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Kidney Stones

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Welcome to our health education library. The information shared below is provided to you as an educational and informational source only and is not intended to replace a medical examination or consultation, or medical advice given to you by a physician or medical professional.

People who form kidney stones often share certain risk factors. Middle-aged men, for instance, are more likely to form stones than other people. A family history of stones also increases your risk. Assess your risk factors by checking the questions below.

Do you drink fewer than eight glasses of water a day?

Do you live in the Southeast or another hot climate?

Have you ever had a kidney stone before?

Has anyone in your family had kidney stones?

Are you a male between the ages of 30 and 50?

Have you had a kidney infection in the last few months?

Do you take large doses of calcium or vitamin C supplements?

Do you often drink or eat dairy products (high-calcium foods)?

Do you often drink cola or tea, or eat chocolates, spinach, or peanuts (high-oxalate foods)?

How Great Is Your Risk?

The more times you answered “yes,” the greater your risk of forming kidney stones. But you can help reduce your risk. Learn more about kidney stones, how they form, and how to prevent them.

Your kidneys are the chemical filters for your body. These bean-shaped organs constantly screen your blood, removing wastes and excess fluids. Healthy kidneys maintain the chemical balance your body needs.

What Are Kidney Stones?

Kidney stones are made up of chemical crystals that separate out from urine. These crystals clump together to make “stones.” They form in the calix of the kidney. They may stay in the kidney or move into the urinary tract.

Why Kidney Stones Form

Kidneys form stones for many reasons. If you don’t drink enough fluid, for instance, you won’t have enough urine to dilute chemicals. Then the chemicals may form crystals, which can develop into stones.

  • Fluid loss (dehydration) can concentrate urine, causing stones to form.
  • Certain foods contain large amounts of the chemicals that sometimes crystallize into stones.
  • Kidney infections foster stones by slowing urine flow or changing the acid balance of your urine.
  • Family history – if relatives have had kidney stones, you’re more likely to have them, too.


Where Stones Form

Stones begin in the cup-shaped part of the kidney (calix). Some stay and grow. Others move within the kidney or into the ureter. There they can lodge, block the flow of urine, and cause pain.


Many stones cause sudden and severe pain and bloody urine. Others cause nausea or frequent, burning urination. Symptoms often depend on your stone’s size and location. Fever may indicate a serious infection. Call your doctor right away if you develop a fever.

There are several types of kidney stones. Your kidney stone’s size and shape determine whether it is likely to pass by itself. Your kidneys filter your blood and release chemicals into the urine. If certain chemicals build up in the kidneys, they can form a stone. Knowing a stone’s composition helps your doctor find its cause. Then he or she can suggest the best treatment.

1.) Size

A stone may be as small as a grain of sand. Or it may be as large as a golf ball. Small stones may pass out of the body when you urinate.

2.) Shape

Small smooth, round stones may pass easily. Jagged-edged stones often lodge inside the kidney or ureter. Staghorn stones can fill the entire kidney.

3.) Composition

Most stones are calcium oxalate, a hard compound. Stones made of cystine or uric acid, or caused by infection, are less dense. Stones often contain more than one chemical.

Treating Your Stones

You and your doctor will work together to form a treatment plan. Your doctor may suggest that you let your stone pass naturally. Or you may manage it with medications. SWL (shock wave lithotripsy) or surgery may also help. And you will be told how you can help prevent kidney stones in the future.

A medical evaluation helps your doctor find out what’s causing your symptoms. A health history and physical exam may reveal signs of a stone. Diagnostic studies can confirm the presence of a stone and locate it. Detailed metabolic tests of your blood, urine, and the stone may also be done. These test results help your doctor recommend treatment.

Diagnostic Tests

These tests confirm your doctor’s diagnosis. They can detect infection or reveal the image of a stone. You may not need all of these tests.

