Osteoporosis Flashcards
what type of disease is osteoporosis
progressive systemic skeletal disease
what is osteoporosis characterised by
low bone mass and micro-architectural deterioration, with consequent increased bone fragility and susceptibility to fracture
what are the main types of bone cells
osteoclasts, osteoblasts, osteocytes
describe what an osteoclast is
multinucleated cells responsible for bone resorption, derived from haematopoietic progenitors
describe what an osteoblast is
mononuclear cells derived from mesenchymal cells in the bone marrow stroma, responsible for bone formation
describe what an osteocyte is
most common type and primary cell of mature bone, derived from osteoblasts thought to sense mechanical strain on skeleton
what are bone remodelling units
distinct sites in the bone where it undergoes a continual remodelling cycle
what regulating factors affect peak bone mass
genetics(70-80%), body weight, sex hormones, diet, exercise
what regulating factors affect bone loss
sex hormone deficiency, body weight, genetics, diet, immobility, diseases, drugs(esp glucocorticoids)
how many people in the UK are estimated to have osteoporosis
3 million
describe the impact of osteoporotic fractures on patients lives
major cause of pain, disability, death, 50% hip fracture patients cannot live independantly
what are common osteoporotic fracture sites
neck of femur, vertebral body, distal radius, humeral neck
in what group of people do hip fractures most commonly occur
women >75y/o
what are the guidelines for osteoporotic fractures based on
based around fracture risk not bone mineral density
what are some non-modifiable clinical risk factors for fragility bone fractures
increased age, F>M, ethnicity, previous fracture, FH, menopause(<45yo), co-existing disease
what are some modifiable clinical risk factors for fragility bone fractures
bone mineral density, alcohol, weight, smoking, physical inactivity, pharmacological risk factors
what are the benefits of the WHO fracture risk calculator
allows calculation of absolute risk by using additional risk factors as well as bone mineral density, also 1o year prediction of major osteoporotic fracture
who should be risk factor assessed for osteoporotic fractures
anyone >50 with any risk factors, <50 with very strong risk factors(eg early menopause, glucocorticoids)
what’s the mainstay of bone mineral density assessment and when would a patient be referred for it
DEXA scans, anyone with 10 year risk assessment for any osteoporotic fractures of at least 10%, or >50 with low trauma fracture
what is DEXA scan result for normal bone and for osteopenia
normal = BMD within 1 of young adult reference mean osteopenia = BMD >1 but <2.5 below young adult reference mean
what is the DEXA scan result for osteoporosis and severe osteoporosis
osteoporosis = BMD >/=2.5 below young adult mean severe = BMD>/= below young adult mean with fragility fracture
what are some secondary endocrine causes of osteoporosis
hyperthyroidism, hyperparathyroidism, Cushing’s disease
what are some secondary non-endocrine causes of osteoporosis
coeliac disease, IBD, COPD, chronic kidney disease
