23- Histopathology of joint diseases Flashcards
What are the 3 main types of joints
- Fibrous
- Cartilaginous
- Synovial joints
Where are fibrous joints found?
Between the bones of the skull
Where are cartilaginous joints found?
Between ribs and sternum allowing certain movements
Where are synovial joints found?
Between 2 bones allowing movement
What are some features of synovial joints?
- covered in cartilage
- capsule of dense fibrous tissue, holds synovial fluid in place
- contains synovial fluid and synovium
What is synovium?
Synovial membrane which lines the inner surface of the joint excluding the cartilage
What are some features of articular cartilage?
Very hard, smooth made up of collagen, no blood supply, receives nutrition from synovial fluid
What happens to articular cartilage when damaged?
It cannot repair itself, it will eventually degenerate
What are 3 types of diseases of synovial joints
- trauma
- inflammatory
- non-inflammatory
E.G of trauma?
hemarthrosis
What are 2 types of infection?
- crystal induced
- primary inflammatory
Example of non-inflammatory?
osteoarthritis
Can you have a tumour in a joint?
No
Who has greater genetic susceptibility of rheumatoid disease?
Women, twins, HLA antigen
What are some immunological markers present in rheumatoid disease?
- Autoantibodies
- Cellular immunity
- cytokines
What are some autoantibodies found in rheumatoid disease?
Rheumatoid factor, citrulline
What are some cellular immunity found in rheumatoid disease?
T cells (CD8+)
What are some cytokines found in rheumatoid disease?
TNFs (tumour necrosis factor alpha),
IL1 (interleukin 1)
What are prostaglandins and leukotrienes classed as?
Arachadonic acid metabolites (small molecules that control pain)
What happens to synovium when inflammed?
normally synovium is flat. when inflamed has small finger-like projections known as pannus, this pannus grows over and destroys articular cartilage, degrading the cartilage from below the marrow surface
What is another name for inflamed synovium?
Pannus
What does destruction of bone lead to?
erosions and osteoporosis
What does the destruction of cartilage, capsule, ligamentsleads to?
Joint instability, subluxation
What is subluxation?
Partial dislocation of joint, the inflammatory process destroys the capsule as well as surrounding muscle making it unstable
