Education
Why are the kidneys
so important?
Most
people know that a major function of the kidneys is to remove waste
products and excess fluid from the body. These waste products
and excess fluid are removed through the urine. The production
of urine involves highly complex steps of excretion and reabsorption.
This process is necessary to maintain a stable balance of body chemicals.
The critical regulation of the body's salt, potassium and acid content
is performed by the kidneys. The kidneys also produce hormones
and vitamins which affect the function of other organs. For
example, a hormone produced by the kidneys stimulates red blood cell
production. In addition, other hormones produced by the kidneys
help regulate blood pressure and others help control calcium metabolism.
The kidneys are powerful chemical factories
that perform the following functions:
- remove waste products from the body.
- balance the body's fluids.
- release hormones which regulate blood pressure.
- synthesize the vitamins which control growth.
- control the production of red blood cells.
Where are the kidneys and how do they function?
There are two kidneys, each about the size of one's fist, located
on either side of the spine at the lowest level of the rib cage.
Each kidney contains about one million functioning units called nephrons.
A nephron consists of a filtering unit of tiny blood vessels called
a glomerulus attached to a tubule. When blood
enters the glomerulus, it is filtered and the remaining fluid then
passes along the tubule. In the tubule, chemicals
and water are either added to or removed from this filtered
fluid according to the body's needs, the final product being the urine
we excrete.
The kidneys perform their life-sustaining job of filtering and returning
to the bloodstream about 200 quarts of fluid every 24 hours.
Approximately two quarts are eliminated from the body in the form
of urine, and about 198 quarts are retained in the body. The
urine we excrete has been stored in the bladder for approximately
1-8 hours.
What are some of the types and causes
of kidney disease?
Kidney disease usually affects both kidneys. If the kidneys'
ability to remove and regulate water and chemicals is seriously damaged
by disease, waste products and excess fluid build up, causing severe
swelling and symptoms of uremia (kidney failure).
There are many different types and causes of kidney disease, and these
can be characterized as either hereditary, congenital, or acquired.
Hereditary disorders can
be transmitted to both males and females and generally produce clinical
symptoms from teenage years to adulthood. The most prevalent
hereditary kidney condition is polycystic kidney disease. Other
hereditary conditions include Alport's Syndrome, hereditary nephritis,
primary hyperoxaluria, and cystinuria.
Congenital disease
usually involves some malformation of the genitourinary tract,
usually leading to some type of obstruction which subsequently produces
infection and/or destruction of kidney tissue. Eventually the
destruction can progress to chronic kidney failure.
Acquired kidney diseases
are very numerous, the general term being nephritis (meaning inflammation
of the kidney). The most common type of nephritis is glomerulonephritis,
and again this has many causes. Your doctor can explain what
is known and not known about the various forms of acquired kidney
disease.
Kidney stones are
very common, and when they pass, the pain can be extremely severe
in your side and back. Stone formation can be an inherited disorder,
secondary to a malformation and/or infection in the kidney, or can
occur without any prior problem. The pain can appear suddenly,
occur in waves, and disappear just as rapidly when the stone is passed.
Evaluation by your doctor can reveal a cause for the kidney stone
formation in about 1/3 of patients who have their first stone.
When kidney stones get stuck in the kidney and ureter (and cannot
pass), a new form of shock wave treatment has been used to destroy
the stone. This treatment is called extra corporeal shock wave
lithotripsy.
Nephrotic syndrome refers
to a large protein loss in the urine, frequently in association with
low blood protein (albumin) levels, an elevated blood cholesterol
and severe retention of body fluid causing swelling (edema).
This disease can be a primary disorder of the kidney or secondary
to an illness affecting many parts of the body (for example, diabetes
mellitus). Your doctor can explain the best approach to this
serious problem which can attack people of any age.
Long-standing high blood pressure
(hypertension) can cause kidney disease itself or be a result of a
kidney disorder. Uncontrolled high blood pressure can accelerate
the natural course of any underlying kidney disease.
Drugs and toxins.
Years of heavy use of headache compounds can slowly produce kidney
failure. Certain other medications, toxins, pesticides, and
"street" drugs (i.e., heroin) can also produce kidney damage.
Your doctor can explain the problems associated with long-standing
use or abuse of these different agents.
Can kidney disease be successfully treated?
Unfortunately, many kidney diseases are still of unknown cause.
Some of the kidney diseases noted above can be successfully treated
and others progress to advanced kidney failure, requiring dialysis
and / or transplantation. For example, kidney infections and
kidney stones can often be successfully treated. Chronic inflammation
of the glomerulus (called glomerulonephritis) is the most common kidney
disease which slowly progresses to kidney failure.
How do we treat advanced
kidney failure?
Research is now being considered on the effect of special diets in
slowing or halting progressive kidney failure, especially if the problem
is approached early. Treatments to slow the progress of kidney
failure hold the promise for the future. When these therapies
are no longer successful, there are now several ways by which chronic,
irreversible kidney failure can be treated. These methods are
listed below and often more than one type of treatment is suitable
for any one person.
Treatment with hemodialysis
(the artificial kidney) may be performed at a dialysis unit
or at home. Hemodialysis treatments are usually performed in
three separate sessions per week. Peritoneal
dialysis is generally done daily at home. Continuous
Cycling Peritoneal Dialysis requires the use of a
machine while Continuous Ambulatory Peritoneal
Dialysis does not. A kidney specialist can explain
the different approaches and suggest what may be best for the individual
patient.
Finally, there has been increasing success with kidney transplantation.
In some cases, the kidney may come from a relative who donates one
of his or her own kidneys, or from cadaver donors, which is more common
in the United States. Under these circumstances, individuals
who have died donated their kidneys for potential transplantation. What
are the warning signs of Kidney Disease?
Although many forms of kidney disease do not produce symptoms until
late in the course of the disease, there are six warning signs of
kidney disease:
1. burning or difficulty during urination;
2. an increase in the frequency of urination;
3. passage of bloody urine;
4. puffiness around eyes, swelling of the hands and feet;
5. pain in small of back just below ribs;
6. high blood pressure. How
common is kidney disease in the USA?
It is estimated that at least 20 million
Americans suffer from kidney or urinary tract related
diseases. Of these, over 100,000 per year will need dialysis
or transplantation in order to survive.
Ultimately, the Kidney Foundation hopes through research to eradicate
these diseases altogether. Until that time comes, the Kidney
Foundation stands ready to provide continuing education and support
to kidney patients and their families. Many thousands of people
have returned to active, productive lives with the help of dialysis
and transplantation. But we still need a cure. When
research renders the kidney machine obsolete, one mission of the
Kidney Foundation will have been realized.
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