Stages of Paget's disease

Paget's disease of bone is not formally staged like a cancer, but it tends to follow three overlapping phases within a bone. Doctors also describe it as active or inactive using blood tests and scans.

Phases within an affected bone

1. Lytic (destructive) phase: bone-resorbing cells (osteoclasts) are overactive and break down bone quickly. X-ray may show areas of bone loss, such as a V-shaped front in a long bone or osteoporosis circumscripta in the skull.
2. Mixed phase: bone-forming cells (osteoblasts) work fast to rebuild, and disorganised bone appears. Bone is thick but weak.
3. Sclerotic (burnt-out) phase: activity slows. Bone is dense, enlarged and deformed. Blood markers may come close to normal.

How doctors judge activity

• Alkaline phosphatase (ALP): the main blood marker. Raised in active disease.
• Bone scan: shows which bones are active
• X-rays: show shape, thickness and fractures
• Other markers: such as P1NP or urine tests, in some cases

Typical course

It progresses slowly over years. A bone that is affected stays affected, but the disease usually does not spread to new bones. Treatment can control activity.

Ayurvedic view