I am copying below an interesting article on Kidney Stones appeared in The News International.
Kidney stones are as old as the human civilisation. Scientists have
found evidence of their existence in a 7000-year-old Egyptian mummy. Despite
the passage of several millennia they still constitute one of the most painful
urologic disorders.
Three million people visit health care providers and more than half a
million go to emergency rooms every year for treatment of kidney stone
problems.
A kidney stone is a hard mass developed from crystals that separate from
the urine within the urinary tract.
Normally urine contains chemicals that prevent or inhibit the crystals
from being formed. These inhibitors, however, do not work for everyone. If the
crystals remain tiny, they travel through the urinary tract and pass out of the
body in the urine without being noticed.
Kidney stones may be as small as a grain of sand or as large as a pearl.
Some stones are as big as golf balls! Stones may be smooth or jagged. They are
usually yellow or brown. About 90% of stones that are 4 mm or less in size
usually pass spontaneously, however 9% of stones are larger than 6 mm. (gallstones
and kidney stones are not related with each other. They form in different parts
of the body. Someone with a gallstone is not necessarily more likely to develop
kidney stones.)
Different studies on kidney stones showed there 4 types of stones. The
most common type contains calcium that is a normal part of a healthy diet. Calcium
that is not used by the bones and muscles goes to the kidneys.
1.
Calcu-ox. In most people, the kidneys flush out the
extra calcium with the rest of the urine. People who have calcium stones keep
the calcium in their kidneys.
2.
Uric-acid
stones: Infection in the urinary system may also cause the formation of stones
in kidney. These stones contain the mineral magnesium and the waste product
ammonia. may form when the urine contains too much
acid.
3. Struvite or infection stone. A less common type of stone is
caused by infection in the urinary tract. Another type of stone, uric acid stones,
are a bit less common, and cystine stones are rare.
Genes also play a role in inheriting the tendency to develop kidney
stones in many patients. More than 70% of people with a rare hereditary disease
called renal tubular acidosis develop kidney stones.
Usually, the first symptom of a kidney stone is extreme pain in back,
bloody urine, fever, chills, vomiting, the urine that smells bad or looks
cloudy or a burning feeling when you urinate.
Sometimes nausea and vomiting may also occur. Later, pain may spread to
the groin.
Most people think that getting rid of an existing stone is the end of
the problem but stone formation can happen again and again. Kidney stones,
acute as well as chronic, can be effectively treated with homeopathic
medicines.
Kidney Stones in Adults
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 and thus better treatments for preventing stones.
Introduction to 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, one on each side
of the spine. The kidneys remove extra water and wastes from the blood,
producing 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
form red blood cells.
The urinary tract.
Narrow tubes called ureters carry urine from
the kidneys to the bladder, an oval-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.
What is a kidney stone?
A kidney stone is a hard mass developed from crystals that separate from
the urine within the urinary tract. Normally, urine contains chemicals that
prevent or inhibit 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.
Kidney
stones in the 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.
Who gets kidney stones?
For unknown reasons, the number of people in the
What causes kidney stones?
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 certain metabolic disorders such as hyperparathyroidism
are also linked to stone formation.
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,
leading to the formation of stones made of cystine. In
patients with hyperoxaluria, the body produces too
much oxalate, a salt. When the urine contains more oxalate than can be
dissolved, the crystals settle out and form stones.
Hypercalciuria is inherited, and it may be 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 elsewhere in the urinary tract.
Other causes of kidney stones are hyperuricosuria,
which is a disorder of uric acid metabolism; gout; excess intake of vitamin D;
urinary tract infections; and blockage of the urinary tract. Certain diuretics,
commonly called water pills, and 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 chronic
inflammation of the bowel or who have had an intestinal bypass operation, or ostomy surgery. As mentioned earlier, struvite
stones can form in people who have had a urinary tract infection. People who
take the protease inhibitor indinavir, a medicine
used to treat HIV infection, may also be at increased risk of developing kidney
stones.
Foods and Drinks
Containing Oxalate
People prone to forming calcium oxalate stones may be asked by their
doctor to limit or avoid certain foods if their urine contains an excess of
oxalate.
High-oxalate foods - higher to lower
rhubarb
spinach
beets
swiss chard
wheat
germ
soybean
crackers
peanuts
okra
chocolate
black
Indian tea
sweet
potatoes
Foods that have medium amounts of oxalate may be eaten in limited
amounts.
Medium-oxalate foods - higher to lower
grits
grapes
celery
green
pepper
red
raspberries
fruit
cake
strawberries
marmalade
liver
What are the symptoms of kidney stones?
Kidney stones often do not cause any symptoms. Usually, the first
symptom of a kidney stone is extreme pain, which begins suddenly when a stone
moves in the urinary tract and blocks the flow of urine. 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 narrow ureter try to squeeze the
stone into the bladder. As the stone moves and the body tries
to push it out, blood may appear in the urine, making the urine pink. As the
stone moves down the ureter, closer to the bladder, a
person 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, a person should contact a doctor immediately.
How are kidney stones diagnosed?
