What is juvenile idiopathic arthritis?
Juvenile idiopathic arthritis (JIA) is a type of inflammatory arthritis that affects children under the age of 16. It was previously known as juvenile rheumatoid arthritis (JRA).
Most forms of JIA are autoimmune. That means your body’s immune system mistakes your own cells for foreign ones and attacks them. The attacks cause joint pain, swelling, and stiffness. An infectious organism such as Streptococcal bacteria can trigger an attack.
You might have a single attack of JIA, or symptoms may last for years. The condition is considered chronic if the symptoms linger for more than three months.
Types of JIA
There are six types of JIA.
Oligoarthritis (previously called pauciarticular JRA) affects four or fewer joints in the first six months. The joints most often affected are the knees, ankles, and elbows. Hip joints aren’t affected, but inflammation in the eye (uveitis) can occur. If antinuclear antibodies (ANA) are present, children who have them need to be monitored closely by an ophthalmologist.
Polyarthritis (also called polyarticular JIA) involves more of the body than oligoarthritis. It affects five or more joints in the first six months of illness. Small joints in the fingers and hand are most affected; it may also affect weight-bearing joints such as the knees and jaw.
There are two forms: RF-positive (rheumatoid factor-positive) and RF-negative (rheumatoid factor-negative). The RF-positive type most closely resembles adult rheumatoid arthritis.
Systemic JIA affects the entire body, sometimes including internal organs such as the heart, liver, and spleen. Symptoms can include high fevers, rashes, anemia, and lymph node enlargement.
Other subtypes include psoriatic and enthesitis-related JIA:
- Psoriatic JIA occurs when psoriasis is present alongside other symptoms such as nail pitting, nail separation (onycholysis), and the swelling of a single whole finger or toe (dactylitis).
- Enthesitis-related JIA involves inflammation of the tendons, ligaments, spine (axial), and sacroiliac (SI) joints. It can also affect the hips, knees, and feet. Uveitis can occur as can the genetic marker HLA-B27.
The last subtype is undifferentiated arthritis, which does not fit within any other subtype. Symptoms can span two or more of the subtypes.
Arthritis symptoms can flare up
The symptoms of arthritis come and go in waves called flare-ups. During a flare-up, symptoms worsen. Symptoms go into remission — become less severe or disappear — between flare-ups.
JIA is different in everyone. You may have a few flare-ups and then never have symptoms again. You may also experience frequent flare-ups or flare-ups that never go away.
Joint pain and other problems
The most common symptom of JIA is joint pain. Joints may swell and grow tender. They can turn red and feel warm to the touch. Your joints can become stiff and lose their mobility. This results in a loss of fine dexterity, especially in your hands. Many people with JIA limp due to joint pain in their hips, knees, or ankles.
You might find yourself becoming less physically active due to the pain and loss of mobility. If your arthritis lasts long enough, your joints may become damaged.
Fatigue and loss of appetite
The joint pain from arthritis can disrupt your sleep, causing you to feel tired. Inflammation can also cause fatigue. You might lose your appetite and have trouble gaining weight as you grow. It’s also possible that you may lose weight.
Don’t let pain and fatigue get worse. Stay active to reset your body’s sleep cycle. Exercise to release endorphins, the body’s natural painkillers. Certain exercises can also strengthen the muscles around your joints, diminish pain, and help you maintain flexibility.
Persistent arthritis can damage your joints. While you’re still growing, you have what are called growth plates on the ends of your bones. These allow your bones to get longer and stronger. Arthritis can distort these plates and the surrounding cartilage. This can inhibit your growth or cause joints to grow at different rates. For example, one arm or leg might become longer or shorter than the other. Treating arthritis early can help protect against growth problems.
Inflammation associated with arthritis can involve the eyes, causing redness and pain. You might be particularly sensitive to bright light if you have eye pain and inflammation. Untreated inflammation can permanently damage your eyes and cause vision problems.
This inflammation is often inside the eyeball instead of on the surface of the eye. Diagnosing this requires a slit lamp exam, a test that detects the inflammation.
Fever and skin rash
If you have systemic JIA, you may experience a high fever and a light pink rash on your skin. The rash most commonly appears on the following body parts:
The rash and the fever appear together and can come and go very suddenly. A fever from JIA can spike above 103°F (39.4°C). It can last for weeks, unlike the fever caused by a cold.
Swollen lymph nodes and internal organs
Systemic JIA can also cause lymph nodes to swell up and become inflamed. Lymph nodes are small glands that act as your body’s filters. They’re found all over the body, including the corners of the jaw, the armpit, and inside the thigh.
Sometimes the swelling can spread to the internal organs, affecting the heart, liver, spleen, and the tissue that surrounds the organs (serositis). In rare cases, lungs can become inflamed. A rare, but serious, complication called macrophage activation syndrome (MAS) can occur when the immune system goes into extreme overdrive.
Living with JIA
Getting diagnosed with arthritis can bring a lot of uncertainty, especially when you’re young. It can also be a difficult, painful condition to live with. However, with proper treatment and symptom management, many young people with juvenile idiopathic arthritis go on to live normal lives. Your arthritis may even go into remission. Monitor your symptoms and work closely with your doctor to ensure the best outcome.