Osteoporosis Flashcards
Osteoporosis
Reduction in the strength of bone that leads to increased risk of fractures
World Health Organization (WHO) for Osteoporosis
A bone density that falls 2.5 standard deviations (SD) below the mean for young healthy adults of the same sex (T score of -2.5)
Postmenopausal women who fall b/w -1.0 and -2.5 also have low bone density and are at increased risk of developing osteoporosis
(>50% of fxs among postmenopausal women occur in this group)
Epidemiology for Osteoporosis
Most common bone disease
Osteoporosis causes around 2 million fractures/yr in US
As many as 8 million women and 2 million men have osteoporosis and an additional 18 million have osteopenia (T score -2.5)
Morbidity and indirect mortality rates are very high
Primarily due to complications of the treatment of fractures
Fractures of distal radius increase in frequency before age 50 and plateau by age 60 w/ only a modest age-related increase thereafter
Complications of Osteoporosis
Wrist Fractures
Hip fractures
Associated with a high incidence of DVT and PE (20-50%)
Mortality rate b/w 5-20% during the 1st year after surgery
Vertebral fractures are relatively asymptomatic
Associated w/ a long-term morbidity and a slight increase in mortality rates primarily due to pulmonary disease.
Multiple fractures lead to loss of height, kyphosis and secondary pain and discomfort in the back.
Thoracic fractures can be associated with restrictive lung disease
Primary type of Osteoporosis
Type I: Postmenopausal (rapid bone loss w/in 6 years of menopause, mainly trabecular bone)
Type II: Senile (men and women >75yr of age), slow progression, both cortical and trabecular bone
Secondary type of Osteoporosis
Sex hormone deficiency (hypogonadism, prolactinoma, orchiectomy for tx of prostate cancer) Hormone excess (hyperthyroidism, hyperparathyroidism, corticosteroids) Increased bone resorption/formation ratio: immobilization, space flight, long term heparin, cancers such as MM, lymphoma, breast cancer Multifactorial (renal failure, anorexia, athletic amenorrhea, ETOH use d/o)
Risk Factors of Osteoporosis Non Modifiable
Women (postmenopausal/low estrogen) White race Advanced age Personal hx of fracture as an adult History of fracture in a first degree relative Dementia
Risk Factors of Osteoporosis Potentially Modifiable
Low body weight Current cigarette smoking ETOH abuse Low calcium intake Vitamin D deficiency Inadequate physical activity/immobility
Risk Factors of Osteoporosis Chronic Disease
Rheumatologic and autoimmune d/o
Endocrine: hypogonadal states, anorexia, DM, Cushings syndrome, hyperthyroidism
GI disorders: Celiac, gastric bypass, Crohn’s, malabsorption
Hematology/Oncology: Multiple Myeloma, lymphoma, leukemia
CNS: Epilepsy, Muscular Sclerosis (MS), Dementia, Parkinsons Dz, poor eyesight
Risk Factors of Osteoporosis Medications
Glucocorticoids (most common), anticonvulsants, immunosuppressants(cyclosporine), cytotoxic drugs, Aromatase inhibitors, long term Heparin, Lithium, hormonal therapies, long term PPIs, high dose inhaled steroids in elderly
Pathophysiology for Normal Growth
Skeleton increases in size by linear growth and by apposition of new bone tissue on the outer surface of the cortex called modeling (allows the long bones to adapt and shape to the stresses placed on them).
During puberty, there is increased sex hormone production that is required for skeletal maturation
In young adults resorbed bone is replaced by an equal amount of new bone (bone mass remains constant after peak bone mass is achieved in adulthood)- equal balance
Pathophysiology for Adults
Bone remodeling (2 primary functions) Repair microdamage w/in the skeleton to maintain skeletal strength To supply calcium from the skeleton to maintain normal serum calcium **Regulated by: estrogen, androgens, vitamin D, Parathyroid hormone (PTH) as well as numerous growth factors
At age 30-45yr: Resorption exceeds formation
Exaggerated in women after menopause
Excessive bone loss can occur if there is an increase in osteoclastic activity and/or a decrease in osteoblastic activity
Signs and Symptoms for Osteoporosis
Usually asymptomatic unless the patient sustains a fracture
Gradual height loss
Increased kyphosis of thoracic spine (Dowager hump) with a secondary protuberant abdomen
Pain (bone pain or deformities may result from fractures)
Diagnosis for Osteoporosis
Made clinically in the setting of a fragility fracture regardless of T-score
In postmenopausal women and men>50 w/ no fragility fracture diagnosed by bone density testing
Labs for Osteoporosis
Primarily used to rule out secondary causes:
CBC (anemia, Multiple Myeloma)
Calcium
elevated hyperparathyroidism
low Vitamin D def or GI malabsorption
Phosphorus (elevated in renal failure)
Vitamin D level (goal is >30ng/mL)
Albumin (nutrition status)
Alkaline Phosphatase
Serum protein electrophoresis- MM
Creatinine (kidney function)
TSH (hyperthyroidism)
PTH
Elevated hyperparathyroidism
Low suggests malignancy
24-h urinary calcium excretion
