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Kidney Stones and Teens: Causes, Symptoms and Prevention

Most likely you or someone you know has experienced kidney stones, which are hard deposits of minerals and salts formed in the kidney and can be painful to pass. While more common in adults, cases of kidney stones in children have increased significantly in recent years, especially in teenagers. We sat down with Dr. Uri Alon, director, Bone and Mineral Disorders Clinic at Children’s Mercy, to find out why this is the case and what can be done to prevent kidney stones.

What causes kidney stones?

Dr. Alon: The most common kidney stones in children are composed of calcium. There are two main reasons why a child might develop stones. The first is genetics. However, only 5% of children that develop kidney stones will have a genetic disorder.

The more prevalent cause that can increase the risk for kidney stones is environmental contributors such as nutrition, geographic location and fluid consumption.

Any salt that is consumed is absorbed in the body and finds its way into the urine. For simplicity, the salt basically drags calcium to the urine and too much calcium can cause hard deposits to develop.

Also, a hot work environment and/or dehydration can promote the development of kidney stones. For example, the Army noticed an increase in kidney stones in soldiers stationed in Iraq and the soldiers were told to drink more water. The incidence of kidney stones decreased significantly simply by drinking more liquids.

Why are more teenagers getting kidney stones?

Dr. Alon: We’ve definitely seen an increase in kidney stones over the last several years. Nationally, there’s been a 3-4 fold increase among teenagers. We’re seeing more cases partly because we have better diagnostic tools in the Emergency Room. Instead of a simple x-ray, we now get a CT of the patient’s abdomen, which is a much better tool to diagnosis kidney stones.

However, the bigger contributor to the increase in kidney stones is excess salt. For adults, the recommended sodium intake is a maximum of 2300 mg. Teenagers should consume much less and maximum consumption is based on the child’s size. For instance, if the teenager is half the size of an adult that teenager should only have half the recommended amount, which would be 1200-1400 mg.

Also just as important, teenagers are not eating enough fruits and vegetables, which contain potassium and counteracts sodium. It’s this imbalance in sodium and potassium that results in excess of calcium that triggers kidney stones.

Does eating more fruits and vegetables help prevent kidney stones?

Dr. Alon: Yes. If someone eats something salty, like pizza or a hot dog, and also eats a fruit or a vegetable with the meal the potassium will counter the effect of sodium. Think of sodium as the bad guy and potassium as the good guy. The good guy will be able to control the bad guy. Because of this, no food is off limits – you just have to have a good balance between the bad and good.

The average American teenager only consumes 1.5 servings of fruit and vegetables daily. The government recommendation is nine servings a day. We know this can be difficult to achieve, so we recommend at least five servings a day, which means there should be a fruit or vegetable at every meal.

We also highly recommend the Dietary Approaches to Stop Hypertension (DASH) diet. While the DASH diet was designed to control blood pressure, it also aims to reduce the amount of sodium and increase potassium in the diet.

You also mentioned the importance of hydration. What should teenagers be drinking?

Dr. Alon: Teenagers need to make sure they’re getting plenty of fluids. They can drink water, flavored water, tea and juice (just make sure the juice doesn’t contain too much sugar).

A misconception is that drinking too much milk can cause kidney stones. A recent study shows that nutritional calcium intake does not have an effect on kidney stones unless consumed in extreme amounts.

What are the symptoms of kidney stones and how do you treat it?

Dr. Alon: It depends on the age of the child. Young children may have general complaints of a tummy ache and sometimes throw up. Older children and adolescents will have pain in the flank, back or lower abdomen, and the pain will often be excruciating. In some cases, blood may be present in the urine.

Most of the time kidney stones will pass on their own. The pain will go away once passed. On average, it takes hours or days to pass a kidney stone. Medications can help dilate the urinary passage to help move the stone out of the system. If it’s too big or if it’s been longer than a week than an urologist will likely intervene to remove the stone. Kidney stones left untreated can deteriorate kidney function.

What is the best advice for preventing kidney stones?

Dr. Alon: Drink more fluids, eat healthy and pay attention to diet. A child that has developed kidney stones in the past is at greater risk for developing additional stones in the future. Preventative measures are key.

We also know that changing diet and habits can’t happen overnight and it’ll take a few weeks to make adjustments. We also know teenagers will follow recommendations for several months and then slowly go back to old habits. It’s not easy and it requires discipline. Support and encouragement are key to success.


Learn more about the Bone and Mineral Disorder Clinic at Children’s Mercy.

Learn more about the Division of Pediatric Nephrology at Children’s Mercy, which is one of the top five kidney care programs in the nation.