Last updated on:October 19th, 2021
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Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease of the joints that is of unknown etiology; systemic involvement may also occur. Genetically susceptible individuals experience dysregulation of both innate and adaptive immunity. This results in the aberrant production of inflammatory cytokines, resulting in chronic inflammation. In addition, these persons also develop autoimmunity against the synovial lining of the joints, bursae and tendon sheath. The combined effects of the above mechanisms results in synovitis, synovial proliferation, and the destruction of cartilage and subchondral bone.
Persistent symmetric polyarthritis and joint stiffness
Patients may experience joint swelling, and stiffness for a prolonged period (>1 hour) on waking. This may involve both the small and large joints. Classically, the small joints of the hands and feet are involved in a symmetrical pattern. Some patients may initially present with involvement of a single joint that then spreads; others have multiple joints involved from the beginning.
Fever and fatigability may occur. This is due to the systemic inflammatory response driven by inflammatory cytokines (i.e., TNF-alpha, Il-1 and IL-6) Cognitive impairment and anemia may also occur. This is due to the inflammation affecting the brain, liver and bone marrow.
Risk factor: smoking
Smoking increases the risk of developing RA by contributing to the formation of citrullinated proteins. Smokers also have a more severe course of rheumatoid arthritis.
Risk factor: female gender
Females are at a higher risk of developing RA. Multiple pregnancies increase this risk further . However, the use of oral contraceptive pills and a younger age at menarche is protective.
Risk factor: genetic susceptibility
The presence of the heterozygotic allele HLA DRB1*0401/*0404 confers an increased risk of developing RA.
Risk factor: middle age
The onset of RA peaks between the ages of 40 to 50 years.
Potential systemic manifestations include: