osteoporosis Flashcards
define osteoporosis
skeletal disorder characterised by compromised bone strength and predisposing a person to an increased risk of fractures
what happens in Osteoporosis?
bones are weak and brittle - new bone is not generated as fast as it is degraded hence leaving a deficit
what appearance does OP have?
hollow bones
what are the general symptoms of OP?
back pain, stooped posture, early menopause, aches and tiredness
what suggest a patient has OP?
age, having a T score of less than -2.5, low calcidol, high parathrome
what is a T score in relation to OP?
T score is the average bone mass of your specific age category and -2.5 is more than 2 standard deviations away
what is calcidol?
form of vit D - vital for bones
what is the purpose of parathormone?
is controls Ca2+ and having too much of PTH causes release of ca from bones
what do osteoclasts do in bones?
they reabsorb bone cells for degradation
what is the function of osteoblasts?
they generate new bone cells
what is the function of osteocytes?
they are the longest living bone cell
what are the treatments for OP?
- anti-reabsorptives
- PTH analogues
- hormone therapy
- exercise
- cutting out smoking and drinking
- surgery
what is the function of anti-reabsorptives in treating OP with examples?
they affect osteoclasts and prevent them reabsopring and degrading the bone
eg denosumab
what does denosumab do?
it is a monoclonal antibody that prevents osteoclast precursors
give an example of an analogue of PTH?
teriparatade
What prevents the mechanotransduction of osteocytes?
anti- sclerosis antibody
what research has been done in NCL relating OP?
using 1000F study to assess sedentary behaviours and bone strength
what links was found between bone strength and sedentary behaviours in the NCL research?
more sedentary time = less bone mineral density (BMD)
what does PHE suggest about physical activity levels in the north east?
NE england has the largest proportion of inactive adults in the UK of which 32% of adults are doing less than 30 min of moderate exercise per week
how much does fractures cost the NHS yearly?
£2.3bn a year
why are women at most risk especially in there 50s?
menopause causes a drop in oestrogen and this lowers BMD
what is the risk of fracture for a woman in her 50s?
50% before she dies
what is osteogenesis imperfecta?
brittle bone disease
what is the prevalence of osteogenesis imperfecta seen at birth?
1/ 20,000
what is the prevalence of osteogenesis imperfecta that is not detected at birth?
1/ 21,000
what does osteogenesis imperfecta entail?
it is a monogenic autosomal dominant disease that affects collagen synthesis, it is very dangerous intra uterine
what is the risk of fractures with a T score of -2.5?
16% risk of femur fracture and 30% risk of femur/ spine and wrist
a 2017 study expanded further into surgery for OP, what happens during an arthroplasty?
in hip surgery, metal plate and screws on bone cortex and hollow bony trabecula.
what year was the 1000F study regarding sedentary behaviours and bone strength
2019
what year was the study about hip surgery from?
2017
how many in the UK are affected by OP?
3 million
what can measure bone mass density?
dual energy X-ray absorptiometry (DEXA)
what is an implication of frequent use of glucocorticoids?
leads to lower bone mass density
what percentage does osteocytes make up of all bone tissue?
90-95%
why is there activation of bone remodelling over the course of a lifetime?
to provide strength and elasticity to skeleton
what activates osteoblasts?
growth hormone, interleukins, parathyroid
what is thought to essentially initiate the activity of osteblasts?
osteocytes by fluid changes or microcracks within deep bone structure and sends paracrine signals to osetoblasts
how does the wnt/ beta catenin pathway link to OP?
critical to osteoblast differentiate
what is oestrogens function within OP?
helps promote osteoblast activity
what is the principal regulator of bone mechanosensation and transduction?
osteocytes
what affects does osteoclast activation have on osteoblasts?
impacts normal function - they both impact each other
what effect does the interaction between oestrogen receptors and wnt/ beta catenin?
impacts the coordination of mechanical stimulation
