It takes time for kidney stones to form, but when a stone gets stuck in your urinary tract, the pain is sudden and surprising. If a serious kidney stone is left untreated, it may even lead to a kidney infection or threaten kidney function.
Can we protect ourselves from kidney stones? According to Walter P. Mutter, MD, the answer is a bit complicated.
Dr. Mutter is a Mass General Brigham nephrologist, and the chief of Nephrology at Newton-Wellesley Hospital. He answers common questions about kidney stones, including when to seek treatment, kidney stone diagnosis, and how you can best reduce the risk of a future stone attack.
Kidney stones are hard masses made up of small crystals. Up close, they can look like small pebbles. They occur when minerals, salts, and other byproducts build up in your kidneys.
“Kidney stones form in the urinary system,” says Dr. Mutter. “Usually, they’ll develop within the kidney and sometimes the bladder. They’re formed from naturally occurring substances in our urine that crystalize and build up layer upon layer over many months and years.”
Kidney stones range in size. Some are as small as a grain of salt and pass through your urinary system unnoticed. Others might be larger, like apple seeds or peas; in rare cases, they can grow as large as golf balls. These larger stones are more likely to get stuck and cause problems in your urinary tract.
“Usually, kidney stones are asymptomatic—they don’t cause symptoms or problems,” says Dr. Mutter. “But sometimes, when they move, they cause pain and discomfort. That’s what we call ‘passing a kidney stone’.”
You might be passing a kidney stone if you experience any of the following symptoms:
Sharp pains felt in your back, side, lower belly, or groin
Nausea and vomiting
Blood in your urine
Pain when urinating
Inability to urinate (or only being able to urinate small amounts at a time)
Urine that is cloudy or smells bad
Kidney stone symptoms can be severe. If you believe you’re experiencing kidney-stone-related pain, it’s important to seek treatment. Call your primary care provider (PCP) first. If you don’t have a PCP or no appointments are available, seek urgent care.
At your appointment, your provider will work with you to figure out whether you have a kidney stone, and then help find the best course of treatment.
“If you had the symptoms that could be a kidney stone…you’d want to schedule a visit with your physician,” Dr. Mutter says. “The testing we’d do would be a urinalysis—because we want to see if there’s blood in the urine, make sure there’s no infection in the urinary system, and do some kind of imaging.”
Typically, imaging for a kidney stone begins with a regular x-ray. In cases where providers need a more sensitive test, they may use a CT scan or ultrasound instead.
“Ultimately, for most patients, we don’t know what causes kidney stones,” says Dr. Mutter. “In a few cases, we will be able to identify a specific medical condition that might put that patient at a higher risk of forming a kidney stone. In those cases, it’s especially important that we do a thorough metabolic workup to try to find the risk factors in that particular patient that are causing the kidney stones.”
That more intensive workup typically involves a patient history and medication review and lab work. It can also involve a 24-hour urine collection, where a doctor collects urine for 24 hours and examines it to find anything in the urine that might increase kidney stone risk.
Although we don’t know exactly what causes kidney stones, there are multiple factors that can contribute to your likelihood of developing them. These include:
Race and sex—white men are most likely to develop kidney stones
Having a blocked urinary tract, having a personal history of urinary infections or diseases, having an endocrine and/or calcium disorder, or having certain bowel conditions
Family history of kidney stones
Eating high-protein foods or intake of oxalate-rich foods such as spinach, almonds, rhubarb, and miso
Use of certain medications and supplements
Your kidney stone treatment plan will depend on your unique needs, lifestyle, and risk factors. Your doctor will talk you through strategies that can help decrease your risk developing kidney stones in the future. These may include diet changes or medication management.
“If you have kidney stones that need removal, there are a lot of different options,” says Dr. Mutter. “You’re going to work with the urologist and talk about the risks and benefits of different choices.”
Treatment options can include:
Ureteroscopy. “This is where your doctor physically goes in with a scope and removes the stone,” says Dr. Mutter. “Sometimes they’ll leave a stent in place to ensure that the urine flows after the stone’s removed.”
Shockwave lithotripsy. “This is a non-invasive procedure where they use sound waves to break up the stones, and then you naturally pass them in your urine,” Dr. Mutter explains. This is most often used for stones that are not causing any symptoms.
According to Dr. Mutter, there are a few lifestyle changes you can make to help prevent kidney stones of any kind.
“You’re going to want to drink at least 3 to 4 liters of fluids a day. That’s three quarters of a gallon or 100 ounces of fluid,” says Dr. Mutter. “We really want to prevent dehydration and get the urine flowing. That will decrease the concentration of substances in the urine that might form kidney stones.”
If you find it difficult to consume enough fluid over the course of a day, try adding fruits and vegetables with high water content to your meals. Water-rich foods—from melons to cucumbers, strawberries, bell peppers, broccoli, and everything between, may support good hydration levels.
“Reducing your salt or sodium intake is especially useful for calcium stones—but it also has cardiovascular benefits,” says Dr. Mutter. “Kidney stones are associated with some of the same metabolic abnormalities we associate with high blood pressure and diabetes—so anything people can do to improve their cardiovascular health may decrease the risk of kidney stones.”
There are certain foods that can increase your risk of kidney stones, and others that can reduce it.
Try to avoid:
Sugar-sweetened beverages like soda or juices
Foods containing high-fructose corn syrup, such as candy and fast food
Animal proteins like meat and eggs
Try to incorporate:
Dietary calcium, found in dairy, fruits, leafy greens, beans, nuts, and certain starches
Magnesium-rich foods like pumpkin seeds, spinach, soymilk, and brown rice
Potassium, which you can get from dried fruits, lentils, bananas, cantaloupe, and tomatoes, among other foods
More fruits of any kind—from apples and grapes to avocado and cucumber
High-fiber foods like pears, strawberries, legumes, and quinoa
As with reducing salt intake, losing weight and increasing movement in your day-to-day life can help decrease your risk of developing kidney stones.
Exercise is an important tool not only for reducing your risk of kidney stones, but for helping you pass stones you already have. However, it’s important to consult with your doctor before beginning or changing your exercise routine. They will be able to help you find an exercise routine that makes sense for you.
According to Dr. Mutter, the very worst thing a person with kidney stones can do is ignore their symptoms. “Most kidney stones will pass by themselves, and they don’t usually cause lingering damage or problems. But a few can—and those stones that don’t pass are, at a minimum, painful; at worst, they can cause complications.”
So, what’s the best thing you can do? “Make sure you’re working with a physician you can trust and work with over time,” says Dr. Mutter. “Kidney stones are unfortunately not curable, but they’re very treatable. You’ll want to work with your urologist to decide what to do about the stones you have. Then, you’ll want to work with a nephrologist to think about strategies to prevent stones in the future and to decrease your risk of kidney stones going forward.”