Kidney stones, renal calculi and urinary stones are different names for crystalline structures which form in the urinary tract from the excretion of excess minerals in the body. Stones that form in the kidneys and urinary tract are one of
the most painful disorders to afflict human beings.
More than a million Americans are hospitalized each year
for the treatment of kidney and urinary tract stones. Today
surgery is rarely necessary, as recent medical advances have
improved understanding and increased the possibility that
many cases of stone disease can be cured or controlled with
noninvasive or endoscopic therapies.
The average kidney stone forms in about 90 days. As blood flows through the kidneys, impurities are filtered along with excess minerals produced by cells within the body. The collected impurities remain and eventually mix with water then leave the body as urine. Occasionally the trapped minerals build up in the kidney. A kidney stone is usually a hard mass formed by the trapped crystallized minerals that deposit on the inner
surfaces of the kidney. As stones irritate the lining of the
kidney, bleeding may occur in the urine.
This bleeding warrants medical attention and evaluation. A stone may be detected if visible on plain X-ray or a CT Scan may be needed.
Sometimes a stone will break off from its location in the
kidney and may result in severe pain as it travels down the urinary tract toward your bladder.
What Are "Urinary" And "Bladder" Stones?
The urinary system consists of two kidneys, located below
the ribs toward the middle of the back; two drainage tubes
called ureters, connect the kidneys to the bladder in the
lower abdomen; and the urethra, the tube through which urine
flows from the bladder to outside of the body.
Kidney stones that remain in the kidney or that break loose
from the lining of the kidney and move to other parts of the
kidney or ureter are sometimes referred to as "upper
tract stones." Sometimes smaller stones pass through
the ureters and lodge in the bladder where they enlarge, or
stones may originate in the bladder. In either case, these
are referred to as "lower tract" stones.
When stones grow so large that they cannot be passed out
of the body easily, they obstruct the normal flow of urine,
causing pain and possibly infection or kidney damage. Many
stones are too large to pass out of the kidney. Other stones
may leave the kidney only to become lodged in the ureter ,
or rarely at the outlet of the bladder.