Rheumatoid Arthritis Flashcards
What does Rheumatoid factor target?
Rheumatoid factor is an IgM antibody that targets the Fc region of an altered IgG
What does Anti-CCP target?
Anti-CCP targets citrullinated proteins.
What will the autoantibodies, Rheumatoid factor and Anti-CCP result in?
These will result in the formation of immune complexes. These immune complexes will accumulate and activate complement. This will cause the process of inflammation to occur.
What is citrullination?
This is where a argine is switched citruline
What are the susceptibility genes of RA?
HLA-DR1 and HLA-DR4
Explain the pathogenesis of RA
Rheumatoid arthritis is caused by a mixture of environmental factors and susceptibility genes. The susceptibility genes are HLA-DR1 and HLA-DR4. The environmental factors include smoking and pollution.
The environmental factors will cause some of the body cells to undergo modification, for example collagen type two. The modification is citrullination, where the arginine base is switched for citrulline. Due to the susceptibility genes, the immune cells do not recognize these genes.
The antigen presenting cell, for example macrophages and neutrophils will pick up these cells and present them to T helper cells. These will then activate B cells and cause the formation of autoantibodies.
The T cells and the B cells will travel to the joints via the blood circulation.
T cell will release IL-17 and IL-gamma. This is recruit macrophages and cause inflammation. Macrophages will release IL-1, TNF and IL-6 and this will increase inflammation and cause synovial cells to proliferate.
The increase in immune and synovial cells will cause the formation of a pannus. This is a thick swollen synovial membrane with immune cells, fibroblasts and myofibroblasts. This will damage and erode bone.
Activated synovial cells will release proteases and this causes cartilage breakdown. This will reveal the underlying bone and cause it to erode.
The inflammatory cytokines will cause the T cells to produce RANKL. This will cause activation of osteoclasts and cause increased bone resorption.
There are two main autoantibodies.
Rheumatoid factor is an IgM antibody that targets the Fc region of an altered IgG. There is also anti-CCP which targets citrullinated proteins.
These will result in the formation of immune complexes. These immune complexes will accumulate and activate complement. This will cause the process of inflammation to occur.
There will also be angiogenesis. The cytokines will increases the vascular permeability of the joints and this will allow more immune and inflammatory cells in.
What is swan neck deformity?
DIP: flexed
PIP: hyperextended
What is Boutonniere deformity?
DIP: hyperextended
PIP: flexed
What are some examples of extra-articular involvement from RA?
Lung scarring Nodules in the skin Anaemia due to increase hepcidin in the liver Depression Malignancy Fatigue Fever Muscle weakness Osteoporosis Carpal tunnel syndrome Eye problems
What are the blood test result for RA?
There will be increase RA factor and Anti-CCP in the blood
What will be shown if the synovial fluid is examined in someone with RA?
- cloudy appearance
- elevated WBCs
What are some symptoms of RA?
Joint pain, stiffness and swelling for more than 6 weeks
Swelling affecting 3-4 different joints or more
Morning stiffness lasting longer than 30 minutes
Symmetrical symptoms affecting both the left and ride sides of the body
Swelling and pain affecting the wrists, hands and finger joints
Rheumatoid nodules developing under the skin
What will imaging tests show on a RA joint?
Reduced joint space, inflammation, synovitis, increased fluid and tendon abnormalities
What is the function of DMARDs?
Reduce inflammation
Give some examples of DMARDs
Methotrexate, gold, hydroxychloroquine
