A metabolic bone disease that involves bone destruction and regrowth that results in deformity.
Causes, incidence, and risk factors
The cause of Paget's disease is unknown. Early viral infection and genetic causes have been theorized. The disease occurs worldwide, but is more common in Europe, Australia, and New Zealand where it is seen in up to 5% of the elderly population. The disease is characterized by excessive breakdown of bone tissue, followed by abnormal bone formation. The new bone is structurally enlarged, but weakened and filled with new blood vessels. The disease may localize to one or two areas within the skeleton, or become widespread. Frequently, the pelvis, femur, tibia, vertebrae, clavicle, or humerus are involved. The skull may enlarge head size and cause hearing loss , if the cranial nerves are damaged by the bone growth.
Signs and tests
Tests that may indicate Paget's disease include:
a bone X-ray that shows increased bone density, thickening, bowing, and overgrowth
a bone scan
elevated serum alkaline phosphatase
elevated markers of bone breakdown (e.g., N-telopeptide) This disease may also alter the results of the following tests:
serum calciumALP (alkaline phosphatase) isoenzyme
Treatment
Drug therapy is aimed at suppressing bone breakdown. Currently, there are several classes of medications that inhibit bone resorption and used in the treatment of Paget's disease. These include: bisphosphonates, calcitonin, and plicamycin. The biphosphonates are the first-line treatment and include the following medications: etidronate (Didronel), alendronate (Fosamax), pamidronate (Aredia), tiludronate (Skelid), and risedronate (Actonel). The Calcitonin class includes intranasal (Miacalcin) and subcutaneous (Calcimar) forms. Plicamycin (Mitrhracin) may also be prescribed. Analgesics or nonsteroidal anti-inflammatory medications (NSAIDS) may be given for pain.
Localized Paget's disease requires no treatment, if there are no symptoms and no evidence of active disease. Orthopedic surgery may be required to correct a specific deformity in severe cases.
Support groups
Paget Foundation 120 Wall St., Suite 1602 New York, NY 10005-4001 Toll-free: 800-23-PAGET Ph: 212-509-5335 Website: http://www.paget.org E-mail: PagetFdn@aol.com
Expectations (prognosis)
Disease activity and symptoms can generally be controlled with current medications. Malignant changes of bone occur in less than 1% of people affected.