2. POST GRADUATE SEMINAR
TOPIC:- OSTEOPOROSIS
Date- 02-03-2016
Presenter- Moderator-
Dr. Baharul Islam Choudhury Dr. C.R.Buragohain
PGT, Orthopedics Asst. Proff
Date – 06- 04- 2016
3. WHAT IS OSTEOPOROSIS
It is a clinical disorder characterized by an abnormally low
bone mass & defects in bone structure, a combination which renders
the bone unusually fragile & greater than normal risk of fracture in a
person of that age, sex & race.
WHO defines osteoporosis as a bone density that falls 2.5 SD
below the mean for young healthy adults of the same sex – also
referred to as T- score of -2.5.
4.
5. Composition of Bone
Bone is composed of :-
a)- Matrix
b)- Salts
c)- Bone cells.
Matrix:- Composed of Type1 collagen fibre produced by osteoblasts,
make up over 80% of the unmineralized matrix.
Salts:- Almost half the bone volume is mineral matter, mainly calcium &
phosphate in the form of crystalline hydroxy-apatite .
6. BONE CELLS
Osteoblasts- concerned with bone formation & osteoclast activation.
Osteocytes- Regarded as spent osteoblast. Under the influence of PTH they
participate in bone resorption (osteocytic osteolysis), & ca ion transport.
Osteoclasts- Large multinucleated cells are principal mediators of bone
resorption.
9. Calcium- Over 98% of body’s calcium are tightly packed as
hydroxy apatite crystal in bone & only small amount exist in rapidly
exchangable form.
Normal Sr. Ca level is 8.8 – 10.4 mg/dl
The recommended daily intake for adult is 800- 1000 mg.
10. Phosphorus- Over 85% of body’s phosphorus present in bone.
Normal plasma concentration of Phosphate is 2.8 – 4
mg/dl.
The main regulators of plasma phosphate concentration
are PTH & 1,25 (OH)2 Vit D.
If the plasma phosphate rises
abnormally a reciprocal fall in calcium concentration will
stimulate PTH hormone secretion which in turn will
suppress urinary tubular reabsorption of phosphate
resulting in fall in plasma phosphate .
High phosphate level also results in
diminished 1,25 (OH) Vit D production causing reduced
intestinal absorption of phosphorus
13. ESTROGEN & BONE PROTECTION
Estrogen appears to act on both osteoblast & osteoclast
via RANKL/ RANK / OPG system.
It increases the production & activity of OPG & thereby
interfering with osteoclast differentiation & bone resorption.
It play an important role in determining the life span of
bone cells by controlling the rate of apoptosis.
It enhances calcium absorption by the intestine.
15. OSTEOPOROSIS CLASSIFICATION
-> PRIMARY OR GENERALIZED OSTEOPOROSIS
> Post menopausal osteoporosis
> Senile/ age related osteoporosis
-> SECONDARY OSTEOPOROSIS
Secondary to various causes
-> REGIONAL OSTEOPOROSIS
Due to prolonged immobilization
25. X- RAY-
> Decreased skeletal radiodensity.
> Loss of trabecular definition.
> Thinning of cortices & insufficiency fractures.
> Compression fractures of the vertebral bodies.
> Wedging at multiple levels.
>Biconcave distortion of vertebral end plate.
26. BONE MINERAL DENSITOMETRY
Bone mineral density ( BMD) is expressed in grms /
unit aerea or volume, & it is recorded in comparison to
the sex & age specific distribution of these values in
general population.
It is based on the principle that a beam of energy is
attenuated as it passes through bone, & degree of
attenuation is related to the mass & mineral component
of the bone.
28. Several techniques are available-
> Single energy X-ray absorptiometry
> Dual energy X-ray absorptiometry (DEXA)
> Quantitative CT
> Quantitative US
34. Urinary free or fasting serum cortisol level-
when there is clinical suspicion of Cushing’s syndrome.
24 hr urine histamine level or serum tryptase-
when osteoporosis associated with rash , multiple allergies,
diarrhea or flushing.
Serum & urine electrophoresis-
When there is suspicion of myeloma
35. BONE BIOPSY-
Tetracycline labeling of the skeleton allows determination of rate
of bone remodelling as well as evaluation for other metabolic bone
diseases.
36. BIOCHEMICAL MARKERS
Provide an index for overall rate of bone remodelling at a single
point in time.
Markers of bone resorption may help in the prediction of
fracture risk.
