Arthritis - Rheumatoid Arthritis

Rheumatoid Arthritis


RA is a type of inflammatory arthritisOther examples include seronegative spondyarthritides, reactive arthritis, lyme arthritis, crystal arthritis and postviral arthritis.

Features of inflammatory arthritis

  • Pain and stiffness worse in the morning and after rest
    • Early morning pain and stiffness may last several hours (in OA, duration is much shorter)
  • Inflammatory markers (ESR, CRP) usually raised
  • Often accompanied by normochromic, normocytic anaemia

Rheumatoid Arthritis

This is a chronic symmetrical arthritisWhen we say it is symmetrical, we don’t necessarily mean a mirror image, just that the same joints are affected on both sides of the body. it is also important to remember that RA is a systemic condition, with many extra-articular manifestations.
Typically it affects the peripheral joints, and there is inflammation of the joint (synovitis). Deformity is common and the course is extremely variable.

Epidemiology and Aetiology

  • affects 0.5-3% of the population worldwide
  • can present at any age (from childhood to old age), but the peak incidence is between 30-50 years
  • women affected more than men (M:F – 1:2)
    • before the menopause, risk is 3x higher for women
    • after the menopause it is equal
    • suggests sex hormones involved in some way
    • the contraceptive pill can delay the onset, but does not reduce the risk
  • Genetic factors are involved. Certain HLA variants are implicated, especially in severe forms of the disease:
    • HLA-DR4 – occurs in 50-75% of patients, and is associated with a particularly poor prognosis
    • HLA-DR1 is another variant associated with RA, and poor prognosis
  • Environmental factors:
    • Smoking
    • Stress
    • Infection

Clinical features

Most commonly, the condition will present as progressive over weeks to months. These patients have the worse prognosis. But in some cases it can come on in days, or even overnight. Also, it is almost always a polyarthritis, but some cases do present as monoarthritis, most commonly of the knee or shoulder, or with carpal tunnel syndrome.