Pathology 1 Flashcards
list 4 types of non-neoplastic conditions
connective tissue
metabolic disease
fractures
degenerative disease
autoimmune disorders can cause connective tissue disease, true or false?
true
inflammatory disease
often present with MSK symptoms and signs but have potential for systemic symptoms
how can autoimmune disorders be diagnosed?
auto-antibodies
however in some conditions there are very strong, specific associations with auto-antibodies and disease while others not so much
give 4 autoimmune markers?
rheumatoid arthritis - rheumatoid factor
lupus - structural parts of DNA
Scleroderma - anti-centromere, antielomere
dermatomyositis - anti Jo
what is rheumatoid arthritis?
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)
histology of rheumatoid arthritis?
plasma cells
lots of inflammatory cells
what happens in the acute phase of rheumatoid arthritis?
pannus formation at edges of articular surfaces and then spreads over - inflammatory granulation tissue
hyperplastic/reactive synovium
what happens in chronic phase?
fibrosis
deformity
cartilage is destroyed by inflammatory processes causing loss of joint space
what is SLE?
systemic autoimmune condition
autoantibodies directed at parts of DNA
name 2 diagnostic markers of SLE
ANA (95%)
anti double stranded DNA (40-60%)
what is often required for diagnosis of inflammatory arthritides?
clinic-pathological correlation - clinical features and biopsy
name 3 metabolic diseases
pagets
osteomalacia
crystal arthropathies
what is crystal arthropathy?
gout - urate crystals in joint space
pseudogout - calcium pyrophosphate crystals in joint space
how does crystal arthropathy occur?
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
what can cause increased production of urate?
usually idiopathic
enzyme defect (HGPRT) = lysch Nyhan syndrome (rare)
Increased cell turnover - psoriasis, cancer following chemotherapy (causes tumour lysis)
what is the most common cause of gout?
under-excretion
can be a drug side effect (thiazides)
how do urate crystals end up in joints?
precipitation of crystals (due to reduced solubility, not necessarily to do with amount)
unclear how they end up in joint
how does urate cause pain?
crystals elicit acute inflammatory reaction which can mimic arthritis or infection in joint
can cause secondary degenerative changes
what other 2 sites can urate crystals deposit in?
soft tissues - gouty tophus
Kidneys - renal disease (stones)
what are the pathological findings in gout?
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
which is 100% diagnostic of gout?
cytology
histology findings could also be pseudogout
what is calcium pyrophosphate?
crystal arthropahy - pseudogout/pyrophosphate arthropathy
usually affects large joints in older people
how does psuedogout present?
usually aymptomatic but can cause pain
crystals are more rhomboid in shape (thicker and bigger than needles in gout)
what is pagets disease of bone?
abnormality of bone turnover
increased osteoclastic activity
more bone but not normally structured - often weaker so can commonly fracture
what can cause pagets disease?
uncertain some genetic elements (RANKL) viral infections - measles - RSV - paramyxovirus
what are the 3 stages of pagets disease?
osteolytic
mixed
burnt out
end result is thick excess bone with abnormal reversal lines - mosaic pattern
what are the 5 symptoms of pagets?
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
osteomalacia?
abnormal vit D metabolism
can cause rickets
what are the initial phases of fracture?
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
2-3 weeks after fracture?
maximum girth of callus
woven bone deposited perpendicular to cortical bone
cartilage deposition at fracture site which undergoes ossification
bridging with a bony callus
remodelling?
woven bone in callus is constantly remodelled - less stress on area, better remodelling to normal shape
why might a fracture be sent to pathology?
abnormal bone before break
break doesn’t match level of trauma
what can cause a fracture other than trauma?
osteoporosis
malignancy
tumours
………..
what can cause a fracture other than trauma?
osteoporosis
malignancy
tumours
what are myeloma/plasmacytoma?
malignant proliferation of plasma cells
can cause bony lesions
osteolytic vs osteosclerotic?
osteolytic = tumour breaks down/thins bone osteosclerotic = tumour causes increase in bone density and hardening of bone
what can cause avascular necrosis?
trauma alcohol (large cause) dysbarism steroid injection sickle cell disease infection
what does avascular necrosis look like?
wedge shaped infarct
often sub cortical
histology - creeping substitution - new bone growing over dead bone (indicative of healing phase)
degenrerative joint disease?
mechanical injury to joints - osteoarthritis
can be secondary to other joint disease
what secondary disease can avascular necrosis cause?
osteoarthritis
what causes degenerative disease?
mechanical injury to joints - osteoarthritis
can be secondary due to other joint disease
what changes occur in joints in degenerative disease?
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
acute features of inflammatory arthritides?
oedema
fibrin
reactive features in synovial cells
what causes pseudogout?
usually idiopathic
can be due to hypercalcaemia, haemachromatosis, hypomagnesia, ochronis, hypothyroidism
loss of joint space on X ray?
cartilage loss
subchondral sclerosis on X ray?
eburnation
sunchondral cysts on X ray?
synovial fluid accumulation
osteophytes on X ray?
disorganised bone remodelling
