Juvenile Arthritis

Children with arthritis do not always complain of pain, so it may be difficult to tell if a child’s joints are inflamed (red, swollen and warm to the touch). Sometimes the only initial clues to arthritis may be that the child is stiff when waking up or there is some difficulty using an arm or leg. In some cases, there may be no signs other than a swollen joint or some loss of movement. As a result, JA can be difficult to detect and may go unrecognized by even the most experienced physician. Your child’s doctor will look carefully for any signs of joint swelling or loss of mobility, which indicate that the joints are inflamed.

Arthritis or its symptoms may be a result of many different illnesses, including infection, injury, allergic/drug reactions or other autoimmune diseases (such as thyroid disease, diabetes, inflammatory bowel disease or lupus). Since there is no single test to diagnose JA, tests to rule out other causes of joint pain and swelling must be done. Your child will likely have X-rays as well as urine and blood tests.

Once the diagnosis of JA has been confirmed, routine tests (such as blood tests, X-rays and eye examinations) will need to be repeated from time to time in order to follow the illness and assess the effects of any medication. Your child’s doctor will discuss with you how often these routine tests need to be done.

The symptoms and nature of JA vary greatly. Once a doctor suspects JA, your child will usually be referred to a specialist, such as a pediatric rheumatologist (a doctor who is specially trained in the diagnosis, evaluation and treatment of disorders of joints, muscles and bones in children).

There are seven major types of JA:

• Oligoarticular–persistent JA
• Oligoarticular–extended JA
• Polyarticular–RF negative JA
• Polyarticular–RF positive JA
• Systemic JA
• Enthesitis–related arthritis
• Psoriatic arthritis

Determining the form of JA your child has is mostly based on the information collected during the initial physical examination and tests. What happens with your child’s disease over the next six to 12 months is also important. It may take time for your child’s doctor to be absolutely certain which of these types of JA your child has. If the course of your child’s disease changes, a different, more appropriate form may be assigned. Your child’s healthcare provider can still begin treatment without knowing exactly what form of JA your child has.  But confirmation of the form of JA will give you, your child and his or her healthcare providers the best information for creating a specially designed treatment plan.

This is the most common and mildest form of JA. Children are classified as having oligoarticular-persistent JA if no more than four joints are involved beyond six months after the diagnosis of JA. Although multiple joints are affected, not all joints may be inflamed at the same time. The most commonly affected joints are the knee, ankle, wrist and elbow, with little to no change in the overall health or growth of the child. Symptoms usually start in children four years old or younger, and girls are affected more often than boys.

Although oligoarticular-persistent JA may involve flares (when symptoms worsen) and remissions (when symptoms decrease or disappear), with the right treatment there is rarely permanent damage to the joints. Although the joint inflammation in this type of arthritis may be mild, up to 20% of children with this type of JA will develop uveitis (inflammation of the eye), so it is crucial that your child’s eyes are examined at least three or four times a year for the first few years after diagnosis. The blood test for antinuclear antibody (ANA) is almost always positive with children who develop eye inflammation with JA. That’s why the ANA blood test helps identify those children who will need more frequent eye checks.

Children are classified as having oligoarticular–extended JA if four or fewer joints are involved within the first six months after the initial diagnosis, but the child develops arthritis in five or more different joints at any time during the course of the disease. Large and small joints may be affected, and flares and remissions may occur. With the appropriate treatment, permanent damage to the joints can usually be prevented. Eye disease is often seen so it is important for children to have their eyes examined at least three or four times a year for the first few years after diagnosis. The blood test for antinuclear antibody (ANA) helps to identify those children who will need more frequent eye checks.

Children with polyarticular-RF negative JA have five or more joints involved within the first six months of diagnosis, but they do not test positive for rheumatoid factor (RF).This type of JA can begin at any age, and is more common in girls than in boys. It usually starts in several joints at the same time but may begin in only one or two joints and then later involve other joints. The joints of the jaw may be affected and this can lead to a reduced ability of the child to open their mouths or chew, and may cause abnormal growth of the jaw. The joints of the neck may also be affected. Your child’s doctor will check these joints by doing a physical examination and may do X-rays or other tests such as an MRI.

