What are kidney stones?
Kidney stones are solid masses of tiny crystals that form inside the kidneys. These crystals can stick together and grow into stones that may stay in the kidney or travel through the urinary tract. Also called renal stones or nephrolithiasis, the stones may block the flow of urine, causing sudden, severe pain. Some stones pass on their own, while others need medical care.
At Penn Medicine, our kidney stone clinic offers advanced treatments, including noninvasive and minimally invasive procedures. Our urinary stones care and kidney medicine specialists are national leaders in the field, using the latest research to help you pass or remove stones and reduce the risk of stones returning. If you have a condition that makes you more likely to develop them, doctors from specialty areas across Penn Medicine can create a treatment plan that helps prevent them from forming.
What does a kidney stone feel like?
You might not feel a stone while it’s inside your kidney. Most kidney stone symptoms start when the stone moves into the ureter, the tube that carries urine to the bladder. If a stone gets stuck, it can block urine flow and cause intense pain. Kidney stone pain often comes in waves and may change location as the stone moves through the urinary tract.
Common signs of kidney stones include:
- Sharp pain in the side, back, lower abdomen, or groin
- Burning or pain while urinating
- Blood in the urine or abnormal urine color
- Feeling the need to urinate often
- Fever or chills if an infection is present
- Upset stomach, nausea, or vomiting
Types of kidney stones
Kidney stones form for different reasons. Knowing the type you have helps your care team determine the cause and guide treatment. If you pass a stone and can save it, bring it to your provider for analysis.
The main types include:
- Calcium stones are the most common and happen when calcium mixes with substances like oxalate, found in foods like spinach, nuts, and chocolate.
- Uric acid stones occur in people who are dehydrated, eat large amounts of animal protein, or have conditions like gout.
- Struvite stones often form after a urinary tract infection (UTI), can grow quickly and become large, sometimes forming staghorn stones that take the shape of the inside of the kidney.
- Cystine stones are caused by a rare genetic disorder that allows too much amino acid to leak into the urine.
What causes kidney stones?
There isn’t always one single reason why stones form, but the biggest risk factor is not drinking enough fluids. If you make less than 32 ounces (1 liter) of urine a day, you’re more likely to develop a stone. When your urine is too concentrated, minerals like calcium and uric acid can’t dissolve properly.
Other factors that may increase risk include:
- Diets high in salt or animal protein
- Medical conditions like hyperparathyroidism, type 1 diabetes, type 2 diabetes, chronic urinary tract infections (UTIs), and others
- Digestive issues that affect nutrient absorption, like inflammatory bowel diseases
- Some medications
- Family history of kidney stones
Tests to diagnose kidney stones
To diagnose kidney stones, your provider will review symptoms and perform a physical exam. Blood tests check kidney function and measure levels of minerals like calcium or uric acid. Urine tests can look for crystals, blood, or signs of infection. Imaging tests help confirm the presence, size, and location of a stone.
How kidney stones are treated
Your treatment depends on the size of the stone and your level of pain. Small stones often pass on their own with fluids, pain relief, and medications that help relax the urinary tract.
If a stone is too large to pass, blocks urine flow, causes infection, or leads to ongoing pain, your provider may recommend a procedure to break the stone into smaller pieces or remove it. These treatments use minimally invasive techniques or advanced sound wave technology to help stones pass naturally.
Some kidney stones develop because of an underlying condition like hyperparathyroidism, which can raise calcium levels in the urine and lead to calcium stones. Treating the condition, including surgery to remove the overactive gland when needed, can help prevent stones from forming again.
How to prevent kidney stones
Your health care team can give you personalized strategies for preventing kidney stones. Start with drinking at least 10 cups of water a day and cutting back on sodium and meat in your diet, focusing instead on eating plant-based protein, like legumes. Your provider may recommend avoiding foods that contain oxalates, like spinach and nuts, while eating more citrus fruits and calcium-rich foods. If you have a condition that contributes to the formation of kidney stones, like diabetes or chronic UTIs, following the treatment plan for that condition can help prevent stones.
Latest advances in kidney stone treatment
Kidney stones can be incredibly painful, but they don’t have to be a permanent part of your life. Penn Medicine specialists can help you find relief and create a plan to prevent recurrence in the future. We offer:
- Advanced ESWL technology: Our experts use the latest shock wave technology to provide a noninvasive experience, meaning no hospital stays and a faster return to your daily life.
- Leading research: We lead clinical trials that investigate why stones form and provide access to the latest breakthroughs before they are available elsewhere.
- Complex stone care:We’re among the few health care centers in the region skilled in removing very large or staghorn stones through tiny, minimally invasive incisions, so even the most difficult cases are handled with care.
- Multispecialty expertise: Our care team extends beyond urology and kidney medicine to include other specialists, like endocrinologists and gastroenterologists. These experts help you manage conditions that can lead to kidney stones, including hyperparathyroidism, malabsorption issues related to nutritional deficiencies, and others.