Paget's Disease.
Last updated Monday, December 27, 2004
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Figure 1 - Bones most often affected by Paget's disease
About
Basics of paget's disease
Paget's disease is a condition in which bone formation is speeded up, changing the strength and shape of the bone.Facts and myths
Paget's disease of the bone, discussed here, is NOT the same thing as
Paget's disease of the breast, which is a rare form of breast cancer.Incidence
Paget's disease is slightly more common in men than in women and
often begins between the ages of 50 and 70. No definite evidence exists
indicating that Paget's disease is hereditary. However, in some
instances, it tends to run in families.
The disease affects mostly Caucasians of northwestern European
ancestry. In the United States, Paget's disease is also seen
occasionally in African-Americans.
Anatomy
The bones most often affected include the pelvis, lumbar spine (lower
back), sacrum (tailbone), skull, and the femur or the tibia (long bones
in the legs). Paget's disease usually centers in one or more of these
areas (see figure 1). Once established, however, it rarely spreads to
other areas. With early diagnosis and treatment, most people who have
Paget's disease are able to lead active, independent lives.Symptoms
Most people with Paget's disease have no symptoms. The condition often
is diagnosed only after an X-ray of the bone or the results of a
routine blood test indicate that Paget's disease may be present. However, some people do experience symptoms, the most common of which is mild pain
(sometimes described as "deep bone" pain). Another symptom is a feeling
of warmth over the affected area. And if the skull is affected, the
person may experience headaches.Causes
The cause of Paget's disease is unknown. One of the most accepted
theories points to an early viral infection of the bone. It is thought
that this infection lies inactive for many years, only to surface later
in life as Paget's disease.Effects
To understand what happens in Paget's disease, it is helpful to
understand the difference between normal bone cell activity and Pagetic
bone cell activity. Bone is active and living tissue that constantly is
being remodeled in a three-stage process. First, old bone is resorbed
(broken down) by cells called osteoclasts to make way for new bone.
Next, cells called osteoblasts lay down an orderly framework for new
bony tissue. Finally, the bone hardens when calcium is added to the
framework laid down by the osteoblasts.
Normal bone cell activity is a very controlled process that is
necessary for bone development and repair throughout life. The bone
turnover process slows somewhat after puberty and continues at a slower
rate through adult life. (This is why an older person's bones break
more easily.)
Bone affected by Paget's disease is broken down faster than usual.
Consequently, new bone formation increases. Because the new bone forms
so rapidly, its structure becomes jumbled and disorganized. Extra blood
vessels appear, and the new formation becomes bulky and somewhat softer
than normal bone. This can result in joints near the affected area
developing arthritis.
Because the bones are weaker than normal, they may break or fracture
more easily. The thigh or leg can become bowed. If the vertebrae (bones
of the spine) are involved, they may collapse, making the spine curve
forward.
A person may experience other forms of discomfort as well. The
increased flow of blood through the bone may cause a feeling of warmth
over the affected areas. Thickened bones in some locations can pinch
nerves. For example, pinched nerves in the spine may cause sciatica, a
syndrome of radiating pain from the back into the buttocks and down the
legs. Paget's disease of the bones inside the ears also can cause
ringing or a decrease in hearing.
Eventually, the rapid bone breakdown and disorganized bone formation
slows down, and Paget's disease appears to "burn out." Symptoms may
come and go. However, any bone enlargement or bowing that has occurred
will remain.
Diagnosis
Although there is no way to prevent Paget's disease, it can be detected before it becomes a serious problem.Diagnostic tests
Diagnosis of Paget's disease can be made by X-rays of the affected
bones. A bone scan often helps to determine the location and extent of
bone involvement.
Blood tests
may be run to determine the presence of increased amounts of alkaline
phosphatase (a product of bone forming cells). Urine tests (such as a
24-hour urine collection) may be run to determine the presence of an
increased amount of hydroxyproline (another product of bone breakdown).
A bone biopsy is rarely needed to ensure the accuracy of the diagnosis.
