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Disorders of Bone Mass

OsteoporosisDefinitionLoss of bone mass associated with deterioration of bone architecture and increasedsusceptibility to fracture

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Epidemiology

75 million in US, Europe and Japan300,000 new hip fractures/ year500,000 vertebral fractures/ year1 of every 4 postmenopausal women

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Osteoporosis Risks Factors

Genetic• Race • Familial

prevalenceAge/ Sex

Endocrine• Menopause • Ovarian/

testicular dysfunction

Osteoporosis Risks Factors

Nutritional• Low calcium • High alcohol• High caffeine/

sodium• High anim. protein

Lifestyle• Low physical

activity• Cigarette

smoking

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• Postmenopausal• Age-related• Idiopathic

OsteoporosisPrimary

• Endocrine disorders• Gastro-intestinal diseases• Chronic Inflammatory diseases• Malignant neoplasms• Connective tissue disorders• Drug-induced

OsteoporosisSecondary

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Endocrine• Ovarian/ testicular dysfunction

early menopause• Cushing syndrome• Hyperthyroidism• Hyperparathyroidism (severe)

OsteoporosisRisk Factors

Fracture sites• Spine• Hips• Distal radius (Colle’s fracture)• Proximal humerus

OsteoporosisClinical

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Unsuitable for early detectionIndicate advanced disease

RadiologyRoutine Xrays

• “Fish-mouth” deformity• Thin cortices• Diffuse osteopenia• Old or current fractures

RadiologyRoutine Xrays

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Diseases of Mineralization

RicketsOsteomalacia

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RicketsPathogenesis

Defective mineralization/ turnover

• Bone matrix• Growth cartilage

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• Cranio-tabes/ frontal bossing• Widely opened fontanels• Rachitic rosary• Harrison groove/pigeon breast• Swelling of wrists and ankles• Genu valgum/ varum

RicketsClinical

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Long bonesDeformitiesFractures

Growth platesBlurred/WidenedEpiphyses cup-

shaped

RicketsRadiology

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Defective mineralization/ turnover

• Bone matrix

OsteomalaciaPathogenesis

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• Bone pain• Fractures• Proximal myopathy• Muscle weakness• Waddling gait

OsteomalaciaClinical

Bowing of long bones (genu varum)

Pseudo-fractures “Looser’s lines”

Fractures (Milkman)

OsteomalaciaRadiology

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Rickets/ OsteomalaciaHistopathology/ Morphometry

↑ ↑↓↑

↓↓

• Osteoid surface/thickness • Mineral apposition rate• Mineralization lag time/

osteoid maturation• Tetracycline double labels• Bone formation rate/

activation frequency

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Renal OsteodystrophyDefinition

A spectrum of skeletal abnormalities resulting from renal failure

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Renal OsteodystrophySubtypes

• Secondary hyperparathyroidism• Mixed bone disease• Low bone turnover

Pure osteomalaciaAplastic/ adynamic bone disease

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CLASS OF 2008

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