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Get the facts. And the help you need.

Kidney Stones

What are kidney stones?
How do you get stones?
What are the symptoms of kidney stones?
What are the different types of kidney stones?
What causes kidney stones?
How are kidney stones diagnosed?
How are kidney stones treated?
How can kidney stones be prevented?
Frequently Asked Questions (FAQ)
Additional Resources

Read, "Preventing and Treating Kidney Stones," article from the 2014 summer edition of Urology Health extra

Kidney stone disease is one of the most common benign (non-cancer) disorders of the urinary system.

Each year, more than a million Americans are diagnosed with a kidney stone and the number keeps rising. For an adult in the U.S., the lifetime risk of developing a stone rose from 3.2% in 1980, to 5.2% in 1994, to 8.8% in 2010. Whites are more likely to develop kidney stones than African Americans or other races. Men are more likely than women to have stones. But the number of women with stones has gone up in the past 10 years. This may be connected to the rise in obesity in women compared to men, as obesity is a known risk factor for kidney stones.

Kidney stones often occur more than once and they can be very painful. They lead to more than two million doctor visits and 600,000 hospital emergency room visits a year. They tend to develop in midlife, when family and work commitments are at their peak. Costs reach $5.3 billion each year for diagnosis, treatment, prevention and lost time from work.

Kidney stones are not a new problem. Scientists found evidence of stones in the bladder of a 7,000 year old Egyptian mummy. Modern research has helped doctors understand why stones form, how to prevent them, and how to reduce the chance a stone will form or grow.

New technologies help doctors manage kidney stones. Imaging studies help doctors diagnose stones quickly and reliably, before kidney damage happens. Modern surgery for stones is effective, minimally invasive and often performed as an outpatient procedure. Medications and diet advice can prevent stones from growing or returning. Better diagnosis, treatments and prevention mean quick recovery and fewer repeat episodes.

Below you will find additional information to help you or your loved one understand how to deal with their stone disorder.

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What are kidney stones?

Kidney stones are solid masses made of crystals formed from salts concentrated in the urine. Urine has many dissolved substances in it, including mineral salts like calcium oxalate and calcium phosphate. Some people have high levels of minerals that help stones form. Or the urine volume could be too low, in which case the salts are too highly concentrated to stay dissolved.

Along with mineral salts, urine has other substances that can increase or decrease the chance for stone growth. Your likelihood to form a stone depends partly on which of these substances you have in the urine and the amount of each of these substances.

Image is courtesy of the National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health.

Kidney stones come in many sizes, shapes and colors. They can be as small as a speck of sand or as large as a golf ball. Some look like smooth, round pebbles and others have rough edges, depending on the chemicals in them. In rare cases, staghorn stones may grow until they fill all or most of the hollow part of the kidney. They are called staghorn stones because they have branches shaped like deer antlers.

Each stone's color depends on what chemicals it's made of. Most stones are yellow or brown. But they can be tan, gold or black. Your doctor can test the stone to find out what it is made of. The results of this test can be used to help decide the best treatment for you.

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How do you get kidney stones?

Image is courtesy of National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health.

The kidneys are fist-size organs that handle the body's fluid and chemical levels. You have two kidneys, one on each side of the spine behind the liver, stomach, pancreas and intestines. Healthy kidneys clean waste from the blood and eliminate it in the urine. They balance elements in the blood, such as sodium, potassium and calcium. The kidneys also make hormones that control blood pressure and red blood cell production.

The kidneys, ureters and bladder are part of your urinary tract - the organs in your body that make, transport, and store urine. The kidneys make urine. The urine then travels down the ureters to the bladder where it is stored and eliminated from your body through the urethra.

Kidney stones form in the kidney. Some stones move from the kidney into the ureter, the tubes leading from the kidneys to the bladder, and then pass out of the body. If a stone leaves the kidney and gets stuck in the ureter it is called a ureteral stone.

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What are the symptoms of kidney stones?

Sometimes stones do not cause any symptoms and they are never diagnosed. Stones in the kidney that don't block the flow of urine often go unnoticed because they usually don't cause pain.

When a stone leaves the kidney and travels to the bladder through the ureter, it can become stuck in the ureter. The stone then blocks the flow of urine out of the kidney, causing the kidney to stretch. This stretching of the kidney is called hydronephrosis and it is often painful.

When a person does have symptoms, they may include:

  • Sharp, cramping pain in the back and side, often moving to the lower abdomen or groin. Some say the pain is worse than childbirth labor pains. The pain often begins suddenly and comes in waves. It can come and go as the body tries to get rid of the stone.
  • A feeling of intense need to urinate
  • Urinating more often or feeling a burning sensation during urination
  • Urine that is dark or red due to blood. Sometimes the urine has only microscopic red blood cells that can't be seen with the naked eye.
  • Nausea and vomiting
  • For men, pain in the tip of the penis

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What kinds are the different types of kidney stones?

