Pathology

Question 1

define osteoarthritis

Answer 1

degenerative change in articular cartilage due to ageing and stress

Question 2

two types of osteoarthritis

Answer 2

primary= age related, presents over 50
secondary= predisposing condition e.g. excessive weight bearing, systemic conditions, etc.

Question 3

what joints does OA affect?

Answer 3

hips
knees
lumbar and cervical vertebrae
PIP and DIP joints

Question 4

pathogenesis of OA

Answer 4

early= chondrocyte injury, proliferation and inflammatory mediators, proteases, collagen and proteoglycans lead to remodelling- fissures and fibrillation

late= chronic inflammation leads to loss of cartilage and change in subchdonral bone and joint. this causes worn away cartilage, subchdonral cysts, eburnation and osteophytes

Question 5

radiological features of OA

Answer 5

LOSS
loss of joint space (cartilage loss)
osteophytes (disorganised bone remodelling, can irritate nerves)
subchondral sclerosis (eburnation)
subchondrial cysts (synovial fluid accumulation)

Question 6

define RA

Answer 6

chronic AI inflammatory disorder

Question 7

presentation of RA

Answer 7

joint pain (small joints before large ones)
malaise
fever

Question 8

progression of RA

Answer 8

ankylosis
herniation (Baker’s cyst)
involvement of tendons and ligaments

Question 9

what can patients have periods of in RA

Answer 9

remission

Question 10

extra-articular manifestations of RA

Answer 10

rheumatoid nodules
small vessel vasculitis
pleural and pericardial effusions
pyoderma gangrenosum

Question 11

cause of RA

Answer 11

genetics (HLA DRB1 alleles)

environmental triggers lead to cytokine production

Question 12

acute phase of RA

Answer 12

pannus formation (granulation tissue) and destroyed cartilage

Question 13

chronic phase of RA

Answer 13

fibrosis and deformity

Question 14

what are seronegative spondyloarthritides associated with?

Answer 14

HLA B27

affect ligamentous attachments

Question 15

types of seronegative spondylarthritides

Answer 15

1. ankylosing spondylitis
2. reactive arthritis
3. enteritis arthritis
4. psoriatic arthritis

Question 16

describe reactive arthritis

Answer 16

reaction to infection e.g. chlamydia, shigella, salmonella, etc.

Question 17

describe enteritis arthritis

Answer 17

organisms with high LPS in cell wall trigger immune reaction

Question 18

infectious arthritis

Answer 18

suppurative: haematogenous spread of organisms, usually affecting a single joint
mycobacterial, Lyme disease and viral

Question 19

cause of crystal arthropathy

Answer 19

hyperuricaemia either by increased production (enzyme defect HGPRT) or reduced excretion by kidney (chronic renal disease or side effect of thiazide diuretics)

Question 20

gout crystals

Answer 20

urate needle shaped crystals

Question 21

pseudo gout crystals

Answer 21

calcium pyrophosphate rhomboid crystals

Question 22

five examples of non-neoplastic bone disease

Answer 22

1. osteoporosis
2. osteomalacia
3. hyperparathyroidism
4. avascular necrosis
5. Paget’s disease

Question 23

when does peak bone mass occur

Answer 23

young adulthood (varies due to diet, activity, genetics, etc.)

Question 24

describe osteomalacia

Answer 24

vitamin D deficiency from diet or lack of sunlight

Question 25

role of vitamin D in bone

Answer 25

vitamin D stimulates absorption of calcium and osteoblasts to release osteocalcin. Deficiency elevates PTH which causes calcium absorption and release form bone, increased osteoclastic activity and loss of phosphate impairs bone mineralisation, leads to thick osteoid seams and weakened bone

Question 26

describe hyperparathyroidism

Answer 26

PTH activates osteoclasts (increased resorption, released Ca2+ and increased phosphate excretion)

Question 27

progression of hyperparathyroidism

Answer 27

Brown tumours and osteitis fibrosa cystica

Question 28

describe avascular necrosis

Answer 28

loss of vascular supply

Question 29

causes of avascular necrosis

Answer 29

predisposing condition e.g. alcohol, drugs | fractures

Question 30

describe Paget's disease

Answer 30

abnormality of bone turnover

Question 31

causes of Paget's disease

Answer 31

``` genetics= p62 viral infection (paramyxovirus, measles and RSV) ```

Question 32

presentation of Paget's

Answer 32

pain (nerve compression and fracture) enlargement increased metabolism secondary malignancy