What is juvenile rheumatoid arthritis?
Juvenile rheumatoid arthritis (JRA) is a form of arthritis in children ages 16 or younger that causes inflammation and stiffness of joints for more than six weeks. Unlike adult rheumatoid arthritis, which is chronic and lasts a lifetime, children often outgrow juvenile rheumatoid arthritis. However, the disease can affect bone development in the growing child.
The disease can be classified into three categories based on the number of and which joints are involved, the symptoms present and their duration, and the presence of specific antibodies produced by the immune system. These three variables often help doctors determine the progression of JRA and include the following:
- Pauciarticular. This form of JRA affects about 50 percent of children with this disease, involving four joints or fewer. Large joints, such as the knees, ankles, or elbows are typically affected.
- Polyarticular. Nearly 30 to 40 percent of children with JRA are affected by this type of the disease, which affects five or more joints. Polyarticular disease is more serious and tends to affect the small joints, such as the hands and feet, and often on both sides of the body.
- Systemic. Systemic onset JRA (also called Still's disease) is the most serious, but least common form of the disease, affecting 10 to 15 percent of children with JRA. It affects one or more joints and causes inflammation of internal organs, including the heart, liver, spleen, and lymph nodes.
What causes juvenile rheumatoid arthritis?
Like adult rheumatoid arthritis, JRA is an autoimmune disease, which means the body's immune system attacks its own healthy cells and tissues.
JRA is considered to be a multifactorial condition. Multifactorial inheritance means that many factors are involved in causing a health problem. The factors are usually both genetic and environmental, where a combination of genes from both parents, in addition to unknown environmental factors, produce the trait or condition. Often one gender (either males or females) is affected more frequently than the other in multifactorial traits. Multifactorial traits do recur in families because they are partly caused by genes.
A group of genes on chromosome 6 codes for the HLA antigens play a major role in susceptibility and resistance to disease. Specific HLA antigens influence the development of many common disorders. Some of these disorders, like JRA, are autoimmune related and inherited in a multifactorial manner. When a child has the specific HLA antigen type associated with the disease, he or she is thought to have an increased chance to develop the disorder. The HLA antigen associated with JRA is called DR4. Children with the DR4 HLA antigen are thought to have an increased chance (or genetic susceptibility) to develop JRA; however, it is important to understand that a child without this antigen may also develop JRA. This means HLA antigen testing is not diagnostic or accurate for prediction of the condition. Females are affected with JRA more often than males.
What are the symptoms of juvenile rheumatoid arthritis?
Symptoms of juvenile rheumatoid arthritis may appear during episodes (flare-ups) or may be chronic and continuous. The following are the most common symptoms of juvenile rheumatoid arthritis. However, each child may experience symptoms differently. Symptoms may include:
- Swollen, stiff, and painful joints, especially in the morning or after a nap (joints in the knees, hands, and feet are most commonly affected)
- High fever and rash, if systemic juvenile rheumatoid arthritis
- Swollen lymph nodes, if systemic juvenile rheumatoid arthritis
- Eye inflammation
- Warmth and redness in a joint
- Decreased use of one or more particular joints
- Decreased appetite, poor weight gain, and slow growth
Symptoms of juvenile rheumatoid arthritis may resemble other medical conditions or problems. Always consult your child's doctor for a diagnosis.
How is juvenile rheumatoid arthritis diagnosed?
In addition to a complete medical history and physical examination your child's doctor will obtain a complete prenatal and birth history of your child and ask if your child has had any recent colds or other infections.
Currently, there is no diagnostic test that definitively tells that a child has JRA. Diagnosis of juvenile rheumatoid arthritis is usually confirmed based on the presence of the following:
- Reported symptoms. Joint inflammation usually must be present for at least six weeks, continuously.
- Laboratory tests. Laboratory tests, such as certain blood tests, can help rule out other conditions and help determine the type of juvenile rheumatoid arthritis present. Tests may include:
- Checking for the presence of antinuclear antibodies (ANA) and IgM rheumatoid factor (RF)
- Blood tests and other laboratory tests, including:
- Antinuclear antibody (ANA) and other antibody tests. These tests measure blood levels of antibodies, which are often present in persons with rheumatic disease.
