Rheumatoid Arthritis Flashcards
what is RA
autoimmune condition that causes chronic inflammation in the synovial lining of the joints, tendon sheaths and bursa
what does RA tend to affect
multiple small joint symetrically across both sides of the body - symmetrical polyarthritis
what are risk factors of RA
F>M
smoking
obesity
FHx
what is the most common gene associated with RA
HLA-DR4
What antibodies are associated with RA
- Fc portion of IgG (RF)
- anti citrullinated cyclic peptide (anti-CCP)
What is the pathophysiology of RA
- citrullination of self antigens which are then recognised by T&B cells that produce antibodies (RF and anti-CCP)
- stimulated macrophages and fibroblasts release TNFa
- inflamm cascade —> proliferation of synoviocytes which results in the typical ‘boggy’ joint swelling
- these grow over the cartilage and lead to restriction of nutrients and cartilage is damaged
- activated macrophages stimulate osteoclast differentiation contributing to bone damage
What are features of a typical history of RA
- hx > 6 weeks
- morning stiffness > 30 mins
- commonly c/o fatigue or malaise
What may be present O/E in RA
- soft tissue swelling and tenderness first
- Z-shaped deformity to the thumb
- ulnar deviation/palmar subluxation of MCPs
- swan-neck & Boutonnière deformity
- rheumatoid nodules on elbow
- check median nerve - carpal tunnel association
Give 5 relevant investigations into RA and state their findings
- RF & anti-CCP antibodies
- FBC - normocytic anemia
- WCC if concerned re septic arthritis
- inflamm markers e.g. CRP, ESR
- X-ray changes apparent in established but need USS/MRI for early disease
- USS!!
What are 5 treatment options for RA
- initially DMARD monotherapy e.g. methotrexate but consider combo DMARDs
- steroids acutely - PO/IM or intra-articular
- symptom control w NSAIDs + PPI cover if no contraindications
- if diseases persists, consider biologics e.g. anti-TNF
- non drug: OT/PT, podiatry, psychological
What type of patients do extra-articular manifestations of RA normally present in
RF + patients with severe articular disease
What are extra-articular manifestations of RA
- 3Cs – Carpal tunnel syndrome, elevated Cardiac risk (CVD), Cord compression (due to atlanto- axial subluxation)
- 3As – Anaemia (normochromic & normocytic), Amyloidosis (very rare now due to improved treatment, can cause nephrotic syndrome and CKD), Arteritis (rare now due to improved treatment, can cause nail fold infarcts, cutaneous vasculitis & mononeuritis multiplex)
- 3Ps – Pericarditis (uncommon), Pleural disease (common), Pulmonary disease (common) e.g. bronchiectasis, bronchiolitis obliterans, fibrosis
- 3Ss – Sjögren’s (common), Scleritis/episcleritis (uncommon), Splenic enlargement (together with neutropaenia = Felty’s syndrome, rare)
what are the distinguishing features of inflammatory vs mechanical disease
What might polarised light microscopy reveal in gout and pseudo-gout
- gout: negatively birefringent needle shaped crystals
- pseudo-gout: positively birefringement rhomboid shaped crystals
What are the adverse effects of methotrexate (5)
- nausea most common
- oral ulcers, hair thinning
- hepatitis, cirrhosis
- pneumonitis
- bone marrow suppression
What are the adverse effects of hydroxychloroquine
- GI disturbance most common
- retinal pigmentation and loss of vision which is rare but screening needed
- no blood tests required
What are the adverse effects of sulfasalazine
- GI upset
- rash
- hepatitis
- bone marrow suppression
What are the adverse effects of azathioprine
- GI upset most common
- bone marrow suppression
What are the adverse effects of cyclophosphamide (3)
- bone marrow suppression
- infertility
- inc risk of cancer
What are the adverse effects of ciclosporin (2)
- renal impairment
- HTN
What are the adverse effects of leflunomide
- GI upset
- HTN
- bone marrow suppression
- hepatitis
what are the 3 joint symptoms of RA
- pain
- stiffness
- swelling
what are the most commonly affected joints in RA
- MCPJ
- PIPJ
- wrist
- MTPJ
- also ankle, knee, hips, shoulders, cervical spine not lumbar
what might the joints feel like on palpation in RA
- tenderness and synovial thickening
- ‘boggy’ feeling
what are associated systemic symptoms of RA
- fatigue
- weight loss
- flu-like illness
- muscle aches and weakness
how can disease activity of RA be monitored
- HAQ measures functional ability and the response to treatment
- DAS28 involves assessing 28 joints and assigning points for: swollen joints, tender joints, ESR/CRP result
in women experiencing a symptom flare for RA during pregnancy, which drugs would be offered and which wouldn’t
- hydroxychloroquine and sulfasalazine (+ extra folic acid)
- methotrexate and leflunomide are teratogenic!
what is the function of TNF
cytokine involved in stimulating inflammation
what are the 4 main biologics to remember for treating RA
- adalimumab
- infliximab
- etanercept (above 3 are TNF-inhibitors)
- rituximab (monoclonal antibody that targets CD20 proteins on the surface of B cells)
what are the risks of monoclonal antibodies
- cause immunosuppression
- increasing risk of infection
- risk of certain cancers e.g. skin
- reactivation of latent TB
how does leflunomide work
immunosuppresant which interferes w the production of pyrimidine (important component of RNA/DNA synthesis)
how does hydroxychloroquine work
suppresses immune system by interfering w TLR
- disrupts antigen presentation
- increases the pH in lysosomes of immune cells
how can RF be detected (2)
- Rose-Waaler test: sheep red cell agglutination
- latex agglutination tests (less specific)
give 3 examples of other conditions associated with a positive RF
- Felty’s syndrome
- Sjogren’s
- infective endocarditis
