It is not unusual for patients with
chronic kidney failure to have problems with their
bones. Their bones tend to become thin and weak, which
causes them to break easily or to begin to hurt. This
happens because the minerals begin to come out of the
bones.
What causes this
problem?
The most common types of bone disease happen when:
- A change occurs in the balance between two
important minerals in your body-- calcium and
phosphorus--leading to loss of calcium from your
bones.
- Four small glands (parathyroid glands), which
help to regulate calcium in your body, become too
active.
- A change occurs in the way your body uses
vitamin D, a mineral that is important to healthy
bones.
- Aluminum may get into your bones from medicines
that contain aluminum.
Your doctor will
examine you and do certain blood tests and, in some
cases, a bone biopsy. These tests help the doctor decide
what type of bone disease you have and what treatment is
best for you.
Each of the four
types of bone disease affect bones in a different way:
- Phosphorus is in most foods you eat and whatever
is not needed in the body is usually removed by your
kidneys. When your kidneys have stopped working
normally, phosphorus may build up in your blood. Too
much phosphorus in your blood leads to loss of
calcium from your bones, which tends to weaken them.
Eating foods that are low in phosphorus can help to
prevent phosphorus from building up in your blood.
(See information on diet.) You may also need to take
a medicine called a phosphorus binder which keeps
phosphorus from being absorbed from your food.
- As phosphorus stays in your body when your
kidneys can no longer remove it, calcium levels of
the blood tend to drop. This causes four small
glands in your neck (parathyroid glands) to become
too active. When this happens, calcium is removed
from your bones over a long period of time, causing
them to weaken.
Usually, this problem can be helped
through changes in your dialysis treatments, a low
phosphorus diet and by taking certain medicines such
as calcium and vitamin D. Sometimes, surgery is
necessary to remove some of these glands
- Vitamin D is an important vitamin that affects
your calcium balance. Normally, vitamin D from the
food you eat and from vitamin and mineral
supplements is changed by the kidneys into an
"active" form that can be used by the body. If your
kidneys have failed, they can no longer do this
important job. Fortunately, the active form of
vitamin D is available as a medicine that can be
ordered for you by your doctor if needed.
- People with chronic kidney disease may get
aluminum in their bones from long-term use of
medicines that contain aluminum.
Simply avoiding medicines that contain aluminum is
the best way to lower aluminum levels. Your doctor
will know which medicines these are. Over time, if
you no longer take aluminum, it is gradually removed
by dialysis. In severe cases, a special medicine may
be ordered to help remove aluminum.
In general, over-the-counter vitamin D supplements
should be avoided by people with kidney disease.
Check with your doctor about the right supplements
for you. The amount of vitamin D found in the foods
you eat is not a problem.
How can diet
help prevent bone disease?
By reducing phosphorus in your diet, you can
help to prevent the amount of phosphorus in your blood
from becoming too high. Foods high in phosphorus
include: dairy products such as milk and cheese, dried
beans and peas, nuts and peanut butter, and beverages
such as cocoa, colas and beer. Using non-dairy creamers
and recommended milk substitutes is a good way to reduce
the amount of phosphorus you eat.
What treatments
are available for bone disease?
Your treatment may include one or more of the
following:
- Reducing phosphorus in your diet
- Taking a medicine called a phosphorus binder
- Taking medicine with the active form of vitamin
D
- Taking calcium supplements
- Changes in your dialysis treatment
- An exercise program approved by your doctor
- An operation to remove some of the parathyroid
glands
Will a kidney
transplant help my bones?
A successful kidney transplant may help your
bones to heal from the damage that might have occurred
during the time that you had kidney failure. However,
the cortisone-like medicine taken by kidney transplant
patients can be a serious problem.
If you would like more information,
please call 1-800-622-9010 or write the National Kidney
Foundation, 30 East 33rd Street, New York, NY 10016.
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