Juvenile Rheumatoid Arthritis (jra)
One of the most frequent chronic diseases of children and the most common rheumatological condition in this group is juvenile rheumatoid arthritis. This is not one disorder but a group of interrelated disorders which all exhibit inflammatory changes in the joints. The triggering factors for these diseases have not been uncovered and it has proven hard to delineate one particular type of condition from another due to the complex genetic factors. While it is often called JRA, there is a move to standardise the naming of these diseases into juvenile idiopathic arthritis.
Juvenile idiopathic arthritis can be classified into three main types, one which affects a few joints (pauciarticular arthritis), one which affects many joints (polyarticular arthritis) and a more overall disease which is termed systemic juvenile arthritis. The disease is chronic, persisting over a long period with flare ups and then periods of remission, with treatments aimed at inducing remissions for as long as possible without toxic effects from medication. More recent biological treatment agents have greatly increased the treatment efficacy against many 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.
Approximately fifty percent of all sufferers from juvenile chronic arthritis fall into the oligoarticular type with few joints affected, making it the most common type. With a greater number of joints affected by arthritis, the polyarticular type occurs in about a third of patients, with the remaining patients having the systemic form. Juvenile arthritis patients may be susceptible to acquiring a second autoimmune disorder. The significant disability and pain causes psychological distress, problems with behaviour, depression and anxiety. Girls are more likely to suffer from the many joint affected and poor joint affected forms, with equal incidence in the systemic form.
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 type of juvenile chronic arthritis which has a system wide onset has typical symptoms of a fever which spikes regularly once or twice a day with the temperature going back towards normal in between the spikes. This is helpful diagnostically as infections do not behave in this way. A skin rash which lasts a few hours only may appear on the trunk and the limbs, the child may not be well and the larger joints may exhibit pain.
Juvenile idiopathic arthritis can be classified into three main types, one which affects a few joints (pauciarticular arthritis), one which affects many joints (polyarticular arthritis) and a more overall disease which is termed systemic juvenile arthritis. The disease is chronic, persisting over a long period with flare ups and then periods of remission, with treatments aimed at inducing remissions for as long as possible without toxic effects from medication. More recent biological treatment agents have greatly increased the treatment efficacy against many 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.
Approximately fifty percent of all sufferers from juvenile chronic arthritis fall into the oligoarticular type with few joints affected, making it the most common type. With a greater number of joints affected by arthritis, the polyarticular type occurs in about a third of patients, with the remaining patients having the systemic form. Juvenile arthritis patients may be susceptible to acquiring a second autoimmune disorder. The significant disability and pain causes psychological distress, problems with behaviour, depression and anxiety. Girls are more likely to suffer from the many joint affected and poor joint affected forms, with equal incidence in the systemic form.
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 type of juvenile chronic arthritis which has a system wide onset has typical symptoms of a fever which spikes regularly once or twice a day with the temperature going back towards normal in between the spikes. This is helpful diagnostically as infections do not behave in this way. A skin rash which lasts a few hours only may appear on the trunk and the limbs, the child may not be well and the larger joints may exhibit pain.