Osteoporosis dr. mmp
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Transcript of Osteoporosis dr. mmp
Prof. Dr. M. M. PrabhakarMedical Superintendent,Director Government Spine Institute,Prof. & Head Department of Orthopaedics,B. J. Medical College,Ahmedabad.
OSTEOPOROSIS
Osteoporosis, which literally means “porous bone”, is a disease in which the density and quality of bone are reduced.
Bones become more porous and fragile
The risk of fractures is greatly increased
The loss of bone occurs “silently” and progressively
Often there are no symptoms until the first fracture occurs.
Compact bone consists of closely packed cylindrical units called osteons.
The osteon consists of a central canal called the Haversian canal, which is surrounded by concentric rings (lamellae) of matrix.
Between the rings of matrix, the bone cells (osteocytes) are located in spaces called lacunae.
• Spongy bone consists of lattice of fine bone plates (trabeculae) that has small, irregular cavities containing red bone marrow.
• The canaliculi connect to the adjacent cavities, instead of a central Haversian canal, to receive their blood supply.
The bone tissue is composed of a hard matrix of minerals (mostly calcium and phosphorus) that is deposited around protein fibers (collagen).
› Osteogenic cells – are precursor cells for all forms of connective tissue.
› Osteoblasts – are responsible for bone formation that secret the organic substances and mineral salts used in ossification process.
› Osteocytes – are osteoblasts that have stopped laying down new bone, but play a role in the maintaining the cellular activities of the bone tissue.
› Osteoclasts – are cells found on the surface of the bone that are responsible for bone resorption.
Bone resorping cells Use acids or enzymes to
dissolve calcium and collagen of old bone
Dissolved calcium reenters blood stream and is carried to various parts of the body
Osteoblasts are cells that build bones.
Produce collagen Then coat the collagen with
a protein "glue" that holds the calcium in place.
Calcium from the bloodstream then automatically adheres to the collagen, forming new bone material.
Bone cells These maintain bones by
maintaining the concentration of calcium
The terms osteogenesis and ossification are often used synonymously to indicate the process of bone formation.
Osteoblasts, osteocytes and osteoclasts are the three cell types involved in the development, growth and remodeling of bones.
Bone formation occurs by three co-ordinated processes: initially osteoblasts deposit collagen rapidly, without mineralization,
producing a thickening osteoid layer.
The ossification process can occur by two ways:
› Intramembranous ossification - involves the replacement of sheet-like connective tissue membranes with bony tissue.
› Endochondral ossification involves the replacement of hyaline cartilage models with bony tissue.
During childhood and the early years of adulthood, while the epiphyses are still open, the skeleton grows in length (growth), and the bones expand in diameter and achieve their external shape (modeling).
During bone modeling, osteoblasts and osteoclasts work independently of each other and on different bone surfaces - often over large surface areas.
The net balance is positive (i.e. there is increased bone mass) and bones reach their final external form and high bone density during this period.
Both the growth and the modeling processes are controlled by hormones and by mechanical forces - mechanical usage.
Around the age 20-25 years, peak bone mass is achieved as a result of these processes. Subsequently, there is continuous revision of bone through resorption and formation, a process known as remodeling.
Remodeling allows for the degradation of worn out bone from damaged and/or unused regions and for the deposition of minerals in regions of greater stress.
