Juvenile idiopathic arthritis (JIA) is a form of arthritis in children. Arthritis causes joint swelling (inflammation) and joint stiffness. JIA is arthritis that affects 1 or more joints for at least 6 weeks in a child age 16 or younger.
Unlike adult rheumatoid arthritis, which is ongoing (chronic) and lasts a lifetime, children often outgrow JIA. But the disease can affect bone development in a growing child.
There are several types of JIA:
Systemic onset JIA. This type affects 1 or more joints. There is often a high fever and a skin rash. It may also cause inflammation of internal organs, including the heart, liver, spleen, and lymph nodes. It is the least common type. It affects 10% to 15% of children with JIA.
Oligoarticular JIA. This type affects 1 to 4 joints in the first 6 months of disease. If no more joints are affected after 6 months, this type is called persistent. If more joints are affected after 6 months, it is called extended.
Polyarticular JIA. This type affects 5 or more joints in the first 6 months of disease. Blood tests for rheumatoid factor (RF) will show if this type is RF-positive or RF-negative.
Enthesitis-related JIA. With this type, a child has arthritis as well as enthesitis. This is a swelling of the enthesis, the tissue where bone meets a tendon or ligament. It often affects the hips, knees, and feet.
Psoriatic Arthritis. With this type, a child may have both arthritis and a red, scaly skin disease called psoriasis. Or a child may have arthritis and 2 or more of the following:
- Inflammation of a finger or toe
- Pits or ridges in fingernails
- A first-degree relative with psoriasis
Undifferentiated arthritis. This is arthritis that has symptoms of 2 or more JIA types above. Or the symptoms might not match any type of JIA.
Like adult rheumatoid arthritis, JIA is an autoimmune disease. This means the body's immune system attacks its own healthy cells and tissues. JIA is caused by several factors. These include genes and environmental factors. This means the disease can run in families, but can also be triggered by exposure to certain things. JIA is linked to part of a gene called HLA antigen DR4. A person with this antigen may be more likely to have the disease.
Symptoms may appear during episodes (flare-ups). Or they may be ongoing (chronic). Each child’s symptoms can vary. Symptoms may include:
- Swollen, stiff, and painful joints in the knees, hands, feet, ankles, shoulders, elbows, or other joints, often in the morning or after a nap
- Eye inflammation
- Warmth and redness in a joint
- Less ability to use one or more joints
- Decreased appetite, poor weight gain, and slow growth
- High fever and rash (in systemic JIA)
- Swollen lymph nodes (in systemic JIA)
These symptoms can seem like other health conditions. Make sure to see your healthcare provider for a diagnosis.
Diagnosing JIA may be difficult. There is no single test to confirm the disease. Your child’s healthcare provider will take your child’s medical history and do a physical exam. Your child's provider will ask about your child's symptoms, and any recent illness. JIA is based on symptoms of inflammation that have occurred for 6 weeks or more.
Tests may also be done. These include blood tests such as:
- Antinuclear antibody (ANA) and other antibody tests. These tests measure blood levels of antibodies that are often seen in people with rheumatic disease.
- Complete blood count (CBC). This test checks for low counts of red blood cells, white blood cells, and platelets.
- Complement test. This test is done to measure the level of complement. This is a group of proteins in the blood that help destroy foreign substances. Low levels of complement in the blood are linked to immune disorders.
- Erythrocyte sedimentation rate (ESR or sed rate). This test looks at 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. They fall and settle faster at the bottom of the test tube. The faster the blood cells fall, the more severe the inflammation.
- C-reactive protein (CRP). This protein shows up when inflammation is found in the body. ESR and CRP show similar amounts of inflammation. But one may be high when the other is not. This test may be repeated to check a child’s response to medicine.
- Creatinine. This is a blood test to check for kidney disease.
- Hematocrit. This measures the number of red blood cells in a blood sample. Low levels of red blood cells (anemia) are common in people with inflammatory arthritis and rheumatic diseases.
- Rheumatoid factor (RF). This test checks to see if RF is in the blood. This is an antibody found in the blood of most people who have rheumatoid arthritis and other rheumatic diseases.
