Rheumatoid arthiritis Flashcards
What is RA
Rheumatoid arthritis is an autoimmune condition that causes chronic inflammation of the synovial lining of the joints, tendon sheaths and bursa.
What type of arthritis is RA
Inflammatory
Synovial inflammation is called synovitis
Is RA symmetrical or unsymmetrical
SYMMETRICAL
RA epidemiology
1% population
2-3x more common in females
Main risks – family history and smoking
Middle age (but any age can be affected)
is RA more common in men or women
WOMEN
Genetic associations of RA
HLA DR4 (a gene often present in RF positive patients)
HLA DR1 (a gene occasionally present in RA patients)
Whats joints are involved in RA
- Symmetrical small joints, hands, wrists, feet
- Big joints involved later, bad prognostic sign if involved at presentation
- No spinal involvement
Pathophysiology of RA
-Rheumatoid factor is an autoantibody
-Targets the fc portion of of the IgG antibody
-Causes activation of the immune system against the patients own Igg
-Causes systemic inflammation
What is the role of T cells once activated
-T cells secrete cytokines (e.g. Interferon-gamma and IL-17) to recruit macrophages.
What is the role of macrophages once activated
Macrophages also produce cytokines (TNF, IL-1 and IL-6) which causes synovial cells to proliferate.
After proliferation what occurs
-This creates a pannus (thick synovial membrane made of fibroblasts, myofibroblasts and inflammatory cells).
- This can damage the cartilage, soft tissue and bones.
Inflammatory cytokines also cause T-cells to express RANKL which can bind to osteoclasts, causing breakdown of bone
Role of ANTI- CCP
targets cirtrullinated proteins. This forms an immune complex which can accumulate and activate complement system, promoting joint inflammation and injury.
Signs of RA
-Symmetrical polyarthritis
- Pain
-Swelling
-Stiffness
Is pain from inflammatory arthritis better or worse after activity
Worse after rest but improves with activity
What hand deformities would be present with RA
- Ulnar deviation
-Swan Neck
-Boutonniere deformity
Clinical presentation of RA
- Pain and Swelling of joints
- Typically small joints hands, wrists, forefeet
- Early morning stiffness (often prolonged)
- Sudden change in function
Physical examination for RA
Decreased grip strength / fist formation
Often subtle synovitis – MCPs, PIPs, MTPs, ankles
DIPs are spared
Usually symmetrical
Primary investigations of RA
ESR and CRP = raised markers of inflammation
RF- in 70% of patients
Anti- CCP- Present in 80% of patients
X-ray of RA
- Soft tissue swelling
- Periarticular osteopenia
- Joint space narrowing
how would synovitis be found
US scan of the joints
When would referral be useful
NICE recommend referral for any adult with persistent synovitis, even if they have negative rheumatoid factor, anti-CCP antibodies and inflammatory markers.
Management of RA
Primary care:
- NSAID : low dose NSAID cover the period between symptom onset and rheumatology referral
Secondary care management of RA
1st line - disease modifying anti- rheumatic drug DMARD
Methotrexate 10-25mg per week
Monitoring methotrexate
Monthly:
- Measure CRP
- Disease activity - using a composite score such as DAS-28. DAS-28 takes into account the overall health of the patient, the number of swollen joints, and the ESR count.
Annually:
- Assess disease activity e.g. DAS-28 score
- Measure impact on life and functional ability e.g. health assessment questionnaire (HAQ)
- Check for comorbidities and complications
- Assess need for surgery
