Bone Disease Flashcards
What is osteomalacia?
Defect of bone with abnormal softening due to deficient mineralisation of osteoid
What is the name for osteomalacia in kids?
Rickets
Describe the aetiology of osteomalacia?
- insufficient calcium absorption/vit D
- inherited
- malabsorption
Describe the pathogenesis of osteomalacia
Vit D stimulates calcium absorption which stimulates osteoblasts to release osteocalcin
Hypocalcaemia leads to increased PTH and increased osteoclastic activity causing calcium release from bone and renal excretion of phosphate
What are the clinical features of osteomalacia?
Fracture
Hypocalcaemia
Reduced calcium, phosphate, increased ALP
How is osteomalacia treated?
Vit D, calcium and phosphate supplements
What does PTH do to calcium reabsorption?
Increases kidney, bone and gut to increase plasma calcium
What is a brown tumour?
Bone is replaced by osteoclasts, fibrous tissue and haemorrhage with haemosiderin which leads to a destructive lesion and stimulation of giant cell tumour
What is bone change due to chronic kidney disease called?
Renal Osteodystrophy
How does renal osteodystrophy arise?
Decreased phosphate and inactive vitamin D results in secondary hyperparathyroidism causing osteomalacia and sclerosis
What is pagets disease?
Abnormality in bone turn over usually occurs late in adulthood
What causes Paget’s disease?
Genetic
RANKL mutations
Viral infection
Describe the pathogenesis of paget’s
- osteolytic - osteoblasts by laying down woven bone
- osteoclasts and osteoblasts - less resorption
- osteosclerosis - thicker but brittle bone
What are the clinical features of Paget’s?
Pain
Enlargement and deformity
Increased metabolism
Arthritis near joint
Where does Pagets affect?
Pelvis Femur Skull Tibia Ear
