Calcium and phosphate regulation

Question 1

Paget’s disease

Answer 1

accelerated, localised and disorganised remodelling of bone

Question 2

Paget’s disease pathophysiology

Answer 2

excessive resorption followed by compensatory increase in bone formation, which is woven bone (structurally disorganised and mechanically weaker) - leads to bone frailty, hypertrophy and deformity

Question 3

Paget’s disease aetiology

Answer 3

usually FHx, and evidence of viral origin, although most patients are asymptomatic

Question 4

Paget’s disease biochemical features

Answer 4

xs numbers of abnormal and large osteoclasts; normal calcium but plasma alkaline phosphatase (bone and liver isotopes also exist)

Question 5

Paget’s disease clinical features

Answer 5

most commonly affects skull, T/L spine, pelvis, femur and tibia

Arthritis

Fractures

Pain

Deformity

Increased vascularity

Deafness (cochlear involvement)

Question 6

Paget’s disease radiological features

Answer 6

lytic lesions on plain XRs, with thickened, enlarged and deformed bones in later stages

Question 7

Paget’s disease treatment

Answer 7

bisphosphonates to reduce bone pain and disease activity

Question 8

Osteoporosis

Answer 8

loss of bony trabeculae causing reduced bone mass and weaker bones that are predisposed to fracture after minimal trauma

Question 9

Osteoporosis diagnosis

Answer 9

bone mineral density >2.5sd below average (T score

Question 10

Osteoporosis risk factors

Answer 10

Postmenopausal oestrogen deficiency: oestrogen deficiency leads to loss of bone matrix and increased risk of fracture

Iatrogenic: heparin / glucocorticoid use

Endocrine: Cushing’s, hyperthyroidism, primary hyperparathyroidism

Hypogonadism

Age: leads to deficiency in bone homeostasis e.g. Osteoblast senescence