Kidney Stones
Kidney stones are solid objects formed from crystals your body makes that can move through your urinary tract. If you've ever passed a kidney stone, you know that kidney stone pain can be intense.
UPMC doctors can treat kidney stones and suggest lifestyle changes to prevent more kidney stones from forming.
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On this page
- What Is Kidney Stones?
- What Are the Symptoms of Kidney Stones?
- How Do You Diagnose Kidney Stones?
- How Do You Treat Kidney Stones?
What Is Kidney Stones?
Kidney stones are hard, pebble-like objects that form in one or both of your kidneys. Your kidneys are part of your urinary tract. They're under your rib cage on either side of your spine. The kidneys filter waste from your blood and produce urine.
Kidney stones happen when chemicals in the urine make tiny crystals that stick together. The resulting stones can be as small as a grain of sand or as large as a pea. They sometimes move from the kidneys through the urinary tract. Kidney stone symptoms vary. Some stones pass through the urinary tract with no problem, while larger kidney stones can get stuck. These bigger stones can cause severe pain, block the flow of urine, and lead to other problems.
Kidney stones are common, more so among men. About 11% of men and 6% of women will have at least 1 kidney stone in their lifetime.
What are the types of kidney stones?
There are different types of kidney stones. Your doctor may base your treatment on what type of stone you have. The types of kidney stones are:
- Calcium oxalate – This is the most common type of kidney stone. They form when calcium in the kidneys combines with the compound oxalate.
- Cystine – This rare type of kidney stone happens if you have a genetic issue called cystinuria.
- Struvite – This less common type of kidney stone forms out of struvite, a substance that occurs after a urinary tract infection.
- Uric acid – This common type of kidney stone forms when compounds in red meat and shellfish make your urine too acidic.
Each type of kidney stone requires targeted treatment, which can range from lifestyle and dietary changes to medical or surgical treatments.
What causes kidney stones?
Kidney stones form when your urine is too concentrated — often from not drinking enough water. The chemicals in the urine make crystals that stick together and form a stone.
Most people who get kidney stones don't drink enough water. Staying hydrated will help stop kidney stones from forming and will also help flush out small stones.
What are kidney stone risk factors and complications?
Being aware of kidney stone risk factors and the issues they cause can help you avoid some kidney stones.
Kidney stone risk factors
Dehydration (not drinking enough fluids) is the main risk factor for getting kidney stones. Other risk factors include:
- Taking certain medicines – Calcium-based antacids and diuretics, which promote the elimination of water, can increase the risk of developing kidney stones.
- Previous kidney stone problems – If you have had kidney stones in the past, you are more likely to develop them again.
- Urinary tract obstruction – Any blockages in the flow of urine can lead to the formation of stones.
- Unbalanced diet – A diet too high in animal protein, salt, or sugar increases the risk of kidney stones.
You may also be at higher risk for kidney stones if you have:
- Chronic UTIs.
- Cystic kidney disease.
- Diabetes.
- Gallstones.
- Gout.
- High blood pressure.
- Hyperparathyroidism.
- Irritable bowel syndrome.
- Metabolic syndrome.
- Obesity.
Complications of kidney stones
Kidney stones increase your risk of getting serious health issues, including:
- Chronic kidney disease.
- Kidney infections and other UTIs.
- Loss of kidney function.
How can I prevent kidney stones?
You may not be able to prevent all kidney stones. But you can reduce your risk of getting kidney stones by making certain lifestyle choices.
To help prevent kidney stones, you should:
- Consume the right amount of calcium – Calcium is essential for bone health and should be consumed in a balanced way through the diet. Your doctor can guide you on the right amount to take.
- Drink plenty of water – Hydration is key to preventing the formation of stones. Aim to drink at least 8 glasses of water a day (about 1.5 liters).
- Limit sodium and animal proteins – Reducing salt intake and animal proteins helps prevent the formation of kidney stones.
- Eat fruits and vegetables – A diet rich in fruits and vegetables is beneficial for kidney health.
- Maintain a healthy weight – Being overweight can increase the risk of kidney stones, so it’s important to maintain a healthy body weight.
What Are the Symptoms of Kidney Stones?
Kidney stone symptoms may vary, depending on how big the stone is.
The most telling sign of a kidney stone is moderate to severe pain. The pain from kidney stones can move into your upper abdomen, sides, lower back, and bladder.
If you have a kidney stone, you may also feel a frequent need to go to the bathroom.
What are four symptoms of kidney stones?
Besides pain and frequent urination, four other signs of kidney stones are:
- Blood in your urine.
- Sand or gravel in the urine, making it look cloudy.
- Fever and chills.
- Nausea and vomiting.
Call your doctor if you have intense pain or any of the symptoms above.
How Do You Diagnose Kidney Stones?
Your doctor will ask you about your health history, especially if you've had kidney stones before. They'll also do a physical exam.
Then your doctor may order:
- Blood work – to find out levels of calcium and uric acid in your blood.
- Imaging tests – to see the size and shape of the kidney stones and where they are.
- Urine tests – to find out what chemicals are in your urine.
How Do You Treat Kidney Stones?
The treatment for kidney stones depends on their size. If the stones are small enough, they may be passed naturally by the body. In this case, the doctor may advise you to go home, drink plenty of water, and monitor your symptoms. They may also ask you to collect the stones using a special strainer to analyze them and identify the type, so they can suggest any changes to your lifestyle and diet to prevent the formation of new stones.
For larger stones, the doctor may prescribe one of the following treatments:
- Extracorporeal shock wave therapy – This non-invasive treatment sends shock waves through your skin to the kidney stone to break it up.
- Medicine – Certain drugs reduce the chemicals in your blood and urine that form stones.
- Percutaneous nephrolithotomy – During this surgery, doctors make an incision in your back and use a tube-like instrument to remove larger stones.
- Ureteroscopy – Doctors insert a scope with a light into your urethra. A basket device collects the stone.
Reviewed February 2024.