Osteoporosis

osteoporosis

occurs when formation of new bone does not keep up with bone resorption due to a decline in osteoblast function

low bone mass, impaired bone quality, decreased bone strength

more common in women; in men = major health problem

primary classifications

postmenopausal & senile

secondary classification

onset is related to another medical condition

density

how many bone cells/square inch

quality

reflects health of bone cells present

when is peak bone mass achieved?

third decade of life

pathogenesis

changes in production of osteoclasts and osteoblasts

altering duration of respective life spans thru apoptosis

bone demineralization

deficit in hormonal levels, inadequate physical activity, poor nutrition

clinical symptoms

postural changes, loss of height, back pain, fractures

increased kyphosis of thoracic

what is the most common fracture?

vertebral compression fractures

BMD testing

measures mineral content of bone in grams per square cm

DEXA

Z score

compares values of those of same age/sex

T score

compares values to young adults of same sex

normal T score

-1.0 or higher

osteopenia score

-1.0 to -2.5

osteoporosis score

-2.5 or lower

osteopenia

low bone density that compromises bone’s ability to absorb loads

what can slow progression towards osteoporosis?

physical activity, diet, medication

FRAX

calculates 10 year risk of sustaining a fracture

integrates clinical risk factors plus BMD at femoral neck

radiographs (x rays)

can reveal signs of osteopenia but 30% or greater bone loss must occur before showing on xray

primary prevention

instilling healthy behaviors to prevent disease

secondary prevention

screening for early disease detection

tertiary prevention

managing disease post diagnosis to slow or stop it

when are medications recommended?

T score below -2.0 w/ no risk factors OR below -1.5 w/ risk factors

patient taking long term steroids

men receiving androgen deprivation therapy

bisphosphonates MOA

binds to key enzyme to inhibit natural bone turnover pathways = ultimately increase osteoclast apoptosis which decreases bone turnover

alendronate

Fosamax

ibandronate

Boniva

bisphosphonates (-dronate)

most popular to treat osteoporosis and 1st line treatment because they increase BMD and reduce risk of fracture

bisphosphonates AE

mild upper GI symptoms

what do you take with bisphosphonates?

water, 30-60 mins before food or meds

stay upright - GI will increase if not

bisphosphonates - rare risk

atypical femur fracture

long term therapy may increase risk (3-5 years)

refer if patient has groin, hip or thigh pain

RANKL inhibitor MOA

denosumab binds to RANKL which ultimately inhibits bone resorption

subcut every 6 months in office

RANKL typical

excreted by osteoblasts, binds to RANK on osteoclast surfaces and activates osteoclast action to promote bone resorption

denosumab - AE

Prolia

arthralgia, limb pain, derm reaction

rare: atypical femur fracture, increased risk of infections

teriparatide (Forteo)- MOA

mimics PTH and binds to cell surface receptors to stimulate new bone formation

teriparatide (Forteo) - AE

dizziness, HA, low mood

subcut injections daily - max 2 years (risk of osteosarcoma)

selective estrogen receptor modulators - MOA

stimulates estrogen receptors on bone, blocks estrogen receptors on breast and uterine tissues

raloxifene (Evista)

only FDA approved SERM for treatment

raloxifene - AE

hot flashes, joint/muscle pain, depression, insomnia, GI disturbance

after 4 years- reduces risk of first vertebral fracture by 50%