When It Comes to the Kidneys, This Center Leaves No Stone Unturned

How precision medicine is personalizing kidney stone treatment

Half a million Americans go to the emergency room annually for kidney stone issues, and one in every 10 people in the United States will develop a kidney stone during his or her lifetime.

Kidney stones are exactly what they sound like — accumulations of minerals like calcium that crystallize into stone-like masses inside kidneys. Their formation isn’t necessarily painful, but passing them can be. If a stone gets lodged in a ureter, it can cause a clog that backs up urine in the kidneys. While stones aren’t life-threatening, complications can include kidney injury and increased risk of urinary infection.

Diagnosis and treatment of kidney stones is a two-part process. When patients come in with a painful kidney stone that won’t pass on its own, physicians identify and remove it. But removing it doesn’t address how to prevent future stones. Patients who’ve developed one stone have about a 50 percent risk for developing another within the next decade.

Prevention involves taking a detailed dietary and medical history, gathering urine and blood samples for analysis, then implementing appropriate strategies based on those findings. It’s a time-consuming and often piecemeal medical assessment that can take weeks, leaving the patient waiting to receive — and understand — the best treatment.

At the Stanford Kidney Stone Center, clinicians are working to provide the best treatment and prevention for kidney stones. In part, that’s because the center draws together experts from nephrology, urology, endocrinology, and nutrition.

Alan C. Pao, MD, assistant professor of nephrology, leads the center with Simon Conti, MD, clinical assistant professor of urology.

“Dr. Conti and I decided to divide the work so that the urologists focus on clinical-radiologic correlations and make surgical plans, and the nephrologists analyze the laboratory data and craft prevention strategies,” Pao says.

“It’s very efficient to discuss medical and surgical options for the same patient at the same time,” adds Pao, who is also joined at the center by nephrologists Robert Isom, MD, Pedram Fatehi, MD, and Fahmeedah Kamal, MD.

Pao says it’s not well understood why kidney stones form, but patients on high-meat and high-sodium diets or who don’t drink enough fluids are typically more at risk for stone recurrence. And appropriate treatments to prevent recurring kidney stones aren’t one size fits all. In fact, they depend on the diet, health, and stone type of each stone-former.

The secret to preventing stones, Pao says, is in a patient’s urine. Urine contents can reveal what minerals are in excess or in deficiency, and those mineral levels can help physicians determine how to help patients. That’s why a simple procedure like 24-hour urine collection is so vital — it provides a road map for improved treatment.

Along with John Leppert, MD, associate professor of urology, Pao is analyzing a national database of 120,000 kidney stone patients cared for in Veterans Affairs hospitals. They’re examining how frequently stone-formers are getting 24-hour urine collections, and whether subsequent analysis of the urine leads to changes in stone-prevention medications and decreases in stone risks.

Pao is also following the breadcrumbs of other kidney stone mysteries, like why patients with normal-looking 24-hour urine collections still develop recurrent stones. That occasional disconnect has also spurred him to work with another colleague, Joseph C. Liao, MD, associate professor of urology, on a new gadget that will allow patients to spot check their urine throughout the day and provide immediate feedback for how diet and medications are affecting their stone risk.

Undoubtedly, precision medicine has trickled into kidney stone treatment, and Pao’s research ensures that patients receive their unique treatments for stone prevention.