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Kidney Stones in Adults
Kidney stones, one of the most painful of the urologic disorders, are
not a product of modern life. Scientists have found evidence of kidney
stones in a 7,000-year-old Egyptian mummy. Unfortunately, kidney stones
are one of the most common disorders of the urinary tract; patients made
more than 1.3 million visits to health care providers to have their stones
treated in 1997. In 1999, more than a quarter million hospitalized
patients had a diagnosis of kidney stones. An estimated 10 percent of
people in the United States will have a kidney stone at some point in
their lives. Men tend to be affected more frequently than women.
Most kidney stones pass out of the body without any intervention by a
physician. Stones that cause lasting symptoms or other complications may
be treated by various techniques, most of which do not involve major
surgery. Also, research advances have led to a better understanding of the
many factors that promote stone formation.
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| The urinary tract |
The urinary tract, or system, consists of the kidneys, ureters,
bladder, and urethra. The kidneys are two bean-shaped organs located below
the ribs toward the middle of the back. The kidneys remove extra water and
wastes from the blood, converting it to urine. They also keep a stable
balance of salts and other substances in the blood. The kidneys produce
hormones that help build strong bones and help form red blood cells.
Narrow tubes called ureters carry urine from the kidneys to the
bladder, a triangle-shaped chamber in the lower abdomen. Like a balloon,
the bladder's elastic walls stretch and expand to store urine. They
flatten together when urine is emptied through the urethra to outside the
body.
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A kidney stone is a hard mass developed from crystals that separate
from the urine and build up on the inner surfaces of the kidney. Normally,
urine contains chemicals that prevent the crystals from forming. These
inhibitors do not seem to work for everyone, however, so some people form
stones. If the crystals remain tiny enough, they will travel through the
urinary tract and pass out of the body in the urine without being noticed.
Kidney stones may contain various combinations of chemicals. The most
common type of stone contains calcium in combination with either oxalate
or phosphate. These chemicals are part of a person's normal diet and make
up important parts of the body, such as bones and muscles.
A less common type of stone is caused by infection in the urinary
tract. This type of stone is called a struvite or infection stone. A bit
less common is the uric acid stone. Cystine stones are rare.
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| Kidney stones in kidney, ureter, and bladder |
Urolithiasis is the medical term used to describe stones occurring in
the urinary tract. Other frequently used terms are urinary tract stone
disease and nephrolithiasis. Doctors also use terms that describe the
location of the stone in the urinary tract. For example, a ureteral stone
(or ureterolithiasis) is a kidney stone found in the ureter. To keep
things simple, however, the term "kidney stones" is used throughout this
fact sheet.
Gallstones and kidney stones are not related. They form in different
areas of the body. If you have a gallstone, you are not necessarily more
likely to develop kidney stones.
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For unknown reasons, the number of people in the United States with
kidney stones has been increasing over the past 20 years. White Americans
are more prone to develop kidney stones than African Americans. Stones
occur more frequently in men. Kidney stones strike most typically between
the ages of 20 and 40. Once a person gets more than one stone, others are
likely to develop.
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Doctors do not always know what causes a stone to form. While certain
foods may promote stone formation in people who are susceptible,
scientists do not believe that eating any specific food causes stones to
form in people who are not susceptible.
A person with a family history of kidney stones may be more likely to
develop stones. Urinary tract infections, kidney disorders such as cystic
kidney diseases, and metabolic disorders such as hyperparathyroidism are
also linked to stone formation.
In addition, more than 70 percent of people with a rare hereditary
disease called renal tubular acidosis develop kidney stones.
Cystinuria and hyperoxaluria are two other rare, inherited metabolic
disorders that often cause kidney stones. In cystinuria, too much of the
amino acid cystine, which does not dissolve in urine, is voided. This can
lead to the formation of stones made of cystine. In patients with
hyperoxaluria, the body produces too much of the salt oxalate. When there
is more oxalate than can be dissolved in the urine, the crystals settle
out and form stones.
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| Shapes of various stones. Sizes are usually
smaller than shown here. |
Hypercalciuria is inherited. It is the cause of stones in more than
half of patients. Calcium is absorbed from food in excess and is lost into
the urine. This high level of calcium in the urine causes crystals of
calcium oxalate or calcium phosphate to form in the kidneys or urinary
tract.
Other causes of kidney stones are hyperuricosuria (a disorder of uric
acid metabolism), gout, excess intake of vitamin D, and blockage of the
urinary tract. Certain diuretics (water pills) or calcium-based antacids
may increase the risk of forming kidney stones by increasing the amount of
calcium in the urine.
Calcium oxalate stones may also form in people who have a chronic
inflammation of the bowel or who have had an intestinal bypass operation,
or ostomy surgery. As mentioned above, struvite stones can form in people
who have had a urinary tract infection. People who take the protease
inhibitor indinavir, a drug used to treat HIV infection and AIDS, are at
risk of developing kidney stones.
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Usually, the first symptom of a kidney stone is extreme pain. The pain
often begins suddenly when a stone moves in the urinary tract, causing
irritation or blockage. Typically, a person feels a sharp, cramping pain
in the back and side in the area of the kidney or in the lower abdomen.
