Which disease interferes with the recycling process of bones and makes them fragile?

• A. Osteoporosis
• B. Paget's Disease
• C. Osteomalacia
• D. Hyperparathyroidism

Answer: (B)

Paget's Disease is characterized by abnormal and excessive bone remodeling, where the typical process of bone turnover is disrupted. In a healthy skeleton, old bone is periodically replaced by new bone in a balanced cycle. However, in Paget's Disease, this balance is disturbed, leading to uncontrolled and chaotic bone remodeling.

This results in the formation of bone that is often enlarged but structurally less stable, making it weaker and more susceptible to fractures. The disease specifically affects the recycling process of bones by increasing the activity of osteoclasts (the cells that break down bone) and then increasing the activity of osteoblasts (the cells that build up bone), which does not produce bone of normal quality. As a consequence, these bones become fragile despite their larger size, ultimately leading to an increased risk of fractures and deformities.

Understanding this mechanism highlights why Paget's Disease can lead to a fragile skeletal structure, distinguishing it from conditions like osteoporosis, which primarily involves the loss of bone density without the same level of abnormal structural changes.