Rheumatoid Arthritis (RA)

Content of This Page

1- Definition and Key Features

2- Epidemiology and Risk Factors

3-Immunopathogenesis of RA

4- Clinical Features of RA

5– Classification Criteria (2010 ACR/EULAR)

6- Laboratory Findings

7- Laboratory Findings

8- Radiological Features

9- Disease Activity Monitoring

10- Treatment Goals and Strategy

11- Non-Pharmacological Management

12- Prognosis and Predictors of Poor Outcome

13- RA vs. Other Arthritis

14- Complications of RA

15- Felty Syndrome

Definition and Key Features

Rheumatoid arthritis (RA) is a chronic, systemic autoimmune inflammatory disorder that:

  • Primarily targets synovial joints, leading to progressive joint destruction, deformity, and disability.

  • Is characterized by symmetrical polyarthritis, especially of the small joints (PIP, MCP, wrists, MTP).

  • Often includes extra-articular manifestations involving the lungs, heart, eyes, skin, and blood.

-It is a relapsing–remitting or progressive condition, with varying severity across individuals.

Key Features of RA:

  • Chronic: Persists >6 weeks (used in diagnostic criteria)

  • Symmetric: Affects both sides of the body equally

  • Inflammatory: Prolonged morning stiffness, warm/swollen joints

  • Autoimmune: Presence of autoantibodies (RF and/or ACPA)

  • Systemic: Can involve skin, lungs, cardiovascular system, and blood

–Mnemonic: “4S” = Synovial, Symmetric, Systemic, Seropositive (often)

Epidemiology and Risk Factors

  • Affects ~1% of the population.

  • Female:male ratio ≈ 3:1.

  • Peak onset: 40–60 years.

  • Risk factors: HLA-DRB1, smoking, silica exposure, periodontal disease.

Immunopathogenesis

  • Initiation by autoreactive T cells and B cells.

  • Cytokines involved: TNF-α, IL-1, IL-6 → drive inflammation and joint damage.

  • Chronic inflammation causes synovial hyperplasia (pannus) and erosive joint destruction.

Clinical Features

Articular:

  • Symmetric small joint arthritis (PIP, MCP, wrists, MTPs).

  • Morning stiffness > 30 minutes, improves with use.

  • Progresses to joint deformities: ulnar deviation, swan neck, boutonnière.

Extra-articular (esp. if RF/ACPA+):

  • Rheumatoid nodules

  • Lung: ILD, pleural effusion

  • Heart: pericarditis, ↑ CVD

  • Eye: episcleritis, keratoconjunctivitis sicca

  • Felty syndrome: RA + splenomegaly + neutropenia

Rheumatoid nodules © image from Wikimedia Commons

Classification Criteria (2010 ACR/EULAR)

Diagnosis requires a score ≥6/10 from four domains:

  • Joint involvement

  • Serology (RF, ACPA)

  • Acute-phase reactants (CRP/ESR)

  • Duration >6 weeks

-Used for early diagnosis before radiologic changes.

Laboratory Findings

  • Rheumatoid Factor (RF): Positive in ~70% (not specific)

  • Anti-CCP (ACPA): More specific, predicts erosive disease

  • ↑ ESR/CRP, anaemia of chronic disease

  • May see leukopenia in Felty syndrome

Radiological Features

  • Early: Soft tissue swelling, juxta-articular osteopenia

  • Late: Joint space narrowing, marginal erosions (esp. MCP, PIP)

  • MRI/Ultrasound: detect early synovitis and bone edema

Disease Activity Monitoring

  • Use DAS28 (Disease Activity Score in 28 joints):

    • Includes joint count, ESR/CRP, and patient global score

    • Guides escalation or tapering of therapy

Treatment Goals and Strategy (Treat-to-Target)

Aim: Achieve remission or low disease activity

Stepwise approach:

  1. Start DMARDs early (methotrexate = gold standard)

  2. Add biologic (e.g. TNF inhibitor) if poor response

  3. Consider JAK inhibitors if unresponsive to biologics

  4. Use short-term steroids as bridge therapy

Non-Pharmacological Management

  • Exercise and joint protection

  • Smoking cessation

  • Vaccination (pneumococcus, influenza, avoid live vaccines if immunosuppressed)

  • Cardiovascular risk assessment

Prognosis and Predictors of Poor Outcome

Worse prognosis with:

  • High RF/ACPA titres

  • Early erosions on X-ray

  • Extra-articular features

  • High initial disease activity

RA vs. Other Arthritis

FeatureRAOsteoarthritisPsoriatic Arthritis
OnsetInsidiousGradualVariable
Joint patternSymmetric, small jointsAsymmetric, weight-bearingAsymmetric, DIP, spine
Morning stiffness>30 min<30 min>30 min
RF/ACPA+––
NodulesYesNoPossible (enthesitis)

Complications

  • Joint deformity and disability

  • Osteoporosis (from disease or steroids)

  • Cardiovascular disease

  • Amyloidosis

  • Infection risk (immunosuppressants)

© image from Wikimedia Commons

Felty Syndrome

  • Triad: RA + splenomegaly + neutropenia

  • ↑ Risk of infections

  • Associated with seropositive, long-standing RA

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