Sometimes nausea and vomiting occur. Later, pain may spread to the groin.
If the stone is too large to pass easily, pain continues as the muscles
in the wall of the tiny ureter try to squeeze the stone along into the
bladder. As a stone grows or moves, blood may appear in the urine. As the
stone moves down the ureter closer to the bladder, you may feel the need
to urinate more often or feel a burning sensation during urination.
If fever and chills accompany any of these symptoms, an infection may
be present. In this case, you should contact a doctor immediately.
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Sometimes "silent" stones--those that do not cause symptoms--are found
on x rays taken during a general health exam. These stones would likely
pass unnoticed.
More often, kidney stones are found on an x ray or sonogram taken on
someone who complains of blood in the urine or sudden pain. These
diagnostic images give the doctor valuable information about the stone's
size and location. Blood and urine tests help detect any abnormal
substance that might promote stone formation.
The doctor may decide to scan the urinary system using a special x ray
test called an IVP (intravenous pyelogram). The results of all these tests
help determine the proper treatment.
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Fortunately, surgery is not usually necessary. Most kidney stones can
pass through the urinary system with plenty of water (2 to 3 quarts a day)
to help move the stone along. Often, you can stay home during this
process, drinking fluids and taking pain medication as needed. The doctor
usually asks you to save the passed stone(s) for testing. (You can catch
it in a cup or tea strainer used only for this purpose.)
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If you've had more than one kidney stone, you are likely to form
another; so prevention is very important. To prevent stones from forming,
your doctor must determine their cause. He or she will order laboratory
tests, including urine and blood tests. Your doctor will also ask about
your medical history, occupation, and eating habits. If a stone has been
removed, or if you've passed a stone and saved it, the laboratory should
analyze it because its composition helps in planning treatment.
You may be asked to collect your urine for 24 hours after a stone has
passed or been removed. The sample is used to measure urine volume and
levels of acidity, calcium, sodium, uric acid, oxalate, citrate, and
creatinine (a product of muscle metabolism). Your doctor will use this
information to determine the cause of the stone. A second 24-hour urine
collection may be needed to determine whether the prescribed treatment is
working.
A simple and most important lifestyle change to prevent stones is to
drink more liquids--water is best. If you tend to form stones, you should
try to drink enough liquids throughout the day to produce at least 2
quarts of urine in every 24-hour period.
People who form calcium stones used to be told to avoid dairy products
and other foods with high calcium content. But recent studies have shown
that foods high in calcium, including dairy foods, help prevent calcium
stones. Taking calcium in pill form, however, may increase the risk of
developing stones.
You may be told to avoid food with added vitamin D and certain types of
antacids that have a calcium base. If you have very acidic urine, you may
need to eat less meat, fish, and poultry. These foods increase the amount
of acid in the urine.
To prevent cystine stones, you should drink enough water each day to
dilute the concentration of cystine that escapes into the urine, which may
be difficult. More than a gallon of water may be needed every 24 hours,
and a third of that must be drunk during the night.
The doctor may prescribe certain medications to prevent calcium and
uric acid stones. These drugs control the amount of acid or alkali in the
urine, key factors in crystal formation. The drug allopurinol may also be
useful in some cases of hyperuricosuria.
Doctors usually try to control hypercalciuria, and thus prevent calcium
stones, by prescribing certain diuretics, such as hydrochlorothiazide.
These drugs decrease the amount of calcium released by the kidneys into
the urine by favoring calcium retention in bone. They work best when
sodium intake is low.
Very rarely, patients with hypercalciuria may be given the drug sodium
cellulose phosphate, which binds calcium in the intestines and prevents it
from leaking into the urine.
If cystine stones cannot be controlled by drinking more fluids, your
doctor may prescribe drugs such as Thiola and Cuprimine, which help reduce
the amount of cystine in the urine.
For struvite stones that have been totally removed, the first line of
prevention is to keep the urine free of bacteria that can cause infection.
Your urine will be tested regularly to be sure that no bacteria are
present.
If struvite stones cannot be removed, your doctor may prescribe a drug
called acetohydroxamic acid (AHA). AHA is used with long-term antibiotic
drugs to prevent the infection that leads to stone growth.
People with hyperparathyroidism sometimes develop calcium stones.
Treatment in these cases is usually surgery to remove the parathyroid
glands (located in the neck). In most cases, only one of the glands is
enlarged. Removing the glands cures the patient's problem with
hyperparathyroidism and with kidney stones as well.
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Surgery should be reserved as an option for cases where other
approaches have failed or should not be tried. Surgery may be needed to
remove a kidney stone if it
 | does not pass after a reasonable period of time and causes constant
pain
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| is too large to pass on its own or is caught in a difficult place
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| blocks the flow of urine
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| causes ongoing urinary tract infection
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| damages kidney tissue or causes constant bleeding
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| has grown larger (as seen on followup x ray studies). |
Until recently, surgery to remove a stone was very painful and required
a recovery time of 4 to 6 weeks. Today, treatment for these stones is
greatly improved, and many options do not require major surgery.