- White blood cell count. This measures the number of white blood cells in the blood. Higher levels of white blood cells may mean an infection. Lower levels may be a sign of some rheumatic diseases or a reaction to medicine.
Your child may also have imaging tests. These can show the extent of damage to the bones. The tests may include:
- X-rays. This test uses a small amount of radiation to make images of organs, bones, and other tissues.
- CT scan. This uses a series of x-rays and a computer to make detailed images of bones, muscles, fat, and organs. CT scans are more detailed than regular X-rays.
- MRI. This test uses large magnets and a computer to make detailed pictures of organs and structures in the body.
- Bone scan. This uses a small amount of radiation to highlight the bones in a scanner.
Other tests may include:
- Urine tests. These look for blood or protein in the urine. This can mean the kidneys are not working normally.
- Joint aspiration (arthrocentesis). A small sample of the synovial fluid is taken from a joint. It's tested to see if crystals, bacteria, or viruses are present.
The goal of treatment is to reduce pain and stiffness, and help your child keep as normal a lifestyle as possible. Your child's healthcare provider will figure out the best treatment plan for your child based on:
- How old your child is
- Your child’s overall health and medical history
- How sick your child is
- How well your child handles certain medicines, treatments, or therapies
- If your child’s condition is expected to get worse
- The opinion of the healthcare providers involved in your child's care
- Your opinion and preference
Treatment may include medicines such as:
- Nonsteroidal anti-inflammatory medicines (NSAIDs), to reduce pain and inflammation
- Disease-modifying antirheumatic medicines (DMARDs), such as methotrexate, to decrease inflammation and control JIA
- Corticosteroid medicines, to reduce inflammation and severe symptoms
- Medicines called biologics that interfere with the body's inflammatory response. They are used if other treatment isn’t working.
Talk with your child’s healthcare provider about the risks, benefits, and possible side effects of all medicines.
Other treatments and lifestyle changes may include:
- Physical therapy, to improve and maintain muscle and joint function
- Occupational therapy, to improve ability to do activities of daily living
- Nutrition counseling
- Regular eye exams to find early eye changes from inflammation
- Regular exercise and weight control
- Getting enough rest
- Learning to use large joints instead of small joints to move or carry things
Nearly 50% of all children with JIA recover fully. Others may have symptoms for years. Some will have rashes and fever, while others may have arthritis that gets worse. Problems may include slow growth and thinning bones (osteoporosis). In rare cases, there may be problems with the kidneys, heart, or endocrine system.
Help your child manage his or her symptoms by sticking to the treatment plan. This includes getting enough sleep. Encourage exercise and physical therapy and find ways to make it fun. Work with your child's school to make sure your child has help as needed. Work with other caregivers to help your child take part as much possible in school, social, and physical activities. Your child may also qualify for special help under Section 504 of the Rehabilitation Act of 1973. You can also help your child find a support group to be around with other children with JIA.
When to Call a Healthcare Provider
Tell the provider if your child's symptoms get worse or there are new symptoms.
- JIA is a form of arthritis in children ages 16 or younger. It causes joint inflammation and stiffness for more than 6 weeks.
- The disease may affect a few joints or many joints. It may cause symptoms all over the body.
- The most common symptoms include swollen, stiff, warm, red, and painful joints.
- Treatment options include medicines, physical therapy, healthy eating and exercise, eye exams, and rest.
Tips to help you get the most from a visit to your child’s healthcare provider:
- Know the reason for the visit and what you want to happen.
- Before your visit, write down questions you want answered.
- At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you for your child.
- Know why a new medicine or treatment is prescribed and how it will help your child. Also know what the side effects are.
- Ask if your child’s condition can be treated in other ways.
- Know why a test or procedure is recommended and what the results could mean.
- Know what to expect if your child does not take the medicine or have the test or procedure.
- If your child has a follow-up appointment, write down the date, time, and purpose for that visit.
- Know how you can contact your child’s provider after office hours. This is important if your child becomes ill and you have questions or need advice.