Metabolic Bone Disease
A 55-year-old woman of South Asian origin presents with diffuse bone pain, proximal muscle weakness, and difficulty rising from a chair. She wears traditional clothing that covers most of her skin and rarely goes outdoors. Blood tests reveal low serum calcium (2.0 mmol/L), low phosphate (0.6 mmol/L), elevated alkaline phosphatase (450 U/L), and very low 25-hydroxyvitamin D (12 nmol/L). Plain radiographs show generalised osteopenia with bilateral symmetric radiolucent lines in the femoral necks. Regarding osteomalacia and vitamin D metabolism:
Mark each as TRUE or FALSE
Osteomalacia is defective MINERALISATION of osteoid in mature skeleton (vs rickets in immature skele...
Vitamin D metabolism: Vitamin D3 (cholecalciferol) synthesised in SKIN from 7-dehydrocholesterol und...
Osteomalacia is defective bone resorption; vitamin D3 is synthesised in the liver; 25-hydroxyvitamin...
1,25-dihydroxyvitamin D (calcitriol) actions: INTESTINE - increases calcium and phosphate absorption...
Vitamin D deficiency causes: LOW serum calcium (from decreased intestinal absorption) → SECONDARY HY...
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Click T (True) or F (False) for each option