Rheumatoid arthritis primarily affects the joints but can also affect the whole body, causing what are called systemic symptoms. These systemic symptoms occur especially in people who have severe disease.

Problems associated with rheumatoid arthritis can develop in the:

• Eyes. Inflammation of the surface of the eye (scleritis) may result in dry, gritty-feeling eyes or pain in the eyes.
• Lungs. Inflammation of the membrane sac surrounding the lungs may cause pain and difficult breathing. Bumps (nodules) may also develop in lung tissue.
• Heart. Thickening and inflammation can develop in the sac around the heart (pericarditis), the heart muscle (myocarditis), and the heart valves (endocarditis). This can result in chest pain and shortness of breath.
• Blood and blood vessels. Low levels of white blood cells (leukopenia) and red blood cells (anemia) as well as spleen enlargement (an organ involved in making blood and immune cells) may occur. When these problems occur together, it is called Felty's syndrome. Inflammation can also affect the blood vessels (vasculitis), causing open sores (ulcers) of the skin.
• Nerves and muscles. There may be a loss of strength in muscles next to affected joints. Inflammation may also cause pressure on the nerves (compression). An example is compression of one of the nerves in the wrist, which affects sensation in the thumb, index, and middle fingers; this is called carpal tunnel syndrome.