Osteomalacia Flashcards
1
Q
What is rickets?
A
Osteopenia with disordered bone mineralisation resulting in increased proportion of osteoid (unmineralised) tissue prior to epiphyseal closure (i.e. childhood)
2
Q
What is osteomalacia?
A
Osteopenia with disordered calcification resulting in increased proportion of osteoid (unmineralised) tissue after epiphyseal closure (adulthood).
3
Q
What are the causes of vitamin D deficiency?
A
- Deficient uptake or absorption (nutritional deficiency, malabsorption)
- Defective 25 hydroxylation (liver disease, anticonvulsant therapy)
- Loss of Vit D binding protein (nephrotic syndrome)
- Defective 1,25a hydroxylation (hypoparathyroidism, renal failure)
4
Q
What are the factors required for mineralisation of bone?
A
- Normal osteoid formation
- Normal concentration of calcium and phosphate in ECF
- Adequate bioactivity of ALP
- Normal pH at site of calcification
- Absence of calcification inhibitors
5
Q
What are the causes of abnormal bone matrix?
A
- Osteogenesis imperfecta
- Fibrogenesis imperfecta
- Axial osteomalacia
6
Q
Radiologic findings of osteomalacia?
A
- Pseudofractures, fissures, narrow radiolucent lines (?healed stress fractures)
- Loss of distinctness of vertebral body trabeculae
- Changes due to secondary hyperparathyroidism
- Bowing of tibia, coxa profundus hip deformity
7
Q
What are the radiological changes due to secondary hyperparathyroidism?
A
- Subperiosteal resorption of the phalanges
- Bone cysts
- Resorption of the distal ends of long bones
8
Q
Rx of osteomalacia?
A
- Reverse underlying cause
- Vit D supplementation
- phosphate/calcium supplements if required
- bicarbonate if chronic metabolic acidosis