Activation : Activation: via recruitment of osteoclasts by cytokines like IL-1, IL-6
Resorption: via proteo-lytic enzymes & acids secreted by osteoclasts
Coupling: recruitment of osteoblasts & secretion of matrix
Mineralization: deposition of Ca & phosphorous
OsteoclastOsteoclast
ResorptionResorption
OsteoblastOsteoblast
Osteoblast Osteoblast RecruitmentRecruitment
Osteoid Osteoid DepositionDeposition
MineralizationMineralization
The Bone Remodeling CycleThe Bone Remodeling Cycle
► High Remodeling
Hypogonadal (including post-menopausal)
Hyperparathyroidism Hyperthyroidism Others
► Low Remodeling
Involutional (Aging) Glucocorticoids (high dose) HIV
Normal RemodelingNormal Remodeling
OsteoOsteocclast Overactivitylast OveractivityHypogonadal StatesHypogonadal States
Parathyroid and ThyroidParathyroid and Thyroid
OsteoOsteobblast Dysfunctionlast DysfunctionInvolutional (Aging)Involutional (Aging)
GlucocorticoidsGlucocorticoidsHIVHIV
To supply Calcium throughout our body
To replace old bones Regeneration ensures
bone remains strong and flexible
Calcium Regulating Hormones
Glucocorticoids
Growth Factors
Tumor Necrosis Factors
1, 25 (OH)2 Vit D (Calcitriol)
Calcitonin
Parathyroid Hormone (PTH)
Calcitriol Calcitonin PTH
Absorbs Ca from intestine
Calcitonin α serum Ca
PTH α 1 / Serum Ca
Bone resorption
Ca absorption from intestine
Ca reabsorption from urine
Bone formation
Ca absorption from intestine
Ca reabsorption from urine
Aging From 40s onwards bone
mass starts declining gradually
Bone formation <Bone resorption
Bones become weak and danger for osteoporosis sets in
Normal Osteopenia Osteoporosis Severe
Osteoporosis
NIH/ORBD (www.osteo.org), 2000
Osteoporosis is responsible for >1.5 million vertebral and non-vertebral fractures annually
Spine, hip, and wrist fractures are most common
OtherVertebralHipWrist
15 % 19 %
19 %
46 %
• Osteoporosis : Almost 50 % of post menopausal women over 50 years. Affects 200 million women worldwide
Osteoporotic fractures
• Approximately 30% of women over the age of 50 have one or more vertebral fractures
• Approximately one in five men over the age of 50 will have an osteoporosis-related fracture in their remaining lifetime
Osteoporosis is highly prevalent in India.
An estimated 61 million people in India are reported to be affected.
Life span of an average Indian has also increased and this also contributes to the increased incidence of osteoporosis.
Recent data indicate that Indians have lower bone density than their North American and European counterparts
Reported that osteoporotic fractures occur 10-20 years earlier in Indians as compared to Caucasians
Projected number of osteoporotic hip fractures worldwide
Projected to reach 3250 million in Asia by 2050
Adapted from Cooper C et al, Osteoporosis Int, 1992;2:285-289
Estimated no of hip fractures: (1000s)
1950 2050
600
3250
1950 2050
668
400
1950 2050
742
378
1950 2050
100
629
Total number ofhip fractures:
1950 = 1.66 million 2050 = 6.26 million
Spine fractures (vertebral compression fractures) can cause intense back pain, and may eventually result in a gradual loss of movement and the inability to carry out daily chores.
Arrr……hh..Ouch
They can lead to loss of height, and in severe cases the spine may curve to form what is termed a “hump”.
Most common fractures (46%)
Insidious
Progressive
Often unrecognized
Associated with
› Deformity, height loss, back pain
› Morbidity and mortality
Predict future vertebral and non-vertebral fractures
Entire skeleton can be involved› Wrist› Ankle› Pelvis› Humerus› Rib› Others
Associated with significant disability
Most serious clinical event Morbidity is high
› 50% do not regain independence› 50% do not regain previous mobility
Mortality is high› 1 in 5 patients die within 1 year
Patients not treated for osteoporosis
Hip FractureHip Fracture
Hip fractures almost always require surgery and in about a third of patients, result in loss of independent living.
