What is Pediatric Arthritis, also known as Juvenile idiopathic arthritis (JIA)?
Juvenile idiopathic arthritis (JIA) is a chronic condition that begins in children age less than age 16 years and causes inflammation (swelling, warmth, and pain with movement) and stiffness of joints for more than six weeks. Since we do not know the cause of the arthritis, it includes the term idiopathic, which means of unknown cause. It is one of the most common chronic childhood diseases- about as common as type 1 diabetes mellitus (juvenile diabetes). The length of the disease and the severity of illness varies depending on many factors, including the type of JIA (there are three different types), the age at which the disease starts, and other factors. Treatment is essential since the inflammation can affect joint, muscle and bone development in the growing child.
What are the three types of JIA?
Pauciarticular (AKA oligoarticular): This is the most common form of JIA, involving four or fewer joints. Large joints, such as the knees, ankles, or elbows are typically affected and the arthritis is usually asymmetrical. This type of disease most often affects girls and often presents as early as 1 year of age (mean 2-4 years of age). The eye is most frequently involved in this type of JIA with inflammation that if untreated may lead to blindness. It is essential that children with this type of JIA see an ophthalmologist every three months.
Polyarticular: This is the next most common type of JIA and this type is the most like adult rheumatoid arthritis (RA) since it affects 5 or more joints in a symmetrical pattern. Polyarticular disease is more serious and tends to affect the small joints, such as the hands and feet, as well as, the large joints such as shoulders, elbows, wrists, hips, knees, and ankles. This type of JIA affects girls more often than boys.
Systemic: Systemic onset JIA (also called Still's disease) is the most serious, but least common form of the disease. It affects one or more joints and causes inflammation of internal organs, including the heart, liver, spleen, and lymph nodes. Boys and girls are equally likely to have systemic JIA.
What causes JIA?
Like adult rheumatoid arthritis, JIA is an autoimmune disease, which means the body's immune system attacks its own healthy cells and tissues.
JIA is considered to be a multifactorial condition. Multifactorial 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 occur in families because they are partly caused by genes.
How is JIA treated?
Symptoms of juvenile idiopathic arthritis may appear during episodes (flare-ups) or may be chronic and continuous. The following are the most common symptoms of juvenile idiopathic 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); as well as warmth and redness in a joint
high fever and rash, if systemic JIA
swollen lymph nodes, if systemic JIA
decreased appetite, poor weight gain, and slow growth
Symptoms of JIA may resemble other medical conditions or problems. Always consult your child's physician for a diagnosis.
Currently, there is no diagnostic test that definitively tells that a child has JIA. Diagnosis of JIA 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. Frequent tests that are checked when suspecting JIA include the ANA (antinuclear antibody), RF (rheumatoid factor), CBC (complete blood count), blood chemistries (including liver and kidney function tests), urine analysis, ESR (erythrocyte sedmentation rate), and CRP (c-reactive protein).
Arthrocentesis (joint aspiration) It is sometimes necessary to confirm the diagnosis of JIA and rule out infection of the joint by removing fluid from the joint space (synovial fluid) and examining it under the microscope for signs of inflammation.
Radiology Studies Different radiology studies are often used to aide in the diagnosis of JIA and to monitor the progression of the disease. X-rays (plain films), CT scans and MRI scans are used in different situations to closely examine the bones and joints.
What are the symptoms of JIA, and how is it diagnosed?
The goal of treatment for juvenile rheumatoid arthritis is to maintain a normal activity level for your child. Specific treatment for juvenile rheumatoid arthritis depends on many factors, including the type of JIA, the severity of the involvement, whether or not eye inflammation exists, and how your child responds to or tolerates different therapies. It is very important to involve both the parents and the child with every decision concerning the treatment plan.
Treatment of JIA begins with an understanding of the disease and the different options available for children. Counseling is an important first step in treatment. Often, we look to other modes of therapy outside of medications to aide in the healing process. This may include physical therapy (which focuses on the lower body and on improving and maintaining muscle and joint function) and occupational therapy (which focuses on the upper body and on improving the ability to perform activities of daily living). In addition, all patients with JIA should be examined by an ophthalmologist (eye specialist) to check for inflammation in the eyes. Pediatric rheumatologists often work very closely with ophthalmologist to coordinate care for both the child’s eyes and joints.
Although there is no cure for JIA, there are many different medications available to treat it. Pediatric rheumatologists choose medications based on the most effective therapy with the fewest side effects.
Common medications used for JIA include non-steroidal anti-inflammatory drugs or NSAIDs (such as naproxen or ibuprofen), disease-modifying anti-rheumatic medications (such as methotrexate), corticosteroids (such as prednisone), intra-articular corticosteroids or steroid joint injections, and biologic agents (such as Enbrel or Remicade). For more information on these medicines and there potential side effects, please ask your pediatric rheumatologist.
Get more information on Pediatric Arthritis from the Arthritis Foundation.