Arthritis Australia and run community seminars. Arthritis is an umbrella term for more than 100 medical conditions that affect the musculoskeletal system, specifically joints where two or more bones meet. The three most significant – osteoarthritis, rheumatoid arthritis and gout – account for more than 95 per cent of cases in Australia. The most common forms of arthritis are: Arthritis-related problems include pain, stiffness, inflammation and damage to joint cartilage (the tissue that covers the ends of bones, enabling them to move against each another) and surrounding structures. This can result in joint weakness, instability and deformities that can interfere with the
Juvenile idiopathic arthritis migration inhibitory factor has been associated with this condition. It is sometimes called "adolescent-onset Still's disease", to distinguish it from adult-onset Still's disease. However, some evidence shows the two conditions are closely related. Rheumatoid factor and ANA are generally negative in systemic JIA. Some doctors include two other, less common forms: enthesitis-related arthritis and psoriatic JIA. Enthesitis is an inflammation of the insertion points of the tendons. This form occurs most often in boys older than 8, large joints of lower extremities are commonly affected; characteristically, it causes back pain, and is linked to ankylosing spondylitis and inflammatory bowel disease.