w5 - bone disorders inc OP Flashcards
(39 cards)
define osteoporosis
progressive systemic skeletal disease
low bone mass, micro-architecture deterioration
incr in bone fragility + fracture susceptibility
how much of the adult keleton is remodelled each year
10%
bone remodelling occurs at discrete foci called bone remodelling units. OUtline
osteoclasts - appear on inactive surface, begin to absorb bone
osteoblasts - replace OC, fill cavity with osteoid, mineralised to form new bone
in OP there is a problem with bone remodelling, what is it
incr in resorption over formation, leading to bone loss
regulating factors for peak bone mass 5
genetics body weight sex hormones diet exercise
regulating factors for bone loss 7
sex hormone deficiency body weight genetics diet immobility diseases drugs (glucocorticoids, aromatase inhibitors)
common fracture sites in OP
neck of femur
vertebral body
distal radius
humeral neck
how is bone density measured
DEXA scans
ranges of normal, osteopenia, oP, sev. OP in BMD
normal: BMD within 1 SD of young adult reference
Osteopenai (low bone m.): BMD: 1-2.5 SD below young a. ref.
OP: BMD >2.5 below young a. ref.
Sev. OP: BMD >2.5 below + fragility fracture
in OP target therapeutic inervention is for those at high risk of …
low impact fracture
SIGN guideline is based on fracture risk and not BMD, and treatment based on addressing risk factures, what are modifiable/non-modifiable risk factors
modifiable BMD alcohol smoking weight inactivity pharmacological factors
non-mod age gender ethnicity pre. fracture FH menopause <45yrs comorbidities
tool used to assess risk of fracture
WHO fracture risk calculator
who to assess? when to refer to DXA
> 50yrs
<50 + early menopause or on glucocorticoids
if risk >10%
investigations for OP
U+Es LFTs Bone biochem FBC PV TSH
protein electrophoresis/bence jones proteins coeliac antibodies testosterone 250H VitD PTH
2ndary causes of OP can be due endo, GI, resp, or others. give examples
endocrine
- hypothyroid
- hypoparathyroid
- cushings
GI
- coeliac
- IBD
- chronic liver disease
- chronic pancreatitis
resp
- CF
- COPD
chronic kidney disease
lifestyle advice for management of OP includes high intensity strength training, avoiding excess alcohol and smoking. name 2 more
low impact weight bearing exercise
fall prevention
diet for op
700mg calcium (2-3portion from dairy) if post menopause - 1000mg calcium (3-4portions)
non-dairy sources of caclium
bread and cereals
fish with bones
nuts
green veg
drug treatments for OP
calcium + Vit D supplemwents biphosphonates denosumab teriparatide HRT SERMS Testosterone
vit D deficiency at risk patients
low exposure to suun
house-boound
calcium supplements should not be taken within 2 hours of oral __
biphosphonates
t.f if dietary calcium is adequate, 700mg Vit D is preferred
true
biphosphonates are ___ agents, examples are alendronate and risedronate. They work by preventing bone loss at all sites vulnerable to OP.
They are 1) anologues of ____, that absorb onto bone within matin the matrix
2) ingested by ___, leading to cell death
biphosphonates are anti-resorptive agents, examples are alendronate and risedronate. They work by preventing bone loss at all sites vulnerable to OP
They are 1) anologues of pyrophosphates, that absorb onto bone within matin the matrix
2) ingested by osteoclasts, leading to cell death
duration of biphosphonate therapy
5yrs
10yrs if vertebral fracture
