What is Paget's disease of bone?
Paget’s disease of bone is named after Sir James Paget, who first identified the condition in the late 19th century. It affects the way your bone develops and renews itself, causing it to become weaker than normal. To understand this, it helps to know a little about normal bone which is made up of 3 main parts; the matrix, minerals and cells.
Bone is a living, active tissue that's constantly being renewed and repaired. Old and damaged bone is removed by cells called osteoclasts, while new, healthy bone is produced by cells called osteoblasts. This process is carried out in an orderly and balanced way to make sure that your bones stay strong and healthy.
In Paget’s disease, the process of renewal and repair is disrupted:
- Bone cells increase in number and become larger and more active.
- The renewal and repair of bone is uncontrolled and the rate of bone turnover increases by up to 40 times.
- The new bone is abnormal in shape and structure and is weaker than usual.
- The weakened bones become bent or deformed and can cause damage to your joints.
The increased activity of the bone cells also increases the blood flow through your bone. The bones most commonly affected are:
- thigh bones
- shin bones