Key takeaways:
Kidney stones are tiny, hard deposits of different substances that develop inside the kidneys. They’re notorious for being painful when they leave the kidney and travel down the urinary tract.
Most kidney stones will pass on their own. So the main treatments are time and pain medications until they pass. If a kidney stone is too big and gets stuck, procedures can help move them along.
The steps you can take to prevent kidney stones from recurring depend on the type of kidney stone.
If you’ve been diagnosed with a kidney stone, you’re not alone. Approximately 9% of people in the U.S. experience kidney stones at some point in their life. But there are a lot of myths and misconceptions about how they’re treated and how to prevent them. We are here to help you separate fact from fiction. For starters, some of the prevention strategies depend on the specific type of kidney stone you have. We’ll also cover the different types of kidney stones, how they’re treated, and how long they typically take to pass.
Kidney stones form when different substances in the urine solidify into crystals. There are actually a few different types of kidney stones. The types depend on the substance that causes them to form. And each type is associated with different risk factors and causes (in a bit we’ll learn how the type of kidney stone also affects prevention).
There are five main categories of kidney stones:
Calcium stones make up about 80% of all kidney stones. Eating too much calcium doesn’t actually cause calcium stones. They form when calcium binds to other substances in the urine (like oxalate and phosphate). Dehydration can increase the concentration of these substances, making stone formation more likely.
Struvite stones form in people who have frequent urinary tract infections (UTIs).
Uric acid stones are formed from urate crystals, which can be high in people who eat a diet with lots of animal protein.
Cystine stones are much less common. They are found in people with a genetic condition that affects how they process the amino acid cysteine.
Other types of stones include those formed in people who take certain medications that can solidify in the urinary tract. Examples include some antiviral medications used to treat HIV, certain antibiotics, and sulfonylureas for diabetes.
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There are a few ways that stones can be treated, depending on their size and if they are causing any complications. Treatment ranges from simply giving the stone time to pass on its own and procedures to break up the stone (or help move it along) to removing the stone completely.
Many stones — especially small ones — will pass on their own. So all you need is time and some pain medication as you wait it out. Your provider may use imaging to help monitor the stone over a few weeks to ensure that the stone passes, especially if you don’t see the stone pass in your urine.
Non-steroidal anti-inflammatory drugs (NSAIDs) seem to work particularly well for pain that kidney stones cause. These include oral medications like ibuprofen and naproxen as well as injected medications like ketorolac that a provider gives.
Your provider may also recommend light physical activity and lots of fluid to help the process. And a few recent studies have even reported that having sexual intercourse may help move the stones along in certain cases.
Sometimes providers recommend medications that may help the stone to pass. Most commonly, they recommend alpha blockers like tamsulosin (Flomax) for this purpose. These medications help to expand the ureter (the narrow tube that connects the kidney to the bladder). This increases space for the stone to pass.
An analysis of multiple studies found that alpha blockers may be slightly more effective at helping larger stones versus smaller stones. And these medications can cause unwanted side effects such as dizziness and low blood pressure. So it’s important to discuss the risks and benefits of taking these medications with your provider.
If the stone is too large to pass on its own — or it’s causing significant symptoms — a specialist called a “urologist” can help. There are a few different treatment options, and the urologist can help you decide which one is best for you. These procedures include:
Shock wave lithotripsy uses sound waves to break the stone into smaller pieces.
Cystoscopy and ureteroscopy are procedures in which a long tube is inserted into the urinary tract through the urethra (the hole you urinate from) to physically remove the stone.
Ureteral stents can be placed in the ureter to help open it up so the stone can pass. The stent is then easily removed once the stone passes.
Percutaneous nephrolithotomy involves a small incision in your back to access the kidney and remove the stone. This is rarely necessary since the other procedures are usually effective.
It can take days to weeks for a stone to pass. But most stones do pass on their own. Smaller stones and those that have already traveled some distance down the urinary tract are more likely to pass on their own. It’s safe to wait up to 4 to 6 weeks for a stone to pass — as long as the pain is manageable and there’s no sign of a UTI (like fever) or worsening symptoms.
If the stone doesn’t pass by itself over time, or your symptoms worsen, you may need a procedure. It’s a good idea to see a provider without delay if:
You have nonstop or worsening pain.
You have signs of infection, including fever, chills, nausea, or vomiting.
UTIs that develop from kidney stones can progress quickly, so it’s best to see a provider as soon as possible if you think you may have an infection.
Some prevention strategies depend on the type of kidney stone you have, while others apply to all kidney stones. Your provider may ask you to strain your urine to collect the stone while it’s passing. This allows them to analyze the stone in the lab and determine its composition. This will help you know how to prevent another stone in the future.
