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Oligoarticular

Oligoarticular means "few joints." In this type of juvenile arthritis, just a few joints are affected. About 50% of children with juvenile arthritis have the oligoarticular type. Girls younger than 8 years of age are more likely to develop it.

In half of children with oligoarticular juvenile arthritis, only one joint is involved, usually a knee or ankle. This is called monoarticular juvenile arthritis. In some cases, this arthritis may require only mild treatment.

For some children, this arthritis affects four or fewer larger joints. Joints commonly affected include the knees or ankles. Involvement of fingers or toes is unusual.

Oligoarticular juvenile arthritis may also cause eye inflammation. To prevent blindness, your child will need regular eye examinations from a doctor who specializes in eye diseases (ophthalmologist). Eye problems may continue into adulthood. 

Polyarticular

About 30% of children with juvenile arthritis have the polyarticular type. This type of arthritis is more common in girls than in boys.

Polyarticular juvenile arthritis affects five or more joints, including both larger joints (knees and ankles) and smaller joints (hands and feet). Often, both sides of the body are affected. 

Children with a certain marker, or antibody, in their blood, called IgM rheumatoid factor (RF), often have a more severe form of the disease.

Antibodies are proteins in the blood usually used by the body to fight off infection through an immune response. In this form of arthritis, the IgM RF antibody attacks the body's own tissues. Doctors believe that this is the same type of arthritis as adult rheumatoid arthritis and can require more significant treatment.

Psoriatic

With psoriatic arthritis, children have both arthritis and either:

• A skin disease called psoriasis
• A parent or sibling with psoriasis

These children can also have nail changes, as well as diffuse swelling in a toe or finger called dactylitis. In some cases, just a few joints are involved; in others, several joints are affected, including both small and large joints. 

In juvenile arthritis, swelling of some of the fingers and toes may be significant.

Courtesy of Texas Scottish Rite Hospital for Children

Enthesitis-related Arthritis

Enthesitis-related arthritis is a form of juvenile arthritis that often involves inflammation of tendons and ligaments, as well as joints. It may also affect the spine. 

Children with this type of arthritis sometimes have joint pain without any obvious swelling and may have back pain. Often, the inflammation in the back occurs later in life.

Enthesitis-related arthritis most commonly affects boys over the age of 6.

Systemic

About 20% of children with juvenile arthritis have the systemic type.

Systemic juvenile arthritis causes swelling, pain, and limited motion in at least one joint. Additional symptoms include rash and inflammation of internal organs such as the heart, liver, spleen, and lymph nodes. A fever of at least 102° every day for 2 weeks or longer suggests this diagnosis.

If not adequately treated, children with systemic juvenile arthritis can develop macrophage activation syndrome, a severe condition that causes multi-organ dysfunction. Untreated, this condition can be fatal. 

Medical History

Your child's doctor will review your child's complete medical history. They will want to know:

• How long your child has had problems with joint pain and swelling
• Whether the symptoms have gotten better or worse
• Whether your child feels stiff when getting up after rest

The doctor will look for other causes of the symptoms, such as:

• An injury
• Another illness (e.g., infections, cancers, or other autoimmune disease)
• A family history of autoimmune disease

Physical Examination

Your child's doctor will examine your child's joints. They will check for signs of:

• Swelling
• Warmth
• Decreased range of motion
• Muscle loss (atrophy) in the muscles near the affected joints

Laboratory Tests

Tests on blood, joints, and tissue fluids can help to rule out other conditions that might cause similar symptoms. These tests may also be used to classify the type of juvenile arthritis.

X-Rays

X-rays provide clear images of dense structures like bone. Your child's doctor may order them to look for injuries to bone or for any unusual development of bone.

Ultrasound

Ultrasounds are often obtained to look at the joint. These tests are helpful in determining how much inflammation is present.

Magnetic Resonance Imaging (MRI) Scans

Your child's doctor may order an MRI to look for inflammation in joints or around tendons. An MRI is most often the best way to determine the degree of inflammation, and it can also check for structural changes and injuries.

If your child is young, the doctor may decide that your child needs medicine (sedation) to help them be still for this test.

Nonsurgical Treatment

Medications. The most important part of any treatment plan for juvenile arthritis is medication. Your child may need certain medications for several years until the juvenile arthritis is no longer active. Your child's doctor will determine if it is safe to discontinue the medications after joint pain, swelling, and warmth disappear.

• Nonsteroidal anti-inflammatory drugs (NSAIDs)are often the first type of medication recommended. Common examples include ibuprofen and naproxen. NSAIDs are used primarily to reduce inflammation and relieve pain and stiffness; they will help calm down the disease.
• Disease-modifying anti-rheumatic drugs (DMARDs) are the next step if NSAIDs do not relieve symptoms. DMARDs slow or stop progression of juvenile arthritis, but may take weeks or months to relieve symptoms. The most commonly used drug is methotrexate. Your child's doctor may want your child to take DMARDs along with NSAIDs.
• Biologic agents are a class of drugs that also slow or stop the progression of the disease. These medications are typically used if DMARDs are insufficient, but they are sometimes used as initial treatment if the disease is severe.
• Corticosteroids are stronger medications that may be used in treating severe juvenile arthritis quickly. They can be given several ways, including by mouth (orally), injected into a vein (intravenously), or injected directly into a joint.  However, corticosteroids can interfere with a child's growth, and cause weight gain, weakening of the bones, and increased susceptibility to infections. It is, therefore, important to follow the doctor's instructions exactly when taking corticosteroids. 

Additional options. In addition to medications, warm baths may help soothe sore joints. 

Surgical Treatment

Surgery is rarely needed in treating juvenile arthritis. In very severe forms of juvenile arthritis or with very severe complications, surgery may be necessary to improve the position of the joint. An example of this might be when a joint has become deformed.

Joint replacement — frequently used to treat adults with arthritis — has almost no place in treating children. In addition, adequate treatment of juvenile arthritis will protect the joint and prevent long-term damage that may ultimately require joint replacement.