Osteitis deformans

Alternative names

Paget's disease

Definition

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

Causes, incidence, and risk factors

The cause of Paget's disease is unknown. There are theories about early viral infection and genetic causes. 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, bones of the pelvis, leg, spine, arm, or the collar bone are involved. The effect on the skull may enlarge head size and cause hearing loss, if the cranial nerves are damaged by the bone growth.

Symptoms

• Bone pain (may be severe and persistent)
  
• Joint pain or joint stiffness
  
• headache
  
• Bowing of the legs
  
• Warmth of skin overlying affected bone
  
• Fracture
  
• Neck pain
  
• Reduced height
  
• Hearing loss
  

Note: Most patients have no symptoms.

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 (for instance, N-telopeptide)
  

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

• Serum calcium
  
• ALP (alkaline phosphatase) isoenzyme
  

Treatment

Drug therapy is aimed at suppressing bone breakdown. Currently, there are several classes of medications that inhibit bone resorption that are used in the treatment of Paget's disease. These include: bisphosphonates, calcitonin, and plicamycin.