Osteoporosis Flashcards
definition
brittle bones that are prone to fracture
what happens to osteoclasts in osteoporosis
increased activity = increased bone ‘chewing’
what happens to osteoblasts in osteoporosis
underactivity in bone remodelling (no bone being ‘born’)
what is the overall pathophysiology of osteoporosis
reduced bone density = increased fragility of bone = increased risk of low impact fracture
aetiology of type 1 osteoporosis (2)
HORMONAL
post-menopausal osteoporosis OR hypogonadism in males (increased osteoclast activity)
aetiology of type 2 osteoporosis (5)
old age steroids alcohol malnutrition vit D deficiency
common fractures in type 1 osteoporosis (1)
post menopausal = colles fractures (think granny pat and her wrists)
common fractures in type 2 osteoporosis (2)
femoral neck fracture, vertebral neck fracture (think old folks home)
risk factors for osteoporosis (6)
elderly females early menopause (always ask!) low BMI in young people (weak bones) steroids calcium deficiency
what should you always ask women with ?osteoporosis
?early menopause
which drugs commonly cause osteoporosis
steroids
how do steroids cause osteoporosis
decrease osteoblast activity (bone isnt being ‘born’) = reduced calcium absorption
what can osteoporosis be secondary to (3)
coeliac disease
parathyroid disease
rheumatoid arthritis
lots more…
how does parathyroid disease contribute to osteoporosis
high PTH = decreases calcitonin = increases osteoclasts = increases bone breakdown (to increase the serum Ca bc PTH is usually made when serum Ca is low)
how does osteoporosis present in the spine
increased thoracic kyphosis
investigations for osteoporosis
DEXA scan general bloods (PTH, sex hormones) etc to see if it is secondary osteoporosis
what is a DEXA scan
calculates bone mineral content and bone mineral density
what are the 2 osteoporosis risk calculators
Q fracture
FRAX
what scan is used to calculate osteoporosis severity
DEXA scan
what is the T score a measure of in severity of osteoporosis (from DEXA scan)
number of standard deviations (SD) from normal (for patients age, sex and race) the bone mineral density is
osteopenia criteria
T score between -1 and -2.5
normal T score
> -1
osteoporosis criteria
T score < -2.5
severe osteoporosis criteria
T score < -2.5 and fracture
complication of osteoporosis
gibbus
treatment (3)
calcium and vit D supplementation
bisphosphonates
denosumab
why do you give vit D supplements
to maximise Ca2+ absorption
how do bisphosphonates work
osteoclasts kill the drug instead of bone = bone breakdown is slowed
bisphosphonate example
alendronic acid
side effect of bisphosphonates
atypical fractures in femoral neck
indication for taking denosumab
renal failure
mechanism of denosumab
inhibits osteoclasts
