Rheumatoid arthritis not only affects the joints, but can have a great impact on other parts of the body like the heart, blood vessels, eyes and muscles. Inflammation plays a major role in rheumatoid arthritis. With rheumatoid arthritis, the immune system, which normally defends the body, turns against certain body parts. The joints are most commonly targeted. With inflammation, there is a brief vasoconstriction of the blood vessels in the injured or arthritic area.
Vasodilation then occurs, followed by a release of enzymes that cause cell necrosis.
Histamine is released from these injured cells. The histamine is a potent vasodilator that increases blood flow to the area. This causes redness and increased temperature in the affected area. The inflammatory process starts in the synovium, the thin membrane that lines the joint. This area becomes very thick and eventually invades cartilage and even the bone.