Pauciarticular juvenile rheumatoid arthritis is the most common type of juvenile rheumatoid arthritis. It affects children under 16. Symptoms include pain and swelling in the knees and other large joints. But treatment might help reduce pain for children and improve how they perform daily activities.
In this article, we take a closer look at pauciarticular juvenile rheumatoid arthritis, including causes, symptoms, diagnosis, and treatment.
Two names for one condition
Pauciarticular juvenile rheumatoid arthritis is an older name for a condition that is now sometimes called oligoarticular juvenile idiopathic arthritis (JIA). While you’ll likely still see both names used, they each refer to the same condition.
Pauciarticular juvenile rheumatoid arthritis (PJRA) is a form of juvenile idiopathic arthritis (JIA). Oligoarticular JIA is a newer name for the condition.
All forms of JIA cause swelling and inflammation in the joints of children under 16. A diagnosis of PJRA means that four or fewer joints are impacted. PJRA generally causes inflammation in the knees or other large joints. About half of children with JIA have PJRA.
PJRA often resolves quickly without resulting in joint damage. When PJRA lasts longer than 6 months, it’s called persistent oligoarthritis. When PJRA lasts longer than 6 months and begins to affect more than four joints, it’s referred to as extended oligoarticular JIA. About one-third of children with PJRA will develop extended oligoarticular JIA.
Pauciarticular juvenile rheumatoid arthritis vs. polyarticular juvenile rheumatoid arthritis
PJRA is distinct from polyarticular juvenile rheumatoid arthritis. At least five joints are affected when a child has polyarticular juvenile rheumatoid arthritis. These often include small joints, such as the joints in a child’s hands and feet. About 50 percent of children with JIA have polyarticular juvenile rheumatoid arthritis.
PJRA doesn’t have a known cause yet. But like all forms of rheumatoid arthritis, PJRA is an autoimmune condition. Autoimmune conditions occur when something causes your immune system to attack your healthy cells and tissues.
PJRA can sometimes run in families. There’s a link between PJRA and an inherited gene called HLA antigen DR4. Researchers believe that people who have this gene are more likely to develop PJRA.
Other risk factors include:
- Developing an infection. An infection or illness can trigger PJRA in children, especially if they have the HLA antigen DR4. But more research into this link still needs to be done.
- Being a girl. Girls might have a higher likelihood of developing PJRA than boys.
- Being a girl younger than 7. Girls between the ages of 2 and 7 may be more likely to develop PJRA.
- Being a boy older than 8. Boys could have an increased chance of experiencing PJRA after 8 years old.
The peak number of new cases of PJRA is 2 to 3 years old. The condition is rarely seen after 10 years old.
The symptoms of PJRA can vary depending on the child and on the joints affected. A child with PJRA typically walks with a limp in the morning and may or may not mention having pain. Children are often brought to a doctor because of a swollen knee.
Some children will have symptoms daily, but other children will only have symptoms during episodes or flare-ups of their PJRA. Symptoms include:
- swollen knee, shoulder, elbow, ankle, or other joints
- painful and stiff joints in the morning or after a nap
- difficulty using joints
- joints that are warm, red, or discolored
- decreased appetite
- eye inflammation
- trouble gaining weight
There’s no single test for PJRA right now. Instead, doctors will look at your child’s symptoms and medical history. Tests will be done to rule out other conditions.
Your child’s doctor might refer to a specialist called a pediatric rheumatologist to confirm a diagnosis of PJRA. As a rule, PJRA can only be diagnosed in children who are under 16 years old, and who have been experiencing symptoms for at least 6 weeks.
The following tests may be done to confirm or rule out other conditions:
Your child will likely have blood drawn. Antibodies that are often seen in other types of rheumatoid arthritis, such as rheumatoid factor (RF), are typically negative. The antinuclear antibody (ANA) can be positive in PJRA, which can increase the chance of eye inflammation (iritocyclitis/uveitis).
Other tests may be done to look for variances that could point to other conditions such as Lyme disease, malignancies, and other types of arthritis. Inflammatory markers may also be elevated, including C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR).
A complete blood count (CBC) or white blood cell count tests will look for elevated white blood cells that indicate an infection,as well as look for anemia that can be seen in PJRA.
Your doctor may order an X-ray, or MRI to get close images of your child’s muscles, organs, and bones. These images can show damage and inflammation, which can help determine a diagnosis.
A joint aspiration is a test that’s done by inserting a hollow needle into a joint to remove fluid called synovial fluid. This test may be done if an infection is suspected.
The treatment for PJRA depends on the child. Doctors will consider your child’s age, symptoms, and overall health when they develop a treatment plan. Treatment will focus on reducing pain and managing symptoms.
Treatments might include:
- Nonsteroidal anti-inflammatory medicines (NSAIDs). NSAIDs may help reduce inflammation and pain.
- Corticosteroid medicines. Intraarticular glucocorticoid injections might reduce inflammation and treat pain for children with severe PJRA symptoms.
- Disease-modifying antirheumatic medicines (DMARDs). Nonbiologic DMARDS — such as methotrexate, sulfasalazine, or leflunomide — work to manage inflammation and reduce symptoms.
- Biologics. Biologics such as tumor necrosis factor (TNF) blockers can calm down your child’s immune system. It might be an option if other medications aren’t helping.
- Physical and occupational therapy. Physical and occupational therapy sessions might help your child improve their strength and their ability to do daily tasks such as dressing and bathing.
- Eye exams. Children with PJRA might experience eye inflammation more often. Regular eye exams may help catch and treat any problems.
- Diet and weight management. Maintaining a moderate weight could reduce the symptoms of PJRA. An anti-inflammatory diet could also help manage pain.
- At home pain relief. Getting plenty of rest, taking warm baths for joint pain, and using ice packs can help your child manage pain at home.
- Low impact exercise. Your child’s doctor might recommend exercise that’s easy on their joints, such as yoga.
The outlook for PJRA can vary. Some children will recover completely within a few months. Other children might have symptoms for years, or symptoms that get worse as they age. Worsening symptoms can lead to complications with bone growth, eye health, and even organ function.
But treatment can help children with PJRA manage their symptoms and prevent complications. Your child’s pediatric rheumatologist can develop a treatment plan focused on managing pain and improving your child’s ability to perform daily activities. Many children with PJRA are able to manage their symptoms, attend schools, and do other activities.
PJRA is a type of juvenile rheumatoid arthritis. The condition is also called oligoarticular JIA.
About half of children with juvenile rheumatoid arthritis have PJRA. PJRA typically impacts large joints such as the knees and shoulders. It causes swelling, pain, and stiffness.
PJRA occurs in children under 16 and can be managed with a combination of pain relieving medication and physical therapy. Some children recover from PJRA without any complications, but other children might experience worsening symptoms as they get older. But treatment may help children with PJRA manage their symptoms and improve how they complete daily tasks.