Calcium stones
Calcium stones are the most common type of kidney stone. There are 2 types of calcium stones: calcium oxalate and calcium phosphate. Calcium oxalate is by far the most common type of calcium stone.

Calcium is important for healthy teeth and bones. It transports nerve impulses, contracts muscles and supports other activities needed for life. A healthy diet gives most people the calcium they need. But the body doesn't need all the calcium it gets. So it gets rid of extra calcium in the urine. Some people have too much calcium in their urine, raising their risk of calcium stones. Even with normal amounts of calcium in the urine, stones may form for other reasons.

For example, some people have high uric acid levels. Because calcium sticks to uric acid crystals, calcium stones can form. High urine oxalate levels also raise the risk of calcium oxalate stones. Some people have low citrate levels in their urine. Because citrate helps prevent calcium stones, low citrate levels can increase the chance that stones will form.

Sometimes several factors together cause calcium stones to form. Treatment depends on the reasons the stones form. Treatment may include diet changes and/or medications to lower levels of calcium, oxalate or uric acid or to raise citrate levels, or a combination of these.

Uric acid stones
Uric acid is a waste product created by normal metabolism. Uric acid dissolves in the blood and passes through the kidneys into the urine, leaving the body. Uric acid does not dissolve well in acidic urine.

So when something causes acidic urine, such as some medications, gastrointestinal conditions, type 2 diabetes or a diet high in meat, uric acid stones may form. People with gout, where there is too much uric acid in the blood, may be more likely to form these stones. Treatment includes giving medicine to make the urine less acidic (more basic), dissolving the stones, and preventing new ones from forming.

Struvite/infection stones
This less common type of stone is associated with chronic urinary tract infections (UTIs). Some bacteria make the urine less acidic and more basic. Magnesium ammonium phosphate (struvite) stones form in basic urine. These stones are usually large, have branches, and grow fast.

People who get chronic UTI's, such as people with long-term tubes in their kidneys or bladders or with poor bladder emptying from neurologic disorders (paralysis, multiple sclerosis, spina bifida) are at highest risk for these stones. Treatment includes removing the stone and preventing UTIs.

Cystine stones
Cystine is an amino acid, a building block of protein. Cystinuria is a rare, inherited metabolic disorder where the kidneys do not reabsorb cystine from the urine. Cystine accumulates in the urine, forming stones. Cystine stones account for only 1 to 6% of all kidney stones.

Cystine stones usually begin to form in childhood. Treatment involves drinking large amounts of fluid and taking medications to lower the concentration of cystine in the urine. Successful treatment of cystinuria is hard. It requires the patient to commit to a lifetime of following a recommended diet and taking medication. Without the right treatment cystinuria can lead to kidney failure.

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What causes kidney stones?

Low urine volume
One of the main reasons kidney stones form is constant low urine volume. This can be due to dehydration (loss of body fluids) from hard exercise, working or living in a hot place, or not drinking enough fluids. When urine volume is low, urine is concentrated and dark in color. Concentrated urine means there is less fluid to keep salts dissolved. This raises the chance that crystals will form from mineral salts in the urine.

You should drink enough fluid to make at least 2.5 liters of urine every day. If you drink enough fluid, your urine should look light yellow. However, the color of your urine is not always a good sign of how much fluid you are drinking.

Diet
Diet can also affect the chance of forming a stone. One of the more common causes of calcium kidney stones is high levels of calcium in the urine. High urine calcium levels may be due to the way your body handles calcium. Lowering the amount of calcium in your diet rarely corrects this issue. Studies have shown that restricting dietary calcium can be bad for bone health. Therefore, doctors usually do not advise people to restrict dietary calcium in order to lower urine calcium.

One way your doctor may try to reduce your urine calcium level is by decreasing your sodium (salt) intake. Too much salt in the diet is a risk factor for calcium stones because too much salt passing into the urine keeps calcium from being reabsorbed out of the urine and into the blood. Reducing salt in the diet lowers urine sodium and urine calcium decreasing the chance for calcium stone formation.

Because oxalate is a component of the most common type of kidney stone, calcium oxalate stones, eating foods rich in oxalate can raise the risk of forming these stones. A diet high in dark green leafy vegetables (like spinach), potatoes, nuts, tea or chocolate may increase the risk of forming these stones.

A diet that is high in protein from red meat, fish, chicken and pork can raise the acid levels in the body and in the urine. This creates an environment for calcium and uric acid stones to form. The breakdown of meat into uric acid also raises the chance that both calcium and uric acid stones will form.

Bowel conditions
Certain bowel conditions that cause diarrhea, like Crohn's disease or surgeries like gastric bypass surgery can raise the risk of forming calcium oxalate kidney stones. Too much loss of water from the body can lower urine volume and abnormal absorption of oxalate from the intestine can increase the concentration of stone-forming oxalate in the urine. Both low urine volume and high levels of urine oxalate can help to form calcium oxalate stones.

