Term
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Definition
- bone disease characterized by compromised bone strength predisposing to an increased risk of fracture.
Bone strength is determined by bone density (peak bone mass and amount of bone loss) and bone quality (architecture, turnover, damage and mineralization).
Because we do not have an easy way to test bone strength, we test bone mineral density as a surrogate method.
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Term
Osteopenia And Osteomalacia |
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Definition
Osteopenia- low bone density/mass (matrix) manifested as radiolucency of bone.
Osteomalacia- progressive loss of calcium and phosphorus from bones with normal bone matrix resulting in increased bone fragility and risk of fracture.
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Term
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Definition
Post menopausal osteoporosis affects:
4 – 6 million postmenopausal white women.
13 – 17 million more have hip osteopenia and are at risk for hip fracture.
Primarily affects white and Asians, however a significant, but lower risk still exists for black women.
About half of white women over age 50 are expected
to fracture in their remaining lifetime.
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Term
Mechanisms of Steroid Induced Osteoporosis
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Definition
Bone loss occurs within the 6-12 months of start of drug 2o:
↑ osteoclast activity
↑ urinary Ca excretion
↓ osteoblast activity (shortened lifespan)
↓ GI Calcium absorption
↓ estrogen and testosterone levels
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Term
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Definition
•Around age 30:
–Formation unable to keep up with resorption
–Resorption cavities are left unfilled
–Resorption/Formation imbalance leads to bone loss
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Term
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Definition
•A – Osteoclastic bone resorption
•B – Recruitment of Osteoblasts to form Matrix
•C – Matrix mineralization to form sturdy bone
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Term
Methods of evaluating BMD
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Definition
-Radiographs
-Single photon absorptiometry- radius or heel
-Quantitative Cat Scan- lumbar spine
-Calcaneal ultrasound
-Dual Energy X-ray Absorptiometry (DXA)- gold standard low radiation exposure and takes 20 minutes
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Term
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Definition
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Z-score defines how the bone mineral density (BMD) compares to age matched controls.
A z-score of < -2.0 is interpreted as “below the expected range for age”.
A z-score of > -2.0 is interpreted as “within the expected range for age”.
As a result, the only reason to order a DXA in premenopausal women and men < 50 years old, is either to establish a baseline BMD prior to treatment or to assess their response to therapy.
At least 2 different locations must be tested:
spine (2 consecutive vertebral bodies)
right hip (total hip or femoral neck or trochanter)
left hip (total hip or femoral neck or trochanter)
nondominant midshaft radius (known as 33% (esp. if a cortical bone disorder such as hyperparathyroidism)
Lowest T score defines the condition.
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Term
General approach to treating the
Osteoporotic patient
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Definition
1. Risk profile modification- such as tobacco and ETOH
2. Fall risk assessment
3. Weight bearing physical activity-
improve muscle strength, mobility,
functional status and stabilize bone mass
4. Assure adequate Calcium and Vitamin D intake
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Term
When to Treat with Medications
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Definition
T score < -2.5
T score < -1.5 with risk factors for low bone mass
Prior fragility (low trauma) fracture
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Term
Selective Estrogen Receptor Modulators (SERMs) Advantages/Disadvantages
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Definition
Potential Advantages
May reduce cholesterol
May protect bone
May reduce breast CA
May reduce uterine CA
May maintain pelvic muscles
May reduce Alzheimer’s disease
Potential Disadvantages
May exacerbate hot flushes
May increase DVT
(esp. if bedridden)
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Term
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Definition
Only used for Osteoporosis treatment not prevention
Special value because of analgesic effects in patients with back pain from acute fracture
Side effects:
nasal dryness, rhinitis and allergy to salmon calcitonin
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Term
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Definition
Alendronate (Fosamax) Ibandronate (Boniva) Risedronate (Actonel)
Zoledronic Acid (Reclast)
Poorly absorbed from GI tract:
1. Must be taken on empty stomach with 6-8 oz H2O,
2. 30 minutes before consuming anything and
3. Must remain upright for at least 30 minutes to
decrease risk of esophagitis.
Weekly, monthly and yearly dosing improves patient compliance.
Avoid in patients with significant GERD (reflux disease) or renal dysfunction.
? Osteonecrosis of the jaw.
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Term
Estrogen Replacement Therapy Pros |
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Definition
PROS
Decreases rate of bone loss after menopause
Maintains/increases BMD
Relieves postmenopausal symptoms
May prevent Alzheimer’s disease
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Term
Estrogen Replacement Therapy Cons
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Definition
CONS
Troublesome side effects:
irregular bleeding,
fluid retention,
mastalgia,
headache,
mood swings
Possible increased risk of breast cancer with long-term use
Must be taken with progestin to avoid risk of endometrial hyperplasia/cancer
Deep venous thrombosis (may be eliminated by transdermal estradiol)
Favorable effects on lipoprotein profile; but does not appear to protect against CVD
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Term
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Definition
•Presentation: nonspecific or vague bone pain, may be malnourished
•Imaging Studies: radiographs show widened physis
•Looser’s transformation zones also known as pseudofractures are lines of radiolucency that represent stress fractures with unmineralized osteoid
•Laboratory Studies: low or normal serum calcium, phosphorus or vitamin D, increased alkaline phosphatase
•Definitive diagnosis by bone biopsy
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Term
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Definition
•Osteitis Deformans is a condition of abnormally increased and disorganized bone remodeling
•Not systemic, but within bones
•Viral infection of osteoclasts in genetic susceptible individuals may be cause
•Rapid resorption-rapid bone formation leads to mosaic of disorganized immature (woven) bone
•May be painful, malignant, may fracture
•Femur, tibia, pelvis and skull
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