Rheumatoid arthritis is a systemic autoimmune disease that causes inflammation of the joints. It is characterized by symmetric inflammation of small joints of the hands and feet that can lead to joint damage and deformity over time if left untreated. Treatment involves medications to reduce inflammation and prevent further joint damage, including DMARDs such as methotrexate and biologic therapies that target cytokines like TNF-alpha. The goal of treatment is to control symptoms, prevent further joint damage, and maximize function.