Rheumatoid Arthritis, or RA, is an autoimmune and inflammatory disease, which means that your immune system attacks healthy cells in your body by mistake, causing inflammation (painful swelling) in the affected parts of the body.
 
RA mainly attacks the joints, usually many joints at once. RA commonly affects joints in the hands, wrists, and knees. In a joint with RA, the lining of the joint becomes inflamed, causing damage to joint tissue. This tissue damage can cause long-lasting or chronic pain, unsteadiness (lack of balance), and deformity (misshapenness).
 
RA can also affect other tissues throughout the body and cause problems in organs such as the lungs, heart, and eyes.
 
Signs and symptoms of RA include:
 
Pain or aching in more than one joint
Stiffness in more than one joint
Tenderness and swelling in more than one joint
The same symptoms on both sides of the body (such as in both hands or both knees)
Weight loss
Fever
Fatigue or tiredness
Weakness