Rheumatoid arthritis is an autoimmune disease where the joints (usually hands and feet joints) are symmetrically inflamed resulting in swelling, pain, and often eventually cause damage to the inside of joints. The exact cause is unknown, but various factors, including genetic predisposition, may affect autoimmune reactions.
Rheumatoid arthritis can appear suddenly, where at the same time many joints become inflamed. Inflammation is usually symmetrical, if a joint on the left side of the body is affected, then the same joint on the right side of the body will also be affected.
You can know more about rheumatoid arthritis and related diseases by reading these references:
