Rheumatoid arthritis (RA) is an autoimmune disease that causes the immune system to attack the joints causing chronic inflammation of synovial tissue which causes pain, inflammation, stiffness and joint damage. RA is symmetrical meaning if one knee or hand has rheumatoid arthritis, usually the other does too. This disease often occurs in more than one joint and can affect any joint in the body. People with RA may feel sick, tired, and sometimes present with mild fevers.
The exact cause of RA is unknown; however, researchers are continuously learning more about the causes of RA. Things that may cause RA are attributed to genes, the environment (smoking, pulmonary disease, infection, obesity), and/or hormones.
Some people have mild or moderate forms of the disease which causes symptoms to get worse or better at different times. Others have a severe form of the disease that can last for many years or a lifetime, eventually causing joint damage.
Over 1 million adults in the US have RA. Anyone can get this disease, though it occurs more often in women. RA develops rapidly and is more prevalent in adults 55-74 years old, but children and young adults can also acquire it.