Markers Of Bone Disease

Question 1

What is the role of osteoblasts?

Answer 1

Make osteoid. Important for making alkaline phosphatase and play a key role in mineralisation.

Question 2

What is the role of osteoclasts?

Answer 2

Resorption of bone. Break down bone using enzymes. They play a key role in calcium homeostasis and bone remodelling. Large multinucleated cells.

Question 3

Why do women lose bone mass after the menopause?

Answer 3

Oestrogen is an important anabolic hormone for bone.

Question 4

P1NP is an important bone marker for what?

Answer 4

Bone formation. P1NP is synthesised by osteoblasts and is a precursor of type 1 collagen.

Question 5

NTZ or CTX is a bone maker for what?

Answer 5

Bone resorption. CTX is produced when osteoclasts break down bone.

Question 6

When is alkaline phosphatase going to be raised in relation to bone disease?

Answer 6

Raised when there is increased bone remodelling. It is released by osteoblasts and involved in mineralisation.

Raised during childhood growth spurts, fractures, Paget’s and hyperparathyroidism

Question 7

Which sites are usually scanned with a DEXA scan?

Answer 7

The hip and spine. DEXA uses x Rays to measure bone density. Generates a score between +1 and -4

Less than -2.5 is osteoporosis. More than -1 is normal

Question 8

What inflammatory condition is a risk factor for osteoporosis?

Answer 8

Loads.

Question 9

What are the other risk factors for osteoporosis?

Answer 9

Alc, low BMI, steroid use, endocrine disorders, female, low Vit D, malabsorption, oestrogen and testosterone levels.

Question 10

How do biphosphonates work as a treatment of osteoporosis?

Answer 10

Mimic the pyrophosphate structure if bone is taken up by osteoclasts.

They have an inhibitory effect on osteoclastic activity.

Reduces osteoblast activity if used for too long.

Question 11

What is the name for osteomalacia in children?

Answer 11

RicketsI

Question 12

What is the pathology behind osteomalacia?

Answer 12

Problem with bone mineralisation. Due to either inadequate levels of phosphate or calcium(Vit D or excess renal excretion). Or overactive resorption of calcium from bone due to hyperparathyroidism

Question 13

What divides the trabecular (spongy) bone and the hard outer cortical bone?

Answer 13

Endosteum. It is a thin layer of connective tissue that lines the surface of the bony tissue that forms the medullary cavity of long bones.

The periosteum is a connective tissue membrane that covers the outer surface of bone.