breaking the kidney stone into small pieces from outside the child’s body. The smaller pieces of the kidney stone then pass through the urinary tract. A urologist gives anesthesia during this outpatient procedure. 

Cystoscopy and ureteroscopy can also be used. During cystoscopy, a health care professional uses a thin tube with a tiny lens at one end to look inside the urethra and bladder to find the stone. During ureteroscopy, a longer and thinner instrument is used to see the lining of the ureters and kidneys. In both procedures, the urologist inserts the scope through the urethra to see the rest of the urinary tract. Once the stone is found, it can be removed or broken into smaller pieces. The urologist performs these procedures in the hospital with anesthesia. A child typically goes home the same day.

With percutaneous nephrolithotomy, a thin viewing tool called a nephroscope is used to locate and remove the kidney stone. A urologist inserts the tool directly into the kidney through a small cut in the child’s back. For larger kidney stones, a laser may be used to break the kidney stones into smaller pieces. A urologist performs percutaneous nephrolithotomy in a hospital with anesthesia. Recovery from percutaneous nephrolithotomy usually takes several days in the hospital.

If your child has experienced kidney stones in the past, your health care team may make diet recommendations to prevent future stones. For example, they may suggest changing your child’s intake of sodium, animal protein, calcium or oxalate. Oxalate is a natural substance found in many foods such as spinach. 

Eating plans like the Dietary Approaches to Stop Hypertension (DASH) diet can help reduce the risk of forming kidney stones in children and adults. DASH is a low-salt eating plan that encourages fruits, vegetables, whole grains, low-fat dairy products, fish, beans and nuts. 

Helping your child maintain a healthy weight can also help prevent kidney stones. If your child is overweight, work with your pediatrician and/or a registered dietitian to develop an eating plan that works for your family. Lastly, it’s important your child drinks enough water. This is the most important lifestyle change a child or teenager can make to prevent kidney stones. 

Please listen to Urology Care Podcast Episode No. 68, When Kids get Kidney Stones with Dr. Gregory Tasian to learn more: