Pathophysiology and Pharmacology of Bone Disease

Flashcards about Pathophysiology/Pharmacology of Bone Disease

What is the definition of osteoporosis according to the World Health Organization?

A progressive systemic skeletal disease characterized by low bone mass and micro-architectural deterioration of bone tissue, with a consequent increase in bone fragility and susceptibility to fracture.

What are the key differences between osteoporosis and osteomalacia?

Osteoporosis involves low bone mass and micro-architectural deterioration, whereas osteomalacia involves a normal amount of bone but inadequate mineralization.

List some common locations for osteoporotic fractures.

Radius, spine (vertebral), and neck of femur (hip).

What is the role of RANKL in bone remodeling?

RANKL, expressed by osteoblasts, binds to RANK on osteoclasts, causing osteoclast activation and bone resorption.

What is the role of OPG?

OPG mimics RANK and binds to RANKL to blocks its action, inhibiting osteoclast activation.

How does estrogen deficiency affect bone remodeling?

Estrogen deficiency leads to increased bone resorption but has no direct effect on bone formation. It also results in increased expression of RANKL.

How does vitamin D deficiency contribute to bone loss?

Vitamin D deficiency leads to decreased intestinal calcium absorption, affecting calcium homeostasis and potentially leading to osteomalacia and increased bone remodeling.

How do glucocorticoids affect bone cells?

Glucocorticoids primarily induce osteoblast apoptosis, suppressing bone formation over time.

What are bisphosphonates and how do they work?

Bisphosphonates are inhibitors of bone resorption that bind to bone mineral, are incorporated onto the bone surface, and cause osteoclasts to stop functioning and increase osteoclast apoptosis.

What are some advantages and disadvantages of Bisphosphonates?

Advantages: Bone selective with few side effects, improves cortical and trabecular bones, can be given as weekly tablet for both men and women. Disadvantages: Incorporated into skeleton and remain for years, risk of blocking repair of micro fractures.

What are the advantages of Anti-RANKL therapy?

It is a highly effective treatment in patients with post-menopausal osteoporosis (6-monthly subcut injection)

What is the role of intermittent PTH injections in treating bone disease?

Intermittent PTH injections promote osteoblast survival, differentiation, and proliferation, leading to increased bone formation.

What is the difference between anti-resorptive and anabolic treatments for bone disease?

Anti-resorptive treatments stop bone resorption, while anabolic treatments stimulate the formation of new bone.