Children with polyarticular-RF positive JA have five or more joints involved within the first six months of diagnosis and test positive for a blood protein called rheumatoid factor (RF). This form of JA can begin at any age, but it occurs more often in girls during their pre-teen or teenage years. Usually, the arthritis starts in several joints at the same time. The onset of this form of JA in teenagers may closely resemble adult rheumatoid arthritis (RA). Occasionally it will begin in only one or two joints, then spreads to involve other joints.

It can affect both the small (especially hands and fingers) and large (knees, hips, ankles) joints, usually on both sides of the body. Some children may also experience a low-grade fever, rheumatoid nodules (bumps under the skin, especially in the hands or along tendons), anemia (a low red blood cell count or a fall in the hemoglobin level), significant fatigue, poor appetite and an overall feeling of being unwell. Severe joint damage is a concern, so stronger medications are recommended at an early stage.

This form of JA affects the body in a general way (frequent fevers) and can affect not only the child’s joints and skin, but also the internal organs. Systemic JA can begin at any age and affects boys and girls equally. It often involves many joints, and some joints may be affected to a severe degree. Children have a spiking (rapidly rising and falling) fever that usually occurs once or twice a day. A pale red rash frequently comes and goes with the fever.

The arthritis usually appears within the first six months after the start of the fever, and can persist even when the fever settles. Children may have swollen lymph glands and an enlarged liver and spleen. They appear listless and unwell during the fever, only to brighten up when their temperature returns to normal. When fever continues on and off for several weeks, the child may become weak, lose weight or become pale from anemia (a fall in the level of hemoglobin in the blood). Flares that last a long time may also interfere with the child’s growth, but growth usually improves as the child’s condition improves. Inflammation of the internal organs may cause stomach pain or affect the heart or lungs, but will not cause permanent damage. Sometimes there is no sign of joint inflammation in the early stages of this form of JA. This can make it very difficult to diagnose, as there are many other illnesses that cause a fever and a rash in children. Because of this, many tests may need to be done.

The course of systemic JA can be unpredictable. With newer medications, even severe cases may go into remission within a few years; however, flares may occur even after the disease has been inactive for a long time.

Medications for systemic JA include drugs that control not only the arthritis, but also the systemic part of the illness, such as the fever and the anemia. Inflammation of the eye is uncommon in this form of JA, but children should still have their eyes examined annually.

Children with enthesitis-related arthritis have inflammation both in their joints (arthritis) and in the spots where tendons attach or insert to bones (entheses). This form of JA generally affects children over the age of 10 and is more common in boys. This is one of the few types of arthritis that may run in families. The legs and hips are usually affected, especially around the knees, ankles and bottoms of the feet. Children may complain of knee, heel or foot pain, which may improve with activity. Joint inflammation often continues into adulthood, sometimes progressing into joints in the back and often leading to pain and stiffness. It may also occur with inflammation of the eyes or the bowel (intestines). Many children with this form of JA carry a specific protein in their cells (called HLA B-27) and lab testing for this protein may help in diagnosis.

This type of JA is when arthritis accompanied by psoriasis, a skin disease that appears as a scaly red rash. Psoriatic arthritis affects both boys and girls, and it can happen at any age. Often only a few joints are affected, but the hips or back or the fingers and toes can be affected. The fingers or toes of some children may look sausage-like because of extreme swelling. The arthritis starts before any sign of skin disease in about half of children with psoriatic arthritis. For this reason, knowledge of a family history of psoriasis may help with the diagnosis.

No one knows exactly what causes JA. It is not caused by any disease or an infection either parent may have had. It is not connected to any event during pregnancy. JA is not caused by eating the wrong foods, and there is no proof that JA can be improved by any specific diets. Many people feel their arthritis is better in warm dry climates, but there is no proof that JA is improved by any particular climate.

JA may begin after an event that turns on the body’s immune system, such as an ordinary infection or injury. The body’s immune system normally flights these infections or injuries by causing inflammation. With JA, the immune system seems to become overactive and causes continuous inflammation.  This continuous inflammation affects and the joints and sometimes skin and internal organs.

Most types of JA are not passed from generation to generation so the chance of your child passing arthritis on to his or her own child is extremely rare.