Flashcards in Rheumatoid Arthritis Deck (41)
Define Rheumatoid Arthritis
Chronic autoimmune disease characterised by pain, stiffness and SYMMETIRCAL SYNOVITIS of synovial (diarthrial) joints
When is the stiffness in the joints particularly bad in rheumatoid arthritis and what can make it better?
In the morning
It gets better with exercise
What is a relatively common extra-articular manifestation of rheumatoid arthritis?
What causes the extra-articular manifestations?
Rheumatoid factor produces immune complexes that can go anywhere
What type of antibody is the rheumatoid factor?
IgM antibody that binds to the Fc portion of IgG
Is rheumatoid arthritis more common in males or females?
More common in females (3:1)
What is the important genetic component that predisposes toRheumatoid Arthritis?
The genetic component comes down to a specific set of amino acids within the beta chain of the DR molecule (amino acids 70-74 of the DR Beta1-chain)
This set of amino acids is conserved among all HLA subtypes that are associated with rheumatoid arthritis – it is called the shared epitope
What important environmental factor can affect the susceptibility and severity of Rheumatoid Arthritis?
State some joints that are commonly affected in Rheumatoid Arthritis.
Metacarpophalangeal joint (MCP)
Proximal interphalangeal joint (PIP)
Metatarsophalangeal joint (MTP)
Name and describe two deformities that are indicative of Rheumatoid Arthritis.
Hyperextension of PIP
Hyperflexion of DIP
Boutonniere deformity (button-like)
Hyperflexion at PIP
What is the term given to fingers that are completely swollen, notjust around the joints?
Dactylitis – this can’t be explained by Rheumatoid Arthritis because it is not just the joints that are inflame
Describe the appearance of extensor tenosynovitis.
There will be swelling around the extensor tendon that is inflamed
When the fingers are extended, the swelling will move showing that the inflammation is around the tendon and not the joint
Other that joints and around tendons, where else can synovium become inflamed?
Bursae --> Bursitis
What are sub-cutaneous nodules?
Central area of fibrinoid necrosis surrounded by histiocytes and a peripheral layer of connective tissue
Why are rheumatoid nodules an important clinical finding?
Patients with rheumatoid nodules are always rheumatoid factor positive
Where are rheumatoid nodules commonly seen?
Along the ulnar border
What proportion of cases of Rheumatoid Arthritis is rheumatoid factor negative?
Name another autoantibody that is very specific for Rheumatoid Arthritis.
Anti-cyclic citrullinated peptide antibody
Which enzymes are responsible for the citrullination of peptides?
Peptidyl arginine deaminases (PADs
Why do citrullinated peptide antigens develop in rheumatoid arthritis?
PADs are present in high concentrations in neutrophils and monocytes so there is increased citrullination of autologous peptides in inflamed synovium
Citrulline binds much better than arginine to the shared epitope (specific peptide sequence that is conserved in all MHC molecules that are associated with Rheumatoid Arthritis)
So Anti-CCP antibodies are more likely to develop in individuals with citrullinated autoantigens and those that have the shared epitope
State some common extra-articular manifestations of Rheumatoid Arthritis.
State some rare extra-articular manifestations of Rheumatoid Arthritis.
Lung disease (nodules, fibrosis, pleuritis)
Felty’s syndrome (triad of splenomegaly, leukopenia and rheumatoid arthritis)
What is an early radiographic abnormality in Rheumatoid Arthritis?
What are some later radiographic abnormalities in Rheumatoid Arthritis?
Joint erosion and, subsequently, joint destruction and deformity
What is the name given to the thickened, chronically inflamed synovial tissue in Rheumatoid Arthritis?
Which area of bone tends to be eroded first in Rheumatoid Arthritis?
Bare area of bone – this is within the synovial membrane but is not covered by articular cartilage (periarticular erosion)
How thick is the normal synovial membrane?
It is normally almost a single cell lining
Which cells are responsible for producing synovial fluid?
NOTE: macrophages are also found within the lining
Why is synovial fluid viscous?
It contains hyaluronic acid