Joint path Flashcards
Where does articular cartilage receive its nutrition?
Synovial fluid
Pathologically, which joints are important?
Joints between the vertebrae, synovial joints
What produces synovial fluid?
The synovial membrane, which lines the inner surface of the joint capsule
What are the important features of synovial fluid?
Viscocity - it needs to be quite viscous. Allows for low friction movement.
What may you see in chronic joint disease?
o Increased opacity around the bone -> with chronic inflammatory changes you get a thickened joint capsule. May begin to see new bone formation.
o May see variation in the gap between the bones as well
What is the usual colour of articular cartilage (hyaline cartilage)?
Blue white as it is far from blood supply (recieves nutrition from synovial fluid)
How do joints respond to injury?
- Articular cartilage has a limited reesponse to injury and minimal capacity for repair
- if subchondral bone is involved, the defect is quickly filled with vascular fibrous tissue which undergoes metaplasia to fibrocartilage
- Articular catilage does NOT particupate in an inflammatory response
- Inflammatory mediators are bad for joints -> inflammatory mediators can damage articular cartilage by degrading collagen or proteoglycan, they also inhibit proteoglycan synthesis
- degenerative changes to articular cartilage is usually accompanied by formation of periarticular osteophytes and synovial inflammation and synovial hyperplasia
- Synovial hyperplasia (chronic)
- synovial membrane hypertrophy and hyperplasia
- synovial fluid loses some of its lubricating properties because hyaluronic acid is degraded by inflammatory products
- pannus may develop in some chronic inflammatory conditions (fibrovascular histiocytic tissue) -> pannus promotes destruction of underlying cartilage
- glucocorticoids are bad for joints by ↓ synthesis of cartilaginous matrix, ↓ repair, ↓ mechanical strength of cartilage, ↑ depletion of proteoglycans
What are some examples of joint disease?
- Degenerative joint disease
- inflammatory joint disease (arthritis)
- osteochondrosis
What changes would you expect to see in chronic degenerative joint disease - hip dysplasia?
- Changes to the density of bone around the joint
- Remodelling of the head of the femur
- may not appear as a ball and socket joint
What are the aims in the treatment of DJD?
- Aims are to reduce inflammatory response to the chronic injury and maintain normal conformation
What animals do we most commonly see inflammatory joint disease (arthritis) in?
Most commonly seen in farm animals
What are the culprits in terms of infectious agens of disease causing inflammatory joint disease (arthritis)?
- Usually bacterial (haematogenous, direct extension) though sometimes viral
- Actinobacillus, Erysipelothrix, E. coli, Haemophilus, Mycoplasma, caprine arthritis-encephalitis virus, bovine ephemeral fever virus
What would you expect to see microscopically in inflammatory joint disease?
strong inflammatory infiltrate (likely plasma cells and lymphocytes), proliferation of the synovium, loss of cartilage, fibrosis around joint capsule, synovial proliferation
What would you expect to see microscopically in septic arthritis?
suppurative response, would likely see organisms present
Explain IVDD
joint material starts to impinge on the spinal cord causing a neuropathy
