Juvenile Rheumatoid Arthritis (JRA)

In childhood the most frequent rheumatological disease is juvenile rheumatoid arthritis which is also one of the most frequent chronic diseases in this age group. There are a number of different but related disorders which are expressed in chronic inflammation of the joints. It is not clear what causes these conditions and the complexity of the underlying genetic bases for them makes it difficult to clearly distinguish the different types. The naming of the diseases is also under review, with juvenile idiopathic arthritis perhaps gaining ground.

Three main divisions of juvenile rheumatoid arthritis can be described, that affecting many joints which is called polyarticular, that involving few joints and termed pauciarticular and a more body wide disease onset known as systemic arthritis. The arthritis is a chronic disease which flares up at times and then goes into remissions, with targeting of the medical treatment towards the induction and maintenance of a remission. Recent advances in the development of drugs have produced the biological agents which are much more effective for arthritic diseases.

How and why juvenile rheumatoid arthritis develops is not well understood, with an autoimmune attack against the tissues of the joints perhaps precipitated by infection or trauma. The lining of the joint, the synovial membranes, becomes larger and becomes chronically inflamed, with this occurring in individuals with some susceptibility of genetic origin. How the disease presents in the person and how it comes on is under the control of a number of genes. The incidence of these arthritic conditions is variable due to variations in influences from the environment, differences in the populations involved and in how susceptible individuals are.

The oligoarticular type of juvenile chronic arthritis, in which a small number of joints are inflamed, is the commonest disease type, consisting of about half of all patients. Thirty percent have a large number of joint affected, the polyarticular type, and the rest have the systemic form. Sufferers from chronic juvenile arthritis may at some type suffer also from another autoimmune disorders. The severe pain and disability due to the arthritis causes significant psychological distress, behavioural problems, anxiety and depression. The polyarticular and oligoarticular forms occur more often in girls than boys with a frequency of three to four and a half to one. The systemic form occurs equally.

There are two peaks of age occurrence in the many joint affected or polyarticular type of juvenile arthritis, at between 6 and 12 years and between 1 and 4 years. The fewer joint or oligoarticular form peaks between 2 and 4 years, with no particular pattern in age incidence for the systemic form. How the disease behaves over the first six months indicates which form of the disease the patient will be classed as. With a fewer affected joints form there will be four or less involved over this time period. The polyarticular type has five or more affected joints during the six months since onset. The systemic form does not have this pattern but its symptoms are rashes, arthritis and a fever.

A six week period of arthritis in a joint is necessary for a diagnosis to be made of one of the forms of juvenile arthritis. Typically there is a complaint of morning stiffness and stiffness after other periods of the joint having been kept still for a while. Disease onset can be insidious, i.e. slow and sneaky, or very abrupt with all the symptoms coming on in a short space of time. These can include joint stiffness after immobility, pain in the joints during the day, limping and school absences, with in some cases the addition of inflammatory disease of the bowel. There may be few complaints from the child of pain in their joints, instead they may just stop using a joint with the consequent contracture or disuse atrophy.

The onset of juvenile arthritis which comes on systemically is indicated by the child spiking a fever either once or twice daily with the temperature going back to normal each time. This pattern allows some diagnostic usefulness as if does not occur in the event of infections. A short lasting skin rash may also be present over the limbs and the trunk, the child may seem unwell and have joint pains in the larger body joints.

Jonathan Blood Smyth, editor of the Physiotherapy Site, writes articles about Physiotherapist, back pain, orthopaedic conditions, neck pain, injury management and Physiotherapists in London. Jonathan is a superintendant physiotherapist at an NHS hospital in the South-West of the UK.