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Kidney Stones

  • A condition in which high mineral levels in urine cause hard deposits to form in the kidneys
  • Often no symptoms but may cause pain when urinating, blood in urine, sharp pain in the back
  • Treatment includes incision-free stone ablation to break stones
  • Involves Stone Disease Program

Kidney Stones


Passing a kidney stone can be excruciating—at times even rivaling the pain of childbirth. Those who have experienced it often say they never want to feel that pain again, yet there's a 50% chance these patients will develop another stone in the next 10 years.

At Yale Medicine, we have a specialized Endourology & Stone Disease Program that offers a multidisciplinary, comprehensive approach to treating kidney stones in both adults and children. We are committed to offering our patients the most advanced diagnostic technologies and treatment strategies available. Our doctors continually integrate the latest in science-based medicine and innovative approaches into their practice to offer patients safer and more effective treatments.

For patients currently struggling with kidney stones, we use the latest imaging technology to determine the stone load and to help them manage their condition with as little discomfort as possible. At Yale Medicine, we believe in using preventative care to help patients with recurrent kidney stones. This includes working with patients to develop a healthy diet plan and prescribing certain medications.

[Watch this 1-minute explainer video on how to prevent kidney stones.]

What are kidney stones?

Kidney stones are hard deposits of mineral and acid salts formed within the kidneys. They can cause significant pain and obstruction as they pass from the kidney to the ureter on the way to the bladder. This can cause infection, impair kidney function and damage the kidney.

There are four main types of kidney stones, ranging in size from tiny to golf-ball sized:

  • Calcium stones: The most prevalent and are composed of calcium oxalate which is found in many foods, including nuts, fruits and vegetables.
  • Struvite stones: These form after a patient has a kidney infection.
  • Uric acid stones: These form when the urine contains too much acid.
  • Cystine stones: These occur when a patient has a condition that allows cystine – an amino acid - to pass from the kidneys into the urine.

What are the risk factors for kidney stones?

There is no definitive answer as to what causes kidney stones.

However, the condition has been linked to diets high in salt and processed foods. Kidney stones are also associated with certain digestive diseases and related surgeries such as gastric bypass surgery. The risk of kidney stones may be somewhat reduced by drinking more fluids, particularly water, and by changes in diet and nutrition.

It is important for patients who are prone to the condition to have a stone analyzed to determine its makeup. This will help determine what triggered the stone’s formation and help prevent future formation of stones.

What are the symptoms of kidney stones?

At first, a kidney stone may not cause any symptoms. But as it moves from the kidneys to the bladder and into the ureter, there can be sudden sharp pains and discomfort.

Other common symptoms of kidney stones include:

  • Pain while urinating
  • Blood in the urine
  • Sharp pain in the back or lower abdomen
  • Nausea and vomiting accompanying extreme pain
  • Cloudy urine

How are kidney stones diagnosed?

When a patient comes to the hospital or emergency room complaining of severe pain in their abdomen, doctors may be on the lookout for possible kidney stones.

Tests to determine whether kidney stones are causing a patient's discomfort may include:

  • Urine tests: By taking multiple urine tests over the course of 48 hours, doctors will be able to ascertain if a patient’s urine contains large amounts of stone-forming minerals.
  • Blood tests: Blood tests may reveal too much calcium or uric acid in the blood. Blood test results also help doctors monitor a patient’s kidney health.
  • Imaging: Our team uses non-invasive radiologic imaging such as ultrasounds and CT scans to identify and quantify any stones that are present.
  • Analysis of passed stones: If a patient has actually passed a stone, they may be asked to urinate through a strainer. The stones can then be analyzed in a lab to determine their specific makeup.

How are kidney stones treated?

Our team uses state-of-the-art treatments, including incision-free stone ablation. In this treatment, shock waves are directed towards stones inside the body, causing them to break into smaller fragments.

Minimally invasive approaches to manually break up and extract stones, including endoscopic (inserting a small tube equipped with a camera) and percutaneous (needle-puncture) techniques may also be used.

What makes Yale Medicine’s approach to kidney stones unique?

At Yale Medicine's Endourology & Stone Disease Program, a multidisciplinary team of experts in urology, nephrology and nutrition works together to develop a preventive, holistic health program for patients with kidney stones.

Because people with recurrent stones often undergo more CT scan imaging than most people, they are susceptible to cumulative radiation exposure putting them at risk to develop secondary cancers. In an effort to reduce such exposure, our Stone Research Team is researching and testing an ultra low dose CT scan with 87 percent less radiation than standard scans.