disorders of the bone by yapa wijeratne

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Presentation on disorders of the bone which explains the biochemical & physiological aspects with illustrations.


  • 1. Disorders of the bone
    by Yapa Wijeratne
    Faculty of Medicine
    University of Peradeniya
    Sri Lanka
  • 2. Osteoporosis
    Osteopetrosis (marble bone disease)
    Pagets disease of bone
    Osteomalacia & rickets
    Osteogenesisimperfacta (brittle bones)
  • 3. 1.Osteoporosis
    Relative excess of osteoclast (OC) function.
    A significant reduction of bone mineral density compared with age & sex match norms.
    susceptibility to fractures.
    Disease of aging.
    Bone density peak at 30 yrs in both sex.
    Rate of bone loss is accelerated in females ,after loss of estrogen (E2) secretion at the menopause.
    E2 inhibits stimulatory effect of certain cytokines which contribute bone resorption on OC. Thereby prevent osteoporosis. At the menopause this inhibitory effect is removed & cytokines are activated.
  • 4.
  • 5. Factors the risk of osteoporosis
    Premature menopause
    alcohol intake
    Excessive exercise
    Poor [Ca+2] intake
    Excessive caffeine intake
  • 6. 2. Osteopetrosis (marble bone disease)
    Rare & often severe disease.
    characterized by increased bone density.
    OC are defective & unable to resorb bone in the usual fashion.
    One form occurs along with renal tubular acidosis and cerebral calcification.
    It is due to mutations in the gene encoding carbonic anhydrase II(provide H+ to neutralize OH-)
    Narrowing & distortion of foramina -> compress nerves ->neurologic defects.
    Crowding out of the marrow cavities ->hematological abnormalities
  • 7. Histological appearance of bone in osteopetrosis
  • 8. 3. Pagets disease of bone
    Localized disorder characterized by accelerated bone turnover.
    Initiated by OC mediated bone resorption.
    ALP activity
    Collagen breakdown by OC result in a
    [Hydroxyproline] & [collagen fragments] in urine.
  • 9.
  • 10. Histological appearance of bone in Pagets disease of bone
  • 11. 4.Osteomalacia & rickets
    Abnormal mineralization of bone & cartilage.
    Vit D -> defective calcification of bone matrix
    Osteomalacia -> adults
    Rickets-> children
    Main defect is failure to deliver adequate amounts of [Ca+2] & [PO4-3] to the site of mineralization.
    In children ,
    Weakness & bowing of Wt bearing bones
    Dental defects
  • 12.
  • 13. 5. Osteogenesisimperfacta (brittle bones)
    Abnormal fragility of bones
    Over 90% of Pt have mutations in the COLIA1,COLIA2 genes
    Expression of collagen or structurally abnormal collagen fibrils

    Weakening of bone

    Affected infants may be bone with multiple fractures & not survive
  • 14. Radiogical appearance of the upper limbs in Osteogenesisimperfacta