Obesity
Obesity is also a risk factor for stones. This can be due to eating too much salt, meat or oxalate. Obesity may also change the acid levels in the urine leading to stone formation. Doctors are studying this and other reasons why obesity can increase the risk of kidney stones.

Medical conditions
Some medical conditions have an increased risk of kidney stones. Abnormal growth of one of the parathyroid glands, which control calcium metabolism, can cause high calcium levels in the blood and urine leading to kidney stones. Another condition called distal renal tubular acidosis, in which acid cannot pass into the urine, can raise the risk of calcium phosphate kidney stones.

Some rare inherited disorders can make certain types of stones more likely. Examples include cystinuria, too much of the amino acid cystine in the urine, and primary hyperoxaluria, the liver making too much oxalate.

Medication
Some medications, and calcium supplements, may increase your risk of forming stones. Be sure to tell your doctor all of the medications and supplements that you take, as these could affect your risk of stone formation. Do not stop taking any of these unless advised by your doctor.

Family history
The chance of being diagnosed with kidney stones is much higher if you have a family history of stones, especially in a close relative such as a parent or sibling.

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How are kidney stones diagnosed?

Sometimes "silent" stones, those that cause no symptoms, are found on X-rays taken during a general health exam or for other reasons. Some stones stay in the kidney for a long time without causing problems. Some small stones pass in the urine unnoticed. Large stones may need to be treated, even when they cause no symptoms.

When a person has hematuria (blood in the urine) or sudden abdominal or side pain, X-rays or a sonogram may find a stone. An X-ray can help the doctor know how big the stone is and where it is.

If your doctor suspects a stone but cannot see it on a simple X-ray, the doctor may scan the urinary system with a special X-ray called a CT or CAT scan. CT is often used in the emergency room when a stone is suspected. It can make the diagnosis quickly and accurately.

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How are kidney stones treated?

Treatment depends on the type of stone and the situation.

Wait for the stone to pass by itself
You can simply wait for the stone to pass. Many stones that get stuck in the narrow parts of the ureter later pass on their own into the bladder. They leave the body in the urine. Smaller stones are more likely than larger stones to pass on their own.

While waiting for the stone to pass, you should drink normal amounts of water. You may need pain medication when there is discomfort. Waiting up to 4-6 weeks for the stone to pass is usually considered safe as long as the pain is bearable, there are no signs of infection, the kidney is not completely blocked, and the stone is small enough that it is likely to pass.

Medication
Certain medications have been shown to improve the chance that a stone will pass. The most common medication prescribed for this reason is tamsulosin. Tamsulosin has been shown to improve the chance that a stone will pass. You may also need pain and nausea medicine to Along with pain medication you may also need nausea medication as youbecause you This medication and medicine to help control nausea can be prescribed along with pain medications while you wait for the stone to pass.

Surgery
Surgery may be needed to remove a stone from the ureter if:

  • Even with time, the stone never passes
  • The pain is too great to wait for the stone to pass.
  • The stone is affecting kidney function (based on blood work)

Some stones that haven't moved out of the kidney may be removed with surgery. Small stones in the kidney may be left alone if they are not causing pain or infection. Some people choose to have them removed because they are afraid the stone will unexpectedly go to the ureter and cause pain.

Other kidney stones should be removed by surgery because they cause repeated infections in the urine or because they are blocking the flow of urine from the kidney. Today surgery usually involves small or no incisions (cuts), relatively little pain, and minimal time off of work.

These are surgeries used to remove stones in the kidney or ureter:

Shock wave lithotripsy (SWL)
SWL is the most common procedure for kidney stones. It can also be used to treat stones in the ureter. Shock waves are focused on a stone seen on X-rays. Repeated firing of shock waves on the stone causes the stone to break into small pieces that pass out in the urine over a few weeks.

Because of possible discomfort caused by the shock waves and the need to control breathing during the procedure, some form of anesthesia is usually needed. SWL does not work well on hard stones such as cystine and some types of calcium oxalate stones or on stones bigger than half an inch.

With SWL, patients usually go home the same day as the procedure. They can resume normal activity in two to three days. Patients are usually given a strainer to collect the stone pieces as they pass, so they can be sent to the laboratory to be analyzed.

Although SWL is widely used and considered very safe, it can still cause complications. Most patients have blood in their urine for a few days after treatment. Although most stone pieces pass painlessly, some larger pieces may get stuck in the ureter, blocking urine flow from the kidney and causing pain.

Image is courtesy of National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health.

Ureteroscopy (URS)
URS is most commonly used to treat stones in the ureter. It can also be used to treat stones in the kidney. USR involves passing a very small telescope, called a ureteroscope, into the bladder, up the ureter and into the kidney. Rigid telescopes are used for stones in the lower part of the ureter near the bladder. Flexible telescopes are used to treat stones in the upper ureter and kidney.

