Rheumatoid arthritis Flashcards
Rheumatoid arthritis
Chronic, progressive autoimmune disease
Inflammation in joints especially hands, wrists and feed.
Symmetric (both hands or both knees)
Both RA and OA are located in joints, are chronic and progressive, and have no cure (OA is erosion, RA is inflammation)
RA symptoms
Simultaneous symmetrical joint swelling
Morning joint stiffness lasting 30-40 minutes
General symptoms associated with many conditions
Rheumatoid factor
Group of auto-antibodies to Fc region of IgG
Found in 80% of RA patients
Also found in unaffected people
Used in diagnosis
RA progression
Synovial membrane responds to inflammatory cytokines
Nodules grow off membrane and capillary formation.
Meniscus invasion
Bone destruction due to osteoclast activation (not balanced by osteoblasts)
Cartilage destroyed (as in OA)
Cartilage destruction
Caused by elevated production of matrix metalloproteinases and ADAMTs (aggrecanases)
RA risk factors
Less common than OA 2-3 times more likely in women (as in OA) Onset commonly between 40 and 60 years High BMI Smoking increases risk by 2x in males Develops faster than OA
Genetic risk
HLA-DRB1 gene accounts for 30% of genetic susceptibility
Codes for part of HLA antigen complex (involves in self recognition)
Polymorphism in PTPN22 (protein tyrosine phosphatase) involved in RA and other autoimmune diseases
TRAF1 linked to RA (interacts with TNF receptor)
RA treatment
Wider range of treatments than OA
70% of patients likely to improve in first 12-24 months (not cured)
NSAIDS manages condition
Gold and penicillamine are slow acting disease-modifying drugs
Methotrexate for immunosuppression
Corticosteroids for short-term pain relief
Anti-TNF therapy
Requires regular injections and is expensive
Etanercept is TNF receptor linked to Fc of human IgG (to solubilise)
Infliximab is chimeric monoclonal antibody against TNF-alpha
