Rickets

Definition:
Rickets is a childhood disorder caused by defective mineralization of growing bones due to Vitamin D deficiency.

Biochemical Basis / Cause:

  • ↓ Vitamin D → ↓ calcium & phosphate absorption from intestine → hypocalcemia → defective bone matrix mineralization.

Types (with cause):

  • Nutritional rickets – diet low in Vitamin D, less sunlight.

  • Renal rickets – chronic kidney disease (↓ 1,25-(OH)₂D₃ formation).

  • Vitamin D–dependent rickets – genetic defect in vitamin D metabolism.

Real Data / Key Points:

  • Serum calcium: ↓ or normal

  • Serum phosphate: ↓

  • Alkaline phosphatase: ↑ (marker of increased osteoblastic activity)

Classical Signs:

  • Bowed legs (genu varum), rachitic rosary (costochondral swelling), delayed dentition.

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