The ureteroscope lets the urologist see the stone without making incisions (cuts). General anesthesia keeps the patient comfortable during the URS procedure. Once the urologist sees the stone with the ureteroscope, a small basket-like device grabs smaller stones and removes them. If a stone is too large to remove in one piece, it can be broken into smaller pieces with a laser.

Once the stone has been removed whole or in pieces, the doctor may place a temporary stent in the ureter. A stent is a small, plastic drainage tube that helps the urine drain from the kidney into the bladder. This tube is completely within the body and does not require an external bag to collect urine.

Patients usually go home the same day as the URS and can begin normal activity in two to three days. If your urologist places a stent, he or she will remove it 4-10 days later. It is very important that the stent is removed as it can cause complications if left in place for an extended period of time (months).

Percutaneous nephrolithotomy (PNL)
PNL is the best treatment for large stones in the kidney as these can rarely be effectively treated with SWL or URS. General anesthesia is required to perform a PNL. PNL involves making a half-inch incision (cut) in the side, just large enough to allow a rigid scope (nephroscope) to be passed from the back directly into the hollow center part of the kidney where the stone is.

An instrument passed through the nephroscope breaks up the stone and suctions out the pieces. The ability to suction pieces makes PNL the best treatment for large stones.

After the PNL, an external drainage tube is usually left in the kidney after surgery to allow drainage of urine and to stop any bleeding. The tube is left in overnight or for a few days. Patients usually stay in the hospital at least overnight for this operation.

Your urologist may choose to do X-rays while you are still in the hospital to see if any stone pieces remain. If there are any, your urologist may want to look into the kidney with a telescope again to remove them. You can begin normal activity after about 1-2 weeks.

Laparoscopic/robotic/open surgery
These procedures are rarely used to remove stones. They are used only if all other less invasive procedures fail. They require a hospital stay and have a longer recovery period.

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How can kidney stones be prevented?

Once you have a stone, here is what the doctor will do to find out why kidney stones are forming and to make a plan for preventing them:

Medical and dietary history
Your doctor will ask questions about your personal and family medical history, such as whether you have had more than one kidney stone or if anyone in your family has had stones. He or she will ask about medical conditions that raise your chance of stones, like frequent diarrhea or gout.

Knowing your eating habits is also helpful because you may be eating foods that are known to raise the risk of stones or you may not be drinking enough fluids or eating the foods that protect against stone formation

By understanding your medical, family and dietary history, your doctor can understand how likely you are to form more stones.

Blood and urine tests
After having a complete history and a physical exam, your doctor may take blood and urine samples for testing. Blood tests can help to diagnose some medical conditions that are known to cause stones. A single urine specimen can be tested to tell if you have a urinary tract infection or crystals in your urine that can lead to certain stone types. If review of your medical and family histories suggest you are at high risk for future stone formation a 24 hour urine collection can be done to test for levels of different stone forming risk factors. The results of this test can help the doctor provide specific dietary and medication recommendations.

Imaging tests
When a doctor sees you for the first time and you have been diagnosed with stones before, the doctor may want to see recent X-rays or order a new X-ray to see if there are any stones in your urinary tract.

Stone analysis
If you pass a stone or a stone is removed by surgery, your doctor will want to analyze it for stone type. Knowing the type of stone may help your doctor decide the best way to prevent future stones.

General diet guidelines
Because there are different types of kidney stones, and because people have different risk factors for them, there is no "one-size-fits-all" diet for preventing kidney stones. Each person's situation is different. But changing your diet may help prevent kidneys stones from forming or returning. Here are some general guidelines:

1. Drink enough fluids each day to produce at least 2.5 liters (about 85 ounces) of urine daily.
Your doctor will advise you to drink at least 3 liters of liquid each day. This equals about 3 quarts (about ten 10-ounce glasses). This is a great way to lower your risk for forming new stones. Remember to drink more to replace fluids lost when you sweat from exercise or in hot weather. All fluids count toward your fluid intake, but it's best to drink mostly non-calorie or low-calorie drinks. This may mean limiting sugar-sweetened or alcoholic drinks.

Know how much you drink in a typical day. This can help you understand how much you need to drink to produce 2.5 liters of urine. Use a household measuring cup to measure your total fluid intake for a day or two. Drink bottles or cans with the fluid ounces listed on the label. Keep a log, and add up the ounces at the end of the day or 24-hour period.

On the same day, or on another day, measure your urine output. Urinate into a measuring cup to measure urine volume each time you urinate. Write down the amount of urine before you flush it. Measure, write the amount and flush each time you urinate that day and night. Add up the total amount of urine for a 24-hour period. Use this total to be sure you are reaching your daily target urine amount of 85 ounces (2.5 liters) of urine daily.

