Kidney stones are small, hard deposits made of minerals and reoccurring materials inside the kidneys. Stones often go unnoticed in the kidney until they move into the ureter —the tube connecting the kidney and bladder.
If a stone leaves the kidney and blocks urine from exiting, usually while in the ureter, it can cause urine to back up and lead to intense pain.
Kidney stones are common, affecting about 12% of the U.S. population. Kidney stone development usually begins when people are in their 20s or 30s, and the problem can continue for years.
Many things can increase your risk for stones, including family history, health factors like diabetes, dietary habits or if your urine lacks substances to prevent crystals from sticking together.
There are four types of kidney stones. Knowing the type of your kidney stone will help determine its cause and give you clues on how to reduce your chance of developing more stones. If you pass a kidney stone, try to save it to give to your healthcare team for analysis.
Types of kidney stones include:
Calcium stones can also be made of calcium phosphate. This type of stone is more common in people with metabolic conditions like renal tubular acidosis. It may also be associated with some medications used to treat migraines (topiramate) or blood pressure (furosemide or triamterene).
Nearly 50% of people who have developed kidney stones will develop another stone in 10 years if they do not take steps to prevent a recurrence. Usually, this includes a combination of lifestyle changes and medications.
You may reduce your risk of kidney stones if you:
A high amount of salt and animal protein in your diet can also increase your kidney stone risk. A diet lower in sodium and higher in potassium — contained in many fruits and vegetables — can reduce the risk of stone formation.
Medications can control the amount of minerals and salts in the urine and may be helpful in people who form certain kinds of stones. The type of medication your doctor prescribes will depend on the type of kidney stones you have and the specific makeup of your urine, which is determined by testing. Some medications can reduce uric acid levels in the blood and reduce your risk of uric acid stones, while others increase the solubility of cystine in your urine and lower your risk of cystine stones.
Kidney stone formation is specific to each person, so it's important to work with your healthcare team to develop a personalized treatment plan. That plan should consider what kind of kidney stones you have, possible causes for their formation and specific steps to prevent them.