Osteoperosis Flashcards
What is osteoporosis?
Low bone mineral density that increases risk of fractures. Asymptomatic till fractures. (T score
Primary causes
Combination of oestrogen deficiency and ageing
Secondary causes
Potentially reversable cause
Should be considered in non ‘at-risk’ groups
What do osteoblast respond to?
Parathyroid hormones secreted by the parathyroid glands. These bind to the receptors on osteoblasts.
What does the binding of parathyroid hormones to osteoblasts do?
Causes osteoblasts to express RANKL which binds on to the RANK on pre mature osteoclasts.
What does the activation of premature osteoclasts via RANKL do?
Releases enzymes and acids to breakdown bone.
Osteoprotegerin (OPG) function
Prevents RANKL dining to RANK, so prevents the activation of osteoclasts.
What are Bisphosphonates
Anti-resorptive agents
When are bisphosphonates used?
First-line treatment in:
- post-menopausal women
- men >50
- Gluccorticoid induced
How do bisphosphonates work? (4)
- Binds to hydroxyapatite sites on bone tissue surface
- Bisphosphonates are taken up by osteoclasts in bone resorption.
- Osteoclasts apoptosis
- Reduced bone resorption
Side effect of bisphosphonates
- Osteonecrosis of jaw
- Atypical femoral fractures (Long term)
- Hypocalcemia
- Hypophosphatemia
- Renal impairment
- Musculoskeletal pain
- GI disturbance
When to take bisphosphonates?
Morning and evening 30 mins before meals to avoid complexes forming with calcium.
Taken with plenty water with an upright position maintained for 30 mins after consumption (Prevents esophagitis).
Drug holiday bisphosphonates
When been taking bisphosphonates for 3 years (IV), or 5 years (oral).
What is Raloxifene?
Selective estrogen receptor modulator (SERM)
How do Raloxifene work? (4)
- Inhibits bone resorption
2. Reuding risk of vertebral fractures and increases bone density.
