First proposed in 1994 and later revised in 1997, the term “juvenile idiopathic arthritis” (JIA) was used as a compromise for the American term JRA (juvenile rheumatoid arthritis) and the European classification JCA (juvenile chronic arthritis).
Because the American and European classifications of the disease were confusing, it was difficult to use them interchangeably. In an effort to improve research and treatment, the International League Against Rheumatism has devised a unifying set of international criteria, using the term “juvenile idiopathic arthritis.”
The word “idiopathic” means “of unknown cause.” This classification is gaining favor among researchers and health professionals, but is not yet universally used.
However, regardless of the classification, children who develop symptoms that persist for at least six weeks before the age of sixteen years are considered to have juvenile arthritis.
The International League Against Rheumatism Classification:
JIA (Juvenile Idiopathic Arthritis) lasting at least 6 weeks:
- Oligoarthritis (persistent, 1-4 joints; extended, affecting 5 or more joints)
- Polyarthritis (RF – positive; RF – negative)
- Systemic arthritis
- Other similar types of childhood arthritis (spondyloarthropathies)
The American College of Rheumatology Classification:
JRA (juvenile rheumatoid arthritis) lasting at least 6 weeks:
- Pauciarticular (1-4 joints involved)
- Polyarticular (5 or more joints involved)
- Systemic JRA
- JRA does not include similar types of childhood arthritis (spondyloarthropathies).
European League Against Rheumatism Classification:
JCA (juvenile chronic arthritis) lasting at least 3 months:
- Pauciarticular (involving 1-4 joints)
- Polyarticular (involving 5 or more joints, RF – negative)
- Juvenile rheumatoid arthritis (involving 5 or more joints, RF – positive)
- Systemic JCA
- JCA includes similar types of childhood arthritis (spondyloarthropathies).
JA (juvenile arthritis) is an inflammatory disorder of the connective tissues, characterized by joint swelling and pain or tenderness. It may also involve such organs as the skin, heart, lungs, liver, spleen, and eyes, producing extra-articular signs and symptoms.
Depending on the type, this disease can occur as early as six weeks of age, but rarely does so before the age of six months.
Peak onsets are usually between the ages of one and three years and between eight and twelve years.
Cause remains unclear; but there appears to be links to genetic factors, abnormal immune responses, viral or bacterial infections, trauma, emotional stress, and nutrient deficiencies.
There are three major types with signs and symptoms varying with the type:
- Systemic arthritis (Still’s disease or acute febrile types) affects both boys and girls almost equally. The majority of children with arthritis have what is known as “acute reactive arthritis” following a viral or bacterial infection. There may be fever and a rash, but joint involvement may not be apparent at first although the child’s behavior may indicate joint pain. Such a child may constantly want to sit in a flexed position, not walk much, or refuse to walk at all. Young children are noticeably irritable and listless. Fever occurs suddenly and spikes to 39.4°C (103°F) or higher once or twice daily, usually in the late afternoon. It then rapidly returns to normal or subnormal. It is this intermittent spiking fever pattern that helps to differentiate the disease from other inflammatory disorders. When the fever spikes, a rheumatoidal rash often appears, consisting of small, pale, or salmon pink macules, mostly on the trunk and extremities. Occasionally it will appear on the face, palms of the hands, and soles of the feet. Massaging or applying heat to the rash will intensify it and will be more conspicuous where clothing has rubbed. Other signs and symptoms may include hepatosplenomegaly (enlargement of the liver and spleen), lymphadenopathy (lymph node involvement), pleuritis (or pleurisy – inflammation of the lining of the lungs or thoracic cavity), pericarditis (inflammation of the sac enclosing the heart), myocarditis (inflammation of the muscular walls of the heart), and nonspecific abdominal pain. This type usually clears up within a few weeks or months.
- Polyarticular arthritis affects girls three times more often than boys and may be sero-negative or sero-positive for RFs (rheumatoid factors). Sero-positive is the more severe type and usually occurs late in childhood. It can cause enough destruction to mimic adult rheumatoid arthritis. Polyarticular JIA involves five or more joints and develops insidiously, that is, gradually with accumulated effects. The joints most commonly involved are the wrists, elbows, knees, ankles, and small joints of the hands and feet. This type can also affect larger joints, as well as those of the cervical spine, hips, and shoulders. These joints become swollen, tender, and stiff and usually are symmetric. The child may run a low-grade fever with daily peaks. Listlessness and weight loss can occur as well as with lymphadenopathy and hepatosplenomegaly. Other signs include subcutaneous nodules on the elbows or heels and a noticeable developmental retardation.
- Pauciarticular arthritisinvolves few joints (usually fewer than four) and most often affects the knees and other large joints. It accounts for almost half of all cases. There are three major subtypes:
- Pauciarticular JIA with chronic iridocyclitis (inflammation of the iris and ciliary body) most commonly strikes girls under the age of six and involves the knees, elbows, ankles, and the iris. Iridocyclitis is often asymptomatic, but may produce pain, redness, blurred vision, and photophobia (sensitivity to light). If left untreated, the eye may develop scarring of the lens with permanent visual damage, even blindness. Because the eye disease is more common in children who test positive for antinuclear antibodies (ANA), these children need to be examined by an eye specialist every three months. Other children with JIA require eye need examinations every six months. The second complication is that it may cause the bones in the legs to grow at different rates so that one leg is longer than the other, causing a limp. Limping damages the knee and hip, leading to premature arthritis from “wearing out” the joints by the time adulthood is reached. This development should be prevented, if at all possible.
- Pauciarticular JIA with sacroiliitis (inflammation of the sacroiliac joint) usually strikes boys, nine times more often than girls, over the age of eight who tend to be HLA-B27 positive. This subtype is characterized by lower extremity arthritis that produces hip, sacroiliac, heel, foot pain, and Achilles tendinitis. These children may later develop the sacroilia and lumbar arthritis characteristic of ankylosing spondylitis. Some also experience acute iritis, but not as frequently as those with the first subtype.
- This last subtype includes patients with joint involvement who are ANA (antinuclear antibody) and HLA-B27 negative and who do not develop iritis. These patients have a better prognosis than those who develop the first or second subtypes.
Treatments are the same as for adult rheumatoid arthritis.