2. Get less salt in your diet
Your doctor will advise you to avoid foods that have a lot of salt. The Centers for Disease Control (CDC) and other health groups advise getting no more than 2,300 mg of salt per day. But, no matter how much salt you get, lowering the amount will help. These foods are high in salt:

  • Cheese (all types)
  • Most frozen foods and meats, including salty cured meats, deli meats (cold cuts), hot dogs, bratwurst and sausages
  • Canned soups and vegetables
  • Breads, bagels, rolls and baked goods
  • Salty snacks like chips and pretzels
  • Bottled salad dressings and certain breakfast cereals
  • Pickles and olives
  • Casseroles, other "mixed" foods, pizza and lasagna
  • Canned and bottled sauces
  • Certain condiments, table salt and some spice blends

3. Don't restrict calcium, but don't get too much calcium.
If you take calcium supplements, make sure that you aren't getting too much calcium. Talk with your doctor or dietitian about whether you need supplements. Remember to eat moderate amounts of cheese, because cheeses are high in salt, which may increase urine calcium levels. If you can't eat dairy, use calcium-fortified non-dairy beverages and foods.

You can usually get enough calcium from your diet without supplements if you eat 3-4 servings of calcium rich food. Good choices include:

Foods rich in calcium

Amount

Calcium (mg)

Calcium-fortified non-dairy milks, juices

1 cup

400-450

Milk, buttermilk, eggnog

1 cup

300

Kefir

1 cup

300

Yogurt from cow's milk; soy yogurt

3/4 cup

150-300

Figs, dried

1 cup

300

Broccoli, cooked

1 cup

180

Canned sardines, canned mackerel

3 oz.

250-350

Tofu, firm, set with calcium

4 oz.

300-600

Cheese (moderate amounts) and cottage cheese

1 oz./ 1 cup

150-200

4. Eat plenty of fruits and vegetables.
At least 5 servings daily is best. Eating a variety of fruits and vegetables gives you potassium, magnesium, fiber, antioxidents, phytate and citrate - all of which may help keep stones from forming.

A serving means one piece of fruit or one potato or one cup of raw vegetables. For cooked vegetable, a serving is 1/2 cup. For smaller fruits and vegetables, a serving equals about 15-20 grapes or 5-8 baby carrots. Don't worry about overeating fruits and vegetables!

5. Calcium oxalate stone formers should reduce oxalate.
If you form stones from high oxalate levels, you may need special diet guidelines to help reduce oxalate. Depending on why your oxalate level is high, your doctor may advise you to get more calcium with meals.

If your calcium intake is too low (less than 1,000 mg/day), eat more Foods Rich in Calcium listed in the table above. Eat one of these foods at each of your 3 daily meals to get more calcium.

Your doctor may also want you to eat fewer oxalate-rich foods. Nearly all plant foods have oxalate, but a few foods have a lot (more than 70 grams). These include:

  • Spinach (1/2 cup cooked or raw)
  • Rhubarb (1/2 cup)
  • Almonds (1 oz or 22 almonds)
  • Miso soup (1 cup)
  • Baked potato (medium, with skin)
  • Bulgur (cooked, 1 cup)
  • Beets (1/2 cup)
  • Navy beans (1/2 cup)

These are very healthy foods, so if you usually eat them, you may find that you can still eat them as long as you eat or drink something with them that has calcium. Your 24-hour urine test will help you check on this.

6. Uric acid stone formers should reduce uric acid levels.
If your doctor thinks your diet is raising your risk for uric acid stones, he or she will advise you to eat less meat, fish, seafood, poultry, pork, lamb, mutton, and game than you eat now. This might mean eating these foods once or twice rather than 2 or 3 times a day, or fewer times each week, or eating smaller portions when you eat these foods. The amount to limit depends on how much you eat now and how much your diet is affecting your uric acid levels.

7. Calcium stone formers should increase citrate levels.
Urinary citrate helps block calcium stones from forming. Low levels of urinary citrate can make your urine more acidic, which may cause calcium stones to form. A diet that makes your urine less acidic (more basic) can help prevent stones from forming. Your doctor may advise you to eat more fruits and vegetables and avoid high acid foods such as meats, fish, poultry, cheese, eggs and grains.

8. Cystine stone formers should drink even more fluids.
Doctors recommend that people who form cysteine stones drink more liquid than other stone formers. Usually 4 liters of liquid is advised to reduce cystine levels in your urine. If you form cystine stones your doctor will also advise you to get less salt in your diet. If you have cystine stones you should get less than 2,300 mg of sodium per day. Your doctor will also want you to limit animal protein (meats) intake.

Medications
Changing your diet and increasing fluids may not be enough to prevent stones from forming. Your doctor may recommend medications. The type of stone and the urine abnormalities you have will help your doctor decide if you need medications and which are best. Common medications include:

Thiazide diuretics are for patients who have calcium stones and high levels of calcium in their urine. Diuretics lower urine calcium by helping the kidney take calcium from the urine and put it back in the blood stream. When taking diuretics, you need to limit salt. These medications work best when urine sodium is low.

