Pathophysiology

Question 1

Name 5 risk factors for osteoporosis

Answer 1

• Smoking
• Post-menopausal
• Low calcium intake
• Alcohol
• Lack of weight-bearing activity
• Medications (heparin, glucocorticoids, L-thyroxine)

Question 2

How do glucocorticoids increase osteoporosis risk?

Answer 2

Glucocorticoids decrease calcium absorption from the gut

Question 3

Name the 2 most common types of osteoporosis

Answer 3

1. Post-menopausal

2. Senile

Question 4

Why are post-menopausal women at increased risk of osteoporosis?

Answer 4

Decreased estrogen levels after menopause actually increase both bone resorption and formation but the latter does not keep up with the former, leading to HIGH-TURNOVER osteoporosis.

Question 5

Briefly outline the pathophysiology of senile osteoporosis

Answer 5

Osteoblasts gradually lose the ability to form bone

Osteoclasts continue resorbing bone

Bone resorption outpaces bone deposition (around the 8th decade of life) –> osteoporosis

Question 6

What effect does decreased oestrogen have on the secretion of inflammatory cytokines, and how does this affect osteoclasts?

Answer 6

Lower oestrogen levels cause increased secretion of inflammatory cytokines from blood monocytes and bone marrow cells.

Inflammatory cytokines stimulate osteoclast recruitment through a number of mechanisms.