The lifestyle changes you can make to help prevent kidney stones include:
Drink at least 2 liters of fluid daily (this includes all fluid intake). You’ll need more if you are exercising or spending time in hot weather.
Limit salt (sodium) intake. Try to stay under 2,000 mg per day. This is because when kidneys filter sodium into the urine, calcium also enters the urine. And that calcium in the urine can form stones.
Decrease intake of meat and animal protein sources. Plant-based protein sources — like beans, lentils, legumes, and tofu — are a better option and don’t increase the risk of kidney stones.
Eat enough dietary calcium. This may sound strange, but decreasing calcium in your diet may actually increase your risk of calcium kidney stones. This is because digested calcium helps remove oxalate from our body before it’s absorbed. So it’s recommended to consume 1,000 to 1,200 mg of calcium from food (not supplements) daily.
Limit foods that have oxalate. This includes spinach, peanuts, nuts, rhubarb, and wheat bran. And it’s especially important for calcium stones.
Avoid high amounts of vitamin C from supplements. Limit to less than 1,000 mg per day. Too much vitamin C can also increase oxalate in the urine.
Maintain a healthy weight. Higher body mass index (BMI) puts people at risk of conditions associated with kidney stone formation, like diabetes and gout.
Prevention of specific types of stones also includes certain medications:
Thiazide diuretics can prevent calcium stones.
Potassium citrate can prevent calcium, uric acid, and cystine stones.
But not everyone with kidney stones needs to take medications — especially if they don’t occur frequently.
There are several different causes of kidney stones. Most kidney stones pass on their own. Treatment includes medications to ease the pain and to help them pass. But sometimes a procedure is needed to help the stone pass. Procedures are usually quick and well tolerated. Luckily, making a few dietary and lifestyle changes can help lower the risk of kidney stones. Prevention includes drinking lots of fluid, limiting sodium intake, and avoiding animal protein.
Ahmed, K., et al. (2006). Cystine calculi: Challenging group of stones. Postgraduate Medical Journal.
Alelign, T., et al. (2018). Kidney stone disease: An update on current concepts. Advances in Urology.
Amer, T., et al. (2017). Medical expulsive therapy for ureteric stones: Analysing the evidence from systematic reviews and meta-analysis of powered double-blinded randomised controlled trials. Arab Journal of Urology.
American Academy of Family Physicians. (2020). Kidney stones.
Campschroer, T., et al. (2018). Alpha-blockers as medical expulsive therapy for ureteral stones. The Cochrane Database of Systematic Reviews.
Coe, F. L., et al. (2005). Kidney stone disease. The Journal of Clinical Investigation.
Coll, D. M., et al. (2002). Relationship of spontaneous passage of ureteral calculi to stone size and location as revealed by unenhanced helical CT. American Journal of Roentgenology.
Davenport, K., et al. (2010). The role of non-steroidal anti-inflammatory drugs in renal colic. Pharmaceuticals (Basel).
Doluoglu, O. G., et al. (2015). Can sexual intercourse be an alternative therapy for distal ureteral stones? A prospective, randomized, controlled study. Urology.
Fontenelle, L. F., et al. (2019). Kidney stones: Treatment and prevention. American Family Physician.
Goldfarb, D. S. (2018). Empiric therapy for kidney stones. Urolithiasis.
Goldfarb, D. S., et al. (1999). Prevention of recurrent nephrolithiasis. American Family Physician.
Hernandez, N., et al. (2018). Cessation of ureteral colic does not necessarily mean that a ureteral stone has been expelled. Journal of Urology.
National Institute of Diabetes and Digestive and Kidney Diseases. (2017). Eating, diet, & nutrition for kidney stones.
National Institute of Diabetes and Digestive and Kidney Diseases. (2017). Treatment for kidney stones.
National Kidney Foundation. (2019). Kidney stone diet plan and prevention.
National Kidney Foundation. (2021). Struvite stones.
National Kidney Foundation. (2021). Uric acid stones.
Pearle, M. S., et al. (2014). Medical management of kidney stones: AUA guideline. The Journal of Urology.
Poore, W., et al. (2020). Obesity and its impact on kidney stone formation. Reviews in Urology.
Scales, C. D. Jr., et al. (2012). Prevalence of kidney stones in the United States. European Urology.
Sorensen, M. D. (2014). Calcium intake and urinary stone disease. Translational Andrology and Urology.
Turgut, H. (2020). Evaluation of the efficacy of sexual intercourse on distal ureteral stones in women: A prospective, randomized, controlled study. Urology.
Urology Care Foundation. (2021). What are kidney stones?