Osteoporosis Flashcards
define
this is a progressive systemic skeletal disease characterised by low bone mass and deterioration of bone tissue, with increased risk of fragility fractures
where does bone undergo remodelling?
at bone remodelling unit which contributes to calcium homeostasis and skeletal repair
bone remodelling
- osteoclast appear on a previously inactive surface and begin to resorb the bone
- osteoclasts are replaced by osteoblasts that fill in the cavity with osteoid that is mineralised
- resorption cavity is filled with new bone
what happens in osteoporotic during the remodelling cycle?
increased resorption over formation leads to loss of bone
causes of bone loss
sex hormone deficiency (post-menopause oestrogen deficiency)
weight
genetics
diet
immobility
disease
drugs (glucocorticoids and aromatase inhibitors)
myeloma presentation
OP
common fracture sites?
neck of femur
vertebral body
distal radius
humeral neck
test to asses bone density
DEXA scan
who should be referred for a DEXA scan?
over 50 with low trauma fractures or other risk factors
what is the T score in a DEXA scan
difference between your measurement and that of a young healthy adult
what is the Z score in a DEXA scan?
difference between your measurement and someone of the same age
what score is used on a DEXA scan if the patient is younger than 20?
Z score
diagnosis on DEXA scan
Normal= BMD within 1 SD of the young adult reference mean
osteopenia (low mass)= BMD >1SD of young adult mean but <2.5 SD below this value
osteoporosis= BMD 2.5 or more SD below the young adult mean
severe osteoporosis BMD of 2.5 or more SD below with fragility fracture
secondary endocrine causes of osteoporosis
hyperthyroidsim
hyperparathyroidism
Cushing’s disease
secondary GI causes of osteoporosis
Coeliac’s disease
IBD
chronic liver disease
chronic pancreatitis
secondary respiratory causes of osteoporosis
CF
COPD
other secondary causes
chronic kidney disease
lifestyle management for OP
strength training low impact weight bearing avoidance of alcohol and drugs fall prevention diet should include calcium
pharmacological options for OP
calcium and vitamin D bisphosphonates zoledronic acid denosumab teriparatide
when should calcium supplements be taken?
not within 2 hours of oral bisphosphonates
examples of bisphosphonates
aldendronate
risedreonate
action of bisphosphonates
ingested by osteoclasts causes cell death and inhibits bone resorption- filling of resorption sites
T score for bisphosphonates to be used
-2.5 or if prolonged steroid use and -1.5
adverse of bisphosphonates
osteonecrosis of the jaw
oesophageal calcium
consider bone holiday
how often is zoledronic acid administered?
once yearly infusion for 3 years
risks acute phase reaction with first infusion
when should zoledronic acid be considered
intolerant to bisphosphonates or unable to comply with regime
action of denosumab
monoclonal antibody that inhibits development and activity of osteoclasts decreasing resorption
how is denosumab administered?
SC every 6 months
adverse of denosumab
hypocalcaemia
eczema
cellulitis
describe teriparatide
parathyroid hormone that stimulates bone growth (anabolic agent)
how do corticosteroids predispose to OP
cause reduction in osteoblast activity, suppression of osteoblast precursors, reduction in calcium absorption, inhibition of gondal and adrenal steroid production
is BMD partially reversible on steroid cessation?
yes
