Pathogenesis
Risk Factors for Rheumatoid Arthritis
- Female sex
- Family history of rheumatoid arthritis
- Infections - EBV, CMV, E coli, periodontal disease (Porphyromonas gingivalis)
- Smoking
Manifestations
Manifestations of Rheumatoid Arthritis
- Symmetrical inflammatory polyarthropathy with sparing of the distal interphalangeal (DIP) joints
- Rheumatoid nodules
- Tendon rupture
- Atlantoaxial instability (severe cases)
- Systemic features - fatigue, weight loss
Complications
- Ocular - sicca symptoms, scleritis, episcleritis, scleromalacia, scleromalacia perforans
- Vasculitis - pulmonary hypertension, palpable purpura, distal gangrene
- Neurologic - compressive neuropathies (e.g. carpal tunnel syndrome), mononeuritis multiplex
- Cardiovascular - pericarditis
- Respiratory - interstitial lung disease, pleurisy, lung nodules
- Haematologic - Felty's syndrome (arthritis, splenomegaly and neutropaenia)
Diagnosis
Examination
- Symmetrical arthropathy with sparing of DIP joints
Wrists
- Prominence of the ulnar styloid
- Radial deviation of the wrist
MCP, PIP and DIP Joints
- Ulnar (medial) deviation of the MCP joints
- Volar (palmar) subluxation of the MCP joints
- Swan neck deformity: hyperextension at the PIP joint with flexion at the MCP and DIP joints
- Boutonniere deformity: flexion at the PIP joints with hyperextension at the MCP and DIP joints
- Z-thumb deformity: flexion at the IP joint of the thumb with hyperextension at the MCP joint
Non-Articular Manifestations
- Evidence of compressive neuropathy - e.g. signs of carpal tunnel syndrome
- Evidence of vasculitis - palpable purpura
- Evidence of interstitial lung disease - fine fibrotic crepitations
- Splenomegaly (Felty's syndrome)
Signs of Severity
- Evidence of active synovitis
- Severe deformity
- Rheumatoid nodules (indicate seropositive disease)
X-Ray Findings
- Reduced joint space - generally symmetric
- Articular surface erosions: discontinuities in the bone plate
- Periarticular osteopaenia - hypodensity of bone surrounding the joint
- Soft tissue swelling
Management
Pearls
- Start treatment as early as possible
- Aim for sustained remission or low disease activity
- Monitor patients frequently
- Change medications if they are not working
Management Options
Non-Pharmacologic
- Smoking cessation
Pharmacologic
- Steroids (for acute flares or bridging therapy only)
- Conventional DMARDs - methotrexate, sulfasalazine, leflunomide, hydroxychloroquine
- Targetted DMARDs - JAK inhibitors
- Biologic DMARDs - TNF blockers, IL-6 blockers, CTLA4-Ig, rituximab
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