Markers are used for monitoring the response to treatment.
38. RISK FACTOR REDUCTION
> Patient should be thoroughly educated to reduce the impact of
modifiable risk factor & associated bone loss & falling.
> Medication should be reviewed to ensure that all are necessary.
> Gluco-corticoid medication if present should be evaluated whether
it is truly indicated & should be given at low doses.
> Effort to facilitate to cessation of smoking.
> Alcohol abuse treatment.
> Frequency of nocturia should be reduced by decreasing or
modifying diuretics.
39. > Treatment of impaired vision.
> Specialized supervision & care of elderly patient with neurologic
impairment.
> Patient should be instructed about environmental safety regarding
eliminating exposed wires, curtain string, slippery rug, mobile
tables.
provides good lights in path to bathroom & outside the home
40. NUTRITIONAL RECOMMENDATION
CALCIUM
Optimal calcium intake reduces bone loss & supresses bone
turnover.
Preferred source of calcium is dairy products & fortified foods (
cereals, snacks, juices).
Calcium is supplemented in doses < 600mg at a time.
41. VITAMIN D
200 IU < 50 yrs age
400 IU 50 – 70 yrs age
600 IU > 70 yrs age
> 1000 IU in the elderly & chronically ill.
OTHER NUTRIENTS
Vitamin K ( carboxylation of osteocalcin).
Magnesium ( for efficient secretion & pereipheral action of PTH)
Dietary Phytoestrogens ( exerts some estrogenic activity).
High animal protein intake.
42. PHARMACOLOGIC THERAPIES
HRT
Various types of estrogen ( estradiol, esterified estrogen,
estrone, ethinyl estradiol, mestranol) reduce bone turnover,
prevent bone loss & induce increase in bone mass.
DOSE-
0.3 mg/day for esterified estrogen.
5 micro gm/day for ethinyl estradiol.
50 micro gm/day for estradiol.
5-10 yrs of continuous therapy reduces the risk of osteoporotic
fractures by 50% but after the medication BMD gradually falls to
usual low level.
Estrogen increases the risk of thromboembolism, stroke , breast
cancer & uterine cancer.
44. BISPHOSPHONATES
( Alendronate, Risedronate, Ibandronate, Zoledronic acid)
Regarded as preferred medication for post-menopausal &
steroid induced osteoporosis.
Decrease the bone turnover & increase the bone mass by
impair osteoclast function & inducing apoptosis.
Alendronate ( 10mg/d or70mg/wk) for 1 yr reduces risk of
vertebral # , hip #, & other non vertebral # by 50%.
Risedronate ( 5mg/d or 35 mg/wk) for 3yrs reduces the risk of
vertebral & other non vertebral # by 40-50%.
Ibandronate (150 mg/month or 3 mg/ 3 month IV) reduces
vertebral # by 40%.
Zoledronic Acid ( 5 mg/ yr IV infusion) for 3 yrs reduces the risk
of vertebral # by 70%, hip # by 40%, & other by 25%.
45. CALCITONIN
It is a polypeptide hormone produced by thyroid gland.
It supresses the osteoclast activity & osteoclast exposed to
calcitonin can’t maintain their active ruffled border.
It has some analgesic effect.
It is supplemented as nasal spray ( 200 IU / day).
46. DENOSUMAB
It is a fully human monoclonal antibody to RANKL.
It binds with RANKL & inhibit the formation of mature
osteoclast.
It also reduce the survival of osteoclasts.
Given twice yearly by SC administration increases the
BMD of spine, hip & forearm & reduces the vertebral, hip & non
vertebral # over a period of 3 yrs by 70, 40 & 20 % respectively.
47. PTH
Although chronic elevation of PTH as occurs in
hyperparathyroidism, is associated with bone loss PTH can also
exert anabolic effect on bone.
In post menopausal women when PTH is administered with
ongoing estrogen therapy, there is substantial increase in bone
mass by 13%. & reduce the risk of vertebral compression deformity.
Treatment is administered as single daily SC injection of 20
micro gm for a maximum of 2 yrs.
48. FLUORIDE
It is a potent stimulator of osteoprogenitor cells.
It increases the bone mass upto 10 %.
OTHER POTENTIAL ANABOLIC AGENT
Anabolic steroid mostly derivatives of testosterone, act primarily
as antiresorptive agent to reduce bone turnover & may stimulate
osteoblastic activity.