Arthritis, Rheumatoid

Key Features

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

  • Joint space narrowing

• Rheumatoid factor and antibodies to cyclic citrullinated peptides (anti-CCP) are present in 70–80% (Table 20–7)

• Extra-articular manifestations

General Considerations

• Cause is unknown

• Multiple genes contribute to susceptibility; best characterized genetic risk factor is inheritance of HLA DRB1 alleles encoding a distinctive five-amino-acid sequence known as the "shared epitope"

• The pathologic findings in the joint include

  • Chronic synovitis with formation of a pannus, which erodes cartilage, bone, ligaments, and tendons

  • Effusion and other manifestations of inflammation are common

  • In the late stage, organization may result in fibrous ankylosis; true bony ankylosis is rare

Demographics

• Prevalence is 1%

• More common in women than men (female:male ratio of 3:1)

• 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

Clinical Findings

Symptoms and Signs

• Joint symptoms

  • 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

  • Monarticular disease is occasionally seen initially

  • Stiffness

    • Prominent in the morning

    • Persists for > 30 minutes (and usually many hours)

    • May recur after daytime inactivity and be much more severe after strenuous activity

  • Distribution of affected joints

    • PIP joints of the fingers, MCP joints, wrists, knees, ankles, and MTP joints are most often involved

    • However, any diarthrodial joint may be affected

  • Synovial cysts and rupture of tendons may occur

  • Entrapment syndromes are common, particularly of the median ...