What Is Paget’s Disease of Bone?
Paget’s disease is
a chronic disorder that can result in enlarged and
misshapen bones. The excessive breakdown and formation
of bone tissue causes affected bone to weaken –
resulting in bone pain, misshapen bones, fractures,
and arthritis in the joints near the affected bones.
Paget’s disease typically is localized, affecting
just one or a few bones, as opposed to osteoporosis,
for example, which affects all the bones in the
body. Scientists do not know for sure what causes
Paget’s disease. In some cases, the disease runs
in families, and so far two genes have been identified
that predispose affected people to develop Paget’s
disease. In most cases, however, scientists suspect
that environmental factors play a role. For example,
scientists are studying the possibility that a slow-acting
virus may cause Paget’s disease.
Who Is Affected?
An estimated one million
people in the U.S.
have Paget’s disease, or about 1.3 people per 100
men and women age 45 to 74. The disease is more
common in older people and those of Northern European
heritage. Men are about twice as likely as women
to have the disease. Research suggests that a close
relative of someone with Paget’s disease is seven
times more likely to develop the disease than someone
without an affected relative.
What Are the Symptoms?
Many patients do not
know they have Paget’s disease because they have
no symptoms. Sometimes the symptoms may be confused
with those of arthritis or other disorders. In other
cases, the diagnosis is made only after complications
have developed.
Symptoms can include:
- pain, which
can occur in any bone affected by the disease
or result from arthritis, a complication that
develops in some patients.
- headaches and hearing
loss, which may occur when Paget’s
disease affects the skull.
- pressure on nerves,
which may occur when Paget’s disease affects
the skull or spine.
- increased head size,
bowing of a limb, or curvature of the spine,
which may occur in advanced cases.
- hip pain, which
may occur when Paget’s disease affects the pelvis
or thighbone.
- damage to cartilage
of joints, which may lead to arthritis.
Any bone or bones can
be affected, but Paget’s disease occurs most frequently
in the spine, pelvis, legs, or skull. Generally,
symptoms progress slowly, and the disease does not
spread to normal bones.
How Is It Diagnosed?
Paget’s disease is
almost always diagnosed using x rays but may be
discovered initially by either of the following
tests:
- Alkaline phosphatase
blood test – An elevated level of alkaline
phosphatase in the blood can be suggestive of
Paget’s disease.
- Bone scans
– Bone scans are useful in determining the extent
and activity of the condition.
If a blood test or
bone scan suggests Paget’s disease, the affected
bone(s) should be x rayed to confirm the diagnosis.
Early diagnosis and
treatment are important to minimize complications.
Siblings and children of people with Paget’s disease
may wish to have an alkaline phosphatase blood test
every two or three years starting around the age
of 40. If the alkaline phosphatase level is higher
than normal, a bone scan may be used to identify
which bone or bones are affected and an x ray of
these bones is used to verify the diagnosis of Paget’s
disease.
What Is the Prognosis?
The outlook for people
diagnosed with Paget’s disease is generally good,
particularly if treatment is given before major
changes in the affected bones have occurred. Treatment
can reduce symptoms but is not a cure. Osteogenic
sarcoma, a form of bone cancer, is an extremely
rare complication that occurs in less than one percent
of all patients with Paget’s disease.
What Other Medical Conditions May
It Lead to?
Paget’s disease may
lead to other medical conditions, including:
- Arthritis –
Long bones in the leg may bow, distorting alignment
and increasing pressure on nearby joints. In
addition, pagetic bone may enlarge, causing
joint surfaces to undergo excessive wear and
tear. In these cases, pain may be due to a combination
of Paget’s disease and osteoarthritis.
- Hearing loss
– Loss of hearing in one or both ears may occur
when Paget’s disease affects the skull and the
bone that surrounds the inner ear. Treating
Paget’s disease may slow or stop hearing loss.
Hearing aids may also help.
- Heart disease
– In severe Paget’s disease, the heart works
harder to pump blood to affected bones. This
usually does not result in heart failure except
in some people who also have hardening of the
arteries.
- Kidney stones
– Kidney stones are more common in patients
with Paget’s disease.
- Nervous system problems
– Pagetic bone can cause pressure on the brain,
spinal cord, or nerves and reduced blood flow
to the brain and spinal cord.
- Sarcoma – Rarely,
Paget’s disease is associated with the development
of a malignant tumor of the bone. When there
is a sudden onset or worsening of pain, sarcoma
should be considered.
- Loose teeth
– When Paget’s disease affects the facial bones,
the teeth may loosen. This may make chewing
more difficult.
- Vision loss
– Rarely, when the skull is involved, the nerves
to the eye may be affected, causing some loss
of vision.
