Final answer:
Rheumatoid arthritis is a chronic inflammatory joint disease with an unclear etiology involving genetic and environmental factors, leading to joint inflammation, pain, and systemic involvement. It commonly manifests in the synovial joints of the hands, feet, and cervical spine, and genetics can increase susceptibility to RA.
Step-by-step explanation:
The primary etiological factor of rheumatoid arthritis (RA) is not fully understood, as it involves a complex interplay between genetic and environmental factors. RA is a chronic inflammatory joint disease characterized by type III hypersensitivity reactions and the activation of CD4 T cells. This immunological activity leads to the chronic release of inflammatory cytokines such as IL-1, IL-6, and TNF-α, stimulating the production of RF antibodies and anti-CCP that form immune complexes and fuel an inflammatory process in joints, frequently starting in the hands, feet, and legs.
Common manifestations of rheumatoid arthritis include joint swelling, stiffness, and pain, particularly affecting the synovial joints of the hands and feet initially. However, RA is not commonly associated with lung fibrosis, vasculitis, coronary heart disease, and premature mortality. Genetics can contribute to the development of RA through an X-linked factor, making some individuals more susceptible to developing the disease.