Bone Density Flashcards
indications for BMD
- primary and secondary osteoporosis or osteopenia
- monitoring treatment (HRT, calcitonin, etc.)
what is secondary osteoporosis/osteopenia?
result of other systemic disorders or medications/treatments that causes an imbalance in bone remodelling
primary osteoporosis
associated with the aging process; divided into Type I and Type II
Type I osteoporosis
in post-menopausal women due to the decreased estrogen levels
Type II osteoporosis
in men and women
- due to the general decrease ability to build new bone as we age
what role does hyperparathyroidism have on bone formation?
it causes increase in PTH = increase bone resorption = which increases serum Ca
post-menopausal women and men 50-64
what makes then at risk?
fragility #, parental hip #, vertebral # or osteopenia on x-ray, smoker, high alcohol intake, those with a lower body weight, RA, and major weight loss (>10% of body weight at age 20)
women and men younger than 50
what makes them at risk?
fragility #, premature menopause (before age 45), malabsorption syndrome, primary hyperparathyroidism, secondary osteoporosis, prolonged use of glucocorticoids, hypogonadism
what are the contraindications for BMD?
- recent barium study (1 week is okay)
- CT or MR with contrast (1 week)
- NM study within 10 t1/2
- spine, hip or radius #, hardware or grafts at the specific sites
- pregnancy
how do you correctly identify the lumbar vertebrae?
count vertebrae starting from bottom up
L5 immediately above sacrum
what are the characteristics of the L1-L4 an L5?
L1-L3 = u shape
L4 = H shape
L5 = dog bone on its side
t-score
Comparison between patients to reference population with peak bone density
*still sex matched but not aged matched
SD from 25-30 yo
Z score
Patients are compared to an age-and-sex-matched database
SD from normal
What is the absolute value of the results?
Greater than 1g/cm2 is normal
WHO BMD relative values are for which group of people?
Women and men over 50
