Osteoporosis Flashcards
Osteoporosis
general
Progressive metabolic bone disease that decreases bone mineral density with deterioration of bone structure
Leads to fractures with minor or inapparent trauma
Most common metabolic disorder
More osteoporotic fractures in the United States than the combined total of heart attacks, strokes, cases of breast cancer, and GYN malignancies
More common in the elderly (> 50 years of age)
♀>♂
Most common in postmenopausal women
osteoporosis
RF
Age
Female gender
White or Asian ethnicity
Family history
Low body mass
Amenorrhea/Late menarche/Early menopause
Physical inactivity/immobilization
Alcohol or tobacco use
Chronic use of PPIs and corticosteroids
Insufficient dietary intake - calcium, phosphorus, magnesium, and vitamin D
Men with low testosterone
Osteoporosis
Pathogenesis
Bone is continually being formed and resorbed
Formation = Resorption
Peak bone mass in ♀ and ♂ around age 30 and plateaus for about 10 years
♂ have higher bone mass than ♀
Bone loss at a rate of about 0.3-0.5%/year
At menopause, bone loss accelerates to 3-5%/year for about 5-7 years
Osteoporotic bone loss affects cortical and spongy/trabecular bone → fragile, porous bone
Osteoporosis
Fragility Fractures & most common sites
Occur after less trauma than might be expected to fracture a bone
Falls from a standing height or less; falls out of bed
Most common sites:
Distal radius (Colles’ fracture)
Spine
Thoracic and lumbar vertebral compression- most common? fractures
Femoral neck
Proximal humerus
Pelvis
Classification of Osteoporosis
Primary Osteoporosis
Type I & II
95% of ♀ cases - majority postmenopausal women
80% of ♂ cases
Types:
Type I: estrogen deficiency
↑ osteoclasts
↓ osteoblasts
Type II: age-related loss of bone mineral density (BMD)
Estrogen inhibits bone resorption (osteoclasts)
Type I = postmenopausal osteoporosis
Type II = senile osteoporosis; osteoblasts lose their ability to build bone, but osteoclasts maintain their ability to breakdown bone
Secondary Osteoporosis
< 5% of ♀ cases
20% of ♂ cases
Causes:
Disease
Bone marrow disorders, endocrine disorders
Deficiency
Malabsorption syndromes, vitamin D deficiency
Drugs
Glucocorticoids, PPIs
Endocrine disorders (hyperthyroidism, hyperparathyroidism, Cushing’s syndrome, hypogonadism, vitamin D deficiency/resistance)
Bone marrow disorders (multiple myeloma, leukemia, lymphoma)
GI disorders (gastrectomy, malabsorption syndromes, Crohn’s disease)
Connective tissue disorders (rheumatoid arthritis, osteogenesis imperfecta, Ehlers-Danlos syndrome, Marfan syndrome)
Drug induced (glucocorticoids, anticonvulsants, cyclosporine, heparin, antiretroviral therapy, aromatase inhibitors, proton pump inhibitors, lithium, calcineurin inhibitors)
osteoporosis
S/Sx
Clinically silent until a fracture occurs
Vertebral fracture: most common
Commonly asymptomatic (~2/3)
Symptomatic - Acute, non-radiating pain for 1 week; aggravated by weight bearing. Residual pain for months.
Multiple fractures:
Loss of height
Kyphosis
Excessive forward curvature of the spine in the upper back
May lead to restrictive lung disease and dyspnea
Dowager’s hump- Exaggerated lordosis at the base of the cervical spine
Hip fracture - leg will be shorter and external rotated
Distal radius fracture (Colles’ fracture) (dorsal angulated)
Other fractures:
Humerus
Pelvis
osteoporosis
Compression fractures leading to kyphosis
Osteoporosis
Dual-energy x-ray absorptiometry (DEXA)
Measures bone density (g/cm2) of the lumbar spine, hip, distal radius, or entire body
Used to:
Define osteopenia and osteoporosis by providing a quantitative measure of bone loss
Predict the risk of fracture
Monitor patients undergoing treatment
Reported as T-scores and Z-scores
osteoporosis
DEXA recommended for
All women ≥ 65 years
Women between menopause and age 65 who have risk factors
Women and men of any age who have had fragility fractures
Individuals with evidence on imaging studies of decreased bone mineral density or asymptomatic vertebral compression fractures
Individuals at risk for secondary osteoporosis
DEXA- osteoporosis
T Score
Standard deviation difference between the patient’s BMD and the reference BMD of a young population of the same sex and race/ethnicity
Normal bone mass density is < 1 standard deviation below the mean
T-score of –1 to –2.5 standard deviation indicates osteopenia
T-score of < –2.5 standard deviation indicates osteoporosis
DEXA osteoporosis
Z-score
Standard deviation difference between patient’s BMD and that of age-matched population of the same sex and race/ethnicity
< –2.0 standard deviation indicatesosteoporosis
light blue is osteopenia.
dark blue is osteoporosis.
DEXA scan report. The area in light blue represents osteopenia and the area in dark blue represents osteoporosis. The patient’s values are represented by the “+” sign inside the circle in each graph.
osteoporosis
A fall from standing height that results in a fragility fracture qualifies as defining osteoporosis if…
It was a hip or spine fracture
OR
if it was a proximal humerus or distal forearm fracture and the T score between –1 to –2.5
Osteoporosis
FRAX Score
When to start?
Fracture risk assessment score
Predicts the 10-year probability of a major osteoporotic (hip, spine, forearm, or humerus fracture in untreated patients)
Based upon:
Age, gender, race
Hx of fragility fracture
Rheumatoid arthritis
Family Hx of a hip fracture (parent)
Low BMI
Hx of steroid Rx (≥5 mg/day for ≥3 months)
Alcohol use
Current smoking
BMD of the femoral neck (hip)
Recommendation:
Screen all patients > 50 with FRAX
screening method for pts over 50
Limitations of FRAX: Does not account for history of falls, BMD at the lumbar spine, and family history of vertebral fractures
FRAX score should not be used for patients who have sustained a defined fragility fracture that meets the definition of osteoporosis or has already received pharmacologic treatment for osteoporosis
