Osteoarthritis Flashcards
What process loop/s is/are associated with acute diseases?
Inhibitory loop
What process loop/s is/are associated with chronic diseases?
Inhibitory loop
Auto-amplifying loop
What are the risk factors for rheumatoid arthritis?
- Genetic factors
- Positive for IgM and IgM rheumatoid factors
- Varied inflammatory cascades
What are the impairments associated with rheumatoid arthritis?
- Synovial inflammation
- Articular cartilage damage
- Bone erosion
- Internal organ damage
What causes rheumatoid arthritis?
An overproduction of tumour necrosis factor (TNF)
What causes the synovitis associated with rheumatoid arthritis?
Joint if infiltrated by:
- Increased number of fibroblast like synoviocytes
- Increased number of macrophage like synoviocytes
What differences exist between +ve RA factor and +ve auto-antibody patients, and +ve RA factor and -ve autoantibody?
+ve RA, +ve antibody:
- More lymphocytes (B and T cells) in the synovial tissue
- More joint damage
- Fewer remissions
+ve RA, -ve antibody:
- More fibrosis and increased thickness of synovium
What are the clinical symptoms of RA?
- Joint swelling
- Pain/stiffness (am, <1hr)
- Weakness
- Deformity
- Fatigue
- Malaise
- Fever
- Weight loss
- Depression
What are the articular characteristics of RA?
- Palpation tenderness
- Synovial thickening
- Effusion (early)
- Erythema (early)
- Decreased ROM (late)
- Ankylosis (late)
- Subluxation (late)
What is the common distribution of RA?
- Symmetrical
- Distal more commonly than proximal i.e. PIP, MCP, wrist, ankle
What is the common distribution of RA?
- Symmetrical
- Distal more commonly than proximal i.e. PIP, MCP, wrist, ankle
Definition of osteoarthritis
A disorder involving movable joints characterised by cell stress and extracellular matrix degradation initiated by micro- and macro-injury that activates maladaptive repair responses including pro-inflammatory pathways of innate immunity
What characteristics are associated with OA?
- Cartilage degradation
- Bone remodelling
- Osteophyte formation
- Joint inflammation
- Loss of normal joint function
Where does articular cartilage receive its nutrients from?
Synovial fluid
What causes the failed recovery of articular cartilage?
Stress
- Genetics
- Overload
- Instability
- Trauma
What are the risk factors of OA?
- Age
- Family history/genetics
- Obesity
- Gender
- Occupation
- Abnormal joint shape
- Limb alignment
- Joint trauma (fractures, instability)
What two aspects do risk factors of OA contribute to?
- Susceptibility of the joint (systemic factors or factors in the local joint environment)
- Increased load
What are the clinical features of OA?
- Joint pain/ache
- Morning stiffness <30 mins
- Joint swelling
- Decreased ROM
- +/- crepitus
- +/- joint line tenderness
- +/- joint deformity
- weakness/atrophy
What are the imaging features of OA?
- Loss of joint space
- Subchondral bone sclerosis
- Para-articular cysts/spurs
- Bone scan - hot spots (bone inflammation)
What are the two major load-bearing macromolecules in articular cartilage? How do they work together?
- Collagens
- Proteoglycans
The interaction between the highly negatively charged cartilage proteoglycans and type II collagen provides the compressive and tensile strength of the tissue.
What articular cartilage changes are present with OA?
- Disorganisation of articular cartilage
- Oedema (of cartilage)
- Chondrocyte apoptosis
- Tide line undulation
- Cartilage loss
- Change in collagen type and reduction of aggrecan
What subchondral bone changes are present with OA?
- Thickening
- Osteoclast resorption and osteoblast bone formation
What is subchondral bone thickening called when seen on x-ray?
Sclerosis
At what stage may OA be somewhat reversible?
There is a momentary increase in the cartilage turnover in response to initial cartilage damage in the first stage of OA development, which may be reversible.
