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Osteoporosis - Wayne State College by ajizai

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									     Osteoporosis


  Stephanie Wetmore, PT
PED 596: Adv. Cardiac Rehab
    Wayne State College
            Osteoporosis
A disease characterized by irregularities in
the quantity and architectural arrangement
of bone tissue that lead to decreased skeletal
strength and increased vulnerability to
fractures.
       Normal Physiology
Functions
  Provides support to body
  Protects vital organs
  Assists in movement via leverage
  Hematopoiesis (blood cell production)
  Storage area for Ca++
                Cell Types
Osteoblasts
  Synthesize bone
  Remodeling and repair
Osteoclasts
  Responsible for bone resorption
  Remodeling and repair
Osteocytes
  Primary cells of mature bone
  Osteoblasts surrounded by matrix during bone
  formation
  Maintenance and resorption
  Bone Formation & Growth
Intermembranous ossification
  Bone forms directly in the embryonic
  connective tissue
Endochondral ossification
  A “scale model” of hyaline cartilage is replaced
  by bone
  Process of formation for most bones
A Closer Look at Endochondral
   Ossification and Growth
1. Formation of cartilage skeleton in
embryo (6-12 wks gestation)
2. Ossification and growth occur in
subsequent months
3. When ossification completed, growth in
length occurs at epiphyseal plates
4. Widen by multiplication of cartilage
cells and cancellous bone replaces the dying
cartilage
5. Growth in width occurs by depositing of
compact bone beneath the periosteum (outer
surface) and enlargement of the marrow
cavity by bone resorption
6. Growth ceases when epiphyseal plate is
replaced by bone.
Endochondral Ossification
      & Growth
            Homeostasis
Balance between bone formation &
resorption
Remodeling process
  Old bone destroyed by osteoclasts
  New bone constructed by osteoblasts
Dependent upon Ca++, P, and vitamins
(esp. vit. D)
Controlled by hormones
Regulation of Bone Formation
         & Growth
Vitamin D
  Increases rate of Ca++ absorption from intestine
Growth Hormone
  Needed to stimulate proliferation of cartilage cells at
  growth plate
Vitamin C
  Important in synthesis of collagen
Thyroxin
  Increases rate of replacement of bone at growth plate
  and needed for synthesis of GH
Vitamin A
  Stimulates resorption of bone
Estrogens & androgens
  Promote ossification and maintenance of matrix
Parathyroid hormone & Calcitonin
  Regulate release of Ca++ from bone
      Parathyroid hormone
          & calcitonin
When blood Ca++ levels are low, PTH is
released.
Release of PTH increases rate of bone
resorption, which increases the
concentration of Ca++ in the blood.
When blood Ca++ levels are high,
calcitonin is released, which inhibits
resorption.
          Pathophysiology
Osteoporosis can be either hormonally
induced or mechanically induced.
Mechanical
  Electrical changes created with weight bearing
  stimulate activity of osteoblasts, which lead to a
  build up of Ca++.
  This does not occur without weight bearing
  (when someone is on bed rest)
       As we age normally
Birth to age 20-30
  GH influences deposition of bone, which
  exceeds resorption rate
Age ~50 to age 80
  Resorption exceeds deposition due to decreased
  osteoblast activity and changes in Ca++
  metabolism
       Rates of Bone Loss
       with Normal Aging
Female >30-35
  Lose .5-1% of bone mass/year
Postmenopausal Females
  Lose 2-3% bone mass/year until ~age 70
Women will lose ~45-50% in lifetime
Men will lose ~20-30% in lifetime
Normal Bone vs. Osteoporosis
Normal vs. Ostoeporosis
Classification System
   Epidemiology of Primary
   Involutional Osteoporosis
Most common fracture sites
  Wrist, vertebrae and hip
           Risk of Fracture
Caucasian Women      Caucasian Men
  Vertebral 15.6%      Vertebral 5%
  Hip 17.5%            Hip 6%
  Wrist 16%            Wrist 2.5%
  Overall 39.7%        Overall 13.1%
Fracture Risk (cont.)
 Wrist & hip fractures are most
 commonly the result of a
 combination of bone loss and
 moderate trauma such as a fall
 Of all NH admissions, 21% are
 made following a hip fracture.
 Vertebral compression fractures
 can occur simply by coughing,
 bending forward or hugging.
        Risk Factors
Advancing age – 1.4 to 1.8 fold
increase with each decade
Gender – women > men
Family or personal hx of fx as an
adult
Repeated fx’s, severe stooped
posture
         Risk factors (cont.)
Race – Caucasian & Asian > African American or
Hispanic
Bone Structure and Body Weight – small-boned
and thin women (<127#) are at greater risk
Menopause/Menstrual history
  Normal, premature (<45 y/o) or surgical
  Late onset menarche (>15 y/o) or prolonged
  amenorrhea – anorexia nervosa, bulimia, excessively
  low body fat
       Risk Factors (cont.)
Lifestyle/Nutrition
  Cigarette smoking – inhibits estrogen
  Alcoholism
  Inadequate intake of Ca++
  Sedentary lifestyle
  High caffeine consumption and phosphoric acid
  intake (cola drinks)
  Eating disorders
Are you getting enough Calcium?
What is adequate Ca++ intake?
 Age 1-3 years     500 mg/day
 Age 4-8 years     800 mg/day
 Age 9-18 years    1300 mg/day
 Age 19-50 years   1000 mg/day
 Age >50 years     1200 mg/day
