What is Rheumatoid Arthritis?

 MedicineNet has various topics of health issues, a broad knowledge to acquire from a website like this. One topic that I was reading up on was Rheumatoid Arthritis. Any idea what it is about? To know more if you have any of the symptoms and signs given below( taken from MedicineNet.com, click on Rheumatoid Arthritis Index.

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What are the symptoms and signs of rheumatoid arthritis?

The symptoms of rheumatoid arthritis come and go, depending on the degree of tissue inflammation. When body tissues are inflamed, the disease is active. When tissue inflammation subsides, the disease is inactive (in remission). Remissions can occur spontaneously or with treatment and can last weeks, months, or years. During remissions, symptoms of the disease disappear, and people generally feel well. When the disease becomes active again (relapse), symptoms return. The return of disease activity and symptoms is called a flare. The course of rheumatoid arthritis varies among affected individuals, and periods of flares and remissions are typical.
When the disease is active, symptoms can include fatigue, loss of energy, lack of appetite, low-grade fever, muscle and joint aches, and stiffness. Muscle and joint stiffness are usually most notable in the morning and after periods of inactivity. Arthritis is common during disease flares. Also during flares, joints frequently become red, swollen, painful, and tender. This occurs because the lining tissue of the joint (synovium) becomes inflamed, resulting in the production of excessive joint fluid (synovial fluid). The synovium also thickens with inflammation (synovitis).
Rheumatoid arthritis usually inflames multiple joints in a symmetrical pattern (both sides of the body affected). Early symptoms may be subtle. The small joints of both the hands and wrists are often involved. Symptoms in the hands with rheumatoid arthritis include difficulty with simple tasks of daily living, such as turning door knobs and opening jars. The small joints of the feet are also commonly involved, which can lead to painful walking, especially in the morning after arising from bed. Occasionally, only one joint is inflamed. When only one joint is involved, the arthritis can mimic the joint inflammation caused by other forms of arthritis, such as gout or joint infection. Chronic inflammation can cause damage to body tissues, including cartilage and bone. This leads to a loss of cartilage and erosion and weakness of the bones as well as the muscles, resulting in joint deformity, destruction, and loss of function. Rarely, rheumatoid arthritis can even affect the joint that is responsible for the tightening of our vocal cords to change the tone of our voice, the cricoarytenoid joint. When this joint is inflamed, it can cause hoarseness of the voice. Joint symptoms in children with rheumatoid arthritis include limping, irritability, crying, and poor appetite.
Since rheumatoid arthritis is a systemic disease, its inflammation can affect organs and areas of the body other than the joints. Inflammation of the glands of the eyes and mouth can cause dryness of these areas and is referred to as Sjogren's syndrome. Dryness of the eyes can lead to corneal abrasion. Inflammation of the white parts of the eyes (the sclerae) is referred to as scleritis and can be very dangerous to the eye. Rheumatoid inflammation of the lung lining (pleuritis) causes chest pain with deep breathing, shortness of breath, or coughing. The lung tissue itself can also become inflamed, scarred, and sometimes nodules of inflammation (rheumatoid nodules) develop within the lungs. Inflammation of the tissue (pericardium) surrounding the heart, called pericarditis, can cause a chest pain that typically changes in intensity when lying down or leaning forward. The rheumatoid disease can reduce the number of red blood cells (anemia) and white blood cells. Decreased white cells can be associated with an enlarged spleen (referred to as Felty's syndrome) and can increase the risk of infections. Firm lumps under the skin (rheumatoid nodules) can occur around the elbows and fingers where there is frequent pressure. Even though these nodules usually do not cause symptoms, occasionally they can become infected. Nerves can become pinched in the wrists to cause carpal tunnel syndrome. A rare, serious complication, usually with long-standing rheumatoid disease, is blood vessel inflammation (vasculitis). Vasculitis can impair blood supply to tissues and lead to tissue death (necrosis). This is most often initially visible as tiny black areas around the nail beds or as leg ulcers.