Joints and joint disease Flashcards
What is the function of aggrecan in cartilage ECM?
Aggrecan is a proteoglycan and contains GAGs (glycosaminoglycans), which are hydrophomoc and so absorb water and help with shock absorbing and resisting compressive forces.
Does cartilage have a blood supply?
NOOO! It is avascular!
What are the three types of cartilage?
Hyaline, Fibrocartilage and Elastic
What type of collagen fibres do hyaline cartilage contain?
Type II collagen fibres
What type of collagen fibres do fibrocartilage contain?
Type I collagen fibres
What type of collagen fibres do elastic cartilage contain?
Abundant elastic fibres interspersed with bundles of Type II collagen fibres
Where do chondrocytes lay in?
Lacuna - in the perichondrium
How do chondrocytes initiate cartilage growth and repair?
In perichondrium, differentiate into chondroblasts and secrete matrix
Is syndesmosis a fibrous or cartilaginous joint?
Fibrous
What type of arthritis is more common?
Osteoarthritis
What are osteophytes?
Outgrowths of bone
What are the radiographic changes seen in osteoarthritis?
Joint space narrowing
Subchondral cysts and sclerosis
Osteophytes
Malalignment
In osteoarthritis, when is joint stiff predominantly seen?
short-lived morning stiffness and post-inactivity stiffness
What nodes form at the distal interphalangeal joints?
Herberden’s nodes (Rheumatoid arthritis - has bouchard’s nodes) (B comes before H, so B nodes are more proximal)
What do monosodium urate crystals in the synovial fluid/around joint cause?
Gout - hyperuricaemia
What can happen as a result of hyperuricaemia?
Tophi
Which disease has crystals are needle shaped and negatively birefringent under polarised light?
Gout
What are the radiographic changes seen in gout?
Joint effusion 'Punched out' bony erosions Tophi Soft tissue swelling Joint space narrowing
What medication (methods) can you use to manage gout?
NSAIDS (acute)
Xanthine oxidase inhibitor (dec uric acid synthesis)
Excretion of uric acid
(can’t use diurectics! - if patients are taking it, stop them)
What general measures can you take to manage gout?
reduce alcohol intake
avoid purine-rich foods
loose weight
review medication - stop diuretics
What happens when there are depositions of calcium pyrophosphate (CPP) crystals in articular and periarticular tissue?
Pseudogout
What kind of crystals form in pseudogout?
Rhomboid shaped and positively birefringent.