- Arthrocentesis (also called joint aspiration). A procedure that involves obtaining a sample of synovial fluid in the joint for examination by inserting a thin, hollow needle into the joint and removing the fluid with a syringe.
- Complement. A blood test that measures the level of complement, a group of proteins in the blood. Low levels of complement in the blood are associated with immune disorders.
- Complete blood count (CBC). A measurement of size, number, and maturity of different blood cells in a specific volume of blood.
- Creatinine. A blood test to evaluate for underlying kidney disease.
- Erythrocyte sedimentation rate (ESR or sed rate). A measurement of how quickly red blood cells fall to the bottom of a test tube. When swelling and inflammation are present, the blood's proteins clump together and become heavier than normal. Thus, when measured, they fall and settle faster at the bottom of the test tube. Generally, the faster the blood cells fall, the more severe the inflammation.
- Hematocrit. This measures the number of red blood cells present in a sample of blood. Low levels of red blood cells (anemia) are common in people with inflammatory arthritis and rheumatic diseases.
- Rheumatoid factor (RF). This detects whether rheumatoid factor is present in the blood (an antibody found in the blood of most, but not all, people who have rheumatoid arthritis, as well as other rheumatic diseases).
- Urinalysis. Testing of a urine sample for protein, red blood cells, white blood cells, or casts to indicate kidney disease associated with several rheumatic diseases.
- White blood cell count (WBC). This measures the number of white blood cells in the blood (increased levels of white blood cells may indicate an infection, while decreased levels may indicate certain rheumatic diseases or reaction to medication).
Imaging tests, to show the extent of damage to the bones, may include the following:
- X-ray. A diagnostic test that uses invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs onto film.
- Computed tomography scan (also called a CT or CAT scan). A diagnostic imaging procedure that uses a combination of X-rays and computer technology to produce horizontal, or axial, images (often called slices) of the body. A CT scan shows detailed images of any part of the body, including the bones, muscles, fat, and organs. CT scans are more detailed than general X-rays.
- Magnetic resonance imaging (MRI). A diagnostic procedure that uses a combination of large magnets, radiofrequencies, and a computer to produce detailed images of organs and structures within the body.
- Bone scan. A nuclear radiology study of the bones.
Treatment for juvenile rheumatoid arthritis
The goal of treatment for juvenile rheumatoid arthritis is to maintain a normal activity level for your child. Specific treatment for juvenile rheumatoid arthritis will be determined by your child's doctor based on:
- Your child's overall health and medical history
- Extent of the condition
- Your child's tolerance for specific medications, procedures, and therapies
- Expectation for the course of the disease
- Your opinion or preference
Treatment may include:
- Nonsteroidal anti-inflammatory medications, NSAIDs, (to relieve symptoms)
- Disease-modifying anti-rheumatic medications (to slow the progress of the disease, such as methotrexate)
- Biologics, drugs designed to interfere with your body's inflammatory response, such as etanercept, infliximab, adalimumab, abatacept, and anakinra. These are used if there is no response to other therapies.
- Corticosteroids (to reduce inflammation and control severe symptoms)
- Physical therapy (to improve and maintain muscle and joint function)
- Occupational therapy (to improve ability to perform activities of daily living)
- Assessment of nutritional status by a nutritionist and ongoing, if necessary, nutritional guidance (to ensure adequate nutritional intake for your child whose appetite may be adversely affected by the disease process itself or some medications used for treatment)
- Regular eye exams to detect early changes of eye inflammations
- Patient education (to help decrease the frequency and severity of flare-ups and prevent complications), including educational topics such as:
- Exercise and weight control
- Adequate rest
- How to use large joints rather than small joints to move or carry things
Bass, Pat F. III, MD, MPH, Fincannon, Joy, RN, MN