  • Urinalysis looks for blood in the urine (hematuria), one sign of a stone. Pus in the urine (pyuria) suggests a stone or infection.
  • A urine culture can reveal a urinary tract infection. Test results appear 24-48 hours after the urine sample is collected.
  • Blood tests can confirm a kidney infection. They show any abnormalities in the white cell count of your blood.
  • A KUB (Kidney, Ureter, Bladder) x-ray provides a view of the entire abdomen. An IVP (intravenous pyelogram) x-ray uses dye to locate your stone.
  • Ultrasound uses sound waves to create a picture of the kidney. This helps show stones and reveal blockages in the urinary tract.
  • A CT (computed tomography) scan takes multiple x-rays of the urinary tract. This helps locate and identify a stone. A CT scan can be done without dye. This makes it safe for patients who have dye allergies or kidney disease.


Metabolic Tests

If you have a stone, your doctor may order one or more metabolic tests. These tests may show why you formed a stone. And they show what kind of stone you may form in the future. This helps your doctor plan your treatment and prevention program.

  • Stone analysis shows your stone’s chemical makeup, if the stone is retrieved. This may suggest the cause of your stone.
  • Blood tests measure your levels of stone-related chemicals, such as calcium.
  • A 24-hour urine sample shows the levels of stone-related chemicals in your urine. You collect all your urine for 24 hours in a special container.
  • Provocative tests show how your kidneys handle chemicals, such as calcium. The tests monitor your response to low- or high-calcium diets.

Most kidney stones are about the size of a grape seed. Stones of this size are small enough to pass naturally. Once it is passed, a stone can be analyzed. This “wait and see” approach is called expectant therapy. Small stones can often be passed with expectant therapy. If pain is a problem, ask your doctor about pain medications. Then follow his or her directions on how much water to drink. Drinking more water creates more urine to “flush out” your stone. Also be sure to strain your urine. Take any stones you pass to your doctor for analysis.

Drink Lots of Water

Drinking lots of water may help your stone pass. Water also dilutes the chemicals in your urine. This reduces your risk of forming new stones. You may be told to drink 8 twelve-ounce glasses of water a day. Avoid liquids that dehydrate you, such as those containing caffeine or alcohol.

Strain Your Urine

Straining your urine lets you collect your stone for analysis. Use the strainer each time you urinate. Strain your urine for as long as your doctor suggests. Watch for brown, tan, gold, or black specks or tiny pebbles. These may be kidney stones.

Follow Up with Your Doctor

Follow up by taking any stones you find to your doctor for analysis. The type of stone you have determines your diet and prevention program. You may need more tests in the future. These tests will ensure that new stones are not forming.

In some cases, your doctor may prescribe medications to dissolve or prevent stones. Or medications may be prescribed to stop an infection. Once the infection is controlled, your stone can be removed.


For uric acid or cystine stones, your doctor may prescribe medications. You’ll take these for your lifetime. Medications can’t dissolve calcium oxalate stones, but often help prevent them. If you have an infection stone, your doctor may prescribe antibiotics. You may take these before and after your stone is removed.

Uric acid stones are caused by too much uric acid in your urine. This can be worsened by a high-meat diet. Allopurinol reduces uric acid. The stone can be dissolved with bicarbonate, potassium citrate, or a similar drug.

Cystine stones are caused by too much cystine (an amino acid) in your urine. This condition is uncommon and inherited. Penicillamine or tiopronin reduces cystine. Bicarbonate, potassium citrate, or a similar drug dissolves cystine stones.

Infection stones are caused by kidney or bladder infections that change the chemical balance of your urine. Antibiotics control the infection and may slow the stone’s growth. Then your stone is removed.

Ureteroscopic stone removal may be done before, after, or instead of other treatments. If you need this procedure, your doctor will discuss its risks and possible complications. You will be told how to prepare. And you will be told about anesthesia that will keep you pain-free during treatment.

Removing the Stone Through the Ureter

Ureteroscopic stone removal extracts a small stone in your ureter without an incision. Your doctor places a viewing tube (ureteroscope) in your ureter. A wire basket inserted through the tube removes the stone. Sometimes, a laser or a mechanical device is used to break up the stone. A soft tube may be left in your ureter briefly to drain urine. The stone may be fragmented. The stone is then withdrawn or passed.

Your Recovery

This is an outpatient or overnight procedure. For a few days after surgery, you may feel some pain when you urinate. Or you may need to urinate more often, or have bloody urine. You may have a ureteral stent. This is a soft tube that prevents blockage from swelling after the procedure. The stent is removed when the swelling goes down, often within days. Follow up as instructed to check for any new stones.

