Calcium%20Homeostasis

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Metabolic Bone Disorders

• Prof. Mohammed Zamzam
• Professor Consultant
• Pediatric Orthopedic Surgeon

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Calcium Homeostasis

• - Bone is not only for support
• - Bone formation bone resorption
• - Hydroxyapatite crystals
• - Calcium phosphate control
• Intestinal absorption
• Renal excretion
• Bone

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Vitamin D

• Sources - Diet
• - Ultraviolet rays on skin
• Cholecalciferol activation
• - PTH
• - Phosphate concentration
• Action - Intestinal absorption of Ca
• - Bone resorption

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Parathyroid Hormone

• - Fine regulator of Ca exchange
• - Serum Ca regulate its secretion
• - Action
• Increase phosphate excretion
• Increase Ca reabsorption
• Vitamin D activation

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Calcitonin

• - C cells of thyroid gland
• - Serum Ca regulates its secretion
• - Action
• Rapid hypocalcaemic effect by inhibiting
• bone resorption

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Secondary ruleOther Hormones
Non-hormonal Factors

• - Mechanical stress
• - Prostaglandin E
• - Acid-base balance

• - Estrogen
• - Corticosteroids
• - Thyroxin

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Rickets Osteomalacia

• - Different expressions of the same disease
• - Inadequate mineralization
• - Rickets
• Areas of endochondral growth
• - Osteomalacia
• All skeleton is incompletely calcified

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Rickets Osteomalacia

• Causes
• - Calcium deficiency
• - Hypophosphataemia
• - Defect in Vitamin D metabolism
• nutritional
• underexposure to sunlight
• intestinal malabsorption
• liver kidney diseases

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Rickets Osteomalacia

• Symptoms Signs
• Rickets
• - Tetany or convulsions ?
• - Failure to thrive , muscle flaccidity
• - Craniotabes , joint thickening
• - Pigeon chest , rickety rosary , Harrisons
  sulcus
• - Deformities

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Rickets Osteomalacia

• Symptoms Signs
• Osteomalacia
• - Bone pain , backache
• - Muscle weakness
• - Vertebral collapse kyphosis
• loss of
  height
• - Deformities stress fractures

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Rickets Osteomalacia

• Biochemistry
• Hypocalcaemia, Hypocalcuria
• High alkaline phosphatase

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Rickets Osteomalacia

• X-rays
• Rickets
• - Growth plate widening thickening
• - Metaphyseal cupping
• - Diaphyseal deformities
• Osteomalacia
• - Looser zone , biconcave vertebra , protrusio
  acetabuli
• - Spontaneous fractures
• Signs of secondary hyperparathyroidism

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Rickets Osteomalacia

• Treatment
• Vitamin D deficiency
• - Rickets controlled Vitamin D
• sun
  exposure
• correct
  residual deformities
• - Osteomalacia Vit. D Ca
• 
  fracture management
• correct
  deformity if needed

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Hyperparathyroidism

• Primary
• hyperplasia - adenoma - carcinoma
• Secondary
• persistent hypocalcaemia
• Tertiary
• secondary leads to hyperplasia

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Hyperparathyroidism

• Pathology
• - PTH overproduction
• - Increased renal tubular absorption , intestinal
• absorption and bone resorption of Ca
• - Hypercalcaemia and hypercalciuria
• - Suppressed phosphate tubular reabsorption
• - Hypophosphataemia and hyperphosphaturia

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Hyperparathyroidism

• Pathology
• Hypercalcaemia
• calcinosis , stone formation , recurrent
  infection and soft tissue calcification
• Bone resorption
• loss of bone substance , subperiosteal erosion
• osteitis fibrosa cystica and brown tumors

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Hyperparathyroidism

• Symptoms Signs
• Hypercalcaemia
• anorexia , nausea , depression and polyuria
• Bone rarefaction
• pain , pathological fractures and deformities
• Biochemistry
• hypercalcaemia , hypophosphataemia , high
• alk. Phosphatase and serum PTH

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Hyperparathyroidism

• X-rays
• - Subperiosteal bone resorption
• - Generalized decrease in bone density
• - Brown tumors
• - Chondrocalcinosis
• knee , wrist and shoulder

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Hyperparathyroidism

• Treatment
• Surgical excision of adenoma or hyperplastic
• parathyroid tissue
• Hungry bone syndrome
• treated by vitamin D

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Osteoporosis

• Normal mineralization
• Decrease bone mass
• (amount of bone per unit volume)
• Age related
• Associated or manifestation of other conditions

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Osteoporosis

• Causes
• Idiopathic
• Nutritional
• Endocrine disorders
• Drug induced
• Malignant diseases
• Miscellaneous

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Osteoporosis

• - Idiopathic osteoporosis - normal investigations
• - In old patients we have to role out malignancy
• and multiple myeloma
• - Younger patients must be fully investigated
• - Several causes may be involved
• - Osteoporosis can be associated with
  osteomalacia

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Osteoporosis

• Symptoms Signs
• - Bony aches
• - Easy fractures
• spine - lower radius - femoral neck
• - Rib fracture , chest pain
• - Normal biochemistry

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Osteoporosis

• X-rays
• - Decrease bone density
• - Wedging or biconcave vertebrae
• - Thin cortex and deformities
• - Dexa Scan
• - Biopsy

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Osteoporosis

• Treatment
• - Treat underlying cause
• - Idiopathic , extremely difficult
• - Calcium and vitamin D
• - Fluoride and triple therapy
• - Calcitonin , Diphosphonate
• - Treat fractures

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Osteoporosis

• Prevention
• Good diet
• Exercise
• Exposure to sun light
• Ca supplement
• Hormone therapy

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