Kidney Stones
Also known as: Nephrolithiasis
What is it?
Kidney stones are hard masses, like stones, that form
in the kidneys and can block the flow of urine.
Who gets it?
Anyone can develop a kidney stone. However, kidney
stones are more common in whites, men, those who have had
an episode of kidney stones in the past, those whose
relatives have had kidney stones, and people older than
30.
What causes it?
Kidney stones form when small crystals mass together.
These crystals can be made up of a number of different
substances. The most common cause of kidney stones is the
presence of too much calcium in the urine. High calcium
levels can be caused by a kidney defect; a diet high in a
chemical called oxalate (found in poultry, meat, and
fish); diseases such as renal tubular acidosis,
inflammatory bowel disease (IBD), some types of cancers;
and certain thyroid disorders. Kidney stones can also be
made of uric acid, which builds up when people become
severely dehydrated. High uric acid levels also occur in
people with gout. Kidney stones are called struvite stones
when they are made up of phosphate, magnesium, and
ammonium. These form when the urine is infected with
bacteria. Kidney stones also occur in a rare inherited
disorder called cytinuria, in which too much of an amino
acid called cystine builds up in the urine and forms
stones.
What are the symptoms?
Kidney stones can block the flow of urine through the
ureters, the tubes that carry urine to the bladder. As the
urine backs ups, it creates pressure, which can cause the
kidneys to swell and become damaged. Sometimes kidneys
stones travel to the ureters, which causes severe spasms
of pain in the abdominal area or back. Pain may also occur
in the genital area. The patient may also experience
nausea and vomiting. When the stones block the flow of
urine, bacteria can grow and cause a urinary tract
infection. These symptoms include pain during urination,
chills, fever, and blood in the urine. Some people may
pass small stones in their urine, yet never have any
symptoms.
How is it diagnosed?
Doctors suspect kidney stones when a patient has sudden
severe pain in the abdominal area or back. He or she will
perform a thorough physical examination and take a
complete medical history to rule out any other possible
causes. To make a definite diagnosis, he or she will order
urine tests to look for blood and traces of crystals in
the urine. X-rays may reveal the presence of a kidney
stone and determine whether it is likely to be passed
through the urine. A more effective x-ray process is
called an intravenous pyelogram (IVP). In this procedure,
a small amount of dye is injected into a vein. The dye
travels through the urinary system and reveals any
blockages caused by the kidney stone.
What is the treatment?
The treatment of kidney stones depends upon their size
and the symptoms they cause. Some patients are able to
pass the stones on their own by drinking plenty of fluids.
Your doctor will order medication to relieve the pain, and
antibiotics if there are signs of infection. If tests
indicate the kidney stone will be passed, you will be told
to strain your urine through a medical sieve so the stone
can be collected and studied in a laboratory. The type of
kidney stone you have will determine further treatment and
prevention, such as diet and medications. If tests
determine that the stone cannot be passed, either because
it is too large or in a location such as the lower part of
the ureter, the stone will need to be removed surgically
or broken up through an ultrasonic procedure called
lithotripsy. Most patients recover completely from kidney
stones. However, more than half are likely to develop more
stones at a later time.
Self-care tips
If you are diagnosed with kidney stones, follow your
doctor’s recommendations for fluid intake and other
methods to ensure you will pass the stone. Report any
signs of infection to your doctor immediately. If you have
a condition that increases your risk of kidney stones,
follow your doctor's instructions for treatment of that
condition. Drinking plenty of water to prevent dehydration
and uric acid build-up is one way to help prevent kidney
stones. Your doctor will also provide you with dietary
guidelines that can help prevent the build-up of calcium
oxalate stones.
This information has been designed as a comprehensive and quick reference
guide written by our health care reviewers. The health information written
by our authors is intended to be a supplement to the care provided by your
physician. It is not intended nor implied to be a substitute for
professional medical advice.
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