300mg/24h indicates hypercalciuria
In men total testosterone and liver transaminases
Imaging for Osteoporosis
Dual-energy X-ray absorptiometry (DEXA)- gold standard test
Measures bone density w/ minimal radiation exposure
Looks primarily at the spine and hip, though portable scans evaluate the heel, forearm or fingers)
Results are reported using T scores and Z scores
T scores:
Compares the individual results to those of a healthy 30 year old of the same race and sex
T score of -2.5 is considered osteopenia (precursor to osteoporosis)
Z scores compare individual results to those of an age-matched healthy person of the same race and sex
not used to diagnose osteoporosis
Approved Testing Guidelines
For postmenopausal women and men >50 years old:
Measure height annually
DEXA scan: All women >65yr All men >70yr Postmenopausal women 3months Primary hyperparathyroidism Monitoring response to an FDA approved medication for osteoporosis
Osteoporosis Treatment- Treat Underlying Fx
Hip fractures: typically require ORIF followed by rehabilitation and pain mgmt
Vertebral fractures: acute pain mgmt if symptomatic, vertebroplasty/kyphoplasty (supplies immediate pain relief), chronic pain mgmt (d/t muscles, ligaments and tendons)
Wrist fractures: may or may not require pinning, ORIF or manual reduction, acute pain mgmt
Osteoporosis Treatment- reduce underlying modifiable risk factors
d/c medications if possible
smoking cessation
alcohol abuse treatment
environmental safety in the home (eliminating throw rugs, move exposed wires/cords, improve lighting at night to eliminate fall risks)
treat impaired vision
Specialized supervision and care for patients with dementia, etc.
Improve Nutrition for Osteoporosis Treatment
Calcium supplementation: normal levels 8.5-10.5mg/dL
Men and Women age 19-50y1000mg/d
Men and Women age 51y and over 1200mg/d
Vitamin D: Target level is >30ng/mL
Synthesized in skin under the influence of heat and UV light
Given in doses of 800IU-2,000IU/day
Vitamin D dosing for treating deficiency is different than for replacement.
High doses must be used to replenish stores. For vitamin D deficient adults (levels <20) 50,000 IU of vitamin D2 or D3 can be given once weekly for six to eight weeks for replenishment.
Once a deficiency has been corrected, the patient is on maintenance doses
Weight Bearing Exercise for Osteoporosis Treatment
Prevents bone loss, but does not necessarily increase bone mass
Improves coordination, strength, and balance and therefore reduces the risk of falling
Needs to be consistent (at least 3 days/week)
Pharmacological Treatment for Osteoporosis
Bisphosphonates—1st line Tx
Estrogen
Selective estrogen receptor modulators (SERM’s)—–
1st line though not as effective as Bisphosphonate
Calcitonin—–Rarely used
PTH
Testosterone
Bisphosphonates MOA
- inhibit osteoclast-induced bone resorption
- Increases bone density and reduce the incidence of both vertebral and nonvertebral fractures
- Prevents corticosteroid induced osteoporosis
Examples of Bisphosphonates
Alendronate (Fosamax) 70mg po once/week (reduce v and nv fxs)
Risendronate (Actonel) 35mg po once/week (reduce v and nv fxs)
Ibandronate sodium (Boniva) 150mg po once/month (reduces v fxs only)
Parenteral agents: used if can’t tolerate oral agent
Zoledronic acid (once/year)
Pamidronate (q3-6 months)
Side Effects of Bisphosphonates
Osteonecrosis of jaw, esophagitis, esophageal cancer
Treatment length for Bisphosphonates
½ life is 10 years; therefore it is now recommended to d/c after 5 years of treatment
Estrogen
Reduces bone turnover, prevents bone loss and causes small increases in bone mass of the spine, hip and total body
Not recommended as first line tx of osteoporosis, best used as prevention
Potential for serious long term side effects (increased risk of CV events, breast cancer, strokes, endometrial hyperplasia/bleeding, DVT/PE) therefore no longer 1st line therapy
Selective estrogen receptor modulators (SERMS)
Used in prevention of osteoporosis in postmenopausal women
ex. Raloxifene (Evista) 60mg/d po
Reduces risk of vertebral fx’s only
Reduces risk of invasive breast cancer, does not cause endometrial hyperplasia, bleeding or uterine cancer
Similar to estrogen, increases risk of DVT/PE
Calcitonin
Role is unclear, produces small increases in bone mass of the spine
Nasal spray of calcitonin-salmon (Miacalcin) 2200U/mL in 2mL bottle
One puff QD (200IU
Less nausea and flushing than parenteral route
SE: rhinitis and epistaxis
Has analgesic affects on bone pain from fractures
Reduces # of new vertebral fractures only; therefore not used in prevention nor is it potent enough to prevent bone loss in early postmenopausal women
PTH MOA
Approved for both men and women w/ established osteoporosis
MOA: Works on osteoblasts. Favors bone formation over bone resorption, produces an increase in bone tissue and restores the microarchitecture
Ex. Teriparatide (Forteo, Parathar)- analog of PTH
Testosterone
Used in hypogonadal men to prevent osteoporosis
