More children are getting kidney stones. Experts think it’s their diet.

When Annabelle Pleskoff was 15, she woke up before school one morning with severe pain radiating from her right side.

After hours of persistent throbbing, she went to the emergency room, where doctors initially thought she had mild appendicitis and sent her home. Later, she received an unexpected diagnosis: kidney stones, typically an affliction of older adults.

Now 25, Pleskoff, a Seattle native who has endured more than 30 kidney stones, is part of a troubling trend in pediatric health. Kidney stone cases are rising among children, and some medical professionals implicate a familiar culprit: ultra-processed foods. Other experts trace the increase to genetics, poor diet and insufficient water intake.

“We see, everyday, children presenting with kidney stones,” Zachary V. Zuniga, a pediatric urologist at Texas Children’s Hospital, said. Some return repeatedly to the emergency room, and while not all require surgery, others will be hospitalized and need antibiotics.

“The thought is that kids don’t get stones,” Zuniga said. “That’s like, the last thing you may think about when a child has pain somewhere as a symptom.”

Some health experts predict the problem will worsen.

“Historically, stones were pretty much a disease of white, middle-aged men, but that’s changed dramatically over the last 30 years,” said Gregory E. Tasian, a pediatric urologist at Children’s Hospital of Philadelphia who has conducted research on kidney stones in children.

Tasian said the disease affects adults and children in similar ways because the stones are often made of calcium oxalate, but the profile of pediatric and adult patients differs.

“They’re young. They’re healthy. They don’t generally have other comorbid conditions,” Tasian said.

Treating stones in children can involve medical management and, in some cases, surgical intervention.

Physicians typically begin by managing pain with over-the-counter medications or prescription drugs that help dilate the ureter muscles, enabling the stone to pass from the ureter to the bladder.

A child experiencing kidney stones may need antibiotics if they develop a urinary tract infection, which can occur when stones obstruct urine flow. Antibiotics can also be prescribed to prevent infections after a stone removal procedure.

For larger stones or those causing significant pain, doctors turn to procedures such as ureteroscopy, which uses a small scope to enter the bladder and break up the stone directly, or shock wave lithotripsy, which breaks up the stone into smaller pieces making it easier to pass.

A 2016 study in the Clinical Journal of the American Society of Nephrology analyzed kidney stone incidence among 15-to-19-year-olds in South Carolina from 1997 through 2012. Researchers found a 28 percent increase over a five-year period for girls. For boys, that increase was 23 percent.

The economic impact of pediatric kidney stones is substantial, with hospitals in 2009 charging about $375 million for inpatient and emergency department services, according to the Nationwide Emergency Department Sample, a database of emergency room visits.

Painful chronic conditions such as kidney stones can profoundly disrupt the lives of teenagers and children, forcing them to confront challenges unfamiliar to many of their peers. Pleskoff’s struggle with stones significantly disrupted daily activities, preventing her from participating in swimming, a sport she loved.

To manage her condition, Pleskoff adhered to a strict diet designed for people beset with kidney stones. The diet became a central focus of her life, dictating her food choices and daily routine. But the pressure to maintain this restrictive diet led to anorexia, she said.

“Just the idea that if I restricted my diet, I wouldn’t be in as much pain, and then I ended up restricting a little too much and not eating enough to keep my body healthy,” Pleskoff said.

The combination of physical limitations, including recurrent back pain, and mental health struggles in some young patients highlights the often-overlooked effect chronic conditions can have.

Some research suggests that genetic predisposition may play a role, but experts say the increase more likely reflects dietary habits and lifestyle.

A North Carolina doctor detected a potential culprit: salt-laden diets. Sodium intake has increased significantly among children in the past few decades.

“There is so much added salt to the American diet today, and when the kidney is excreting the sodium, it pulls calcium with it and increases the risk of calcium-based stones,” John S. Wiener, a pediatric urologist at Duke Health, said.

