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:
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.
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:
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:
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:
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.