Low BMD Fracture after 50 years Age 65 years Maternal history of fracture after 50 years Low body weight (125 lb) Smoking Corticosteroid use Other secondary causes
All postmenopausal women with the following:
Risk of FractureRisk of Fracture
40%
Unable to walk independently
30%
Permanentdisability
20%
Death within one year
80%
One year after an
hip fracture:
Pat
ien
ts (
%)
Unable to carry out at least one independent activity of daily living
1996 new cases,all ages184 300
750 000 vertebral
250 000 other sites
250 000forearm
250 000hip
0
500
1000
1500
2000
Osteoporotic Fractures
HeartAttack
Stroke BreastCancer
An
nu
al in
cid
enc
e x
10
00
1 500 000
annual incidenceall ages
513 000
annual estimatewomen 29+
228 000
annual estimatewomen 30+
The incidence of osteoporotic fractures is highest in women and
more than heart attack, stroke and breast cancer put together
Non-modifiable Caucasian /Asian race Advanced age Female sex Premature menopause (<45 years)
Modifiable Cigarette smoking Excessive alcohol intake Inactivity Low body weight Poor general health Prolonged immobilization
If you are beyond 50 years of age And feel you have more than onerisk factors
Or
had a broken a bone after a minor bump or fall
Need to consult immediately
Initial physical examination
X-ray. Laboratory
blood tests. Bone
densitometry (Bone Mineral Density-BMD).
As osteoporosis has no obvious symptoms other than a fracture when the bone is already significantly weakened, it is important to go to the doctor if any of the risk factors apply to you.
A number of different types of BMD tests are available, but the most accurate is DXA (dual energy X-ray absorptiometry).
DXA is a low radiation X-ray capable of detecting quite low percentages of bone loss. It is used to measure spine and hip bone density.
The World Health Organization has defined a number of threshold values for osteoporosis.
The reference measurement is defined as healthy bone density in a young female of around 25 years.
‘ T- score’ is number that indicates whether or not bone loss has occurred
-1
- 2.5
Normal bone mass
Osteopenia
Low bone mass
Osteoporosis
T score > -2.5
If the results of your BMD test show osteopenia or osteoporosis it does not automatically mean that you will have a fracture.
There are a number of therapies available that your doctor might prescribe that slow down the rate at which bone loss occurs and help prevent fractures.
In addition, there are important nutritional and lifestyle changes that you can make to help reduce your risk
of fracture.
Encourage good general nutrition
Promote a diet with adequate calcium content
Promote adequate vitamin D intake
Regular weight-bearing exercise
Avoid smoking and alcohol
Prevention of falls
1. Exercise is not just important to generalhealth, it helps build bone mass in youth and slows down bone loss in adults
Weight-bearing exercise in particularis good for bone health. This type ofexercise includes walking, jogging,tennis and similar sports, aerobics anddancing.
Both calcium and vitamin D are essential to maintain healthy bones. As we grow older we absorb calcium from food less efficiently. This means that over time we need higher amounts of calcium
Milk and other dairy products like cheese and yogurt are the most readily available dietary sources of calcium.
Other good food sources include Tofu, soya bean, Apricots, Almonds, fishes and fruits like Orange
Good dietary sources of vitamin D include oily fishes,fortified dairy foods and egg yolks
Avoid : caffeine , high salt diet, alcohol – which increase calcium loss
Take an additional measure to reduce the risk of fractures by fall-proofing your home.
Reduce clutter at floor level Wear well-fitting shoes or slippers Make sure surfaces are slip-proof: rugs should have a skid-proof
backing Have grab rails installed in the bathroom and toilet Make sure that lighting is bright enough. Have regular eye checkups –vision is crucial in judging distances
and detail.
Calcium and Vitamin D supplementation is basic requirement before any other treatment is begun.
Recommended daily dietary allowance (RDA) › Vitamin D (RDA : 400 – 800 IU)› Calcium (RDA : 1200 – 1500 mg/day)
Treatment Options
Prevent Resorption
Hormone Replacement Therapy (HRT)
Raloxifene
Bisphosphonates
Build New Bone
Parathyroid hormone (PTH) - Teriparatide
• There is no cure, but several medications have been approved
• Each stops or slows bone loss, increases bone density, and reduces fracture risk.
Oral : Alendronate – daily or weekly dose Risedronate – daily or weekly dose Ibandronate – monthly dose IV
› Intravenous Ibandronate – inj. once in 3 month › IV Zolendronate – inj. once a year
All biphsphonates have been shown to act quickly (within one year), to maintain bone density and to reduce the risk of having fractures
They differ in their degree of reduction of risk
Health professionals Osteoporosis patient support groups Practical tips Get the information regarding treatments available
lessening the feelings of isolation and depression experienced
by many patients with severe osteoporosis