Urinary Stones (Urolithiasis, Nephrolithiasis)
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Urinary Stones (calculi) are hardened mineral deposits that form
in the kidney. They originate as microscopic particles and develop
into stones over time.
Urinary Stones may contain various combinations of chemicals. The
most common type of stone contains calcium in combination with either
oxalate or phosphate. 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. Much less common are the uric acid stone and the
rare cystine stone.
Urinary Stones usually arise because of the breakdown of a delicate
balance. The kidneys must conserve water, but they must excrete
materials that have a low solubility. These two opposing requirements
must be balanced during adaptation to diet, climate, and activity.
The problem is mitigated to some extent by the fact that urine contains
substances that inhibit crystallization of calcium salts and others
that bind calcium in soluble complexes. These protective mechanisms
are less than perfect. When the urine becomes supersaturated with
insoluble materials, because excretion rates are excessive and/or
because water conservation is extreme, crystals form and may grow
and aggregate to form a stone.
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 the back and side in the area of the kidney or in the lower
abdomen. Sometimes nausea and vomiting occur with this pain. Later,
the pain may spread to the groin.
If the stone is too large to pass easily, the 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 be
found in the urine. 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 doctor should be contacted immediately.
The urologist will order laboratory tests, including urine and
blood tests. He or she will also ask about the patient's medical
history, occupation and dietary habits. If a stone has been removed,
or if the patient has passed a stone and saved it, the lab can analyse
the stone to determine its composition.
X-ray is the chief method used to diagnose kidney stones. Ultrasound
can also be used to detect stones and urinary obstruction.
Your doctor might ask you to undertake a battery of tests to confirm
that the stone disease is not the result of any primary disease.
Conservative. In asymptomatic patients
a wait-and-see course may be recommended by the doctor. Many stones
will become symptomatic and produce acute renal colic while traveling
down the ureter some time in the future. The stones may enlarge
and then become more problematic and difficult to treat.
Pain control. The severe pain of renal
colic needs to be controlled by potent pain killers. Don't expect
an aspirin to do the trick. Get yourself to a doctor or an emergency
room. Also, the pain may be caused by some other problem needing
ESWL. stands for "extracorporeal shock
wave lithotripsy" (shattering a stone with a shock wave
produced outside the human body). There are several methods for
producing an acoustical or ultrasonic "big bang" which
is then focused from outside into the kidney and the kidney stone.