rheumatoid arthritis Flashcards
What is the definition of rheumatoid arthritis?
Rheumatoid arthritis is a chronic autoimmune inflammatory disease which affecting mainly the peripheral joints in a symmetrical fashion and if untreated can cause joint destruction and irreversible deformity
What sex is rheumatoid arthritis more common is?
Rheumatoid arthritis is 3x more common in woman
What HLA molecules mediate rheumatoid arthritis?
Rheumatoid arthritis is mediated by HLA-DR4 and HLA-DR1
What are thought to be causative factors in rheumatoid arthritis?
Causative factors are thought to be smoking, stress and infections
What is the main structure involved in rheumatoid arthritis?
The main structure involved in rheumatoid arthritis is the synovium, which is also known as the synovial membrane which is responsible for producing synovial fluid
The classical sign is synovitis
What is the pathophysiology of rheumatoid arthritis?
Rheumatoid arthritis occurs when an unknown antigen is presented to T cells, the T cells activate B cells which produce rheumatoid factor and IL-1 and also activate macrophages which produce IL-1, IL-6 and TNF- alpha, these cytokines then activate fibroblast like synoviocytes which increase osteoclastic activity causing erosion of bone and produce protests which destroy chondrocytes
What is the classic inflammatory condition which occurs in rheumatoid arthritis?
The classic inflammatory structure seen in rheumatoid arthritis is a pannus which invades the synovium and covers the articular cartilage
What joints are affected in rheumatoid arthritis?
Rheumatoid arthritis causes painful symmetrical inflammation of the proximal interphalyngeal joints and the metacarpohalyngeal joints
What joints does rheumatoid arthritis never affect?
Rheumatoid arthritis never affects the distal interphalyngeal joints
What other joints can also affected in rheumatoid arthritis?
Other joints affected in rheumatoid arthritis are the wrist, elbow, schouder, TMJ, hip, knee, ankle foot, and C1 and C2
What rare joint but most important joints which can be affected in rheumatoid arthritis?
the atlas and axis (C1 and C2) are covered in synovium so they can be involved and it can cause atlanto-axial subluxation which can cause spinal cord compression and result inquadraplegia
deformities in rheumatoid arthritis
- swan neck deformity: hyperextension of the PIP joints and flexion of the DIP joints
- boutonnieres deformity: flexion at the PIP joints and extension at the DIP joints
- ulnar deviation due to involvement of the MCP joints
- z shaped thumb deformity: fixed flexion and subluxation of the metacarpohalyngeal joint and hyperextension of the intevrphalyngeal joint
other symptoms of rheumatoid arthritis
- early morning stiffness which lasts longer than 30 minutes
- rheumatoid nodules in chronic RA which is not well managed
- sjogrens syndrome: ketaoconjuncitivitis sicca and xeroderma
- episcleritis, scleritis and uveitis
- fibrosing alveolitis, pleurisy and pleural effusion
- bilateral carpal tunnel syndrome
- osteoporosis
investigations
- ANA, rheumatoid factor and anti-CCP
- X-rays may not show anything in early disease so ultrasound and MRI better initially
- raised ESR, CRP and PV
- FBCS show anaemia of chronic disease
x-ray findings in rheumatoid arthritis seen later in disease
Joint space loss
Erosion of joint
Synovial thickening
Subluxation and deformity
what is the best antibody for diagnosis of rheumatoid arthritis
ANTI-CCP because it is the most specific but is still not 100% sensitive this means that if you have anti-CCP you most likely have rheumatoid but if not it doesn’t definitely rule it out
Diagnostic criteria
6 points of more= definitive RA A: number of joints affected B: rheumatoid factor or anti-CCP C: elevated ESR and CRP D: onset for more than 6 weeks
what scoring system is used to assess activity of disease when it has already been diagnosed
DAS 28 which takes into account the number of joints affected, ESR and CRP and the patients global health (i.e. their perspective on how active it is)
important values in DAS28 scoring system
- 5.1 or above indicates active disease
- score of 2.6 or less indicates remission and is what you would aim to achieve
management
- methotrexate+ NSAIDS+ paracetamol+ sulfasalazine or azathioprine
- add in hydroxochloroquine
- move onto biological agent, TNF- alpha inhibitors such as infliximab adalilumb or entercept
what should be used initially with methotrexate to induce remission
steroids as methotrexate takes around 8 weeks to work but they should never be us as a mono-therapy
what should always be prescribed with methotrexate
folic acid as methotrexate is a folic acid antagonist
issues with methotrexate
- methotrexate can cause a pneumonitis reaction and cause liver cirrhosis
- methotrexate is also teratogenic so if someone wants to get pregnant they must be off methotrexate for 3 months prior to conception during this time they use sulfasalazine or biologic agent
- methotrexate is also an immunosupressant so as well as LFTS white cell count must also be regular monitored
issues with steroids
can cause osteoporosis, glaucoma, diabetes, worsening of heart failure, weight gain, adrenal suppression resulting in cushing syndrome, immunosuppression
issues with biological agents
if someone has TB they will reactivate latent TB so before anyone gets a biological agent they must be screened for tb and if they have it they must be treated for TB first
criteria for prescribing a biological agent
person must have tried at least 2 DMARDS for a minimum of 6 month and DAS28 must be 5.1 or more on 2 occasions at least 4 weeks apart
when should you avoid sulfasalazine
in septrin allergy (co-trimoxazole) and G6PD deficiency
what is always used with biological agents
methotrexate
