Joint Pathology Flashcards
What is bone congruence?
How well the bones fit each other, important for the distribution of pressure
What is the content of cartilage matrix?
Collagen, GAGs, hyaluronic acid
What is the function of GAG in the cartilage
attract water
Why isn’t the synovial membrane classified as an epithelium
It doesn’t have basement membrane or junctional complexes like desmosomes
What are the type A chondrocytes like?
Macrophage
What are the type B chondrocytes like?
Fibroblast
What is the function of type B chondrocyte?
produce ECM (hyaluronic acid production)
How can we tell between type A and type B chondrocytes on histology?
Type A cells are multi-nucleated giant cells
What are the treatments of osteoarthritis?
physiotherapy, pain relief and joint replacement
What are the main differences between RA and osteoarthritis?
RA tends to be diffused. It can affect skin, heart and lung
RA stiffness gets better through the day. OA gets worst with use
T/F RA usually starts in the major large joints of the body
False, they start in the small joints of hands and feet
T/F Gout is an acute form of osteoarthritis
True, inflammation is caused by crystalisation of uric acid
What are the treatments of gout?
anti-inflammatory medication, urate lowering therapy, lifestyle changes
What are the major enzymes and cytokines involved is OA?
collagenase, MMP
IL-1
What is the trigger of OA?
chondrocyte damage, leading to proliferation and enzyme/cytokine secretion
What are some bone changes that can occur with OA?
bone thickening, microfractures,
What is fibrillation of cartilage
erosion of cartilage
What is bone eburnation?
thickening, and bone appears white and shiny
T/F OA is a diffused degenerative disease in the joint
False, it is focal. You get non-uniform loss of cartilage, subchondral thickening and osteophytes
What are the signs of OA?
reduced RoM
Crepitus (grinding of joint)
Osteophytes
What are the symptoms of OA?
insidious onset, deep achey pain that is worse with activity
no systemic symptoms
What is the diagnosis of OA?
Mostly clinical
What is the underlying pathological process of RA?
T helper cells activation, especially Th1 and Th17
TNF-a is central to RA inflammatory process, activating B plasma cells
What kind of change do activated B cells do to the synovium?
they induce fibroblasts, macrophages and osteoclasts to make synovium hyperplastic, and deposit abnormal granulation tissue “pannus”
What is the role of activated macrophage in RA?
secrete collagenases and MMPs to break down cartilage and bone
What is the morphology of RA on histology?
villous hyperplasia
mononuclear infiltrate
germinal centres
What is the presentation of late stage RA?
union of bones due to extensive fibrosis and destruction of capsule and ligaments
What are the signs of RA?
warm, swollen joints
rheumatoid nodules
joint deformity in later stage
T/F there are systemic symptoms from RA
True, patients can have fever, loss of weight, anaemia
T/F RA is usually asymmetrical
False, the disease process is symmetrical
Which joint is often sparred in RA?
distal interphalangeal joint
T/F Granulomatous inflammation is typical of RA
True, there is central necrosis, epithelioid macrophages and surrounding lymphocytes
What are the specific tests for RA?
Test for rheumatoid factor or anti-cyclic citrullinated peptided
What is the effect of crystals on neutrophils in gout?
they are spiky and can pierce neutrophils, killing them and release internal inflammatory mediators
T/F Pannus can occur in both OA and gout
True
What is tophi?
urate deposition that can be seen superficially
T/F Granuloma can be seen in RA, but not in gout
False, you can see granuloma in tophi
T/F Serum urate is a good diagnostic technique for gout
False, acute gout attack lowers serum urate + most people with high urate don’t have gout
What is the gold standard test for gout?
joint aspiration
