By: Timothy Hahn, MD, FAAP
Juvenile idiopathic Arthritis (JIA) is a chronic form of arthritis that affects children and teens. There are multiple types of arthritis that can affect young people, but JIA is the most common.
The majority of children diagnosed with JIA are between ages 2 to 5 years old. However children can be diagnosed with JIA as young as 18 months and as old as 16 years.
What causes JIA?
This is a great question that, unfortunately, does not have a perfect answer. What we do know is that in children with JIA, the immune system causes inflammation in joints. What we do not know yet is why. It is likely that multiple factors can contribute to developing JIA. Some children may have been exposed to an illness, a certain medication or something else in their environment that triggers the immune system. Once the immune system is active, it can attack joints by mistake. The trigger is usually never identified.
Some children may be more likely to develop arthritis because of the genes they inherited from their parents. It is important for children with JIA and their parents to understand that there is not anything you can do to prevent JIA from developing.
What are the symptoms of JIA?
For the most part, JIA symptoms affect only a child's joints and not other organs such as the heart, kidneys, lungs and intestines. The most common joints to be affected by JIA are the knees, ankles, wrists, elbows and small joints in the hands. The symptoms of JIA may vary depending on the child's age and the type of JIA. However, there are some symptoms that are common among all children.
Swelling is the most common symptoms and almost always seen in joints with arthritis. The swelling is limited to just the joint (not the whole foot or arm, for example). It will not come and go over the course of the day. It persists and will slowly get worse over time.
Stiffness is usually worst in the morning or after being inactive for a long time (such as sitting in class or long car rides). Stiffness usually improves throughout the day or with activity. In some children with arthritis, stiffness limits their ability to completely straighten or bend a joint.
Pain in joints with arthritis mostly happens in the morning and can improve with activity, just like stiffness. For most children with JIA the pain is mild. They may not complain of any pain, especially early in the disease process. Some joints may be more painful than others.
Limping is a result of arthritis affecting the knees, ankles, feet or hips. This is a common early symptom of arthritis, especially in young children who are not able to describe their other symptoms well.
Change in function such as trouble using crayons, not holding a fork normally, or not playing or climbing may be a sign of arthritis. Many children find a way to make up for their stiffness and pain, and learn how to do certain activities a different way.
How is JIA diagnosed?
The diagnosis of JIA is made based on a careful physical exam and review of the child's symptoms and medical history. In some cases, blood work and imaging (x-ray, ultrasound, MRI) tests may be needed. In many patients, lab tests may be normal, however. It is important to know that there are no labs that diagnose JIA.
Is all JIA the same?
Not all cases of JIA are the same. There are certain features that may provide an idea of what symptoms to expect, and how severe they may be for a child. For example:
Children with multiple joints involved, those with arthritis that affects the hip, ankle or wrist, or who have joint damage that can be seen on x-rays are likely to have more challenging cases of JIA. Children with these symptoms are more likely to need more aggressive treatment, and often longer courses of treatment. This also includes children with a positive
Rheumatoid Factor (RF) in their blood work. This is rare, though.
Some children with JIA develop
dactylitis which is when a finger or toe is swollen and red (sometimes called “sausage-like" swelling). These children are more likely to develop
psoriasis later in life.
Children with a specific genetic marker called
HLA-B27 are more likely to develop inflammation in their sacroiliac joints, where the base of the spine connects to the hip bones. This can cause stiffness and pain in the lower back. It is more common in older children and boys.
What are the treatment options for JIA?
The treatment of JIA is centered on controlling abnormal inflammation in joints. It is important to work with a pediatric rheumatologist who understands your goals to create a treatment plan that is right for you and your child.
Some children can be treated by injecting a steroid into the joint or joints with arthritis. For many, treatment will require a medication that targets the immune system. As researchers work towards understanding immune system triggers and how they cause inflammation, our treatments have become more targeted and specific. Many of the newer medications for JIA use “biologic" ways to treat the disease, such as helping the body block signals that lead to inflammation.
In addition to medicine, treatment of JIA often involves physical therapy. This can help a child regain their normal range of motion in joints. Physical therapy can also help strengthen muscles that may have become weak when the child's swollen and sore joints prevented normal activity.
What is uveitis and why do I see an ophthalmologist?
Uveitis is a type of inflammation inside the eye. About 10-20% of children with JIA will develop uveitis. Unfortunately, there are often no symptoms until the inflammation has already caused damage. To help catch and treat uveitis before there is damage, children with JIA need to see an ophthalmologist for frequent screening eye exams.
Does JIA ever go away?
For some children, yes. This is called remission. For some children, arthritis will go into remission only to come back months to years later. It is difficult to predict which children will go into permanent remission and which children will need to continue treatment into adulthood. Fortunately, advances in the treatment and monitoring of JIA have improved the prognosis for all children.
About Dr. Hahn
Timothy Hahn, MD, FAAP, is a fellow in Pediatric Rheumatology at Penn State Children's Hospital in Hershey Pennsylvania. He completed his medical degree at Georgetown University School of Medicine and completed his residency in general pediatrics at Penn State Children's Hospital. Within the American Academy of Pediatrics he is an executive committee member of the Section on Rheumatology.