Definition of Paget's disease of the bone:

Paget's disease is a disorder that involves abnormal bone destruction and regrowth, which results in deformity.

Causes, incidence, and risk factors:

The cause of Paget's disease is unknown, although it might have to do with genes or a viral infection early in life.

The disease occurs worldwide, but is more common in Europe, Australia, and New Zealand.

In people with Paget's disease, there is an abnormal breakdown of bone tissue, followed by abnormal bone formation. The new bone is bigger, but weakened and filled with new blood vessels.

The disease may only be in one or two areas of the skeleton, or throughout the body. It often involves bones of the:

• Arm
• Collar
• Leg
• Pelvis
• Spine

Symptoms:

• Bone pain (may be severe and persistent)
• Bowing of the legs and other visible deformities
• Enlarged head
• Fracture
• Headache
• Hearing loss
• Joint pain or stiffness
• Neck pain
• Reduced height
• Skull deformities
• Warmth of skin over the affected bone

Note: Most patients have no symptoms.

Signs and tests:

Tests that may indicate Paget's disease include:

• Bone scan
• Bone x-ray
• Elevated markers of bone breakdown (for instance, N-telopeptide)
• Elevated serum alkaline phosphatase

This disease may also affect the results of the following tests:

• ALP (alkaline phosphatase) isoenzyme
• Serum calcium

Treatment:

Not all patients need treatment. For example, patients who have abnormal blood tests only may not need treatment.

People with Paget's disease who are commonly treated include:

• Patients with deformities
• Patients with no symptoms when certain bones (such as weight-bearing bones) are involved, especially if the bony changes are progressing quickly, to reduce the risk of fractures
• Patients with symptoms

Drug therapy helps prevent further bone breakdown. Currently, there are several classes of medications used to treat Paget's disease. These include:

• Bisphosphonates -- These drugs are the first-line treatment, and they help increase bone density. Types of bisphosphonates include:
  • Alendronate (Fosamax)
  • Etidronate (Didronel)
  • Pamidronate (Aredia)
  • Risedronate (Actonel)
  • Tiludronate (Skelid)
  • Zoledronic acid (Zometa)
• Calcitonin -- This hormone is involved in bone metabolism. Types include:
  • Intranasal (Miacalcin)
  • Subcutaneous (Calcimar)
• Plicamycin (Mithracin)

Analgesics or nonsteroidal anti-inflammatory medications (NSAIDs) may also be given for pain.

Localized Paget's disease needs no treatment, if there are no symptoms and no evidence of active disease. Orthopedic surgery may be needed to correct a deformity in severe cases.

Support Groups:

For additional support and resources, see the Paget Foundation.

Expectations (prognosis):

Disease activity and symptoms can generally be controlled with current medications. A small percentage of patients may develop a cancer of the bone called osteosarcoma. Some patients will need joint replacement surgery.

Complications:

• Bone fractures
• Deafness
• Deformities
• Heart failure
• Paraplegia
• Spinal stenosis

Calling your health care provider:

Call for an appointment with your health care provider if you develop symptoms of Paget's disease.