Kidney stones are small mineral crystals that stick together in urine. They can range from the size of a grain of sand to the size of a golf ball. Some kidney stones stay where they are, causing no problems until they increase in size. Others may move and cause pain as they pass from the kidney.
Kidney stones may be difficult for children to pass. They can also cause other problems in the urinary tract. When they are too large to pass naturally, kidney stones can get stuck in the bladder or the tubes (ureters) that drain the kidney. This obstruction can block the flow of urine. At some point, kidney stones can become large enough that they prevent the kidneys from removing waste in the blood, balancing fluids in our bodies and performing other important functions.
Symptoms of kidney stones include:
- Side pain that moves from the back to the front toward the bladder and pelvic area
- Painful urination
- Pain in the testes and/or penis in boys
- Pain in the labia/vagina in girls
- Bloody urine, known as gross hematuria
- Urgent or frequent need to use the bathroom—a sign that the stone has reached the level of the bladder
- Urinary tract infection
Although kidney stones are rare in children, they are more common than they were a few decades ago. There has been a sharp increase in the number of Americans affected by kidney stones over the past 20 years, and some researchers say the fastest rise has been in kids.
What causes kidney stones?
Many people mistakenly believe kidney stones are the result of too much calcium in the diet. Researchers agree that there is a strong dietary connection to kidney stones, but it has little to do with calcium consumption. Most Americans, including children, consume too much sodium, sugar and caffeine and too little water. This combination sets up ideal conditions for forming kidney stones.
Some studies suggest there is a connection between sugar intake and kidney stone formation and obesity and kidney stone formation (obese children typically consume foods that are high sodium). For this reason, reducing sugar intake and optimal weight maintenance may help prevent kidney stones.
Some research suggests kidney stones have a genetic link. If someone in your immediate family has been diagnosed with stones, you have a higher risk, and the same is true for your children. People who live in warm climates have a slightly higher rate of kidney stones, probably due to the greater chance of dehydration.
Other reasons kidney stones can form in children include:
- Defects in the urinary tract can block the flow of urine and create pools of urine. Minerals such as calcium, magnesium, oxalate and phosphorus tend to settle together in these pools and form kidney stones.
- Metabolic disorders can lead to kidney stones because the body cannot properly break down minerals. The most common metabolic condition that leads to kidney stones in children is hypercalciuria, a condition that causes extra calcium to collect in the urine.
- Children with inflammatory bowel disease and/or ulcerative colitis have an increased risk for kidney stones.
Diagnosis of Kidney Stones
Kidney stones are easily missed as a possible diagnosis because they are uncommon in children. They are sometimes detected for the first time when a pediatrician or pediatric urologist has ordered a computed tomography (CT) scan to help diagnose unexplained abdominal pain.
Even in such cases, kidney stones may or may not be the source of the abdominal pain. If they do not cause symptoms or complications, kidneys stones may be left untreated until one of three things happen: 1) they become symptomatic, 2) they become too large to pass naturally (greater than 5-10 mm) or 3) they are growing quickly.
Kidney stones only cause symptoms when they pass from the kidney(s) to the ureter(s) or bladder. The blockage of urine flow causes swelling of the kidney, and this is what causes pain.
Through our Kidney Stone Program, our pediatric urologists treat kidney stones, working together with pediatric nephrologists (kidney doctors) to help families make lifestyle and dietary changes that can prevent stones. Consuming more water, fewer processed foods, less sugar and getting more exercise are just a few of the changes we encourage at-risk families to make. Preventive care is especially important for children who are more likely to form stones. We use a variety of tests to assess kidney stones, including:
- Blood tests. Sodium, potassium, magnesium, uric acid, phosphate and calcium levels in blood tests may reveal abnormalities that could cause stones to develop.
- Urinalysis. Analysis from a 24-hour collection of your child’s urine can help specialists evaluate your child for possible kidney stone risk factors. Pediatric urologists and nephrologists are interested in the amount of urine collected and certain levels of acidity, uric acid, citrate, sodium, calcium and creatinine. This analysis is usually done after your child has already passed a stone.
- Kidney, ureter and bladder (KUB) X-rays. These X-rays are less revealing than other tests, but doctors sometimes use them to get a quick image of the urinary tract or to monitor known kidney stones. There is some radiation exposure with this test, and for that reason, it is not always the first diagnostic choice.
