Arthritis Dr Trisha Macnair Arthritis doesn't only affect older people - children get it too. In most cases children recover from juvenile arthritis with few long-term problems.

In this article

What is it? What causes it?

Who's affected? What are the symptoms?

How is it diagnosed? What's the treatment?

Arthritis is an inflammation of the joints, with pain or stiffness. It may be acute or chronic.

Acute arthritis is also called septic arthritis and may affect one or more joints.

Chronic arthritis is also known as juvenile idiopathic arthritis (JIA). It is classified depending on its initial symptoms as systemic (throughout the body, also called Still's disease), polyarticular or polyarthritis (affecting more than four joints), and pauciarticular or oligoarticular (up to four joints affected).

It's also classified depending on the results of blood tests for a variety of different antibodies.

Infection is an important but treatable cause of arthritis

Infection is an important but treatable cause of arthritis, especially in the under-two age group. Infections include bacteria and viruses, such as mumps, rubella and herpes, and Lyme disease.

Polyarthritis may be caused by many different things including inflammatory bowel disease, such as Crohn's disease, inflammatory blood vessel disease or vasculitis, blood disorders such as sickle cell anaemia or haemophilia, malignancy, cystic fibrosis and connective tissue disorders often because of problems linked to the immune system, such as systemic lupus erythematosus and ankylosing spondylitis.

The cause of systemic juvenile idiopathic arthritis is unknown. Genetic factors may play a part and disease may be triggered by a viral infection (although none has been identified), which causes overactivity of the immune system.

Children with a family history may be at increased risk.

Symptoms depend on the type of arthritis and joints affected

Symptoms depend on the type of arthritis and joints affected but include painful, swollen, stiff and tender joints, an acute illness with fever and lethargy, loss of appetite, weight loss and refusal to use the affected joint or limb.

In systemic arthritis, there may be high fever, rash, swollen glands, muscle pain, anaemia and inflammation of other organs, including the heart or eye. Joints may develop deformities over time.

Diagnosis is made on the basis of a combination of clinical examination, x-rays, bone scans and blood tests. It may be necessary to take a sample of fluid from the joint to test for infectious organisms.

Septic arthritis needs urgent treatment with antibiotics to reduce the risk of damage to the joint.

Treatments include drugs to control pain and inflammation, steroids (in more severe cases, which may include injections into the joint) and powerful medicines that alter the immune system (such as methotrexate, salazopyrin and cyclosporin).

Physiotherapy to keep the joints mobile and build muscle strength is also important. Splinting or surgery is sometimes needed.

In most cases, children recover from juvenile arthritis with few long-term problems. However, some do experience considerable difficulties from ongoing disease or damaged joints throughout adolescence and into adulthood.

This article was last medically reviewed by Dr Rob Hicks in November 2007