Rheumatoid arthritis is a chronic or lifelong inflammatory disease which mainly affects the joints. Approximately 1 percent of Americans suffer from one kind or another of rheumatoid arthritis, according to the Merck Manuals. The disease begins most frequently between the ages of 30 and 50, and it affects women more than twice as often as men. Sometimes children suffer from one of an uncommon group of diseases known collectively as juvenile rheumatoid arthritis.
Rheumatoid Arthritis or RA
The most common of the joint disorders of this kind is called simply rheumatoid arthritis, or RA. In this disease the immune system attacks body tissues, resulting in inflammation, pain and swelling in the joints. It occurs typically in the hands and feet, and in the long run can cause deformation of joints and erosion of bone tissue. Although no cure exists, the Arthritis Foundation emphasizes that medications, exercises and joint protection measures can help control rheumatoid arthritis.
Systemic Onset Juvenile Rheumatoid Arthritis
Juvenile rheumatoid arthritis, or JRA, is a distinct group of diseases that affects nearly 50,000 American children, notes KidsHealth, a health education website sponsored by the Nemours Foundation. The National Institute of Arthritis and Musculoskeletal and Skin Diseases points out that under an alternative classification system, pediatric rheumatologists around the world have begun to use the term juvenile idiopathic arthritis, or JIA, in place of JRA. In either case, one of the three kinds or subtypes of this group, called systemic onset JIA, affects approximately 20 percent of those with JIA, according to the Merck Manuals. Painful joint inflammation preceded or accompanied by a high fever lasting up to two weeks may signal the onset of this kind of juvenile rheumatoid arthritis. A person may also develop a skin rash and swollen lymph nodes.
Pauciarticular Onset Juvenile Rheumatoid Arthritis
The pauciarticular onset kind of JIA, also know as oligoarthritis, involves arthritis in one to four of the child's joints during an initial six-month period. The National Institute of Arthritis and Musculoskeletal and Skin Diseases points out that two subcategories exist: in persistent oligoarthritis, the number of joints involved never exceeds four, while extended oligoarthritis affects five or more joints after the initial six-month period.
Polyarticular Onset Juvenile Rheumatoid Arthritis
With the polyarticular onset kind of JIA, a child will have arthritis symptoms in five or more joints during the initial six-month period of the disease. The number of involved joints could reach as high as or even exceed 20.
