Metabolic Bone Diseases
Disorders of bone strength and mineralization. Osteoporosis affects bone quantity (mass), while Rickets/Osteomalacia affects bone quality (mineralization).
1. Osteoporosis
- Definition: Low bone mass + micro-architectural deterioration -> Fragility fractures.
- Diagnosis: DEXA Scan (Gold Standard). T-score < -2.5 SD.
- Common Fractures: Vertebral compression, Hip (Neck of femur), Wrist (Colles).
- Treatment: Bisphosphonates, Calcium/Vitamin D, Weight-bearing exercise.
2. Rickets & Osteomalacia
- Defect: Defective mineralization of osteoid due to Vitamin D/Calcium/Phosphate deficiency.
- Rickets: In Children (Growth plates open).
- Osteomalacia: In Adults (Growth plates fused).
- Signs (Rickets): Bow legs, Knock knees, Rickety Rosary, Widened wrist.
- Signs (Osteomalacia): Bone pain, Muscle weakness, Looser's Zones (Pseudofractures) on X-ray.
25 Practice MCQs
Q1. Osteoporosis is defined by a T-score of:
Answer: A). WHO definition.
Q2. Rickets is due to defect in:
Answer: A). Bone is soft.
Q3. Looser's Zones (Pseudofractures) are pathognomonic for:
Answer: A). Incomplete stress fractures with callus.
Q4. Which is NOT a sign of Rickets?
Answer: C). Blue sclera is OI.
Q5. Gold standard for diagnosing Osteoporosis is:
Answer: A). Measures Bone Mineral Density (BMD).
Q6. Bisphosphonates (e.g., Alendronate) work by:
Answer: A). Mainstay of osteoporosis treatment.
Q7. Cupping and Fraying of the metaphysis is seen on X-ray in:
Answer: A). Classic radiographic signs.
Q8. Post-menopausal osteoporosis is Type:
Answer: A). Affects trabecular bone mostly.
Q9. Renal Osteodystrophy (Renal Rickets) is caused by:
Answer: A). 1-alpha-hydroxylation happens in kidney.
Q10. Codfish Vertebrae (biconcave) are seen in:
Answer: B). Disc pressure indents the soft vertebral body.
Q11. Scurvy is deficiency of:
Answer: A). Causes subperiosteal bleeding.
Q12. Alkaline Phosphatase in Rickets/Osteomalacia is:
Answer: A). Classic lab finding.
Q13. "Windswept Deformity" (One Varus, One Valgus) is seen in:
Answer: A). Due to soft bones bending.
Q14. Which fracture is an "Osteoporotic Fracture"?
Answer: A). Fragility fractures from low energy.
Q15. The best exercise for Osteoporosis is:
Answer: A). Wolffe's Law: Bone strengthens under load.
Q16. Brown Tumor is seen in:
Answer: A). Lytic lesion filled with blood/fibrous tissue.
Q17. Vitamin D Resistant Rickets is:
Answer: A). Treat with Phosphate + Vit D.
Q18. Teriparatide (PTH analogue) is:
Answer: A). Unlike bisphosphonates.
Q19. Milkman's Syndrome is:
Answer: A). Pseudofractures.
Q20. Which drug causes Osteoporosis?
Answer: A). Major risk factor.
Q21. Osteogenesis Imperfecta involves defect in:
Answer: A). Multiple fractures.
Q22. Champagne Glass Pelvis is seen in:
Answer: A). Dwarfism.
Q23. Craniotabes (Soft skull) is a sign of:
Answer: A). Skull indents like a ping-pong ball.
Q24. FRAX score calculates:
Answer: A). Treatment guideline tool.
Q25. Proximal myopathy (waddling gait) is common in:
Answer: A). Vitamin D deficiency affects muscle function.
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