- Ultrasound. This pain-free test uses sound waves to help visualize the urinary tract. It requires no anesthesia and allows the doctor to see the location of most stones. Sometimes ultrasounds will miss stones and/or see stones when none are present.
- CT scan. CT scans make precise three-dimensional images of your child’s body, combining technology from X-rays and computers. A CT scan can show the exact count of stones and visualize areas that may not be seen with ultrasound. CT scans are the standard test for seeing kidney stones. Since this test involves radiation, doctors try to use it infrequently.
If kidney stones are small enough, the preference is to help children pass them with assistance from pain medicine. There is some evidence that medications called alpha blockers may promote safe passage of kidney stones in children by relaxing the lower (distal) ureter(s). Pediatric urologists also encourage patients to increase fluids, which can quicken the process.
When a kidney stone reaches a certain size, drainage of urine may be blocked. The larger the stone grows, the greater the chance of symptoms and health consequences, such as impaired kidney function. The kidneys are important to good health because they remove waste in our blood and regulate the body’s fluids.
Young adults and teens may pass larger stones, but because of their size, younger children may have limited ability to pass large stones naturally. For this reason, surgical intervention may be necessary to treat some children. Your child's doctor may use one or more of the following procedures:
- Flexible ureteroscopy. If your child needs surgery, a pediatric surgeon may perform flexible ureteroscopy or endoscopy as an outpatient procedure. This minimally invasive option makes no incisions and inserts a small telescope through the bladder (using the urethra), running up to the affected kidney. Through this telescope, your child’s surgeon can see, crush and remove the stones. Your child will be under anesthesia for this procedure.
- Ureteroscopy with laser lithotripsy. Your child will be under anesthesia for this outpatient procedure. Once he or she is sedated, the doctor inserts an ureteroscope through the urinary tract to the location of the stone. The ureteroscope is equipped with a laser, which is used to break the stone into smaller pieces that pass out of the body through the urine.
- Percutaneous nephrolithotomy. For large, numerous or complex kidney stones located in hard-to-reach places, the pediatric urologists at Riley at IU Health often partner with a world-renowned expert at Indiana University Health Methodist Hospital who performs an advanced procedure known as percutaneous nephrolithotomy (PCNL). This open surgery is rarely needed for children, but it is useful when surgeons need maximum access to remove kidney stones. If your child is a candidate for PCNL, he or she may take an antibiotic a few days before surgery to minimize the likelihood of infection from bacteria during the procedure. Pediatric urologists at Riley at IU Health accompany the adult urologist during the procedure and remain part of your child’s care team. During this procedure, the doctor inserts a tube directly into the kidney through an incision in your child’s back. The doctor then uses a tiny viewing instrument to locate and remove the stone. If the stone is very large, the doctor may need to use a probe to deliver shock waves and break it up into smaller pieces. This makes removal easier. Your child will receive general anesthesia for this procedure. Depending on the nature of this procedure, your child may need to stay in the hospital for several days for close monitoring.
- Shock wave lithotripsy (SWL). In this outpatient procedure, doctors use a machine called a lithotripter to crush the kidney stone. Your child will lie on a table below the lithotripter. The lithotripter generates shock waves, which pass through your child’s body and break the kidney stone into smaller pieces. This makes it easier for the stones to travel through the urinary tract and out of the body in the urine. SWL takes about an hour to complete.
Key Points to Remember
Key Points to Remember
- Parents may reduce a child’s risk of kidney stones and minimize their growth by increasing fluid intake and reducing dietary caffeine, sodium and sugar.
- Preventing stones in children is just as important as treating them.
- Kidney stones are rare in children, but some children are more prone than others through a genetic link or health conditions such as inflammatory bowel disease.
- Pediatric urologists usually prefer that children pass kidney stones without surgical treatment, but this depends upon the size of the stone and how long it has been causing symptoms.
- In some cases, your child may need surgery to remove large or hard-to-reach kidney stones.
Support Services & Resources
Support Services & Resources
Visit the trusted websites below to learn more about kidney stones:
Riley at IU Health offers a broad range of supportive services to make life better for families who choose us for their children's care.
This website is supported by the American Academy of Pediatrics and provides health resources about kidney stones in children and teens.
This National Institutes of Health website provides answers to common questions about kidney stones in children.