Disorders of Bone Health including Osteoporosis Flashcards
What is osteoporosis
Progressive systemic skeletal disease characterised by low bone mass and microarchitectural deterioration of bone tissue, with a consequent increase in bone fragility and susceptibility to fracture
How common is osteoporosis
One in two women
one in six men
All over the age of 50 will develop osteoporosis
Where are the common fracture sites for osteoporosis
Neck of femur
Vertebral body
Distal radius
Humeral neck
How much of the adult skeleton is remodelled each year
10%
What does osteoporotic bone look like
Loss of bone
large spaces and breaks in the microscopic architecture
What contributes to peak bone mass
Genetics Body weight sex hormones diet exercise
What contributes to bone loss
Sex hormone deficiency Body weight Genetics Diet Immobility Diseases Drugs. e.g. steroids, aromatase inhibitors
What are the modifiable factors for reducing the risk of fragility fractures
BMD Alcohol weight smoking physical inactivity
What are the non-modifiable factors or reducing the risk of fragility fractures
Age gender ethnicity preious fracutre family history early menopause (
What is involved in the WHO fracture risk calculator
Allows calculation of absolute risk for incorporating additional risk factors rather than just BMD
Prediction of 10 year fracture risk of major osteoporotic fracture or hip fracture
Some limitations
What are some of the pros of FRAX
Freely available
calculates 10 year absolute risk of hip or major OP fracture
What are some of the cons of FRAX
Underestimates vertebral fracture risk
Same level of risk assigned to all secondary causes
Dichotomised variable smoking/ alcohol
What can bone mineral density predict
risk independently of other risk factors
What type of scans are used to measure BMD
DEXA
What BMD result diagnoses osteopenia
BMD >1 SD below the young adult mean
What BMD result diagnosis osteoporosis
BMD >2.5 SD below the young adult mean
What BMD result diagnosis severe osteoporosis
BMD >2.5 SD below the young adult mean with fragility fracture
To assess someone with suspected bone disease, what should we investigate
U&E LFT Bone biochemistry FBC PV TSH
What other factors should be considered when investigating someone with suspected bone disease
Protein electrophoresis Coeliac antibodies Testosterone Vitamin D PTH
What is a endocrine causes of bone disease
hyperthyroidism, hyperparathyroidism, Cushing’s
What are some GI causes of bone disease
Coeliac disease
IBD
chronic liver disease
chronic pancreatitis
What are some Resp causes of bone disease
CF
COPD
What are 5 bits of lifestyle advice that are recommended in managing a patient with osteoporosis
High intensity strength training Low impact weight bearing exercise Avoidance of excess alcohol Avoid smoking Fall prevention
How much calcium should be taken in from the diet
700mg calcium or 1000mg for postmenopausal women
What are some non-dairy sources of calcium
Bread and cereals fish with bones nuts green veg beans
What are the drug treatment options for bone disease
calcium and vitamin D supplementation bisphosphonates denosumab teriparatide strontium ranelate HRT testosterone
What are bisphosphonates
Antiresorptive agents
What do bisphophonates do
Prevent bone loss at all sites vulnerable to osteoporosis
Reduce risk of hip and spine fractures
Where do bisphosphonates work
Ingested by osteoclasts leading to cell death thereby inhibiting bone resorption
What are some long term concerns of bisphosphonates
Osteonecrosis of the jaw, oesophageal Ca, atypical fractures
How is Zoledronic Acid given
Once year IV infusion for 3 years
5mg in 100mls NaCl over 15 mins
What is the success rate of using Zoledronic acid
Around 70% reduction in vertebral fracture and 40% reduction rate in hip fractures
How does Denosumab work
Targets and binds with high affinity and specificity to RANKL
This prevents activation of its receptor RANK, inhibiting development and activity of osteoclasts, decreasing bone reposition and increasing bone density
How is denosumab given
SC injection 6 months
What is the 3rd line agent for osteoporosis
Strontium Ranelate
What are the contraindications of Strontium Ranelate
History of thromboembolic disease
IHD
peripheral arterial disease
uncontrolled hypertension
How does Teriparatide work
Recombinant parathyroid hormone
stimulates bone growth rather than reducing bone loss
When should treatment be started for those with bone disease
When the T score is
What are the direct affects of corticosteroids and bone
reduction of osteoblast activity and lifespan
suppression of replication of osteoblast precursors
reduction in calcium absorption
What are the indirect effects of corticosteroids and bone
Inhibition of gonadal and adrenal steroid production
Biochemically, how do glucocorticoids affect calcium metabolism
Increase PTH and decrease bone mass
What is Paget’s disease of bone
Abnormal osteoclastic activity followed by increased osteoblastic activity
Abnormal bone structure with reduced strength and increased fracture risk
What is the aetiology of Paget’s disease
Uncertain
Viral
encironmental
biomechanical trigger in genetically predisposed individual
What bones are affected in Paget’s disease
long bones, pelvis, lumbar spine and skull
How does Paget’s disease present
bone pain, deformity (bowed legs) deafness or compression neuropathies
What is a rare complication of Paget’s disease
osteosarcoma
What is used to diagnose Paget’s disease
XR
isotope bone scan shows distribution
raised alkaline phosphatase with normal LFT
What can be used to treat Paget’s disease
Analgesia
if not responding bisphosphonates
What type of condition is Osteogenesis Imperfecta
Rare group of genetic disorders mainly affecting bone
Autosomal dominant inheritance
What might also be seen in osteogenesis imperfecta
blue sclerae and dentinogenesis imperfect
How do severe forms of osteogenesis imperfecta present
Fractures in childhood (could be mistaken for non-accidental injury)
What is the treatment for osteogenesis imperfecta
no cure - fracture fixation, surgery to correct deformities, bisphosphonates