  Risk Factors…Medications
Glucocorticoids          Cyclosporine A
Corticosteroids          Heparin or Coumadin
Excessive thyroid        Cholestyramine
hormones                 No ERT or HRT
Anticonvulsants          Low testosterone levels
Gonadotropin releasing   Chemotherapeutics
hormones                 Antacids
Methotrexate             Isoniazid
Cyclophosamide           Immunosuppressants
Dexamethasone            Diuretics
Lithium
Risk Factors…Chronic Diseases
Arthritis                Turner syndrome
Glycocorticoid excess    CVA
Lung disease (COPD)      MS
Organ transplants        Lupus
SCI                      IDDM
Hyperthyroidism          Chronic inflammation
Hyperparathyroidism      Chron’s disease
Chronic kidney/liver     CA
disease                  Burns
RA                       Asthma
RSD                      Mental illness
Malabsorption problems   (depression)
Bone Mineral Density Testing
Painless, non-invasive test, which identifies
osteoporosis, determines fx risk and
monitors response to treatment.
          WHO Definitions
Normal
  +/- 1 SD of the young adult mean
Low Bone Mass (osteopenia)
  -1 to –2.5 SD of the young adult mean
Osteoporosis
  >-2.5 SD of the young adult mean
Severe (established) osteoporosis
  >-2.5 SD of the young adult mean & one or more
  osteoporotic fractures
DEXA Images & Reports
           Pharmacology
Estrogen Replacement Therapy/Hormone
Replacement Therapy
  Reduces bone loss, increases bone density,
  reduces risk of fx in postmenopausal women
  Increase risk of uterine and breast CA,
  increased risk of thromboembolism
          Biphosphonates
Alendronate Sodium (Fosamax)
  Reduces bone loss, increases bone density,
  reduces risk of spine and hip fractures
  Side effects include bone, muscle and/or joint
  pain and headache
Risedronate Sodium (Actonel)
  Slows bone loss, increases bone density and
  decreases spine and hip fractures
  Also approved for men & women to prevent
  and/or treat steroid-induced osteoporosis
           SERMs family
Selective estrogen receptor modulators
Raloxifene (Evista)
  Prevent bone loss, increase bone mass and
  decrease risk of vertebrae fracture
  Side effects: DVT, leg cramps, syncope,
  arthralgia, tendon disorder and vertigo – chest
  pain, myalgia and arthritis possibly (<placebo).
     Calcitonin (Miacalcin)
Naturally occurring hormone involved in
Ca++ regulation and bone metabolism
Slows bone loss, increases bone density and
relieves pain associated with vertebral
fractures
   Exercise Testing Modification/
   Exercise Limitations/Capacity
Weight-bearing exercise and resistance
training recommended with precautions
    Weight-bearing Exercise
Brisk walking is ideal
Alternatives: hiking, stair climbing, dancing and
racquet sports
Contraindicated = stair steppers, bicycling
(including stationary), rowing machines, running
and high-impact aerobics
  Stair steppers – combination of unilateral WB and force
  to depress step
  Bicycle – increased flexion
  Rowing machines – deep forward bending (flexion)
   Testing Contraindications
Sub maximal cycle ergometer
Step-tests
        Resistance Training
Light weights recommended
Major muscle groups emphasized
Slow progression over several months
  Fatigue after 10-15 reps
  Increases do not exceed 10% per week
  Proper technique
  Every third day
  If joint swelling, limping or pain after, decrease weight
  by 25-50%.
        Resistance Training
         Contraindications
Weight carrying tests
Repetitive lifting tests
       Flexibility Exercises
Flexion exercises contraindicated if
vertebral bone density decreased or risk of
compression fx
  Avoid knee to chest
  Forward bending
  Touching the toes
  Partial sit-up
    Okay if thoracic spine stabilized and do not lift head
    and chest above T-6 level.
      Flexibility Exercises
       Contraindications
Sit-and-reach test
Curl-up muscular endurance test
          Other exercise
HR, BP, ECG, ventilation frequency, tidal
volume, oxygen saturation and expired
oxygen and carbon dioxide should not be
affected by osteoporosis medications.
Increasing kyphosis of the thoracic spine
will make it more difficult to expand the
lungs fully during inspiration
 Sample Exercise Prescription
Brisk walking 15-20 minutes 3-4x/wk
  Begin with 5-minute walks and increase by one minute
  every other session
Flexibility program – body extender, shoulder
pinches, chin tucks, elbow backs, arm reaches and
back arches daily
Sinaki & Mikkelsen study
  Flexion programs – 86% fx rate
  Extension programs – 16% fx rate
  Control group – 67% fx rate
  Flex/Ext programs – 57% fx rate
    Sample Exercise (cont.)
Resistance Training
  Every third day
  Major muscle groups especially those integral
  to fall prevention
    Hip extensors, flexors, adductors, abductors,
    quadriceps, ankle dorsiflexors & plantar flexors and
    trunk extensors & stabilizers
  One set 10-15 reps
  Increase no greater than 10% per week for
  amount of weight
                Resources
National Osteoporosis Foundation
  http://www.nof.org
American Academy of Orthopedic Surgeons
  http://www.aaos.org
Lewis, C.B. (1990), Aging: The Healthcare
Challenge (2nd ed.)
Sinaki & Mikkelsen (1988)
Katz & Sherman (1998)

								
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