Ortho Flashcards
Osteoporosis
Low bone mass and microarchitectural deterioration of bone tissue. Leads to enhanced bone fragility and an increased fracture risk
Most common types of osteoporosis related fractures
1/2 vertebral, 1/4 are hip, 1/4 are wrist
Fracture rate increases after age…
75
After what age are women 3x more likely to have a fragility fx
50
Risk factors for osteoporosis
Caucasian, female, late menarche, nulliparity, early menopause, excessive exercise, age > 75, family hx, small body frame
Idiopathic secondary osteoporosis
Subset of women with no apparent etiology or secondary cause
Nutritional osteoporosis
Milk intolerance, vegetarianism, low calcium diet, excessive alcohol intake
Lifestyle osteoporosis
Caused by smoking, inactivity
Medical osteoporosis
Type 1 diabetes, cushings, chronic renal disease, IBD, cystic fibrosis, hyperparathyroidism, hyperthyroidism, anorexia nervosa, celiac disease, idiopathic hypercalciuria, premature ovarian failure
Medications causing osteoporosis
glucocorticoids, long term lithium therapy, chemotherapy, antivonculsants like phenytoin, phenobarbital, valproate, and carbamazepine… long term phosphate binding antacid, thyroid replacement drugs, methotrexate
Prevent bone loss in asymptomatic females
change nutrition, change lifestyle
decreased bone strength is related to many factors other than bone mineral density
effected by rates of bone formation, rates of bone resorption (turnover), bone geometry (size and shape), microachitecture
Age related loss of trabecular bone
breakdown of the trabecular network where it thins with separation of vertical structures or horizontal structures – pictures c and d are defined as osteoporosis
bmd screening for postmenopausal women and men
no universally adapted approach for screening
premenopausal women bmd screening
not routinely recommended. healthy, premenopausal women with concerns about bone health may request one, but it is not recommended
international society of clinical densitometry guidelines allow screening for premenopausal women with 2 select circumstances
- history of fragility fracture, known secondary causes of osteoporosis, needing pharmacological therapy for osteoporosis, need to monitor drug therapy for osteoporosis, women in menopausal transition with a specific risk factor like low body weight, low trauma fx or high risk med
T Score
diagnostic threshold for low bone mass and osteoporosis based upon BMD measurements compared with a young adult reference population
The majority of postmenopausal women with osteoporosis have bone loss related
estrogen deficiency and/or age
WHO defines osteoporosis as bone mineral density score of
2.5 standard deviations less than the mean value for a young person of the same gender
vertebral fx are assoc with
loss of stature caused by a progressive increase in the degree of kyphosis and lordotic curve flattening – causing shrinking leading to vertebral collapse
premenopausal considerations
bmd alone cannot define osteoporosis. like fragility fx, bmd is an indicator for further evaluation. fx and low bone mass are less common in premenopausal women.
low bone mass may be related to
either inadequate peak bone mass acquisition and or ongoing bone loss
postmenopausal considerations
no manifestations until fx, if no s/s they assume they do not have osteoporosis, vertebral fx is the most common fx, 2/3 of fxs are asymptomatics dx as incidental findings on xray, hip fx common in 15 percent of women and 5 percent of men by age 80
making the dx of osteoporosis
may be made with a fragility fx particularly spine, hip, wrist, humerus, rib, pelvis without a measurement of BMD
Fragility fx
occur from a fall from a standing height or less, without major trauma like a MVA
Bones not a/w fragility fx
skull, cervical spine, hands, feet, ankles
stress fx
associated with repetitive injury and are not fragility fx
BMD useful for
dx osteoporosis, predict fracture risk, monitor response to therapy. Low BMD a/w increased risk of fx, regardless of the technique of measurement
serology evaluation of osteoporosis
CMP, CBC, TSH. Normal ca, tsh and cr rule our hyperparathyroid, hyperthyroid and renal disease. normal blood count, serum protein and normal ca rule out multiple myeloma. for elderly, order 25-hydroxyvitamin D and PTH
radiography imaging osteoporosis
plain radiography are unremarkable until bone loss has reached 30%. signs of overall bone loss density (osteopenia) can be caused by moderate osteoporosis of the thoracic and lumbar spine. widening of the medullary canal with thinning of the cortices can be seen with long bones. fx may not be seen on initial radiographs, and may require bone scintigraphy, CT, MRI or repeat plain radiographs
BMD Zscores - age matched comparison will
identify individuals requiring futher evaluation for secondary causes of osteoporosis
clinical risk factors for fracture
advancing age, previous fx, glucocorticoid therapy, partental hx of hip fx, low body weight, current cigarette smoking, excessive alcohol consumption, RA, secondary osteoporosis