What is the pathology of rheumatoid arthritis?

Answer 1

Rheumatoid Arthritis, is a chronic, often progressive disease where inflammatory changes occur connective tissues of the body. Inflammation and the resultant thickening of the synovial membranes (the sacs holding the fluid that lubricates the joints) cause irreversible damage to the joint capsule and the articular (joint) cartilage as these structures are replaced by scar like tissue called pannus. RA (Rheumatoid arthritis) is about three times as common in women as in men and afflicts about 1 percent of the adult population in developed coutrys, It primarily affects the middle-aged. (Children may also be affected by a similar disorder known as juvenile rheumatoid arthritis.)

Usually rheumatoid arthritis begins by affecting joints of the hands and feet symmetrically then progressing to the wrists, knees, or shoulders; the onset of the disorder is gradual. Pain and stiffness in one or more small joints are usually followed by swelling and heat, accompanied by muscle pain that may last for weeks or months, and may subside suddenly. Joint pain is not always proportionate to the amount of swelling and warmth generated. Fatigue, weakness, and loss of weight are common symptoms. Often, before prominent signs appear, the affected person may complain of coldness of hands and feet, numbness, and tingling, all of which suggest compression of the vasomotor nerve.

Active inflammation is first seen in the synovial membranes of the joints, which become red and swollen. Later, a layer of roughened granulation tissue, or pannus, protrudes over the surface of the cartilage. Under the pannus the cartilage is eroded and destroyed. The joints sease in place or (ankylosed) by thick and hardened pannus. This also may cause displacement and deformity of the joints. The skin, bones, and muscles adjacent to the joints atrophy from disuse and destruction. Painful nodules over bony prominences may persist or regress. Complex collections of cells surrounded by lymphocytes in the connective tissue of muscle and nerve bundles cause pressure which leads to pain, the nodular lesions may invade the connective tissue of the blood vessel walls.

People that have RA often have characteristic autoantibodies in their blood, one of the pieces of evidence implicating an autoimmune mechanism in the disease process. An autoimmune reaction is an immune reaction against the body's own tissues, and an autoantibody is an antibody that attacks parts of the body These called rheumatoid factor. It is not known what causes the autoimmune reaction, but there is evidence that persons afflicted with the disease have a genetic susceptibility to an environmental agent such as a virus. Once activated by such an agent, a series of immune system reactions causes inflammation.