Potassium citrate is for patients with calcium stones and low urinary citrate and for those with uric acid and cystine stones. Potassium citrate makes the urine less acidic or more alkaline (basic). This helps prevent cystine and uric acid stones. It also raises the citrate level in the urine, helping to prevent calcium stones.

Allopurinol is prescribed for gout, which is caused by a high uric acid in the body. Allopurinol lowers the level of uric acid in the body and therefore in the urine, helping to prevent calcium and uric acid stones.

Acetohydroxamic acid (AHA) is for patients who produce struvite or infection stones. These stones form because of repeated urinary tract infections (UTI). AHA makes the urine unfavorable for struvite stones to form. Because the best way to prevent stuvite stones is to prevent repeated UTI with bacteria known to cause the stones and to completely remove the stones with surgery.

Cystine-binding thiol drugs are used only for patients who form cystine stones. These medications bind to cystine in the urine and form a compound that is less likely than cystine to crystallize in the urine. They are often used when other measures fail, such as raising fluid intake, reducing salt intake, or using potassium citrate.

Vitamin supplements may reduce the risk of stones in people who form calcium oxalate stones. Vitamin B6, Omega-3 fatty acids and probiotics have been shown to reduce the risk of forming stones in some situations. If you form these types of stones you should not take Vitamin C and cranberry tablet supplements. They may increase your risk for stones.

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Frequently Asked Questions (FAQ)

1. What happens if my stones come back?
Even if you've had surgery to treat your kidney stones and have changed your diet or are taking medications, your body may still form another stone. However, with appropriate dietary and medical therapy recurrent stone formation can be dramatically reduced.

2. Why is it important that I follow-up with my doctor about my kidney stones?
During treatment your doctor may ask you to collect another 24-hour urine specimen and have your blood work checked to see if your urine abnormalities have improved and if you are having any side effects from your medications.

If you form stones often, you will need monitoring with X-rays and urine studies to be sure no new stones are forming and to make sure your mediations and diet changes are working.

3. How can producing kidney stones affect my life?
Kidney stones can cause pain that comes and goes. They may require a trip to the emergency room and surgery to remove them. Surgery, medications and diet changes to prevent kidney stones can be inconvenient and expensive. Kidney stones can be costly due to lost time at work.

4. Can kidney stones damage my kidneys?
Yes, but rarely. Kidney stones can cause damage if they cause repeated or serious infection or cause kidney blockage for a long time. If left untreated, they can cause the kidney to stop working.

5. How do I manage my kidney stone along with my other health problems such as diabetes and/or heart disease?
Diet changes recommended for heart disease often also help prevent stones. A healthy diet with lots of fruits and vegetables and less animal protein and salt can help avoid stones and other conditions. But there can be some conflicting diet recommendations for diabetes and stones. You can learn more from your doctor or dietician. Keeping a normal weight can also help avoid diabetes and stone disease.

6. My stone has not passed. Do I need surgery?
If a stone in the ureter does not pass in a reasonable time or is causing pain or infection, you will need surgery to remove it.

7. Will my children get kidney stones because I have them?
Kidney stones are more common in relatives of a person with kidney stones. Some conditions that cause stones may be inherited. But sometimes kidney stones form in relatives because of similar diet and lifestyle.

8. Are gallstones and kidney stones related?
No. There is no known link between gallstones and kidney stones. They form in different areas of the body and are made of different substances. If you have a gallstone, you are not necessarily more likely to develop kidney stones.

9. What is a staghorn stone?
Because they look like the horns of a stag, or deer, these stones get their name from the shape they take as they grow to fill the inside or drainage part of the kidney. Staghorn stones often form because of repeated urinary tract infections (UTI) with certain kinds of bacteria. Even though they can grow to a large size, they are often overlooked by patients because they cause little or no pain. A staghorn stone can lead to poor kidney function, even without blocking the passage of urine.

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Additional Resources

1. Academy of Nutrition and Dietetics: "Nutrition Care Manual"
Review evidence based diet manuals from registered dietitians, dietetic technicians and allied health professionals.

2. Medline Plus
Kidney Stones

Interactive Kidney Stones Module (English)

Interactive Kidney Stones Module (Spanish)

3. National Kidney and Urologic Diseases Information Clearinghouse (NKUDIC)
Kidney Stones in Adults

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Kidney and Ureteral Stones Glossary
  • abdomen: Also referred to as the belly. It is the part of the body that contains all of the internal structures between the chest and the pelvis.

  • abdominal: in the abdomen, the cavity of this part of the body containing the stomach, intestines and bladder.

  • anesthesia: Loss of sensation in any part of the body induced by a numbing or paralyzing agent. Often used during surgery to put a person to sleep.

  • bacteria: Single-celled microorganisms that can exist independently (free-living) or dependently upon another organism for life (parasite). They can cause infection and are usually treated with antibiotics.

  • benign: Not malignant; not cancerous.

  • bladder: The bladder is a thick muscular balloon-shaped pouch in which urine is stored before being discharged through the urethra.

