Rheumatoid Arthritis Flashcards
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?
Rheumatoid nodules
What causes the extra-articular manifestations?
Rheumatoid factor produces immune complexes that can go anywhere
What type of antibody is the rheumatoid factor?
IgM autoantibody that binds to the Fc portion of IgG
IgM anti-IgG antibody
Is rheumatoid arthritis more common in males or females?
More common in females (3:1)
What is the important genetic component that predisposes to Rheumatoid Arthritis and what is it referred to ?
- a specific set of amino acids within the beta chain of the HLA- 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?
Smoking
contributes to 25% of population attributable risk
State some joints that are commonly affected in Rheumatoid Arthritis.
Metacarpophalangeal joint (MCP) Proximal interphalangeal joint (PIP) Wrists Knees Ankles Metatarsophalangeal joint (MTP)
- my poor willy knows all mothers
Name and describe three deformities that are indicative of Rheumatoid Arthritis.
- Symmetrical polyarthritis
- Swan-neck deformity
- Hyperextension of PIP
- Hyperflexion of DIP - Boutonniere deformity (button-like)
- Hyperflexion at PIP
What is the term given to fingers that are completely swollen, not just 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
e.g olecranon bursa
What are sub-cutaneous nodules and what percentage of patients have them?
Central area of fibrinoid necrosis surrounded by histiocytes and a peripheral layer of connective tissue
-occurs in 30% of patients
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?
1/3
Name another autoantibody that is very specific for Rheumatoid Arthritis.
Anti-cyclic citrullinated peptide antibody
CCP
Which enzymes are responsible for the citrullination of peptides?
Peptidyl arginine deaminases (PADs)