Paget’s disease is not associated
with the following disorder:
- Osteoporosis
– Although Paget’s disease and osteoporosis
can occur in the same patient, they are completely
different disorders. Despite their marked differences,
several medications for Paget’s disease are
also used to treat osteoporosis.
Who Treats It?
The following types
of medical specialists are generally knowledgeable
about treating Paget’s disease:
- Endocrinologists
– doctors who specialize in hormonal and metabolic
disorders.
- Rheumatologists
– doctors who specialize in joint and muscle
disorders.
- Others – orthopaedic
surgeons, neurologists, and otolaryngologists
(physicians who specialize in ear, nose, and
throat disorders) may be called upon to evaluate
specialized symptoms.
How Is It Treated?
Drug Therapy:
The Food and Drug Administration (FDA) has approved
several medications to treat Paget’s disease. The
medications work by controlling the excessive breakdown
and formation of bone that occurs in the disease.
The goal of treatment is to relieve bone pain and
prevent progression of the disease. People with
Paget’s disease should talk to their doctors about
which medication is right for them.
Bisphosphonates
are a class of drugs used to treat a variety of
bone diseases. Of the five bisphosphonates currently
available to treat Paget’s disease, the most commonly
prescribed are the three most potent: Actonel®*,
Fosamax®, and Aredia®. Didronel® and Skelid® may
be appropriate therapies for selected patients,
but are less commonly used. None of these drugs
should be used by people with severe kidney disease.
Actonel®
(risedronate sodium) – Tablet; 30 mg once daily
for two months; patients should wait at least 30
minutes after taking before eating any food, drinking
anything other than tap water, taking any medication,
or lying down (patient may sit).
Fosamax®
(alendronate sodium) – Tablet; 40 mg once daily
for six months; patients should wait at least 30
minutes after taking before eating any food, drinking
anything other than tap water, taking any medication,
or lying down (patient may sit).
Aredia®
(pamidronate disodium) – Intravenous; approved regimen
30 mg infusion over four hours on three consecutive
days; more commonly used regimen 60 mg over two
to four hours for two or more consecutive or nonconsecutive
days. Generic pamidronate disodium for injection
is also available.
Didronel®
(etidronate disodium) – Tablet; approved regimen
is 200-400 mg once daily for six months; the higher
dose (400 mg) is more commonly used; no food, beverages,
or medications for two hours before and after taking;
course should not exceed six months, but repeat
courses can be given after rest periods, preferably
of three to six months.
Skelid®
(tiludronate disodium) – Tablet; 400 mg (two 200
mg tablets) once daily for three months; may be
taken any time of day, as long as there is a two-hour
period before and after eating, drinking, and taking
medications.
Calcitonin
is a naturally occurring hormone made by the thyroid
gland. The medication may be appropriate for certain
patients but is less effective than bisphosphonates
and seldom used. The nasal spray form of this medication
is not approved for the treatment of Paget’s disease.
Miacalcin®
(salmon calcitonin) – administered by injection;
50 to 100 units daily or three times per week for
six to18 months; repeat courses can be given after
brief rest periods.
* Brand names included
in this fact sheet are provided as examples only,
and their inclusion does not mean that these products
are endorsed by the National Institutes of Health
or any other Government agency. Also, if a particular
brand name is not mentioned, this does not mean
or imply that the product is unsatisfactory.
Surgery:
Medical therapy before surgery helps decrease bleeding
and other complications. Patients who are having
surgery should discuss pretreatment with their physician.
Surgery may be advised for three major complications
of Paget’s disease:
- Fractures –
Surgery may allow fractures to heal in better
position.
- Severe degenerative
arthritis – Hip or knee replacement
may be considered if disability is severe and
medication and physical therapy are no longer
helpful.
- Bone deformity
– Cutting and realigning pagetic bone (a procedure
called an osteotomy) may reduce the pain in
weight-bearing joints, especially the knees.
Complications resulting
from enlargement of the skull or spine may injure
the nervous system. However, most neurological symptoms,
even those that are moderately severe, can be treated
with medication and do not require neurosurgery.
Diet and Exercise:
There is no special diet to prevent or help treat
Paget’s disease. However, according to the National
Academy of Sciences, everyone over age 50 should
get 1,200 mg of calcium and at least 400 International
Units (IU) of vitamin D every day to maintain a
healthy skeleton. People over the age of 70 need
to increase their vitamin D intake to 600 IU. People
with a history of kidney stones should discuss calcium
and vitamin D intake with their physician.
Exercise is important
because it helps preserve skeletal health, prevent
weight gain, and maintain joint mobility. Patients
should discuss any new exercise program with their
doctor before beginning, to ensure that undue stress
on affected bones is avoided.
Resource
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 10005-4001
Tel: 800-23-PAGET (free of charge) or 212-509-5335
Fax: 212-509-8492
Internet: www.paget.org
E-mail: PagetFdn@aol.com
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