Non-neoplastic Bone Disease

Question 1

what are the different types of non-neoplastic bone disease

Answer 1

osteoporosis, osteomalacia, hyperparathyroidism, avascular necrosis, Paget’s disease

Question 2

what is osteoporosis

Answer 2

decreased bone mass

Question 3

what is osteopenia and osteoporosis defined as

Answer 3

osteopenia = 1-2.5 SD below normal bone mass`
osteoporosis = >2.5 SD below normal bone mass

Question 4

what risk is osteoporosis associated with

Answer 4

significant risk of fracture

Question 5

what causes localised osteoporosis

Answer 5

lack of use

Question 6

what can cause primary generalised osteoporosis

Answer 6

idiopathic, post-menopausal, senile(with age)

Question 7

give some secondary causes of generalised osteoporosis

Answer 7

endocrine disorders(eg Cushing’s), drugs(eg alcohol), GI disorders(eg malabsorption)

Question 8

what hereditary factors affect bone mass

Answer 8

polymorphisms in bone affecting bone metabolism

Question 9

what environmental factors affect bone mass

Answer 9

physical activity, muscle strength, diet, hormonal status

Question 10

describe how increased age changes the bone

Answer 10

reduced proliferative and biosynthetic capacity of osteoblasts

Question 11

what is the main cause of osteomalacia

Answer 11

Vitamin D deficiency, due to diet or lack sun exposure

Question 12

what role does vitamin D play in the bone

Answer 12

stimulates absorption of calcium and stimulates osteoblasts to release osteocalcin

Question 13

what does vitamin D deficiency lead to the in the bone

Answer 13

hypocalcaemia and elevated PTH(parathyroid hormone)

Question 14

what pathology is seen in osteomalacia

Answer 14

impaired mineralisation of bone matrix, newly formed osteoids are not fully mineralised

Question 15

what effect does osteomalacia have on the bone

Answer 15

weakens it, more susceptible to fracture

Question 16

describe what avascular necrosis is

Answer 16

necrosis of bone and marrow

Question 17

what is avascular necrosis a result of

Answer 17

result of loss of effective vascular supply, can result from trauma/fractures

Question 18

what can avascular necrosis lead to

Answer 18

bone and joint damage can lead to total hip replacement

Question 19

give some examples of predisposing factors for avascular necrosis

Answer 19

alcohol, corticosteroids, connective tissue disorders, sickle cell disease

Question 20

describe the usual shape and location of the infarct in avascular necrosis

Answer 20

shape = wedge

usually subchondral

Question 21

describe the effects of parathyroid hormone(PTH) in bones

Answer 21

activates osteoclasts, increases resorption Ca, increases urinary phosphate excretion, increases synthesis active Vit. D

Question 22

describe the interplay between PTH and Ca in hyperparathyroidism

Answer 22

PTH elevates serum Ca, Ca usually inhibits PTH, but not in hyperparathyroidism

Question 23

what pathology is seen in bones in hyperparathyroidism

Answer 23

continued osteoclasis, osteoporosis, brown tumours and osteitis fibrosa cystica(rarely seen)

Question 24

what effect does osteoclasis have on the bone

Answer 24

decreases bone mass and increases risk of fracture, deformity and degenerative joint disease

Question 25

describe the brown tumour pathology seen in hyperparathyroidism

Answer 25

mass of reactive tissue, includes giant cells, osteoporotic, can become cystic

Question 26

describe what Paget's disease(osteitis deformans) of bone is

Answer 26

abnormality of bone turnover

Question 27

when is Paget's disease seen in patients

Answer 27

late adulthood

Question 28

what are the common symptoms of Paget's disease

Answer 28

often asymptomatic

Question 29

what are the causes of Paget's disease

Answer 29

cause uncertain, may be gene related or viral infection

Question 30

what are the 3 stages of Paget's disease

Answer 30

osteolytic, mixed and osteosclerotic

Question 31

what occurs in the osteolytic and mixed stages of Paget's disease

Answer 31

``` osteolytic = resorption pits with large osteoclasts mixed = osteoclasis and osteoblastic activity ```

Question 32

what is the net results of the different stages of Paget's disease

Answer 32

thick excess bone with abnormal reversal lines(mosaic pattern), bone matures but is porous and soft

Question 33

what bones can Paget's affect and where does it usually affect

Answer 33

``` can affect any bones usually axial(small bones less likely) ```

Question 34

what pathology is seen in Paget's disease

Answer 34

pain, secondary malignancy, increased metabolism, enlargement and abnormal bone shape