Paget's Disease.

Last updated Monday, December 27, 2004

Figure 1 - Bones most often affected by Paget's disease
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) 509-5335

Condition 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.