Juvenile arthritis (JA) is an umbrella term used to describe the many autoimmune and inflammatory conditions that can develop in children ages 16 and younger.
Arthritis typically affects joints -- the word “arthritis” literally means joint inflammation: arth (joint) and itis (inflammation) – but JA can involve the eyes, skin and gastrointestinal tract as well.
In addition, there are several different types of juvenile arthritis. As JA’s prevalence rises, researchers and doctors alike are working to develop a more sophisticated understanding of the differences between the different forms.
The most common type of JA is juvenile idiopathic arthritis (JIA). To receive a diagnosis, a child should be younger than 16 and have initial swelling in one or more joints for at least six weeks. Over time, a child with JIA, now an umbrella term for several types of arthritis previously known as juvenile rheumatoid arthritis, may exhibit a variety of symptoms including muscle and soft tissue tightening, bone erosion, joint misalignment and changes in growth patterns.
Once a child is diagnosed with JIA, the next challenge is to determine the specific type of JIA I he’s experiencing. The first six months after onset are extremely important. Your child’s doctor, likely a pediatric rheumatologist, will monitor the number of joints affected during those first six months, as well as administer the rheumatoid factor blood test, which checks for a substance in the blood that’s usually found in people with this condition.
Based on her symptoms, your child may be diagnosed with one of the following categories of JIA: link to to http://www.arthritistoday.org/conditions/juvenile-arthritis/all-about-ja/what-is-juvenile-arthritis.php
Oligoarthritis: This type of JA, which accounts for 40 percent of new JIA patients is diagnosed when four or fewer joints are involved within the first six months.
Polyarthritis: A child is diagnosed with polyarthritis when five or more joints are involved during the first six months.
Systemic: Though broad in reach, with the potential to involve the entire body – systemic JIA is narrow in scope, comprising only about 10 percent of JIA cases.. Symptoms may include a non-contagious fever and rash, and inflammation can particularly the spleen or the membranes that covering the lungs and heart.
Enthesitis-related: This type is characterized by the inflammation of the entheses, or sites where tendons attach to the bone.
Other types of arthritis: Though JIA is the most common type of JA, it certainly isn’t the only type. Other forms include juvenile lupus, juvenile scleroderma, juvenile psoriatic arthritis and juvenile dermatomyositis Children can also experience non-inflammatory disorders, which are characterized by chronic pain associated with heredity, injury or unknown causes.