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Rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic systemic inflammatory disease which affects many organs, but predominantly attacks the synovial tissues and joints.

Epidemiology

RA has an overall prevalence of 0.5-1%.  There is a female predominance, with the disease being 2-3 times more common in women1.

Onset is generally in adulthood, peaking in the 4th and 5th decades. The paediatric condition, juvenile rheumatoid arthritis, will be discussed separately.

Clinical presentation

Onset may be insidious or abrupt, and the early features commonly include tiredness, malaise and generalised aches. Usually arthritic symptoms first develop in the hands and wrists in a characteristic symmetric , proximal distribution. Feet and large joints may also be involved.

Pathology

Pathogenesis

Aetiology is unknown, and probably multifactorial. It is generally considered that a genetic predisposition (HLA DR4) and an environmental trigger lead to an autoimmune response that is directed primarily against synovial structures.

The inflammatory response leads to synovial hyperplasia, pannus formation and destruction of cartilage and subchondral bone 2,3.

Diagnostic criteria

Diagnosis is based on a combination of clinical, radiographic and serological criteria. The American College of Rheumatology revised criteria require that 4 out of 7 of the following are present 4:

  • morning stiffness lasting at least 1 hour before maximal improvement
  • soft tissue swelling of 3 or more joints observed by a physician
  • swelling of the proximal interphalangeal, metacarpophalangeal, or wrist joints
  • symmetric swelling
  • rheumatoid nodules
  • the presence of rheumatoid factor; and
  • radiographic erosions and/or periarticular osteopenia in hand and/or wrist joints.
Non-musculoskeletal features of RA tend to occur late in the disease and include:
  • pulmonary involvement
  • cardiovascular disease
    • accelerated coronary artery and cerebrovascular atherosclerosis which contribute significantly to the excess mortality of RA
    • pericarditis
    • vasculitis : occurs more commonly with severe erosive disease, rheumatoid nodules, high RF titres.
  • cutaneous involvement
    • rheumatoid nodules are usually seen in pressure areas : elbows, occiput, lumbosacral3. They generally occur in RF positive patients 9.
Diagnostic tests

There are several serological markers for rheumatoid arthritis -

  • Rheumatoid Factor (RF) : RF is a traditional marker, rather nonspecific. It is associated with several autoimmune and chronic infectious diseases.
  • Anti-cyclic citrulinated peptide (anti-CCP): It is more than 80% sensitive and more than 95% specific11.
  • Elevated ESR or C-reactive protein.
Associations

Radiographic features

Musculoskeletal

Musculoskeletal manifestations are generally the earliest and the dominant features of rheumatoid arthritis.

For further details, please refer to : musculoskeletal manifestations of rheumatoid arthritis

Respiratory

Please refer to the article : respiratory manifestations of rheumatoid arthritis

Abdominal

Splenomegaly may be seen as part of Felty syndrome, usually in longstanding RA.

Treatment and prognosis

Treatment of RA is aimed at improving the symptoms and slowing disease progression.  Therapy is with a combination of corticosteroids, NSAIDs, DMARDs (Disease Modifying Anti-Rheumatic Drugs) and TNF antagonists.  The anti-TNF treatments and variants of, which supress the immune system, are known collectively as biological therapies.

The disease carries a significant burden of disability. There is also a reduction in life expectancy, with excess mortality usually related to its non-articular manifestations 5,6.

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