Rheumatoid Arthritis Flashcards
Define rheumatoid arthritis?
An autoimmune disease causing a symmetrical, small joint, inflammatory polyarthritis
What are the 5 signs of inflammation?
Dolor Rubor Calor Tumour Loss of function
Which specific small joints does RA typically affect?
Metacarpophalangeal joints and proximal interphalangeal joints
What hand deformities does RA typically cause?
Ulnar deviation Muscle wasting Z-thumb Swan neck deformity Boutonnière deformity
How can RA present outside of the joints?
Stroke Scleritis Ischaemic heart disease Serositis Nodules Peripheral neuropathy Lymphoma Amyloidosis Anaemia Pulmonary fibrosis Myelopathy
Describe the epidemiology of RA.
Around 1% prevalence in the UK
Most common in the 60s/70s - but can present at any age
Mostly occurs in women (2:3)
What causes RA?
Genetics - HLA DR4 serotypes - 15% twin concordance Modifiable risk factors - omega 3 rich diet reduces risk - smoking - infection
Describe the pathophysiology of RA
Proliferation of the synovium is caused when the immune response localises in synovial tissue
- this causes excessive synovial fluid and swelling of the joints
- influx of immune cells (B cells, T cells, macrophages and antigen-antibody complexes). The body produces an RF antibody against it;s own antibody IgG
- oxygen radicals, arachidonic acid radicals and lysosomes begin to destroy the synovial tissue
- large amount of synovial fluid and hyperplastic synovium impinge onto the bone area (makes bone ill-defined on X-Ray) - pannus
- the pannus can erode and destroy articular cartilage, resulting in bone erosion, none cysts and fissures
What are the differential diagnoses of a patient presenting with a new inflammatory arthritis?
Rheumatoid arthritis
Seronegative spondylitis-athritides (psoriatic arthritis, ankylosis spondylitis, reactive arthritis and enteropathic arthritis)
- no antibodies are present
- usually have a different pattern of joint involvement from RA
Connective tissue disease (lupus, systemic sclerosis, mixed CTD)
- systemic symptoms
- ANA presence
Crystal arthritis (gout, pseudogout)
- patient has risk factors of gout
- usually only affects one joint at a time
Osteoarthritis
- non-inflammatory, bony swelling (not a boggy swelling like in RA)
What blood tests can be done to test for RA, and explain the results.
Erythrocyte sedimentation rate (ESR) mm/hr
- plasma proteins that are produced in response to infection reduce the charge on RBCs, causing them to fall more quickly
- non specific
C-reactive protein (CRP)
- Pentamer protein produced by the liver during an acute phase response
- more specific than ESR
Rheumatoid factor
- IgM directed against Fc component of other antibodies
- positive in 70% of RA patients
- associated with worse prognosis and extra-articular features
Anti-CCP antibodies
- 98% specific for RA
- risk of over diagnosis if the person doesn’t even have symptoms yet
List the treatments available for RA.
Analgesia - NSAIDs Corticosteroids DMARDS Biologic therapies The multi-disciplinary team
What are the possible side effects of NSAID use?
Gastritis and ulceration Renal failure Asthma (sometimes) Fluid retention - ankle swelling Cardiovascular disease LFTs
What are the benefits of steroid use for RA treatment?
Anti-inflammatory action
Rapid acting
Disease-modifying
What are the cons of steroid use for RA treatment?
Gastritis and ulceration Infection risk - immunosuppressive Diabetes and metabolic syndromes CVD risk - increased blood pressure Bruising and thin skin Osteoporosis Cataracts
How are steroids administered in RA?
IM depot
- easy and effective
- 48 hours to kick in
- requires a smaller dose than oral administration
Oral - not often done because it is hard to wean the patients off
Intra-articular - effective but tricky
