Juvenile Arthritis - An Overview

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Juvenile Arthritis – An Overview

by Colin Dunn, Ph.D. ArthritisSupport.com 12-05-2001 Associating the chronic and debilitating pain of arthritis with the faces of growing young children and teenagers can be difficult to imagine. Yet it is an unfortunate fact that hundreds of thousands of children in the United States and across the world suffer from Juvenile Arthritis. Juvenile Arthritis is an obscure and difficult disease that affects the lives of so many young people every year. In an effort to raise awareness of this unfortunate disease, the following discussion offers an informative overview of the conditions, causes, and treatment options for Juvenile Arthritis. Types of Juvenile ArthritisArthritis is characterized by inflammation (pain, swelling and stiffness) of joints and supporting tissues that can lead to joint destruction and disability. While adults suffer from many different forms of arthritis, children are most prone to Juvenile rheumatoid arthritis (JRA). This disease occurs in children under 16 years of age, and is associated with persistent inflammation in one or more joints for at least 6 weeks. JRA is classified into three different types according to the number of joints involved, the symptoms, and the presence or absence of antibodies (proteins produced by the immune system that attack and injure tissues). Pauciarticular JRA, the most common form, is so called because it affects fewer than four joints in the body. Although large joints such as the knees are predominantly involved, 25% of children with pauciarticular JRA show evidence of eye inflammation and the presence of antinuclear antibodies (ANA) in the blood. Young girls under the age of 8 are the most likely to suffer from pauciarticular JRA, although they tend to outgrow the disease by adulthood. Approximately 30% of children with JRA are afflicted with polyarticular JRA, and have arthritis in at least five of the large and small joints. The disease follows a similar course to adult rheumatoid arthritis (RA) – children with polyarticular JRA have high levels of rheumatoid factor (RF), an antibody that is related to the severity of RA – and carries a high risk for long-term joint damage and defective bone growth. Systemic JRA accounts for 20% of children with JRA, and is characterized by inflammation of several tissues throughout the body in addition to the joints. Typically, injury of the heart, liver, spleen, and lymph nodes is accompanied by spiking fevers and a pink rash. ANA and RF are absent in children with systemic JRA. However, arthritis can be severe and may progress into adulthood in a small number of patients. Causes of JRAAlthough the cause of JRA is unknown, it is widely held that genetic defects may predispose some children to autoimmunity, a process whereby the immune system attacks and destroys the patients’ tissues as though they were foreign invaders, like bacteria and viruses. Experts also believe that infections may trigger the disease, although no specific virus or bacterium has yet been identified. Whatever the causes may be, JRA should not be viewed as hereditary since it seldom affects more than one family member. JRA Differs from Adult ArthritisSpecialists emphasize that juvenile arthritis is quite different from adult arthritis. It is estimated that children with JRA are more likely than their adult counterparts to outgrow the disease, with more than half experiencing complete symptomatic relief by adulthood. Compared to adults with RA, significantly fewer children with JRA test positive for RF, decreasing the likelihood that disease will progress into adulthood. On the other hand the rapid development of bones occurring in childhood places children with JRA at greater risk for growth defects than adults with RA. Juvenile arthritis should not be confused with osteoarthritis, a disease that is caused by constant wear and tear of the joint tissues and is prevalent in the elderly population. Current Treatment OptionsThe treatment of JRA generally parallels that of adult RA, and consists of a physical therapy program combined with medications that act in different ways to control arthritis. Treatment is primarily aimed at reducing pain and swelling using non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen and aspirin. Glucocorticoids (steroids with powerful anti-inflammatory effects, such as prednisone) are reserved for those children with systemic JRA who have severe disease that is unresponsive to other types of therapy. In addition to the alleviation of joint symptoms, glucocorticoids are extremely effective at reducing fever and blocking the life-threatening inflammatory changes that occur in the heart (pericarditis) and lungs (pleuritis). However, specialists caution that glucocorticoids should be used conservatively since they carry a high risk for development of osteoporosis (fragile bones), infections, and a host of other serious side effects. Sulfasalazine, methotrexate, and gold – a class of drugs called “slow-acting antirheumatic drugs” (SAARs) because they have a delayed onset of action – provide useful treatment options for children unresponsive to NSAIDs or unable to take glucocorticoids. These agents control disease by preventing white blood cells from releasing molecules that are responsible for inflammation and tissue injury. In contrast to NSAIDs and glucocorticoids, SAARs need to be given for several weeks or months to be truly effective. Because of their potential for serious side effects, these agents should be carefully monitored. While most available therapies afford significant symptomatic relief they fail to alter the progression of arthritis, particularly that seen in polyarticular and systemic JRA. In recently reported clinical studies at least two agents designed to interfere with the underlying causes of disease have shown promising activity in children with JRA. Over 50% of patients with active JRA responded favorably to a 26-week course of treatment with leflunomide, a drug that suppresses tissue damage induced by cells of the immune system. More impressive results were observed in a 7-month study of 69 children taking etanercept – 80% of the patients receiving treatment showed a significant reduction of disease activity, compared to 35% in the placebo group. According to Dr C. J. of the Immunex Corporation “Etanercept represents an exciting new therapeutic option for the treatment of JRA.” Etanercept is a protein that acts by attaching to and removing specific molecules that cause inflammation and destruction of joint tissues, and is currently available under the brand name Enbrel for treating polyarticular JRA and adults with RA. Prevalence and Awareness of JRAAccording to current estimates, over 280,000 children under the age of 16 suffer from juvenile arthritis in the United States, of whom 100,000 are afflicted with JRA. Pediatricians estimate that JRA is as common as juvenile diabetes mellitus. The American Juvenile Arthritis Organization, a council of the American Arthritis Foundation, sponsors Juvenile Arthritis Awareness Week, an annual educational program designed to promote increased understanding and awareness of juvenile arthritis. Since JRA is increasingly viewed as a more diverse collection of arthritic conditions, disease classification guidelines were recently revised by an expert panel of rheumatologists and are due to be published in the coming year.