Paget’s Disease of the Bone
Paget’s disease is a chronic disorder that can result in enlarged and mis-shapen bones. The excessive breakdown and formation of bone causes the affected bone to weaken leading to bone pain, mis-shapen bones, fractures, and arthritis in the joints near the affected bones. Paget’s disease typically is localized, affecting just one or a few bones. Osteoporosis on the other hand, affects all the bones in the body.
Currently this is no known cause for Paget’s disease. Researchers believe there are likely genetic and environmental factors which play a role. In some cases, the disease runs in families.
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.
Many patients are asymptomatic. 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 – may occur when Paget’s disease affects the skull.
- Numbness – due to 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.
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.
Paget’s disease may lead to the development of other conditions, including: kidney stones and heart disease. 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.
Paget’s disease is almost always diagnosed using X-rays but may be discovered initially by either of the following tests:
- Alkaline phosphates – 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 phosphates blood test every two or three years starting around the age of 40. If the alkaline phosphates 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.
The prognosis 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. Treatment should be initiated by a doctor who specializes in Paget’s disease, typically rheumatologists or endocrinologists.
Treatment typically involves drug therapy to 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.
Bisphosphonates – 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: Risedronate (Actonel), Alendronate (Fosamax), and Pamidronate (Aredia). Etidronate (Didronel) and Tiludronate (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.
Calcitonin (Miacalcin) – 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 Pagetâ€™s disease.
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.
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: fracture, severe degenerative arthritis and bony deformities.