Extracorporeal shockwave lithotripsy (ESWL) is the most frequently used
procedure for the treatment of kidney stones. In ESWL, shock waves that
are created outside the body travel through the skin and body tissues
until they hit the denser stones. The stones break down into sand-like
particles and are easily passed through the urinary tract in the urine.
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| Extracorporeal shockwave lithotripsy |
There are several types of ESWL devices. In one device, the patient
reclines in a water bath while the shock waves are transmitted. Other
devices have a soft cushion on which the patient lies. Most devices use
either x rays or ultrasound to help the surgeon pinpoint the stone during
treatment. For most types of ESWL procedures, anesthesia is needed.
In some cases, ESWL may be done on an outpatient basis. Recovery time
is short, and most people can resume normal activities in a few days.
Complications may occur with ESWL. Most patients have blood in their
urine for a few days after treatment. Bruising and minor discomfort in the
back or abdomen from the shock waves are also common. To reduce the risk
of complications, doctors usually tell patients to avoid taking aspirin
and other drugs that affect blood clotting for several weeks before
treatment.
Another complication may occur if the shattered stone particles cause
discomfort as they pass through the urinary tract. In some cases, the
doctor will insert a small tube called a stent through the bladder into
the ureter to help the fragments pass. Sometimes the stone is not
completely shattered with one treatment, and additional treatments may be
needed. ESWL is not ideal when stones are larger than 2 centimeters, about
0.8 inches.
Sometimes a procedure called percutaneous nephrolithotomy is
recommended to remove a stone. This treatment is often used when the stone
is quite large or in a location that does not allow effective use of ESWL.
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| Percutaneous nephrolithotomy |
In this procedure, the surgeon makes a tiny incision in the back and
creates a tunnel directly into the kidney. Using an instrument called a
nephroscope, the surgeon locates and removes the stone. For large stones,
some type of energy probe (ultrasonic or electrohydraulic) may be needed
to break the stone into small pieces. Generally, patients stay in the
hospital for several days and may have a small tube called a nephrostomy
tube left in the kidney during the healing process.
One advantage of percutaneous nephrolithotomy over ESWL is that the
surgeon removes the stone fragments instead of relying on their natural
passage from the kidney.
Ureteroscopic stone removal |
Although some kidney stones in the ureters can be treated with ESWL,
ureteroscopy may be needed for mid- and lower-ureter stones. No incision
is made in this procedure. Instead, the surgeon passes a small fiberoptic
instrument called a ureteroscope through the urethra and bladder into the
ureter. The surgeon then locates the stone and either removes it with a
cage-like device or shatters it with a special instrument that produces a
form of shock wave. A small tube or stent may be left in the ureter for a
few days to help the lining of the ureter heal. Before fiber optics made
ureteroscopy possible, physicians used a similar "blind basket" extraction
method. But this outdated technique should not be used because it may
damage the ureters.
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The Division of Kidney, Urologic, and Hematologic Diseases of the
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
funds research on the causes, treatments, and prevention of kidney stones.
NIDDK is part of the Federal Government's National Institutes of Health in
Bethesda, Maryland.
New drugs and the growing field of lithotripsy have greatly improved
the treatment of kidney stones. Still, NIDDK researchers and grantees seek
to answer questions such as
| Why do some people continue to have painful stones?
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| How can doctors predict, or screen, those at risk for getting
stones?
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| What are the long-term effects of lithotripsy?
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| Do genes play a role in stone formation?
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| What is the natural substance(s) found in urine that blocks stone
formation? |
Researchers are also working on new drugs with fewer side effects.
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| If you have a family history of stones or have had more than one
stone, you are likely to develop more stones.
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| A good first step to prevent the formation of any type of stone is
to drink plenty of liquids--water is best.
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| If you are at risk for developing stones, your doctor may perform
certain blood and urine tests to determine which factors can best be
altered to reduce that risk.
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| Some people will need medicines to prevent stones from forming.
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| People with chronic urinary tract infections and stones will often
need the stone removed if the doctor determines that the infection
results from the stone's presence. Patients must receive careful
followup to be sure that the infection has cleared. |
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1. You want to breakdown any stones you may have
2. You want to flush from your body the stones
3. You want to help your body from having the stones come back.
1. To help break down the stones:
Hydrangea (Hydrangea
arborescens)
Hydrangea has been called "the most powerful solvent of stones"
in the world. It is an old Native American remedy still effective
today. In The Encyclopedia of Medicinal Plants, Andrew Chevallier
notes: “Western herbal medicine considers the diuretic hydrangea as
being particularly helpful in the treatment of kidney and bladder
stones. It is thought both to encourage the expulsion of stones and to
help dissolve those that remain.”
Gravel Root (Eupatorium
purpureum)
This is another important Native American Herb. As the name
implies, it is specific for "gravel"--stones! The Encyclopedia of
Medicinal Plants says, “It helps to prevent the formation of kidney
stones and bladder stones and may diminish existing stones."
Marshmallow Root (Althea
officinalis)
This is included in the kidney stone formula because it one of
the very best demulcent herbs in the world, (demulcent means soothing
and slippery). As stones move from the system, demulcent herbs may help
ease their passage.
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Therapeutic
Dosage
