Overview
Definition
A chronic, systemic autoimmune inflammatory disorder that primarily affects the synovial lining of joints.
Epidemiology
Affects ~1% of the population. Women are affected 2-3 times more than men. Peak onset in 40s-50s.
Etiology & Risk Factors
- Autoimmune destruction of the synovium, leading to pannus formation (thickened synovial tissue) which erodes articular cartilage and bone.
- Strong association with HLA-DR4.
Clinical Symptoms
- Symmetrical, polyarticular joint pain and swelling (especially hands: MCP and PIP joints, wrist, knees, ankles)
- DIP joints are characteristically SPARED (unlike Osteoarthritis)
- Prolonged morning stiffness lasting > 1 hour, which improves with activity
- Systemic symptoms: Fatigue, low-grade fever, weight loss
- Rheumatoid nodules (firm lumps under the skin, often on elbows)
Clinical Approach
Diagnosis
- Serology: Rheumatoid Factor (sensitive but not specific) and Anti-CCP Antibodies (highly specific)
- Inflammatory Markers: Elevated ESR and CRP
- X-rays: Initially soft tissue swelling and periarticular osteopenia; later joint space narrowing and marginal bone erosions
Management
- First-line Disease Modifying Antirheumatic Drug (DMARD): Methotrexate (Start immediately to prevent irreversible joint damage)
- Biologic DMARDs (Anti-TNF like Infliximab, Adalimumab, Etanercept) if inadequate response to Methotrexate
- Symptom control / Flares: NSAIDs and short courses of Corticosteroids (e.g., Prednisone)
Complications
- Irreversible joint destruction and severe deformity (Boutonniere, Swan-neck, Ulnar deviation)
- Cervical spine instability (atlantoaxial subluxation - high risk during intubation)
- Increased cardiovascular risk