Bone Abnormalities

Question 1

What is the difference between Woven and Lamella bone?

Answer 1

Woven - (weak) rapid osteoid production, collagen is haphazard
Lamella - (strong) parallel collagen in lamellae (sheets)

Question 2

What are the main biochemical measurements for assessing bone (4)

Answer 2

Serum Calcium
Serum Phosphate
ALP
PTH

Question 3

What is OI characterised by in terms of bone production?

Answer 3

Defective production of Type I collagen (genetic mutations)

Question 4

What are the symptoms of OI?

Answer 4

Brittle bones (frequent fractures)
Hearing loss (~50%)
Blue sclera
Teeth problems
Growth retardation
Child Abuse investigations

Question 5

What is Paget’s Disease characterised by In terms of bone production?

Answer 5

Disorder of bone remodelling leading (eventually) to the formation of structurally abnormal bone

Question 6

What are the symptoms of Paget’s Disease?

Answer 6

(None)
Fractures
Bowing of limbs
Increased skull size
Arthritis
(Usually affects >40 years old)

Question 7

What causes Paget’s?

Answer 7

Increased osteoclastic activity, causing a compensatory increase in osteoblast activity - bone replaced with woven bone

Question 8

Where can be affected by Paget’s?

Answer 8

Localised: doesn’t often spread beyond original affected area (commonly femur, spine, skull, tibia)

Question 9

What is the treatment for Paget’s?

Answer 9

Inhibit Osteoclasts using bisphosphonates

Question 10

What are Rickets / Osteomalacia characterised by in terms of bone formation?

Answer 10

Inadequate mineralisation of bone

Question 11

What is the difference between Rickets and Osteomalacia?

Answer 11

Rickets - affects children ; defective mineralisation at growth plate
Osteomalacia - affects everyone ; defective mineralisation of osteoid

Question 12

What is the most common cause of Rickets / Osteomalacia?

Answer 12

Vitamin D deficiency, leading to low phosphate +/- calcium levels

Question 13

What are the symptoms of Rickets / Osteomalacia?

Answer 13

Proximal muscle weakness
Bone pain
Fractures
(Rickets) - growth retardation and bony deformities of weight bearing limbs

Question 14

What is Osteoporosis characterised by in terms of bone structure?

Answer 14

Low bone density and micro-architectural defects, leading to increased bone fragility and susceptibility to fracture

Question 15

What are the two important properties of bone?

Answer 15

Strength and Flexibility