While arthritis is an umbrella term for many conditions that cause joint inflammation and damage, juvenile idiopathic arthritis (JIA) is the most common form in children. This type used to be known as juvenile rheumatoid arthritis.
Signs and symptoms
Some symptoms of JIA include redness or warmth in a joint, fevers and rashes, and persistent joint pain.
JIA is a complex disease spectrum with several different subtypes. However, there are general symptoms to look out for.
According to the Rheumatoid Arthritis Support Network, medical attention should be sought if a child is displaying any of the following:
- persistent joint pain, swelling, or stiffness, usually in knees, hands, and feet
- redness or warmth in one or more joints
- fevers paired with fleeting rashes
- swollen lymph nodes, especially in the neck
It can be difficult for parents or carers to be aware of some of these symptoms, as young children might not be able to express exactly what they are feeling. Some nonverbal cues that a child is experiencing arthritic pain could be:
- preference for one arm over the other
- limping, often due to knee stiffness after waking
- excessive clumsiness
Most scientists believe that there are two main factors responsible for juvenile arthritis:
- genetic mutations that cause the immune system to act abnormally
- an environmental trigger, such as a virus or a bacterial infection
While genetic mutations might not affect immune function early in the child's life, exposure to a virus or bacterial infection might launch those abnormal genes into action.
Most cases of JIA are believed to be autoimmune disorders. Usually, when the immune system encounters a foreign substance, it makes a protein called an antibody that can attach to that substance and mark it as a threat.
Diagnosis of JIA may follow a multistep protocol that includes laboratory tests of blood.
Each antibody is unique to the particular substance it was made for and can be produced again if the same substance is found in the future. In the case of an autoimmune disorder, the immune system mistakenly makes antibodies against its own tissues, marking them to be attacked.
However, some cases of JIA are better classified as autoinflammatory conditions.
While the body is still attacking its own tissue, the immune system dysfunction seen in autoinflammatory diseases does not involve antibodies. Instead, it occurs when the immune system initially detects an infection, or a gene mutation has occurred.
The body's first line of defense is to send out white blood cells, which swarm around infected tissue and destroy microbes. In the case of an autoinflammatory disorder, this white blood cell response is overactive, causing consistent inflammation and tissue damage.
Diagnosis and subtypes
Because the exact cause of JIA is unknown, no single test can detect the disease. Instead, doctors follow a thorough, multistep protocol to make a diagnosis.
According to the National Institute of Arthritis and Musculoskeletal and Skin Diseases, these diagnostic steps include:
- Analysis of symptom characteristics and duration: Joint swelling or pain must be consistent for at least 6 weeks for JIA to be diagnosed.
- Evaluation of family history: While it is rare for multiple immediate family members to have JIA, children whose parents have the disease are at a slightly higher risk of developing it. A family history of other autoimmune or autoinflammatory diseases is also a risk factor.
- Performing laboratory tests: These analyze the blood for substances linked with autoimmune problems; including antibodies directed against the body's own cells. Another test, called erythrocyte sedimentation rate (ESR), may also be performed. This analyzes how quickly red blood cells fall to the bottom of a test tube and helps to determine whether inflammation is present. Blood work is also used to rule out other similar conditions, such as Lyme disease, lupus, or some forms of cancer.
- Conducting X-rays: This can be used to detect bone or soft tissue abnormalities or damage.
If a child is diagnosed with JIA, the doctor will classify their condition into a specific subtype. This will allow for more targeted, effective treatment.
The six subtypes of JIA are:
This is the most common form of JIA, affecting about 50 percent of children diagnosed. Children with this form of JIA experience inflammation in only five joints or fewer, usually in the wrists or knees.
If a child is diagnosed before they are 7 years old, it is more likely that they will go into long-term remission. However, if a child starts showing symptoms when they are older, there is more chance that the JIA will continue into adulthood and spread to other joints.
Children with this form of JIA experience inflammation in more than five joints, usually in the legs, arms, jaw, or neck. These children might also have swelling in the liver, spleen, or lymph nodes.
