What is it?
Juvenile Idiopathic Arthritis (JIA), also sometimes called Juvenile Rheumatoid Arthritis (JRA) or Juvenile Chronic Arthritis (JCC), affects about 1 in 1000 children in the UK. It is a chronic condition that causes joint inflammation, pain, swelling, redness, and stiffness. It may also affect the eyes and internal organs. About one-fifth of those with JIA have an enlarged spleen.
There are three main types of Juvenile Idiopathic Arthritis:
Pauciarticular or Oligoarticular – about 50%. It affects four or less joints and is most common in girls less than 8 years old.
Polyarticular – about 30%. It affects five or more joints, especially in the hands and feet but also other larger joints.
Systemic – about 20%. It affects both joints and internal organs. Children with this type may have frequent fevers and rashes that can come and go rapidly. Also known as Still’s disease.
Each patient’s symptoms will differ and will frequently change over time, with flare-ups and remissions. In a few children the symptoms may be persistent, in a few others they may permanently disappear.
Doctors consider the diagnosis of JIA in patients who have had symptoms for at least 6 weeks. These symptoms may include morning stiffness, limping, reluctance to move an affected joint, joint pain and swelling. Patients with systemic JIA may have intermittent fever, rash, swollen lymph nodes, and in some cases liver, spleen, and (very rarely) lung involvement. Complications of JIA may include eye inflammation and problems related to joint growth. The disease may cause the affected joints to grow either too quickly or too slowly, causing one arm or leg to be shorter or longer than the other. It may also cause uneven growth in the joint itself. General growth may also be affected by JIA.
No single conclusive test is available for the diagnosis of juvenile idiopathic arthritis. The goals with testing are to help diagnose juvenile rheumatoid arthritis, to distinguish it from other forms of arthritis and conditions with similar symptoms, and to evaluate its severity. Testing can be used to monitor the condition, its potential complications, response to treatment, and to monitor for potential side effects associated with some treatments.
Laboratory Tests
- Full blood count (FBC) – to check for anaemia and to check for a normal response to infections
- Erythrocyte sedimentation rate (ESR) or C-reactive protein (CRP) – to detect inflammation
- Antinuclear antibody (ANA) – to detect the presence of autoantibodies; about 80% of those with eye involvement will test positive for ANA
- Rheumatoid factor (RF) – may be positive (present) or negative (absent) depending on the type of JRA
- HLA B27 – detects a type of protein (called an ‘antigen’) in the blood. Can be positive or negative in JIA. If it is positive it can help confirm a suspected diagnosis
- Urea and Electrolytes – to assess the patient’s kidney function
- Liver function tests – to assess the liver function
- Histocompatibility antigens (HLA) – may show the presence of antigens specific to autoimmune diseases
- Synovial fluid analysis – Fluid from an affected joint may be examined to detect crystals and to look for signs of joint infection
Non-Laboratory Tests
- X-rays of the joints – to detect narrowing of the joint spaces or erosions caused by joint inflammation
- Magnetic resonance imaging (MRI) – to detect increased joint fluid and joint inflammation
- Chest x-ray - to identify fluid build-up around the heart or lungs
- Eye exam - to detect the development of eye inflammation
- ECG- to detect inflammation of the heart
There is no cure for juvenile rheumatoid arthritis. The goals with treatment are to decrease pain and inflammation, maintain mobility and joint function, and to minimize joint damage and complications. Treatment will vary from patient to patient and frequently varies over time.
Medications may include pain relievers, disease-modifying antirheumatic drugs (DMARDs), immunosuppressants, steroids and biologic agents.
Physiotherapy and regular exercise are very important. They can help maintain flexibility, range-of-motion, muscle strength and joint mobility. Splints may be used in some cases to help keep a joint in the proper position. Hot and/or cold treatments may help relieve morning stiffness.
Some changes may need to be made at school and at home for a child with JIA but in most cases they can lead and should be encouraged to lead relatively normal lives.
The cause of JIA is unknown, but it is thought to be an autoimmune disorder. The tendency to develop it may be inherited but it is believed that a triggering event is required for it to emerge. It usually begins between the ages of 2 and 5 years or between 9 and 12 years. More girls than boys develop JIA.