Paget's disease of bone

What is Paget's disease?

Bones in your body continuously break down and form again in a natural and tightly balanced process called bone remodeling. Bone remodeling also occurs in response to stress or injury placed on the bone. For example, weight-bearing exercise leads to increased bone formation.

In Paget's disease, more bone breaks down than usual and more new bone forms than usual. These changes in the bone can lead to bone enlargement and deformity. The new bone growth tends to be softer and more fragile than normal bone and can develop in a haphazard pattern. Because of this, the bone can fracture. The long bones, especially the legs, tend to bow, and the skull may enlarge, particularly the forehead.

Paget's disease is the second most common bone disorder in people over 50, after osteoporosis. It is rarely diagnosed in young adults.

Although the cause is unknown, genetics may play a role because the disease sometimes runs in families. Research suggests a slow-growing virus may trigger the disease; some cells in the bone of people with Paget's disease look like they are infected with a virus. However, no virus has been identified.

The condition is rare in certain parts of the world, such as Japan, but more common in the United States and Australia. In the United States, an estimated 10% of people older than age 80 have Paget's disease.

In about 20% of people with Paget's disease, only one area of the body – the spine, pelvis, thigh, lower leg, or skull – is affected. The rest have many areas involved. In serious cases, complications can include deafness, congestive heart failure (caused by the extra blood flow required by the diseased bone), an elevated calcium level, and cancer of the bone.

Symptoms of Paget's disease

An estimated 70% of people with Paget's disease do not have any symptoms. Symptoms are more likely to occur in people who have many areas of the body affected. Symptoms can include:

• bone pain and warmth
• headache
• head enlargement
• bowing of the legs
• hearing loss
• shortness of breath (due to heart failure).

Diagnosing Paget's disease

Because many people with Paget's disease do not have symptoms, the condition often is not discovered until an x-ray or blood test (called the alkaline phosphatase) obtained for other reasons suggests the disease may be present.

If your doctor thinks you may have Paget's disease, specific blood and urine tests can measure the levels of certain byproducts of bone formation and breakdown. More detailed x-rays or a bone scan also may be done.

In rare instances, a doctor may recommend a bone biopsy to confirm the diagnosis and exclude other possibilities. In a bone biopsy, a small piece of bone is removed with a needle so it can be examined in a laboratory.

Expected duration of Paget's disease

Paget's disease cannot be cured, but treatment (if necessary) can control the symptoms.

Preventing Paget's disease

There is no way to prevent Paget's disease.

Treating Paget's disease

Most people with Paget's disease do not need treatment, as treatment is generally reserved for people with symptoms. In some cases a doctor may recommend treatment even if you don't have symptoms, if imaging tests (such as a bone scan) and blood tests detect enough disease, especially if it is in areas of bone where complications may be likely (such as the skull, spine, or near joints).

Medications, including aspirin, mild pain relievers, and anti-inflammatory drugs can help treat pain and inflammation. In advanced cases, your doctor may recommend medications such as alendronate (Fosamax), risedronate (Actonel), zoledronic acid (Reclast, Zometa), or calcitonin (Miacalcin) to reduce the activity of cells that remodel bone.

Surgery to correct deformities is rarely necessary. If Paget's disease causes significant damage to a hip, hip replacement surgery may be considered. Hearing aids may be helpful if Paget's disease affects the bones inside the ear.

A person with Paget's disease will be monitored carefully for complications such as heart failure or an elevation in blood calcium, and these conditions will be treated if necessary.

When to call a professional

Contact your doctor if you experience any of the symptoms of Paget's disease for more than two weeks.

Prognosis

Paget's disease is a long-lasting (chronic) condition. The outlook is generally good, especially if the condition is diagnosed and treated before major changes in bones have occurred.

Additional info

American Academy of Orthopaedic Surgeons (AAOS)
http://www.aaos.org/

Bone Health & Osteoporosis Foundation
https://www.bonehealthandosteoporosis.org/pagets/

American College of Rheumatology (ACR)
https://rheumatology.org/patients/pagets-disease-of-bone