  • bowel: Another word for intestines or colon.

  • calcium: A mineral that the body needs for strong bones and teeth. Calcium may form stones in the kidney.

  • calcium oxalate stones: Most common kidney stones, made up of hard crystalline compound, often mixed with calcium phosphate.

  • cancer: An abnormal growth that can invade nearby structures and spread to other parts of the body and may be a threat to life.

  • CAT scan: Also known as computerized tomography, computerized axial tomography or CT scan. A diagnostic imaging procedure that uses a combination of X-rays and computer technology to produce cross-sectional images of the body. Shows detailed images of any part of the body, including bones, muscles, fat and organs. CT scans are more detailed than general X-rays.

  • chronic: Lasting a long time. Chronic diseases develop slowly. Chronic renal (kidney) failure may develop over many years and lead to end-stage renal (kidney) disease.

  • citrate: A salt of citric acid.

  • contract: To shrink or become smaller.

  • crystals: Solids formed by a repeating, three-dimensional pattern of atoms, ions or molecules.

  • cutaneous: Relating to the skin.

  • cyst: An abnormal sac containing gas, fluid or a semisolid material. Cysts may form in kidneys or other parts of the body.

  • cystine: An amino acid found in blood and urine. Amino acids are building blocks of protein.

  • cystine stone: A rare form of kidney stone consisting of the amino acid cystine.

  • cystinuria: A condition in which urine contains high levels of the amino acid cystine. If cystine does not dissolve in the urine, it can build up to form kidney stones.

  • dehydration: Dangerous lack of water in the body resulting from inadequate intake of fluids or excessive loss through sweating, vomiting or diarrhea.

  • diabetes: A medical disorder of increased blood sugar levels that can cause bladder and kidney problems.

  • diagnosis: The process by which a doctor determines what disease or condition a patient has by studying the patient's symptoms and medical history, and analyzing any tests performed (e.g., blood tets, urine tests, brain scans, etc.).

  • distal: Location of urethral opening between the middle or the penile shaft and the head of the penis (glans).

  • diuretic: A drug that increases the amount of water in the urine, removing excess water from the body.

  • gas: Material that results from: swallowed air, air produced from certain foods or that is created when bacteria in the colon break down waste material. Gas that is released from the rectum is called flatulence.

  • gastrointestinal: Also referred to as GI. The stomach and the intestines.

  • gene: The basic unit capable of transmitting characteristics from one generation to the next.

  • gland: A mass of cells or an organ that removes substances from the bloodstream and excretes them or secretes them back into the blood with a specific physiological purpose.

  • groin: The area where the upper thigh meets the lower abdomen.

  • hematuria: Blood in the urine, which can be a sign of a kidney stone or other urinary problem. Gross hematuria is blood that is visible to the naked eye. Microscopic hematuria cannot be seen but is detected on a urine test.

  • hormone: A natural chemical produced in one part of the body and released into the blood to trigger or regulate particular functions of the body. Antidiuretic hormone tells the kidneys to slow down urine production.

  • hydronephrosis: Swelling of the top of the ureter, usually because something is blocking the urine from flowing into or out of the bladder.

  • hydronephrosis: Swelling at the top of the ureter, usually because something is blocking the urine from flowing into or out of the bladder.

  • hydronephrosis: Swelling at the top of the ureter usually because something is blocking the urine from flowing into or out of the bladder.

  • hyperoxaluria: Unusually large amounts of oxalate in the urine, leading to kidney stones.

  • incision: Surgical cut for entering the body to perform an operation.

  • infection: A condition resulting from the presence of bacteria or other microorganisms.

  • intestine: The part of the digestive system between the stomach and the anus that digests and absorbs food and water.

  • intestines: the portion of the alimentary canal extending from the stomach to the anus consisting of two segments, the small intestine and the large intestine.

  • invasive: Having or showing a tendency to spread from the point of origin to adjacent tissue, as some cancers do. Involving cutting or puncturing the skin or inserting instruments into the body.

  • invasive: Not just on the surface; with regard to bladder cancer, a tumor that has grown into the bladder wall.

  • ions: Electrically charged atoms.

  • kidney: One of two bean-shaped organs that filter wastes from the blood and discharge these waste products in urine. The kidneys are located on either side at the level of the 12th ribs toward the back. The kidneys send urine to the bladder through tubes called ureters.

  • kidney stone: A stone that develops from crystals that form in urine and build up on the inner surfaces of the kidney, in the renal pelvis or in the ureters. (Also see nephrolithiasis.)

  • kidneys: One of two bean-shaped organs that filter wastes from the blood and discharge these waste products in urine. The kidneys are located on either side at the level of the 12th ribs toward the back. The kidneys send urine to the bladder through tubes called ureters.

  • laser: Device that utilizes the ability of certain substances to absorb electromagnetic energy and re-radiates as a highly focused beam of synchronized single wave-length radiation.