Call Your Doctor If:

  • You have sudden pain or flank pain.
  • You have a fever over 100.1°F.
  • You have nausea that lasts for days.
  • You have heavy bleeding when you urinate.
  • You have heavy bleeding through your drainage tube.
  • You have swelling or redness around your incision.

Percutaneous lithotripsy may be done before, after, or instead of other treatments. If you need this procedure, your doctor will discuss its risks and possible complications. You will be told how to prepare. And you will be told about anesthesia that will keep you pain-free during treatment.

Lithotripsy with Incision

Percutaneous lithotripsy removes larger stones through a small incision in your side. Your doctor places a viewing tube through your incision. The stone is sighted, shattered with a special device if needed, and removed. Afterward, you’ll briefly have a small soft tube in your incision. This tube carries urine away from your kidney and out of your body. Pieces of stone are plucked or sucked out through the incision.

Your Recovery

You may spend 1-3 days in the hospital. The tube in your side will be removed during or shortly after your hospital stay. A follow-up visit in three months will ensure that your stone is gone. Later visits will help your doctor spot new stones if any form.

Call Your Doctor If You Have:

  • Sudden pain or flank pain.
  • A fever over 100.1°F.
  • Nausea that lasts for days.
  • Heavy bleeding when you urinate or through your drainage tube.
  • Swelling or redness around your incision.

Open surgery may be done before, after, or instead of other treatments. If you need surgery, your doctor will discuss its risks and possible complications. You will be told how to prepare. And you will be told about anesthesia that will keep you pain-free during treatment.

Open Surgery

Open surgery removes very large stones or stones that cannot be removed by other means. For this surgery, your doctor makes an incision in your side. Your kidney or ureter is opened, and the stone is removed. Then your kidney or ureter is sutured closed. A drain is left near the incision to carry urine away from the wound. The drain is later removed.

Your Recovery

You may spend up to 7 days in the hospital. The drain in your incision will be removed before you leave. You’ll need about 4-6 weeks of rest at home to recover fully. Follow-up visits will help your doctor spot any new stones early. This may help you avoid future surgeries.

Call Your Doctor If:

  • You have sudden pain or flank pain.
  • You have a fever over 100.1°F.
  • You have nausea that lasts for days.
  • You have heavy bleeding when you urinate.
  • You have heavy bleeding through your drainage tube.
  • You have swelling or redness around your incision.

If you’ve had a kidney stone, you may worry that you’ll have another. Removing or passing your stone doesn’t prevent future stones. With your doctor’s help, though, you can reduce your risk of forming new stones. Follow up with your doctor to help detect new stones. You may need follow-up every 3 months to a year for a lifetime.

Drink Lots of Water

Staying well-hydrated is the best way to reduce your risk of future stones. Drink 8 twelve-ounce glasses of water daily. Have two with each meal and two between meals. Try keeping a pitcher of water nearby during the day and at night.

Take Medications If Needed

Medications, including vitamins and minerals, may be prescribed for certain types of stones. You may want to write your doses and medication times on a calendar. Some medications decrease stone-forming chemicals in your blood. Others help prevent those chemicals from crystallizing in urine. Still others help keep a normal acid balance in your urine.

Follow Your Prescribed Diet

Your doctor will tell you which foods contain the chemicals you should avoid. Your doctor may also suggest talking to a dietitian. He or she can help you plan meals you’ll enjoy. These meals won’t put you at risk for future stones. You may be told to limit certain foods, depending upon which type of stones you’ve had.

For calcium oxalate stones: Limit high-calcium foods (dairy products), and calcium or vitamin C supplements. Limit high-oxalate foods (such as cola, tea, chocolate, and peanuts).

For uric acid stones: Limit high-purine foods, such as anchovies, poultry, and organ meats. These foods increase uric acid production.

For cystine stones: Limit high-methionine foods (fish is the most common). These foods increase production of cystine.

Health Education Library by The Wisconsin Institute of Urology Urologists Team serves patients in Neenah, Oshkosh, Fond Du Lac, New London, Shawano, & Waupaca, in Northeast Wisconsin

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