More than 90 percent of children ages 6 to 18 consume 3,300 milligrams of sodium daily, far exceeding the 2,300 recommended by the Dietary Guidelines for Americans, which are updated every five years and published by the Departments of Agriculture and Health and Human Services.

Processed and fast foods are among the main sources of excess sodium. Because many processed foods are deficient in essential nutrients, they can disrupt the body’s mineral balance, affecting calcium and oxalate levels. These minerals are crucial in the formation of kidney stones.

Even when a normal amount of sodium is consumed daily, some people are more prone to kidney stones. Experts suggest that people with a family history of the condition are especially susceptible, but that could reflect shared environmental and lifestyle factors, according to Wiener.

Rare genetic causes can contribute to the formation of kidney stones in children.

“There are some well-defined genetic diseases that affect metabolism and can cause people to form stones, but that’s a very small proportion of Americans with stones,” Wiener said.

In some cases, a patient can be an outlier in the family. Hunter Beck, 21, who lives in Media, Pennsylvania, is the youngest of five children and said that when he developed his first kidney stone at age 12, his diet and exercise were typical for a young adolescent.

“My family has no history of kidney stones, so we had no idea that was even a possibility,” Beck said.

Similar to Pleskoff, Beck found that experiencing kidney stones as a child compromised his life so much he had to quit school sports. He said he coped with at least 15 kidney stones from age 12 through 18, with three or four stones present when he received an ultrasound.

In the past few years, he has mitigated kidney stones by avoiding teas, energy drinks and sodium. He has taken daily water pills and potassium citrate, which decrease acid.

Understanding his condition, Beck said, required a learning curve about kidney stones.

“Everyone knows about them, but nobody knows anything about the actual specifics in kids,” Beck said. “There’s not a lot of research and development going into it compared to other things in the medical field, so I hope there is light shined on kidney stones.”

The evidence available on how to best treat children, whether medical or surgical, is “very weak,” Tasian said. “We know little about why kidney stones occur at a younger age when they didn’t occur at that age 30 years ago.”

Another theory intriguing some scientists: the potential role of climate change in the increase in kidney stones. While research in that realm is in its infancy, some experts hypothesize that environmental factors influenced by climate change could be culpable in the uptick in kidney stone cases among children.

Climate-related disruptions can lead to food insecurity, pushing families toward diets high in salt, sugar and processed foods. When combined with inadequate hydration, these dietary options significantly elevate the risk of kidney stone formation. As fresh, healthy food becomes less accessible because of food deserts and high cost, the likelihood of kidney stones in children rises.

David J. Sas, a pediatric nephrologist at the Mayo Clinic who studies kidney stones, said his research finds a link between kidney stones and urban heat islands - densely populated swatches in cities packed with buildings and extensive paved surfaces. They typically experience higher temperatures compared with suburban or rural regions.

This temperature difference is ignited by concrete and asphalt absorbing and retaining heat throughout the day, with the heat released slowly at night. In contrast, regions with abundant vegetation and open green spaces allow for more efficient heat dissipation, maintaining a cooler environment.

“Temperature, humidity plus diet equals stones,” Sas said.

The rising temperatures can cause dehydration, a well-documented risk factor for kidney stones, exacerbated by frequent heat waves driven by climate change.

Children are more susceptible to dehydration compared with adults, losing water more quickly through sweating. This increased fluid loss leads to a higher concentration of minerals in the urine, creating fertile ground for kidney stone formation.

With their heat-retaining infrastructure, cities create environments where dehydration and its consequent health issues become more prevalent. Sas said these health risks are poised to intensify as temperatures continue to rise.

Sas also pointed to school policies that act as barriers to proper hydration and kidney stone prevention.

The Healthy, Hunger-Free Kids Act of 2010 requires schools participating in the National School Lunch Program to make water available to students during meal times free of charge, but some schools limit access to water systems and prohibit students from carrying water bottles.

“I write a lot of letters saying that so-and-so must have free access to water and the restroom due to a risk of kidney stones,” Sas said.

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Dan Keating contributed to this report.