Rheumatology Flashcards
What is osteoporosis?
Systemic skeletal disease with low bone mass and architecturale deterioration of bone tissue and increase in bone fragility and susceptibility
What is the most common presentation of osteoporosis?
Fractures
Who does osteoporosis affect?
1/2 women and 1/5 men over 50
Why are hip fractures bad?
kills 20% 80% lose some function
What affects bone strength?
Bone mass density, bone size, bone quality
What affects Bone mass density?
Peak bone mass, rate of bone loss
What can affect bone quality?
Bone turnover, architecture mineralisation
Which fractures are very common in the elderly?
Coles’ vertebrae and hip
What is the best risk factor for fractures?
age
Why are hip fractures more common in older people?
Cant protect with their hands
What happens in postmenopausal osteoporosis?
Loss of restriang effect of oestrogen on bone turnover, high bone turnover but too fast for osteoblasts to rebuild, disrupts the architectural integrity of the bone
When is peak bone mass reached?
In the 30s
Which cells sense bone stress and direction?
Osteocytes
What is Eula’s buckling theory?
need crosslinking of bone struts to give 16 times strength
What is Eula’s buckling theory?
need crosslinking of bone struts to give 16 times strength
How is osteoporosis diagnosed?
Bone densitometry that looks at bone mineral density
What is DEXA scan?
Dual energy X-ray absorptiometry. Looks at resorption in low dose radiation and measure lumbar spine hip and distal radius
What are the measures of a dexa scan?
Bone mineral density, T score Z score, T score is for diagnosing osteoporosis
What is a T score?
Standard deviation score, compared with gender-matched young adult average
How are T scores classified ?
> -1 is normal,
What can increase risk of osteoporosis?
Infammatory diseases (Rheumatoid artheritis, arthritis and inflammatory bowel diseases) Endocrine disease(hyperthyroid and hyperparathyroidism, crushing’s kills osteoblasts and oestrogen and testosterone lowering causes it) low skeletal loading , glucocorticoids, depo-provera aromatase inhibitors, GnRH anlogues Androgen deprivation
What can cause low skeletal loading?
Low bodyweight and immobility
What separate other risk factors for osteporosis exist?
Previous fracture, family history of osteoporosis or fracture alcohol and smoking
What is FRAX?
Uses weight height previous fractures history current smoking RA and bone density to give risk of fracture