Rheumatoid Arthritis Flashcards
What is inflammatory arthritis?
Clearly defined group of conditions where there is tendon or joint inflammation and abnormal blood results and x-rays, rapidly destructive if untreated
How does rheumatoid arthritis present?
Pain and stiffness in small joints (usually hands and feet), reduction in grip strength, rapid onset, swelling of affected joints, usually symmetrical
Who gets rheumatoid arthritis?
Affects women three times more commonly than men, can affect any age group, UK prevalence is about 1%
What are potential triggers of rheumatoid arthritis?
Infections and cigarette smoking
What determines the severity and course of rheumatoid arthritis?
Genetic factors and presence of antibodies
What is the main structure involved in rheumatoid arthritis?
The synovium
What is the synovium?
Lines synovial joint capsules and tendon sheaths, makes direct contact with the synovial fluid
What do susceptibility genes cause?
Conversion of arginine into citrulline = causes protein unfolding due to loss of positive charge
What acts as an antigen in rheumatoid arthritis?
Unfolded protein
What recognises citrullinated proteins?
Anti-citrullinated peptide antibodies (anti-CCP)
What do anti-CCP antibodies do?
Distributed through circulation and form immune complexes with citrullinated proteins produced in the inflamed synovium
What are the immune complexes formed between anti-CCP antibodies and citrullinated proteins associated with?
Infiltration and activation of neutrophils
What are the categories in the 2010 ACR/EULAR classification criteria for rheumatoid arthritis?
Joint distribution, serology, symptom duration, acute phase reactants
What score on the 2010 ACR/EULAR classification criteria indicates definite rheumatoid arthritis?
> =6
What inflammatory markers should be measured in rheumatoid arthritis?
CRP, ESR/PV
What are the clinical features of rheumatoid arthritis?
Prolonged morning stiffness (> 30mins)
Involvement of small joints of hands and feet (PIP, MCP, MTP)
Symmetrical
Positive compression tests of MCP and MTP joints
Synovitis = warm, soft joints
What antibodies can be measured to investigate rheumatoid arthritis?
Rheumatoid factor, anti-CCP antibodies
What are some features of rheumatoid factor as a diagnostic test?
Sensitivity 50-80%, specificity 70-80%, not very useful
What is the sensitivity and specificity of anti-CCP antibodies?
Sensitivity = 60-70% Specificity = 90-99%
What are some features of anti-CCP antibodies?
Can be present several years prior to articular symptoms, correlates with disease activity, remains positive despite treatment
What are some associations of anti-CCP antibodies?
More likely to be associated with erosive damage, linked to current or previous smoking history
Can rheumatoid arthritis occur in the absence of anti-CCP antibodies?
Yes = seronegative rheumatoid arthritis
What are some features of rheumatoid arthritis x-rays?
Early disease = normal, soft tissue swelling, periarticular osteopenia
Late disease = erosions, subluxation
What are some features ultrasound scans of rheumatoid arthritis?
Increased sensitivity for synovitis in early disease
Consistently superior to clinical examination
Can detect more MCP erosions than plain x-ray in early disease
Useful in making treatment changes
