Rheumatoid Arthritis: Commonly Affected Joints and Systemic Manifestations

Rheumatoid arthritis (RA) is a symmetric, inflammatory polyarthritis primarily targeting synovial joints.

Typical Joint Involvement (Symmetrical, Small → Large)

• Hands: MCP, PIP (spares DIP), wrists — early, characteristic.
• Feet: MTP, ankles, subtalar.
• Large joints: Knees, elbows, shoulders, hips (later).
• Cervical spine: C1–C2 (atlantoaxial) subluxation risk.
• TMJ: Pain, limited opening.

Extra-Articular Manifestations

• Eyes: Scleritis, episcleritis, keratoconjunctivitis sicca (Sjögren’s overlap).
• Skin: Rheumatoid nodules (olecranon, forearm), vasculitis (ulcers, purpura), palmar erythema.
• Lungs: Interstitial lung disease (UIP/NSIP), pleural effusions, nodules, airway disease.
• Heart: Pericarditis, myocarditis, accelerated atherosclerosis, conduction defects.
• Vascular: Vasculitis (rare), increased CVD risk.
• Hematologic: Felty’s syndrome (neutropenia, splenomegaly).
• Neurologic: Compression neuropathies (carpal tunnel), cervical myelopathy.

Diagnosis and Monitoring

• 2010 ACR/EULAR criteria: Joint involvement, serology (RF, anti-CCP), acute-phase reactants (CRP, ESR), symptom duration.
• DAS28, CDAI for disease activity; radiographs/US/MRI for erosion.

Early DMARD initiation (methotrexate ± biologics/JAK inhibitors) prevents joint damage and systemic complications.