Disorders of Bone Flashcards
Osteoporosis is:
*The most common metabolic bone disease in the US
* Is a chronic and progressive disease
* Becomes clinically apparent once a fracture occurs
Osteoporosis
The imbalance of new bone formation and old bone resorption. For some they may not make enough new bone, for others have too
much reabsorption of old bone, and for others both may occur
Osteopenia
A condition of low bone density with a T-score below normal range from -1.0 to -2.5
Normal bone is defined by a T-score higher than -1.0
Osteoporosis T score & FRAX score
T-score of -2.5 or below in the spine, femoral neck, or total hip
Any fragility fracture
Osteopenia + FRAX score > 3% risk of hip fracture or > 20% risk of major osteoporotic
fracture
Severe Osteoporosis T-score -2.5 with fragility fracture or T-score -3.0
or greater
Who gets osteoporosis?
- Postmenopausal women – most common
- Men – over 65 or secondary cause
- Premenopausal women – usually a secondary cause
Pathogenesis of Osteoporosis
Menopause
Cellular Senescence of osteoblasts and osteoclasts
Changes to Gut Microbiome
Sex steroid deficiency
Clinical Manifestations of Osteoporosis
No clinical manifestations until a fracture is present
Pain? – many with hip or feet pain assume they have osteoporosis, but
osteoporosis is painless until a fracture occurs
Osteomalacia causes bone pain
Common Fractures of Osteoporosis
Vertebral are the most common, 2/3 are asymptomatic
Hip Fracture affects up to 15% of women or 5% of men by age 80
Risk of hip fracture increases exponentially with age
Colles fracture (distal radius) most common after menopause
Diagnosis of Osteoporosis
Usually occurs in the presence of a fragility fracture
Fragility fractures occur from a fall at a standing height or less, without major trauma
Fragility fractures of the spine can occur spontaneously with minimal or no trauma
Fracture of the skull, cervical spine, hands, feet, and ankles are not associated with
fragility fractures
Stress fractures are not fragility fractures since these are due to repetitive injury
The WHO states that _____ is the standard test to diagnose osteoporosis in the absence of a fragility fracture.
BMD assessment by DXA
Dexa Scan
DXA gives an accurate and precise estimate of bone mineral density
Usually provides measurements of the spine and hips since these sites have
the greatest impact on patient’s health.
BMD has the highest predictive value for hip fracture
If pharmacologic therapy is initiated – BMD of the spine detects earlier
responses to therapy than hip BMD
T-score is the standard deviation difference between the bone mineral density
of a patient and a ______
young-adult reference population.
A T-score of_____ mean is
defined as osteoporosis.
2.5 standard deviation or more below the young-adult
A T-score of _____ mean is defined
as osteopenia.
1 to 2.4 stand deviation below the young-adult
Z-score is the comparison of _____
a patient’s bone mineral density with that of an age-matched population.
A Z-score of _____ should alert one to other coexisting problems that
can contribute to osteoporosis.
less than 2
coexisting problems that
can contribute to osteoporosis
Glucocorticoid therapy
Alcoholism
Hyperparathyroidism
Cushing’s Syndrome
Celiac Disease
Renal or Liver Disease
When to Screen for Osteoporosis
All women aged 65 or older should be screened
Postmenopausal women younger than age 65 with clinical risk factors should
be screened
Males >70 or 50-69 with osteoporosis risk factors
Risk Factors for osteoporosis
Low body weight, history of hip fracture/fragility fracture, tobacco use, glucocorticoid therapy, excessive alcohol intake, rheumatoid arthritis, chronic liver disease, inflammatory bowel disease
Laboratory Testing for Osteoporosis
Vitamin D, CBC, and BMP
Other tests if secondary causes are a concern:
TSH, PTH, Celiac panel, 24-hour urine for calcium, Cr measurement, urinary cortisol
Treatment for Osteoporosis
Oral Bisphosphonates are initial therapy of choice. Bisphosphonates inhibit resorption of bone by osteoclasts. They may have an effect on osteoblasts as well.
For postmenopausal women with osteoporosis (T-score < -2.5) or with a
history of a fragility fracture.
High-risk postmenopausal women with T-score between -1.0 to -2.5
Risk fracture is determined based on Fracture Risk assessment Tool (FRAX)
FRAX score
Gives the 10-year probability of developing a hip fracture or other major
osteoporotic fractures given BMD of the femoral neck and assessing for other
clinic risk factors for fracture.
High risk is 10-year probability of > 3% of hip fracture and >20% for major
osteoporotic fracture.
Bisphosphonates
Fosamax – alendronate, 70 mg weekly
Actonel – risedronate, 35 mg weekly or 150 mg monthly
Take on an empty stomach and remain upright for 30 to 60 minutes
Reclast – zoledronic acid, 5 mg once a year (tx), 5 mg every two years (prevention)
For those who cannot tolerate oral form or have impaired renal function
Bisphosphonates contraindications
Esophageal disorders (oral formulation)
Inability to follow dosing requirements
Chronic kidney disease, GFR <30
Bariatric Surgery – Roux-en-Y gastric bypass (oral formulation)
