RHEUMATOID ARTHRITIS & SEROPOSITIVE ARTHRITIDES

Rheumatoid Arthritis (RA)

•    Autoantibodies:

o    Rheumatoid Factor (RF): 70–80% sensitivity; low specificity

o    Anti-CCP: ~98% specificity; predicts erosive disease

•    Clinical features:

o    Symmetrical small joint polyarthritis: MCP, PIP, wrists

o    Morning stiffness >1 hr

o    Spares DIPs

•    Extra-articular features:

o    Rheumatoid nodules (extensor surfaces)

o    Episcleritis, scleritis

o    Interstitial lung disease (NSIP > UIP pattern)

o    Vasculitis: mononeuritis multiplex, skin ulcers

o    Felty’s syndrome: RA + splenomegaly + neutropenia

•    Investigations:

o    Bloods: RF, anti-CCP, CRP/ESR, normocytic anaemia

o    Imaging:

    X-ray hands/feet: joint space narrowing, marginal erosions, periarticular osteopenia, subluxation

    Ultrasound/MRI: detects early synovitis/erosions

•    Diagnosis: clinical + supported by 2010 ACR/EULAR classification criteria

•    Management:

o    NSAIDs: symptom relief only

o    Steroids: short-term (e.g. flares or bridging)

o    DMARDs:

    First-line: methotrexate (monitor FBC, LFTs, U&E)

    Others: sulfasalazine, hydroxychloroquine, leflunomide

o    Biologics:

    Indicated if inadequate response to ≥2 DMARDs

    Anti-TNF (e.g. etanercept, adalimumab)

    Screen for TB and hepatitis B/C before starting

•    Complications:

o    Cervical spine instability (atlantoaxial subluxation)

o    Osteoporosis (disease + steroid use)

o    Cardiovascular risk ↑

o    Amyloidosis (rare)

Palindromic Rheumatism

•    Recurrent, brief episodes of mono- or oligoarthritis (resolves spontaneously)

•    No joint damage between episodes

•    ~30–40% are anti-CCP positive

•    ~50% develop full-blown RA

•    Treatment: often NSAIDs ± hydroxychloroquine

Seronegative RA

•    Clinical picture of RA but RF and anti-CCP negative

•    May have milder disease or slower progression

•    Still classified as RA if ACR/EULAR criteria met

•    Management similar to seropositive RA