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.

An estimated 1 million people in the U.S. have Paget’s disease, or about 1.3 people per 100 men and women age 45-74. 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.

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.

Diagnosis

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.

Causes

Recent studies suggest that genetics plays a role in at least some cases of Paget’s disease. Scientists have identified several genes that are associated with Paget’s disease, such as SQSTM1 and TNFRSF11A.

It is likely that environmental factors, such as viruses, may be involved in the development of Paget’s disease.

Reference:

National Institute of Arthritis and Musculoskeletal and Skin Diseases, USA.