Clinical meaning
Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease primarily affecting the synovial joints. Autoantibodies (rheumatoid factor and anti-citrullinated peptide antibodies/anti-CCP) form immune complexes that deposit in the synovium, activating complement and recruiting inflammatory cells. CD4+ T cells, macrophages, and fibroblast-like synoviocytes proliferate, creating the pannus - a destructive inflammatory tissue that invades cartilage and subchondral bone. Pro-inflammatory cytokines (TNF-alpha, IL-1, IL-6) drive joint destruction, while RANKL-mediated osteoclast activation causes periarticular erosions. RA characteristically presents as symmetric polyarthritis of small joints (MCP, PIP, wrist, MTP) with morning stiffness > 60 minutes. Extra-articular manifestations include rheumatoid nodules, interstitial lung disease, pericarditis, vasculitis, and Felty syndrome. Early aggressive treatment following the treat-to-target strategy (targeting remission or low disease activity) prevents irreversible joint destruction.
Diagnosis & workup
Diagnostics & workup: - RF (rheumatoid factor) - present in 60-80% of RA, but non-specific - Anti-CCP antibodies - highly specific for RA (> 95%), positive early in disease - ESR and CRP for inflammatory activity assessment - CBC (normocytic anemia of chronic disease, thrombocytosis) - Hand and foot radiographs (erosions, joint space narrowing) - Ultrasound or MRI of affected joints for early synovitis detection - ACR/EULAR 2010 classification criteria (score >= 6/10)