This is the least common form of JIA, affecting about 10 percent of diagnosed children. It is characterized by episodes of spiking fevers and rash. Unlike the other two forms, joint inflammation may not appear until many months or years after these episodes begin.
Juvenile psoriatic arthritis
This type of JIA involves arthritis that tends to occur alongside a disorder called psoriasis that affects the skin. Psoriasis symptoms, such as a scaly rash, are most often seen at the scalp, elbows, knees, eyelids, belly button, and behind the ears. These symptoms can appear several years before joint pain and inflammation occur.
This form is marked by feelings of tenderness where a bone meets connective tissue and occurs alongside joint inflammation. The hips, knees, and feet are commonly affected.
Enthesitis-related JIA is also referred to as spondyloarthritis.
Any form of JIA that does not fit into any of the above five subtypes, or shares features with more than one of them, is defined as undifferentiated arthritis.
Once a child is diagnosed with JIA, a doctor will most likely prescribe a medication regimen and therapy plan. Some options include:
Nonsteroidal anti-inflammatory drugs (NSAIDs) and corticosteroids
These both work to alleviate inflammation and are usually used in combination to treat less severe oligoarticular cases. However, NSAIDs can only be used for very short periods of time, because they have serious side effects, including liver damage, gastrointestinal damage, and heart problems.
Corticosteroids can be used for a bit longer, but they also have adverse effects, including steroid dependency, weight gain, hyperglycemia, and calcium deficiency.
Disease-modifying antirheumatic drugs
These prevent the immune system from attacking the body and can be used for extended periods. For severe cases, they are often combined with or taken in place of corticosteroids. One of the most commonly prescribed of these is methotrexate.
A subset of these medications, called targeted biologic drugs, block specific immune system proteins that contribute to the overactive inflammatory response. If a blood test reveals elevated levels of the protein that one of these drugs targets, a doctor may suggest trying this form of therapy.
Many of these drugs are still experimental, but have shown promise in trials.
Along with medication, physical therapy can strengthen muscles without further damaging joints. Some people also find chiropractic treatment helpful. However, it is important to avoid chiropractic treatment during flare-ups, as it can aggravate inflammation.
Though it often occurs without symptoms, eye inflammation can be a very serious complication of JIA. Mostly, it is a problem for children with oligoarticular arthritis, but it can occur with any of the six subtypes.
This inflammation can cause vision damage if not addressed, so it is important for children with JIA to have regular optometrist check-ups.
Some children with JIA might also experience growth problems. Bones at the affected joints may grow too fast or too slow, causing arm or leg asymmetry. Overall growth may also be stunted. If growth problems are severe, a doctor may suggest growth hormone therapy.
Outlook and long-term management
The impact of JIA on a child's life varies greatly from case to case. While some children may only ever have one or two flare-ups and remain in remission, others might experience frequent episodes or face joint pain constantly.
Controlling inflammation is the most important way to prevent joint damage and disability. Affected children should see a rheumatic pediatrician regularly.
Low-impact sports, such as swimming, are a good option to help manage JIA.
It is also important to track a child's symptoms, reactions to medications, and flare-up frequency. All of this can be discussed with a pediatrician, so that the child's treatment regimen can be adjusted to keep them as healthy and comfortable as possible.
It is important for both the physical and mental health of an affected child that their lifestyle remains as normal and active as possible.
Participation in low-impact sports and activities is highly encouraged when a child is not experiencing a flare-up. Swimming is an especially good option, as it exercises the whole body without putting weight on the joints.
Therapists and social workers can help a great deal in guiding children to cope with the stresses and difficulties of rheumatoid arthritis.
Finally, opportunities for children to connect with other young people dealing with the same condition can also be deeply therapeutic.
One good resource is the Arthritis Foundation, which operates 50 summer camps across the U.S. for children with JIA.
Living with arthritis is difficult, especially for a child. However, with the proper care, children with JIA can have full and active lives.