Juvenile idiopathic arthritis

What is juvenile idiopathic arthritis?

Juvenile idiopathic arthritis (JIA) is a collective term for chronic inflammatory joint diseases in children and young people. There are various forms of the disease, differing in the number and pattern of joints affected. Only a few joints are inflamed initially in some patients. In about half of JIA patients the large joints are affected, such as the knees and ankles. This form of JIA is termed oligoarthritis (from the Greek “oligos” meaning few).

When the disease is active, the joints are painful, swollen and overheated, and their movement is clearly impaired. Patients assume typical abnormal and compensatory postures to ease the joints. Performance is reduced and the young patients seem tired and exhausted.

In cases of polyarthritis (from the Greek “poly” meaning many), the number of limbs affected is higher. Usually the smaller joints, such as finger and wrist joints, are inflamed. Sometimes changes are observed that are recognisable from other rheumatic diseases. For example, the abnormal positions of the fingers resemble those of adult rheumatoid arthritis.
Restricted finger mobility may make it much more difficult for the young patient to learn new skills, for example reaching for objects or writing.
If the affected child is suffering from inflamed joints plus psoriasis, this form of JIA is termed psoriatic arthritis. Typically, a first-degree relative of the patient suffers from psoriasis, too. Enthesitis-related arthritis is present if the tendon insertion points are inflamed as well as the joints (the Latin word  enthesis refers to attachment of tendon to bone). Between 70 and 80 per cent of patients are boys. 

The systemic form of JIA is fundamentally different from other forms of JIA. Recurrent episodes of fever, typically one or two peaks per day, and skin rashes accompany the joint involvement. Organs may also be affected.

Some patients with JIA may develop an inflammation of the iris of the eye. This generally occurs gradually and symptoms may include pain, sensitivity to light and red eyes.

About 15,000 young people under the age of 16 suffer from juvenile idiopathic arthritis in Germany, and between about 750 and 1,000 children visit a physician for the first time with this disease each year. Juvenile idiopathic arthritis is therefore the most common chronic inflammatory rheumatic disease of childhood. The majority of patients are girls.

What are the causes and risks for the development of juvenile idiopathic arthritis?

Little is known about the cause of juvenile arthritis. It is assumed, however, that the decisive process is a malfunctioning immune system response. The task of this immune system defense is to detect dangerous pathogens (e.g. germs), foreign bodies and pollutants and to destroy them in a targeted fashion. The body’s own substances and surrounding tissue are normally recognised by the immune system cells and tolerated. Yet if the communication between cells is impaired, the immune system will also direct its destructive activity against the body’s own tissue, resulting in an inflammatory reaction.

What role does lifestyle play in juvenile idiopathic arthritis?

The German Society for Childhood and Adolescent Rheumatology (in German: Deutsche Gesellschaft für Kinder- und Jugendrheumatologie) recommends a balanced diet with an adequate supply of energy sources, vitamins, fibre and trace elements. An imbalanced diet should be avoided in any case. The majority of children eat more meat and sausage and less fruit and vegetables than recommended. A calcium supply appropriate to the patient’s age should always be ensured.

Considerable weight loss may occur. Parents should take care that the child does not lose too much weight.

No additional stress should be placed on the young patients; the family should try to continue to live as normally as possible.

How is juvenile idiopathic arthritis diagnosed?

In order to make a diagnosis, the doctor asks the patient about the type, onset and progression of the current symptoms. Information about triggering events and other cases of inflammatory rheumatic disease in the family history is important. Each of the painful joints is included in a thorough physical examination. The doctor will also take note of any changes in the skin and involvement of the eyes.

The following procedures are available for diagnosis:

  • Physical examination
  • Blood test
  • X-ray examination
  • Ultrasound examination

The blood test provides information about the current inflammatory process. The blood values show the functional state of the internal organs and allow more precise statements on the disease’s progression.

The doctor also uses imaging procedures to find out more about the condition of the inflamed joints and detect any damage. X-ray and ultrasound examinations are suitable for this investigation, too.

If the patient is still in an early stage of development or very young, it is sometimes not easy to diagnose juvenile idiopathic arthritis. Only after a certain age are children able to report their symptoms themselves and describe them exactly.

In the early stages, the symptoms of juvenile idiopathic arthritis resemble those of other rheumatic diseases. A paediatric rheumatologist specialises in the particular characteristics of diagnosis and will be able to initiate and monitor effective and tolerable treatment.

How is juvenile idiopathic arthritis treated?

The principal medicines available for treating juvenile idiopathic arthritis are nonsteroidal antirheumatic agents – abbreviated NSAR (e.g. the active substance diclofenac), so-called disease-modifying drugs and corticosteroids (e.g. the active substance prednisolone).

The NSAR help to combat joint pain, swelling and fever. They act quickly with improvement usually occurring within hours or days. For mild cases, this treatment is often sufficient, but if the disease advances into a chronic form, disease-modifying drugs will also be necessary. They intervene with the malfunctioning immune system and are able to attenuate and prevent the disease from progressing.

Disease-modifying drugs include, for example, the active substances methotrexate, leflunomide, sulfasalazine, azathioprine and antimalarial drugs. Methotrexate is regarded as the gold standard for JIA.

Corticosteroids are considered a third pillar of drug treatment. They have a strong anti-inflammatory action and are taken either in tablet form or injected as a solution directly into the inflamed joint. These substances act very quickly to alleviate pain and as short-term anti-inflammatories, but they do not affect the actual course of the disease. In the majority of patients, corticosteroids are used until the inflammation and pain have subsided to a significant extent. Their dose is then often reduced or the product is tapered off entirely.

Non-drug treatments are also available in addition to medicinal treatment. The most important of these are physiotherapy, physical therapy, patient training sessions and aids such as insoles.

Physiotherapy is used to prevent impaired mobility, stiffening of the joints and incorrect posture, and to avoid compensatory movements and awkward patterns of movement. If changes of this type have already developed, physiotherapy attempts to correct them with the aim of restoring normal conditions.