Osteoporosis Flashcards
stats: how many women are affected by osteoporosis?
1 in 3
stats: how many men are affected by osteoporosis?
1 in 12
what structural changes occur in osteoporosis?
- decreased size of osteons
- thinning of trabeculae
- enlargement of Haversian and marrow spaces
what are the risk factors of osteoporosis?
- genetic/gender
- lifestyle/nutritional
- medical conditions
- drugs
- previous fragility fracture
what are lifestyle/nutritional risk factors for osteoporosis?
- smoking
- excess alcohol
- sedentary
- prolonged immobilisation
what are some medical conditions that are risk factors for osteoporosis?
- anorexia nervosa
- rheumatoid arthritis
- early menopause <45
- primary hypogonadism
- secondary amenorrhoea for more than 1 year
- hyperthyroidism
primary hyperparathyroidism - multiple myeloma
- transplantation
- chronic
- cushing’s disease
what drugs are a risk factor for osteoporosis?
- chronic corticosteroid therapy
- excessive thyroid therapy
- gonadotrophin releasing hormone agonist/antagonist
- anticoagulants
- anticonvulsants
- chemotherapy
a previous wrist fracture is a risk factor that does what?
- doubles the risk of future hip fracture
- triples the risk of future vertebral fracture
what are the non-modifiable risk factors for osteoporosis?
- gender/biological sex
- age
- previous fracture
- family history
- long term steroid therapy
- race
what are modifiable risk factors for osteoporosis?
- oestrogen deficiency
- smoking
- alcohol
- low calcium
- low BMI
- vitamin D deficiency
- inactivity
what is type 1 osteoporosis?
post menopausal:
- affects mainly cancellous bone
- vertebral and distal radius fracture is common
- related to loss of oestrogen
- F:M=6:1
what is type 2 osteoporosis?
age related >75:
- affects cancellous and cortical bone
- is related to poor calcium absorption
- hip and pelvic fractures common
- F:M=2:1
where are common sites for osteoporotic fractures?
- distal radius
- neck of femur
- vertebral body
- proximal humerus
- spine
what diagnostic investigations can be carried out for osteoporosis?
- blood tests
- FBC
- serum biochemistry
- bone profile
- thyroid function tests
- testosterone and gonadotrophin levels in men
- x-rays
- bone mineral density measurement
- DEXA scan
what is a DEXA scan?
dual-energy x-ray absorptiometry scan:
-low dose x-rays with two distinct energy peaks (subtracting one from another gives patient’s bone mineral density (BMD))
what are treatment methods for osteoporosis?
- bisphosphonates
- anabolic agents
- ca2+ supplements
- hormone replacement therapy
- increase exercise
what is the function of osteoprogenitor cells?
- stem cells population
- gives rise to osetoblasts
what is the function of osteoblasts?
- responsible for bone formation
- cover the surface of bone
what is the function of osteocytes?
- mature bone cells
- embedded in lacunae
- relatively inactive
- maintain bone matrix through cell-to-cell communication
- influence bone remodelling
- mechanosensing
what is the role of osteoclasts?
- multinucleated
- derived from haematopoietic cells
- in response to mechanical stresses and physiological demands they resorb bone matrix by demineralisation
what is the relationship between chronic corticosteroid therapy and osteoporosis?
can increase risk of fracture by 2-3x
what is disuse osteoporosis?
conditions resulting in prolonged immobilisation, typically in neurological or muscle disease
what is a fragility fracture?
- “low energy” trauma
- mechanical forces that would not ordinarily cause fracture
- WHO: “fall from standing height or less”
what percentage of hip fracture cases are fatal?
20-30%
what percentage of those with hip fractures fully recover?
30%
what percentage of those with hip fractures are left permanently disabled?
50%
what percentage of bone loss must there be for it to be visible on x-ray?
> 30%
what are the DEXA T score values and meanings?
> -1 : normal
-1 to - 2.5 : osteopenia (bone thinning)
< - 2.5 : osteoporosis
what is the DEXA Z score?
comparison of the patients’s BMD with data from same age/sex/size
what are examples of bisphosphonates used in treatment of osteoporosis?
- alendronate
- risedronate
how are bisphosphonates used to treat osteoporosis?
disrupt osteoclast activity
what are potential side effects of bisphosphonates treatments?
- oesophagitis
- mandibular necrosis
what are examples of anabolic agents used to treat osteoporosis?
- intermittent PTH
- strontium ranelate