Treatment
With or without symptoms, if Paget's disease seems to be active, most doctors will prescribe treatment, usually focusing on on pain relief and prevention of bone deformities, fractures, hearing loss, and loss of mobility.
Health care team
If Paget's disease affects your ability to do your daily activities,
your doctor may refer you to an occupational or physical therapist. For
examples if bowing of a leg bone interferes with walking, a shoe lift
may help. Canes may also help. Your doctor or a physical therapist can
give you an exercise program that will help you maintain flexibility and strength. If your hearing has been affected, a special hearing aid may help.Diet
A healthy diet
can help a person with Paget's disease maintain normal weight. Extra
weight can put too much stress on certain bones or joints that already
are weak from Paget's disease.Medications
Aspirin, other nonsteroidal anti-inflammatory medications (NSAIDs),
and non-narcotic analgesics (pain relievers) help reduce pain that
might be associated with Paget's disease. Anti-Pagetic treatment
includes medications that slow down or block the rate of bone breakdown
and formation. Medications most often prescribed include calcitonin S
(calcimar, Miacalcin, or Cibacalcin) or bisphosphonates (Didronel). A
third medication, plicamycin (Mithracin)--previously called
mithramycin--is prescribed in rare instances where there is serious and
extensive disease activity.
Calcitonin is a natural hormone that reduces the breakdown of
bone. Calcitonin must be injected to be used as a treatment (a person
can learn self-injection). Initial treatment usually involves a daily
injection, but over time some people find that two or three injections
per week are sufficient. Improvement of some symptoms may be seen
within the first two weeks to two months. However, it often takes three
to six months to see evidence of the anti-Pagetic effects.
Bisphosphonates, especially etidronate (Didronel), are oral
medications that slow down both the breakdown and formation of bone.
Etidronate is best absorbed when the stomach is empty. (Don't take the
tablets with milk, vitamins, or calcium, all of which may block
absorption.) Etidronate should never be used longer than six months at
a time and is most effective when the person waits another six months
before resuming the medication.
Other, newer bisphosphonates are being studied. A new
bisphosphonate--pamidronate (Aredia)--has been approved by the U.S.
Food and Drug Administration for use in treating other calcium
disorders in an intravenous form, but specialists in the field of
Paget's disease are also occasionally using it for that condition as
well.
Plicamycin is administered by intravenous injection.
Plicamycin can slow down the activity of cells that make and remove
bone in Paget's disease. Because the drug can produce serious side
effects to bone marrow, the liver, and the kidneys, its use in Paget's
disease is still quite limited.
Each of these medications requires close supervision by a
doctor and must be taken exactly as prescribed. Regular blood and urine
tests are required to determine whether or not the medication is
producing the desired effect.
Surgery
For some people who have Paget's disease near the hip or knee joint, joint replacement surgery
can help to relieve pain and improve function. In some situations,
surgery may also help correct leg or thigh bowing or hearing loss due
to Paget's disease.Strategies for coping
Understanding the disease is the first step in self-help.
Just because you have Paget's disease does not mean that you will
have pain, fractures, or deformity. For people with these problems, it
may be difficult to cope. It is usually easier to adjust if you can
talk about your feelings with a friend or someone who also has the
disease.
Resources
For more information about Paget's disease, contact: The Paget Foundation for Paget's Disease of Bone and Related Disorders, 120 Wall Street, Suite 1602, New York, NY 10005-400, (212) 509-5335Condition research
Research is now underway on a number of key factors involved in Paget's disease. These include:
- its cause
- how the disease affects quality of life
- improved treatment (including several new bisphosphonates and a nasal spray form of calcitonin)
- the study of bony tissues (the basic structure, breakdown, and formation)
- a way to measure bone turnover
- how to halt or slow down the disease process
Credits
Some of this material may also be available in an Arthritis Foundation
brochure. Contact the Washington/Alaska Chapter Helpline: (800)
542-0295. If dialing from outside of WA and AK, contact the National
Helpline: (800) 283-7800.
Adapted from a pamphlet originally prepared for the Arthritis Foundation. This material is protected by copyright.