Sometimes “silent” stones (do not cause symptoms) are found on x rays
taken during a general health exam. If the stones are small, they will often
pass out of the body unnoticed. Often, kidney stones are found on an x ray or
ultrasound taken of 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 test
called a computerized tomography (CT) scan or an intravenous pyelogram (IVP). The results of all these tests help determine
the proper treatment.
Preventing Kidney Stones
A person who has had more than one kidney stone may be likely to form
another; so, if possible, prevention is important. To help determine their
cause, the doctor will order laboratory tests, including urine and blood tests.
The doctor will also ask about the patient’s medical history, occupation, and
eating habits. If a stone has been removed, or if the patient has passed a
stone and saved it, a stone analysis by the laboratory may help the doctor in
planning treatment.
How are kidney stones treated?
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, the patient can stay home during this
process, drinking fluids and taking pain medication as needed. The doctor
usually asks the patient to save the passed stone(s) for testing. It can be
caught in a cup or tea strainer used only for this purpose.
Lifestyle Changes
A simple and most important lifestyle change to prevent stones is to
drink more liquids (water). Someone who tends to form stones should try to
drink enough liquids throughout the day to produce at least 2 quarts of urine
in every 24-hour period.
In the past, people who formed calcium stones were told to avoid dairy
products and other foods with high calcium content. Recent studies have shown
that foods high in calcium, including dairy products, may help prevent calcium
stones. Taking calcium in pill form, however, may increase the risk of
developing stones.
Patients may be told to avoid food with added vitamin D and certain
types of antacids that have a calcium base. Someone who has highly acidic urine
may need to eat less meat, fish, and poultry. These foods increase the amount
of acid in the urine.
To prevent cystine stones, a person 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.
Medical Therapy
A doctor may prescribe certain medications to help prevent calcium and
uric acid stones. These medicines control the amount of acid or alkali in the
urine, key factors in crystal formation. The medicine 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 medicines decrease the amount of calcium released by
the kidneys into the urine by favoring calcium
retention in bone. They work best when sodium = salt intake is low.
Rarely, patients with hypercalciuria are given
the medicine 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, a doctor may prescribe medicines 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. A patient’s urine will be tested regularly to ensure
no bacteria are present.
If struvite stones cannot be removed, a doctor
may prescribe a medicine called acetohydroxamic acid
(AHA). AHA is used with long-term antibiotic medicines 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, which are
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 kidney
stones.
Surgical Treatment
Surgery may be needed to remove a kidney stone if it
does not
pass after a reasonable period of time and causes constant pain
is too
large to pass on its own or is caught in a difficult place
blocks
the flow of urine
causes an
ongoing urinary tract infection
damages
kidney tissue or causes constant bleeding
has grown
larger, as seen on follow-up x rays
Until 20 years ago, open surgery was necessary to remove a stone. The
surgery required a recovery time of 4 to 6 weeks. Today, treatment for these
stones is greatly improved, and many options do not require major open surgery
and can be performed in an outpatient setting.
Extracorporeal Shock Wave
Lithotripsy
Extracorporeal shock wave 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 small particles and are
easily passed through the urinary tract in the urine.
Several types of ESWL devices exist. 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 many cases, ESWL may be done on an outpatient basis. Recovery time is
relatively short, and most people can resume normal activities in a few days.
Complications may occur with ESWL. Some 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 can occur. To reduce the risk of complications,
doctors usually tell patients to avoid taking aspirin and other medicines that
affect blood clotting for several weeks before treatment.
Sometimes, the shattered stone particles cause minor blockage as they
pass through the urinary tract and cause discomfort. 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.
As with any interventional, surgical procedure, potential risks and
complications should be discussed with the doctor before making a treatment
decision.
Percutaneous Nephrolithotomy
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.
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. Often, 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 is that the surgeon can remove some of the
stone fragments directly instead of relying solely on their natural passage
from the kidney.
Percutaneous nephrolithotomy.
Ureteroscopic Stone Removal
Although some 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 urine flow. Before fiber optics made ureteroscopy
possible, physicians used a similar “blind basket” extraction method. But this
technique is rarely used now because of the higher risks of damage to the ureters.
Hope through Research
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. The NIDDK is part of the National Institutes of Health in
NIDDK researchers and grantees seek to answer questions such as
Why do
some people continue to have painful stones?
How can
doctors predict, or screen, those at risk for getting stones?
What
are the long-term effects of lithotripsy?
Do
genes play a role in stone formation?
What is
the natural substance(s) found in urine that blocks stone formation?
Researchers
are also developing new medicines with fewer side effects.
Points to Remember
A person with a family history of stones or a personal history of more
than one stone may be more likely to develop more stones.
A good first step to prevent the formation of any type of stone is to
drink plenty of liquids—water is best.
Someone who is at risk for developing stones may need certain blood and
urine tests to determine which factors can best be altered to reduce that risk.
Some people will need medicines to prevent stones from forming.
People with chronic urinary tract infections and stones will often need
a stone removed if the doctor determines that the stone is causing the
infection. Patients must receive careful follow-up to be sure that the
infection has cleared.
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