Pathology 1

Question 1

list 4 types of non-neoplastic conditions

Answer 1

connective tissue
metabolic disease
fractures
degenerative disease

Question 2

autoimmune disorders can cause connective tissue disease, true or false?

Answer 2

true
inflammatory disease
often present with MSK symptoms and signs but have potential for systemic symptoms

Question 3

how can autoimmune disorders be diagnosed?

Answer 3

auto-antibodies
however in some conditions there are very strong, specific associations with auto-antibodies and disease while others not so much

Question 4

give 4 autoimmune markers?

Answer 4

rheumatoid arthritis - rheumatoid factor
lupus - structural parts of DNA
Scleroderma - anti-centromere, antielomere
dermatomyositis - anti Jo

Question 5

what is rheumatoid arthritis?

Answer 5

inflammation of joints with autoimmune basis
- rheumatoid factor
- auto antibodies against Fc IgG
can be systemic (can occur in absence of joint disease but with manifestations in other places like soft tissue etc)

Question 6

histology of rheumatoid arthritis?

Answer 6

plasma cells

lots of inflammatory cells

Question 7

what happens in the acute phase of rheumatoid arthritis?

Answer 7

pannus formation at edges of articular surfaces and then spreads over - inflammatory granulation tissue
hyperplastic/reactive synovium

Question 8

what happens in chronic phase?

Answer 8

fibrosis
deformity
cartilage is destroyed by inflammatory processes causing loss of joint space

Question 9

what is SLE?

Answer 9

systemic autoimmune condition

autoantibodies directed at parts of DNA

Question 10

name 2 diagnostic markers of SLE

Answer 10

ANA (95%)

anti double stranded DNA (40-60%)

Question 11

what is often required for diagnosis of inflammatory arthritides?

Answer 11

clinic-pathological correlation - clinical features and biopsy

Question 12

name 3 metabolic diseases

Answer 12

pagets
osteomalacia
crystal arthropathies

Question 13

what is crystal arthropathy?

Answer 13

gout - urate crystals in joint space

pseudogout - calcium pyrophosphate crystals in joint space

Question 14

how does crystal arthropathy occur?

Answer 14

uric acid is end product of purine synthesis (adenine and guanine)
so urate is formed in DNA replication etc
either increased production or reduced excretion of urate

Question 15

what can cause increased production of urate?

Answer 15

usually idiopathic
enzyme defect (HGPRT) = lysch Nyhan syndrome (rare)
Increased cell turnover - psoriasis, cancer following chemotherapy (causes tumour lysis)

Question 16

what is the most common cause of gout?

Answer 16

under-excretion

can be a drug side effect (thiazides)

Question 17

how do urate crystals end up in joints?

Answer 17

precipitation of crystals (due to reduced solubility, not necessarily to do with amount)
unclear how they end up in joint

Question 18

how does urate cause pain?

Answer 18

crystals elicit acute inflammatory reaction which can mimic arthritis or infection in joint
can cause secondary degenerative changes

Question 19

what other 2 sites can urate crystals deposit in?

Answer 19

soft tissues - gouty tophus

Kidneys - renal disease (stones)

Question 20

what are the pathological findings in gout?

Answer 20

cytology - cross polarised light used to see needle shaped crystals in joint fluid
histology - amorphous eosinophilic debris and inflammation (giant cells - almost like granuloma reaction), crystals lost during tissue processing

Question 21

which is 100% diagnostic of gout?

Answer 21

cytology

histology findings could also be pseudogout

Question 22

what is calcium pyrophosphate?

Answer 22

crystal arthropahy - pseudogout/pyrophosphate arthropathy

usually affects large joints in older people

Question 23

how does psuedogout present?

Answer 23

usually aymptomatic but can cause pain

crystals are more rhomboid in shape (thicker and bigger than needles in gout)

Question 24

what is pagets disease of bone?

Answer 24

abnormality of bone turnover
increased osteoclastic activity
more bone but not normally structured - often weaker so can commonly fracture

Question 25

what can cause pagets disease?

Answer 25

``` uncertain some genetic elements (RANKL) viral infections - measles - RSV - paramyxovirus ```

Question 26

what are the 3 stages of pagets disease?

Answer 26

osteolytic mixed burnt out end result is thick excess bone with abnormal reversal lines - mosaic pattern

Question 27

what are the 5 symptoms of pagets?

Answer 27

can affect all bones pain - microfracture or nerve compression enlargement and abnormal shape increased metabolism - heat, AV shunt (can cause heart failure) secondary malignancy - osteosarcoma

Question 28

osteomalacia?

Answer 28

abnormal vit D metabolism | can cause rickets

Question 29

what are the initial phases of fracture?

Answer 29

haematoma - fibrin mesh influx of inflammatory cells cytokine release - osteoprogenitor cells after week 1 - callus forms - organised haematoma, early recruitment and remodelling at the ends of the bone

Question 30

2-3 weeks after fracture?

Answer 30

maximum girth of callus woven bone deposited perpendicular to cortical bone cartilage deposition at fracture site which undergoes ossification bridging with a bony callus

Question 31

remodelling?

Answer 31

woven bone in callus is constantly remodelled - less stress on area, better remodelling to normal shape

Question 32

why might a fracture be sent to pathology?

Answer 32

abnormal bone before break | break doesn't match level of trauma

Question 33

what can cause a fracture other than trauma?

Answer 33

osteoporosis malignancy tumours ………..

Question 34

what can cause a fracture other than trauma?

Answer 34

osteoporosis malignancy tumours

Question 35

what are myeloma/plasmacytoma?

Answer 35

malignant proliferation of plasma cells | can cause bony lesions

Question 36

osteolytic vs osteosclerotic?

Answer 36

``` osteolytic = tumour breaks down/thins bone osteosclerotic = tumour causes increase in bone density and hardening of bone ```

Question 37

what can cause avascular necrosis?

Answer 37

``` trauma alcohol (large cause) dysbarism steroid injection sickle cell disease infection ```

Question 38

what does avascular necrosis look like?

Answer 38

wedge shaped infarct often sub cortical histology - creeping substitution - new bone growing over dead bone (indicative of healing phase)

Question 39

degenrerative joint disease?

Answer 39

mechanical injury to joints - osteoarthritis | can be secondary to other joint disease

Question 40

what secondary disease can avascular necrosis cause?

Answer 40

osteoarthritis

Question 41

what causes degenerative disease?

Answer 41

mechanical injury to joints - osteoarthritis | can be secondary due to other joint disease

Question 42

what changes occur in joints in degenerative disease?

Answer 42

fibrillation (roughening) cartilage is worn away until surface becomes polished bone on bone - eburnation/erosion synovial fluid leaks through bone forming subchondral cysts remodelling of bone to cope with stress produces outgrowths - osteophytes

Question 43

acute features of inflammatory arthritides?

Answer 43

oedema fibrin reactive features in synovial cells

Question 44

what causes pseudogout?

Answer 44

usually idiopathic | can be due to hypercalcaemia, haemachromatosis, hypomagnesia, ochronis, hypothyroidism

Question 45

loss of joint space on X ray?

Answer 45

cartilage loss

Question 46

subchondral sclerosis on X ray?

Answer 46

eburnation

Question 47

sunchondral cysts on X ray?

Answer 47

synovial fluid accumulation

Question 48

osteophytes on X ray?

Answer 48

disorganised bone remodelling