Juvenile rheumatoid arthritis
What is it?
Juvenile rheumatoid arthritis, also known as juvenile idiopathic arthritis, is the most common type of arthritis in children under the age of 16.
Juvenile rheumatoid arthritis causes persistent joint pain, swelling and stiffness. Some children may experience symptoms for only a few months, while others have symptoms for the rest of their lives. There are several types of juvenile rheumatoid arthritis, each classified according to:
- The number of joints affected
- The signs and symptoms
- The results of blood tests
Some types of juvenile rheumatoid arthritis can cause serious complications, such as growth problems and eye inflammation. Treatment of juvenile rheumatoid arthritis focuses on controlling pain, improving function and preventing joint damage.
The most common signs and symptoms of juvenile rheumatoid arthritis are:
- Pain. While your child might not complain of joint pain, you may notice that he or she limps — especially first thing in the morning or after a nap.
- Swelling. This sign is most often seen in the knees, but the small joints of the hands and feet also can be affected.
- Stiffness. You might notice that your child appears more clumsy than usual.
There are three main types of juvenile rheumatoid arthritis:
- Oligoarthritis. This variety affects fewer than five joints during the first six months of the disease. It also is the variety most likely to feature eye inflammation, which can cause blindness in rare cases.
- Polyarthritis. This variety affects five or more joints during the first six months of the disease. Signs and symptoms are usually confined to the joints.
- Systemic. Formerly known as Still's disease, this type can feature swollen lymph nodes, rashes and fever — which may come and go quickly. It can also cause inflammation of internal organs.
Like other forms of arthritis, juvenile rheumatoid arthritis is characterized by times when symptoms flare up and times when symptoms disappear.
Doctors believe that juvenile rheumatoid arthritis is an autoimmune disorder. This means that the body's immune system attacks its own cells and tissues. It's unknown why this happens, but both heredity and environment seem to play a role. Certain gene mutations may make a person more susceptible to environmental factors — such as viruses — that may trigger the disease.
Risk factors for juvenile rheumatoid arthritis include:
- Sex. In general, juvenile rheumatoid arthritis is more common in girls.
- Race. Juvenile rheumatoid arthritis appears to be more common in white children than in black or Asian children.
Several serious complications can result from juvenile rheumatoid arthritis. But keeping a careful watch on your child's condition and seeking appropriate medical attention can greatly reduce the risk of these complications:
- Eye problems. Some forms of juvenile rheumatoid arthritis can cause eye inflammation. If this condition is left untreated, it may result in cataracts, glaucoma and even blindness. Eye inflammation frequently occurs without symptoms, so it's important for children with juvenile rheumatoid arthritis to be examined regularly by an ophthalmologist.
- Growth interference. Juvenile rheumatoid arthritis can interfere with the development of your child's bones and growth. Some medications used to treat juvenile rheumatoid arthritis, mainly corticosteroids, also can inhibit growth.
Diagnosis of juvenile rheumatoid arthritis can be difficult because joint pain can be caused by many different types of problems. No single test can confirm a diagnosis, but tests can help rule out some other conditions that produce similar signs and symptoms.
Some of the most common blood tests for suspected cases of juvenile rheumatoid arthritis include:
- Erythrocyte sedimentation (sed) rate. Sedimentation rate is the speed at which your red blood cells settle to the bottom of a tube. An elevated rate can indicate inflammation. Measuring the sed rate may be used to rule out other conditions, to help classify the type of juvenile rheumatoid arthritis and to determine the degree of inflammation.
- Anti-nuclear antibody. Anti-nuclear antibodies are proteins commonly produced by the immune systems of people with certain autoimmune diseases, including arthritis.
- Rheumatoid factor. This antibody is commonly found in the blood of adults who have rheumatoid arthritis.
In many children with juvenile rheumatoid arthritis, no significant abnormality will be found in these blood tests.
X-rays may be taken to exclude other conditions, such as:
- Congenital defects
X-rays may also be used from time to time after the diagnosis to monitor bone development and to detect joint damage.
Joint fluid removal
The doctor may use a needle to remove some fluid from your child's swollen joint. Analysis of the joint fluid can help the doctor identify the cause of the arthritis.