  • lithotripsy: A method of breaking up kidney stones using shock waves or other means.

  • liver: A large, vital organ that secretes bile, stores and filters blood, and takes part in many metabolic functions, for example, the conversion of sugars into glycogen. The liver is reddish-brown, multilobed, and in humans is located in the upper right part of the abdominal cavity.

  • metabolism: The ongoing interrelated series of chemical interactions taking place in living organisms that provide the energy and nutrients needed to sustain life

  • multiple sclerosis: A serious progressive disease of the central nervous system.

  • nephroscope: A telescope used to examine the interior of the kidney and for removing stones within the kidney.

  • neurologic: Pertaining to the nervous system.

  • oxalate: A chemical that combines with calcium in urine to form the most common type of kidney stone (calcium oxalate stone).

  • penis: The male organ used for urination and sex.

  • PNL: Also known as percutaneous nephrolithtomy. A method for removing kidney stones through keyhole surgery using an instrument called a nephroscope.

  • potassium: An alkali element.

  • primary hyperoxaluria: A rare metabolic disease caused by the liver making too much oxalic acid that is excreted in the urine of the affected person.

  • renal: Pertaining to the kidneys.

  • renal tubular acidosis: A defect in the kidneys that hinders their normal excretion of acids. Failure to excrete acids can lead to weak bones, kidney stones and poor growth in children.

  • sonogram: Also referred to as a ultrasound. A technique that bounces painless sound waves off organs to create an image of their structure to detect abnormalities.

  • spina bifida: A condition at birth in which part of the vertebral bodies (or back bones) fail to seal off completely and some part of the spinal cord protrudes through this opening. This condition is often associated with bladder and bowel control problems as well as lack of control of voluntary movement in the lower body.

  • stent: With regard to treating ureteral stones, a tube inserted through the urethra and bladder and into the ureter. Stents are used to aid treatment in various ways, such as preventing stone fragments from blocking the flow of urine.

  • stoma: An opening.

  • stone: Small hard mass of mineral material formed in an organ.

  • stone disease: An abnormal concretion of mineral salts around organic material found especially in hollow organs or ducts.

  • struvite stone: A type of kidney stone caused by bacterial urinary infection.

  • SWL: Also referred to as shock wave lithotripsy. High energy shock waves, in conjunction with X-ray and/or ultrasound, are focused on kidney or ureteral stones and cause the stone to break into tiny pieces which pass easily out of the body during urination.

  • thyroid: An endocrine gland located in the neck that secretes the hormones responsible for controlling metabolism and growth.

  • urate: A salt of uric acid.

  • ureter: One of two tubes that carry urine from the kidneys to the bladder.

  • ureteral: Pertaining to the ureter. Also referred to as ureteric.

  • ureteroscope: A tool for examining the bladder and ureters and for removing kidney stones through the urethra. This procedure is called ureteroscopy (yoo-ree-tur-AH-skoh-pee).

  • ureters: Tubes that carry urine from the kidneys to the bladder.

  • ureters: Pair of tubes that carry urine from each kidney to the bladder.

  • urethra: A tube that carries urine from the bladder to the outside of the body. In males, the urethra serves as the channel through which semen is ejaculated and it extends from the bladder to the tip of the penis. In females, the urethra is much shorter than in males.

  • urge: Strong desire to urinate.

  • uric: Relating to urine.

  • uric acid: A slightly soluble acid present in urine and blood produced by the body's breakdown of waste nitrogenous substances.

  • uric acid stone: A kidney stone that may result from animal protein in the diet. When the body breaks down this protein, uric acid levels rise and can form stones.

  • urinary: Relating to urine.

  • urinary tract: The system that takes wastes from the blood and carries them out of the body in the form of urine. Passageway from the kidneys to the ureters, bladder and urethra.

  • urinary tract infection: Also referred to as UTI. An illness caused by harmful bacteria, viruses or yeast growing in the urinary tract.

  • urinate: To release urine from the bladder to the outside. Also referred to as void.

  • urination: The passing of urine.

  • urine: Liquid waste product filtered from the blood by the kidneys, stored in the bladder and expelled from the body through the urethra by the act of urinating (voiding). About 96 percent of which is water and the rest waste products.

  • urologist: A doctor who specializes in diseases of the male and female urinary systems and the male reproductive system. Click here to learn more about urologists. (Download the free Acrobat reader.)

  • urology: Branch of medicine concerned with the urinary tract in males and females and with the genital tract and reproductive system of males.

  • URS: Also known as ureteroscopy. A ureteroscope is inserted through the urethra and bladder to inspect the ureters. Often used for retrieval of kidney stones.

  • UTI: Also referred to as urinary tract infection. An illness caused by harmful bacteria growing in the urinary tract.

  • vas: Also referred to as vas deferens. The cordlike structure that carries sperm from the testicle to the urethra.

  • void: To urinate, empty the bladder.

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