Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Rheumatoid Arthritis ?
    ### Response:
    Rheumatoid arthritis is an inflammatory disease that causes pain, swelling, stiffness, and loss of function in the joints. It can cause mild to severe symptoms. People with rheumatoid arthritis may feel sick, tired, and sometimes feverish. Sometimes rheumatoid arthritis attacks tissue in the skin, lungs, eyes, and blood vessels.
    