ESSENTIALS OF DIAGNOSIS
Usually insidious onset with morning stiffness and joint pain.
Symmetric polyarthritis with predilection for small joints of the hands and feet; deformities common with progressive disease.
Radiographic findings: juxta-articular osteoporosis, joint erosions, and joint space narrowing.
Rheumatoid factor and antibodies to cyclic citrullinated peptides (anti-CCP) are present in 70–80%.
Extra-articular manifestations: subcutaneous nodules, interstitial lung disease, pleural effusion, pericarditis, splenomegaly with leukopenia, and vasculitis.
Rheumatoid arthritis is a chronic systemic inflammatory disease whose major manifestation is synovitis of multiple joints. It has a prevalence of 1% and is more common in women than men (female:male ratio of 3:1). Rheumatoid arthritis can begin at any age, but the peak onset is in the fourth or fifth decade for women and the sixth to eighth decades for men. The cause is not known. Susceptibility to rheumatoid arthritis is genetically determined with multiple genes contributing. Inheritance of HLA-DRB1 alleles encoding a distinctive five-amino-acid sequence known as the “shared epitope” is the best characterized genetic risk factor. Untreated, rheumatoid arthritis causes joint destruction with consequent disability and shortens life expectancy. Early, aggressive treatment is the standard of care.
The pathologic findings in the joint include chronic synovitis with formation of a pannus, which erodes cartilage, bone, ligaments, and tendons (eFigure 20–7). Effusion and other manifestations of inflammation are common. In the late stage, organization may result in fibrous ankylosis; true bony ankylosis is rare.
Synovitis bilaterally at multiple metacarpal phalangeal joints in a patient with rheumatoid arthritis. (Used, with permission, from Nicole Richman, MD.)
The clinical manifestations of rheumatoid disease are highly variable, but joint symptoms usually predominate. Although acute presentations may occur, the onset of articular signs of inflammation is usually insidious, with prodromal symptoms of vague periarticular pain or stiffness. Symmetric swelling of multiple joints with tenderness and pain is characteristic. Monarticular disease is occasionally seen initially. Stiffness persisting for longer than 30 minutes (and usually many hours) is prominent in the morning. Stiffness may recur after daytime inactivity and be much more severe after strenuous activity. Although any diarthrodial joint may be affected, PIP joints of the fingers, MCP joints (Figure 20–3), wrists, knees, ankles, and MTP joints are most often involved. Synovial cysts and rupture of tendons may occur. Entrapment syndromes are common—particularly of the median nerve at the carpal tunnel of the wrist. Rheumatoid arthritis can affect the neck but spares the other components of the spine and does not involve the sacroiliac joints. In advanced disease, atlantoaxial (C1–C2) subluxation can lead to myelopathy.
Rheumatoid arthritis with ulnar deviation at the metacarpophalangeal (MCP) joints. (Used, with permission, from Richard P. Usatine, MD.)