Renal osteodystrophy and rickets

  • Skeletal abnormalities due to chronic renal failure
  • Kidneys are vital of vit D metabolism, and phosphate secretion – when disturbed results in:
    • Osteomalacia (or rickets)
    • Secondary hyperparathyroidism
    • Metastatic calcification
    • Osteoporosis
Chronic renal failure flow chart


Deficiency of vitamin D during bone development (infancy)

  • Essential for absorption and metabolism of calcium and phosphate
  • Deficiency leads to:
    • Defect in bone matrix mineralization and skeletal development
    • Defective absorption of calcium and phosphate
    • Chronic renal disease: renal rickets


  • 1. Vitamin D deficiency
    • Reduced endogenous synthesis due to lack of exposure to the sun
    • Dietary deficiency (fish, eggs, butter, milk)
    • Malabsorption and metabolism failures due to liver disease, pancreatic insufficiency, kidney
  • 2. Abnormal metabolism of vitamin D:
    • Chronic renal failure
    • Vitamin D resistant rickets
    • Anticonvulsant osteopathy
  • 3. Phosphate depletion: antacids contain al(oh)3 which bind phosphate, excess renal secretion of po4
    • Fanconi syndrome
    • X linked hypophosphatemic rickets
  • 4. Renal tubular acidosis


  • Vit D is essential for intestinal absorption of Ca++ and po4
  • Co-factor in mobilization of Ca++ from bone
  • Stimulates PTH dependent re-absorption of Ca++ by the distal renal tubules


  • Craniotabes – unossified areas of cranium
  • Rachitic rosary – overgrowth of costochondral cartilage
  • Pigeon chest deformity
  • Lordosis
  • Knock knees/ bow legs
  • Enlarged epiphyses
  • Osteomalacia
  • Hypocalcaemic tetany
  • Dental:
    • Multiple spontaneous periapical abscess in 1ry & 2ry dentition
    • Enlarged pulp chambers
    • Thin easily abraded enamel
    • Marked interglobular dentine

Histology: ↑ Osteoid matrix in bones


  • Normal or ↓ ca++
  • ↓ po4
  • ↓ vit D metabolites
  • ↑ alkaline phosphatase

Management: Replacement therapy


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