Rheumatoid Arthritis Flashcards
Definition of RA
Chronic autoimmune disease
Characterised by pain/stiffness/synovitis of synovial joints
Key features
Chronic arthritis
- Polyarthritis (swelling of small joints of hand/wrist)
- Symmetrical
Sub-cutaneous nodules (deposition of immune complexes -> macrophages cause inflammation)
Epidemiology?
1% of population
F:M = 3:1
Genetic factors?
HLA-DR molecules have Shared Epitope on peptide binding region
Variants/mutation of this epitope strongly associated with RA
Environmental factors?
Smoking
Primary site of pathology?
Synovium
This can be in synovial joints, the Tenosynovium surrounding tendons of hand, and the Bursa
What is rheumatoid factor?
IgM antibodies
Bind to IgG as antigen, causing inflammation
What other antibodies are related to RA?
Anti-CCP antibodies
Extra-articular features of RA?
Fever, weight loss
Subcutaneous nodules
Features of synovial joint?
Synovium - 1-3 cell deep Synovial fluid (viscous) Articular cartilage (Type 2 collagen)
Pathogenesis of RA?
Macrophages release TNF-a (pro-inflammatory cytokines) in the rheumatoid synovium
Management of RA?
Multidisciplinary (physio, surgery, occupational therapy)
Medications:
Disease-Modifying Anti-Rheumatic drugs (DMARDs) started early in therapy
Glucocorticoid therapy (steroids, prednisolone) but AVOID long-term due to side effects
Biological therapies
What are DMARDs?
Drugs that may induce remission of RA (but not cure)
Prevent joint damage
Reduces inflammation in synovium
Slows/prevents bone erosions/joint damage
What are examples of biological therapy?
Anti-TNF antibodies (Inflixamab)
Antibodies against CD20 -> B-cell depletion (Rituximab)
Inhibition of IL-6
Downside of biological therapy?
Expensive
Side effects -> Increased infection risk
