2. • It is systemic skeletal disorder characterized by
decreased bone mass & deterioration of bony
• the result is fragile bones & increased risk for
fractures with minimal trauma
• It is a chronic condition of multifactorial
• & is usually clinically silent til fractures occur .
3. • Osteoblasts form osteoid
• Oseoclasts resorb bone
• Bone formation is not static
• It is a system that is remodelled constantly
• Bone resorption is always followed by bone
formation a phenomena referred to as
• The hallmark of osteoporosis is reduction in
skeletal mass caused by an imbalance btn
bone resorption & bone formation.
4. Factor influencing osteoporosis:
• Loss of gonadal function &
• Aging are the 2 most important factors
contributing to the development of this
• Lack of gonadal hormones is believed to up-
regulate osteoclast progenitor cells. Bone loss
will accelerate rapidly after menopause.
• Osteoporosis is commonly confused with osteomalacia.
• The normal human skeleton is composed of mineral component,
ca2+hydroxyapatite(60%) & organic material mainly collagen(40%)
• In osteomalacia the bones are porous and brittle
• In osteomalacia the bones are soft
• The difference in bone consistency is related to the proportion of
mineral to organic material content.
• In osteoporosis the mineral –to collagen is within reference range
• In osteomalacia the proportion of mineral composition is reduced
relative to organic mineral content.
• Bone mineral density(BMD)in a patient is related to peak bone
mass 7 subsequent bone loss
8. TYPE1; POSTMENOPAUSAL OSTEOPOROSIS
• Result from gonadal estrogen & testosterone deficiency
• Result in accelerated bone loss
• After menopause women experience an accelerated bone
loss of 1-5%per year for the first 5-7 yrs
• Estrogen deficiency cause bone to become more sensitive
to the effects of PTH; leading to an increase in ca2+ release
from bone, a decrease in ca2+ excretion & increased
production of 1,25, dihydroxyvitamin D.
• Vit Dcauses increased ca2+ absorption from the gut,
increased calcium resorption from bone & increased renal
tubular calcium re-absorption. PTH then decreases by a
negative feed back mechanism
• Cytokines: TNF ALPHA, IL1&6 influence osteoclasts.
9. TYPE2; senile osteoporosis
• Occur in women & men
• Because of decreased formation of bone and
decreased renal production of vitD occuring
late in life
• Result in loss of cortical & trabecular bone &
increased risk for fractures of hip, long bones
10. TYPE3 OSTEOPOROSIS
• An underlying dx cause osteoporosis
– Metabolic dx
– Connective tx dx
– Bone marrow dx
– & drug use