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| The Urinary System and How It Works |
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The urinary system includes two
kidneys,
two tube-like
ureters
that connect the kidneys to the
bladder,
and another tube, the
urethra,
that connects the bladder to the outside of the body. The parts of the urinary system are shown below.
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| Front Interior View of Urinary System (Male or Female) |
Each kidney is bean-shaped and about the size of an adult's fist. The kidneys are located below the ribs and toward the back. They contain nearly 40 miles of tubes, most of them tiny, that process some 100 gallons of blood each day. The kidneys filter and clean the blood, and they produce urine from excess water and dissolved solids.
The ureters carry waste, as urine, from the kidneys to the bladder. The bladder, located in the lower abdomen, is a balloon-like organ that stores urine. A bladder can hold over a pint of urine. During urination, the urethra carries urine from the bottom of the bladder out of the body.
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| What causes kidney stones? |
Kidney stones are hardened crystal clumps that can develop in the urinary system. They usually form because there is a breakdown in the balance of liquids and dissolved solids in the urine. The kidneys must keep the right amount of water in the body while they remove materials that the body cannot use. If this balance is disturbed, the urine can become overloaded with substances (usually small crystals) that won't dissolve in water. Crystals begin to stick together and slowly add layer upon layer to form a stone. A kidney stone may grow for months or even years before it causes a problem.
Experts suggest that age, diet, climate, infection and inherited disorders are some possible causes of kidney stones. |
| What Does a Kidney Stone Look Like? |
| Kidney stones don't all look the same. The color depends on what chemicals are in it. Most are yellow or brown, but they can be tan, gold, or black. Stones can be round, jagged, or even have branches. They vary in size from specks to pebbles to stones as big as golf balls. |
| Can kidney stones damage the kidney? |
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Kidney stones can cause kidney damage. Whether there is damage and, if so, how much there is depends on the location of the stone in the urinary system. To avoid or minimize damage, it is important to eliminate stones that form and to prevent new ones from developing. Therefore, your family doctor may refer you to a
urologist
, a doctor who specializes in urinary diseases.
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Anyone can get kidney stones, but some people are more likely to develop stones than others. Typically, a person with a kidney stone is a man 20 to 60 years old. Although four out of five kidney stone sufferers are men, women also get kidney stones. Often, there is a family history of kidney stones. Chronic dehydration (lack of body water) can lead to kidney stones. Very hot weather, heavy sweating, or too little fluid intake contribute to the formation of kidney stones. People who work outdoors in hot weather and who do not drink enough fluids may increase their risk of getting stones.
Some physicians believe that our rich diet in the U.S. may promote the development of kidney stones. Experts note that the incidence of kidney stones has tripled in Japan since World War II - at the same time the Japanese diet has become more like our own.
A variety of other conditions are linked with kidney stone development. These include urinary tract blockage, urinary infections that recur, bowel disease, and certain inherited disorders. People who are paralyzed or who have to rest in bed for long periods of time are also at increased risk for kidney stones, as are men and women who fly long space missions.
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| Types of Stones and Their Causes |
Calcium oxalate and phosphate stones.
Calcium oxalate and phosphate stones are made up of a hard crystal compound. These stones have become more common in recent years with about 70% to 80% of all kidney stones currently made up of calcium oxalate and phosphate. Calcium oxalate is often mixed with phosphate, but either pure calcium oxalate or calcium phosphate stones may occur.
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Hypercalciuria (too much calcium in the urine) often causes calcium oxalate stones to develop. Almost 40% of patients with calcium oxalate stones have an inherited
metabolic disorder
that causes a build-up of calcium in the urine. Certain drugs, such as furosemide (a diuretic), antacids, and steroids, also may cause an overload of calcium in the urine. Other factors associated with hypercalciuria include overactive parathyroid glands, too much vitamin A or D, and a diet high in purine from meat, fish, and poultry.
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| Another cause of calcium oxalate stones is too much oxalate in the urine. This can result from too much oxalate production by the body or not enough calcium in your diet. Large doses of vitamin C or not enough vitamin B can also lead to excess oxalate in the urine. |
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Struvite (or infection) stones
. About 10% to 28% of all stones are associated with bacterial urinary infections. Such stones are called struvite stones, and like urinary infections, are more common in women. In patients with struvite stones, it is important not only to remove the stone but also to prevent recurrence of the urinary infection.
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Uric acid stones
. About 5% to 13% of kidney stones contain uric acid, which arises when the body breaks down certain foods, especially meats. These stones are more common among men and develop when there is too much uric acid in the urine. Patients with
gout,
a metabolic disorder associated with high uric acid levels, are especially prone to uric acid stones.
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Cystine stones
. Another inherited condition can cause too much cystine (produced by the breakdown of protein from your diet) to collect in the urine. The cystine tends to form crystals that develop into cystine stones. These stones are relatively rare, accounting for only about 1% to 3% of all kidney stones.
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Rare stones. Other rare stones (xanthine, silicate) may occur. |
| Five Common Types of Kidney Stones |
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Calcium oxalate
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Calcium phosphate (can be mixed with Calcium oxalate)
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Struvite (infection)
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Uric acid |
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Cystine |
| Pre-Treatment Instructions |
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For two weeks before the procedure do not take Aspirin or aspirin containing medications such as Ibuprofen (Motrin), Indocin or Persantine. Please refer to the
list of other medications
to be avoided. If you take any of these medications for your heart or to prevent stroke,
consult your family doctor before stopping them.
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Laboratory Testing |
| Certain blood tests and other examinations may be required within 2 weeks prior to undergoing your lithotripsy procedure. Please be sure your urologist has either 1) scheduled testing for you at an independent laboratory or 2) arranged testing through your family medial doctor. |
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Diet Instructions |
The day before the procedure (for example, on Sunday if your procedure is scheduled for Monday) please:
Eat a low fiber breakfast and lunch (eggs, white bread, tuna salad, cold cuts; no cereal, whole grain breads, or vegetables). For supper, have only clear liquids. These may include clear soups, Jell-O, fruit juice, coffee, tea or sodas. Drink at least three glasses of clear liquids (including water), but no solid food in the afternoon and evening (after 6:00 pm).
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| DO NOT EAT OR DRINK ANYTHING AFTER MIDNIGHT. |
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On The Day of the Procedure |
Please:
Do
not
eat or drink anything for breakfast. You may rinse your mouth for tooth brushing.
Although you may be scheduled as an outpatient, occasionally hospitalization is recommended following the procedure. Please leave your valuables at home (the hospital is not responsible for personal property), but bring any items (eyeglasses, toothbrush, etc.) you might need for an overnight stay. Gowns and robes will be provided.
Bring your medications in their original containers.
If you are on heart, blood pressure or asthma medication,
please take your usual morning dose with a sip of water.
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If you are a diabetic, be sure to ask your doctor for any necessary modifications to the above instructions.
You may take a bath or shower the night before or morning of the procedure. Do not use body lotions, oils or powders after. |
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Women |
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The procedure should not be done if there is a chance you may be pregnant.
You should have a pregnancy test unless: a) you are using a reliable form of contraceptive (such as tubal ligation, hysterectomy, birth control pills, vasectomy); b) your last period began less than 5 days ago; or c) you have passed menopause.
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If you have any questions concerning the above instructions, please contact your urologist.
If a change in your physical condition develops prior to treatment, or if you develop a cold, persistent cough, rash or fever, please notify your urologist prior to your treatment. |
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