Juvenile idiopathic arthritis (JIA), also commonly referred to as juvenile rheumatoid arthritis (JRA), is defined as joint inflammation lasting more than 6 weeks in a child younger than 16 years of age. This is the most common type of arthritis in childhood, affecting about 1 in 1,000 children in the United States. The exact cause of JIA is not known, but it is thought to be due to a combination of genetic predisposing factors and the environment. JIA is considered a chronic condition, meaning that these symptoms may last for a long time, and sometimes continue into adulthood. There are several different types of JIA, which are based on the number of joints with arthritis, the types of joints affected, and other symptoms your child may have. These types include:
Other types of JIA with a much different set of causes, symptoms and treatment include enthesitis-related arthritis and systemic-onset JIA.
Children with arthritis may experience a wide variety of symptoms. Children may develop joint pain, swelling, stiffness, or warmth. Frequently, younger children may not complain at all, but may develop a limp or difficulty using their fingers. Joint symptoms are typically worse first thing in the morning or after rest, and improve throughout the day. Children with oligoarticular JIA usually have involvement of larger joints such as the knee or ankle, while those with psoriatic or polyarticular JIA may also have involvement of small joints such as the fingers and toes. Because arthritis is associated with inflammation, the child may feel tired, have a decrease in appetite, or have slow growth. JIA can also be associated with eye disease (uveitis), which may cause symptoms such as redness and decreased vision, or may be clinically silent.
There is no one specific test to diagnose juvenile idiopathic arthritis. Imaging and laboratory studies may be used to support a diagnosis of JIA in a child who has symptoms of arthritis, and to help rule out other underlying causes. Elevated inflammatory markers and anemia may be seen, as well as certain antibodies including antinuclear antibody (ANA), Rheumatoid factor (RF), and citric citrullinated peptide (CCP). Some children have JIA with no positive antibodies. To rule out infection, tests for Lyme and other diseases may be sent from the blood or the joint fluid. Imaging studies such as X-ray, ultrasound and MRI, may be ordered to look for inflammation and damage to the joints. All children with a suspected diagnosis of JIA should be seen by an ophthalmologist to rule out uveitis.
The main goals of treating arthritis are to decrease joint pain and stiffness, control inflammation, and maximize growth and function. Treatment depends on the type and severity of the arthritis in addition to factors specific to the child and family. Medications that may be used include nonsteroidal anti-inflammatory drugs (NSAIDs), disease-modifying anti-rheumatic drugs (DMARDs), biologic medications, and injection of steroid directly into the affected joint(s). Physical and occupational therapy are crucial for restoring mobility and joint function. Children with JIA have the best prognosis when they have a cohesive care team involving the parents, teachers, pediatric rheumatologist, ophthalmologist, and physical and occupational therapist.