osteoporosis Flashcards
presumptive diagnosis of osteoporosis
all individuals over the age of 50 who sustain a fracture from minimal truam a
diagnositc investigations
bone mineral density scan using at least two skeletal sites
should be measured to determine baseline
how to perform a BMD scan
total hip is the preferred site, forearm BMD can be used if the total hip or lumbar spine cannot be assessed
repeat BMD measurements should be performed on the same machine because BMD measurements are not standardised between machines and facilities
T score
the numer of standard deviatons by which the patients BMD varies for the young adult mean for their sex, as measured by DXA
how to interpret the T score
relative fracture risk doubles for each standard devation decrease in T score
Z-score
the numer of standard deviatons a person’s BMD varies from the age and sex matched BMD
a Z score below -2 warrants investgation for secondary cause of low bone density
lifestyle modifications
adequate calcium and protein intake
adequate but safe exposure to sunlight as a source of vitamin D
healthy BMI
cessation of smoking
avoidance of excessive alcohol consumption
exercise
individuals over 50 should participate regularly in progressive resistance training and balance training exercises
treatment
bisphosphonates
denosumab
hormone therapy - oestrogen replacement therapy or SERM
SERMs may be useful for
women with a prior history of breast cancer
indications to medicate for osteoporosis
T score < -2.5 in patients over 70
or minimal trauma fracture in patients > 50
or in corticosteroid induced osteoporosis: T score < -1.5
denosumab
monoclonal antibody
reversibly inhibits bone resorption by reducing osteoclast formation and increasing osteoclast apoptosis
can be used in chronic kidney disease (unlike bisphosphonates)
6 monthly subcut injection
bisphosphonates
inhibit osteoclasts
avialable as orals or zoledronic acid which is a 15 minute IV infusion once per year
common sites for osteopororsis fracture
vertebral bodies
distal radius
proximal humerus
pelvis
proximal femur
modifiable risk factors than increase the risk for minimal trauma fracture
falls and factors that increase the risk of falls
drugs that affect bone homeostasis or density
lifestyle and nutrition factors
disorders that affect bone homeostasis or density
preventing falls
improving vision
adjusting drug therapy
minimising household risks
providing aids for daily living
minimising periods of immobilisation
promoting exercise
calcium intake advice
intake should ideally be achieved from dietary sources
calcium suppliments cause bloting and constipation
three servings of dairy products are recommended each day
dairy is also a good source of protein, which may independently contribute to bone health
calcium drug of choice
calcium carbonte is a reasonable first line choice
calcium citrate does not require gastric acidity for absoprtion, so may be better abserobed in people taking a proton pump inhibitor
investigations for common secondary causes of osteoporosis
serum calcium concentration
serum phosphate concentraton
serum alkaline phosphatase concentration
serum 25-hydroxyvitamin D concentration
liver biochemistry
kidney function
how to work up a patient following minimal trauma fracture
DXA scan, treat if osteopaenic or osteoporotic
if within the normal range, consider further investigations based on patient history and clinical examination
DXA scan screening
measure BMD in patients with significant risk factors for practure, and in patients 70 or older
delaying denosumab dosage
increased incidence of multiple spontaneous vertebrl fractures if stopped or delayed by more than 4 weeks
