JUVENILE ARTHRITIS: Arthritis Foundation

Most people, when first told that a child has arthritis, find it difficult to believe. Isn’t arthritis an old person’s disease? Unfortunately, this is one of the many misconceptions the general public has about arthritis.

What causes arthritis in children?

No life style activities or inherited factors have been identified as causing or contributing to arthritis in children, however some genes seems to increase the chance of developing specific forms of JA as noted in the section on types of arthritis.

Even though some children may develop a sore throat or other infections before developing arthritis, no germ has been linked with the onset of arthritis.

As yet, the cause or causes have not been identified but research is continuing. It is most important for parents not to believe they may be responsible in anyway.

Different terms are often used when referring to arthritis in childhood. This can be very confusing. The reason for this is that difference countries use different names, but they are all describing the same condition. In Australia, the United Kingdom and Europe it is common to use the term Juvenile Arthritis (JA), in the USA and Canada, Juvenile Rheumatoid Arthritis (JRA) is used. In some literature childhood arthritis may be called Still’s Disease, after a children’s medical specialist, George Frederic Still, who first described the differences between adult and childhood arthritis in 1896. Idiopathic Arthritis of Childhood (IAC) or Juvenile Arthritis (JA) may also be used. An international committee is currently finalising appropriate terminology for the various conditions of childhood arthritis. In this document we will be using the acronym JA.

JA is used as an ‘umbrella’ term for arthritis in childhood, and is the diagnosis when the child’s symptoms occur between birth and sixteen years of age. Several forms of JA have been identified therefore children may be further classified into a sub-group. Some children’s arthritis may not follow the general pattern of one of the sub-groups, making it unclear which type of arthritis they have. JA is a condition where symptoms may alter over the course of the disease.

The seven recognised sub-groups of JA are:

Systemic means "affecting many parts of the body." Children with this condition may be very ill at the onset with a fever being the first sign you notice. This may fluctuate during the day and night and persist for days or possibly weeks. An obvious rash may be present, often coinciding with the high temperature fluctuations, and the child’s glands are usually swollen. These symptoms can sometimes be confused with infections such as measles. Children with systemic arthritis may require hospitalisation to rule out other childhood infections and stabilise their condition. At this stage the child may have little or no pain, and possibly no swelling of the joints. A child’s internal organs as well as the joints may be affected.

It a less common type of JA, is more common in children under the age of five, and affects boys and girls equally.

Outlook:

The terms Oligoarthritis and Pauciarticular Arthritis mean that arthritis is present in four or fewer joints during the first six months after the onset of symptoms. If only one joint is affected, the term Monoarticular arthritis is used.

Oligoarthritis is generally not symmetrical, meaning that it does not usually affect the same joint on both sides of the body. Although the swelling may first appear after a minor injury, such as a fall, there is no evidence to suggest that the injury caused the arthritis. The child’s general health is not commonly affected by Oligoarthritis, and the child may not complain of any pain. Often the first sign parents will notice is that their child walks with a limp, or is reluctant to bend or use the affected joint.

There is a risk of an eye condition called uveitis (also known as iritis and iridocyclitis) in 30% or more of children with Oligoarthritis. As there is no obvious signs of uveitis developing, it is essential that the child’s eyes are checked regularly by an eye specialist (opthamologist), even for many years after a child is in remission from JA. An instrument called a slit lamp is used to make the diagnosis. This eye condition, if undetected and untreated, can cause severe eye damage.

This is the most common form of JA, affecting girls more commonly than boys. It often commences at the age of two to three.

Sometimes a child with Oligoarthritis can develop arthritis in more than four joints after the initial six month period. In this case, the term Extended Oligoarthritis is used. The joint involvement is usually symmetrical, affecting the same joints on both sides of the body. As with Oligoarthritis, there is a risk of the eye condition, uveitis occuring, and regular checks are required.

Girls are more commonly affected than boys.

Polyarticular means "many joints." In this form of JA, five or more joints will be affected. Rheumatoid factor is an antibody in the blood, and is detected by a simple bloodtest. Bloodtests in the majority of children with JA will show a negative result for rheumatoid factor and this is certainly not a definitive diagnostic tool.

The onset may be sudden, with a number of joints being affected at one time or in rapid succession. The joint involvement is usually symmetrical. At the beginning, as with systemic arthritis, the child may be generally unwell. Later, symptoms of listlessness and fatigue may occur, and the child may be reluctant to move his or her joints.

It can develop at any age from a few months to adolescence. It is more commonly diagnosed in girls aged between six and ten years.

This form of Polyarticular arthritis also affects five or more joints. The joint involvement is usually symmetrical. The rheumatoid factor antibody is present in the blood, but may not show at the onset of symptoms.

Girls are more commonly affected than boys and it occurs more often from the age of ten. However, it also affects some younger children. This can be a severe form of JA, but is quite rare, affecting approximately 1% of children with arthritis. This form of JA appears to be very similar to adult type rheumatoid arthritis, but with a very early onset. Sometimes there may be involvement of internal organs or a child may be anaemic.

Entheses are areas where tendon and other connecting tissues join to bone. Pain at these points of connection is known as enthesopathy, and inflammation at these sites is known as enthesitis. Therefore, Enthesitis related arthritis is the name given to a group of conditions in which there may be inflamation particularly of the large joints of the lower limbs, the spine and also of the entheses. Other names which have been used for this group of conditions include Juvenile Spondylitis, Juvenile Spondylarthropathies and Seronegative-enthesopathy-arthropathy syndrome.

Enthesitis related arthritis is more common in boys than girls and often appears to begin between the ages of nine and twelve years. Sometimes other family members may have the same condition or associated condition, for example, Ankylosing Spondylitis. There is a higher prevalence of the HLA-B27 marker in children who have enthesitis related arthritis, but as with the rheumatoid factor antibody, a percentage of the general population who show no signs of arthritis also have this marker.

This is an inflammatory arthritis affecting several or numerous joints, and is usually associated with the skin condition psoriasis. The psoriasis may not appear for many years after the onset of arthritis, or may precede symptoms. There is commonly a family history of psoriasis, and less commonly, a family history of arthritis. Psoriatic arthritis is often characterised by the appearance of sausage shaped fingers or toes.

It can occur at any age in childhood. It generally affects girls more often than boys where onset is before the age of six, and boys more often than girls where onset is around the age of puberty.

As with Oligoarthritis, there is a risk of the eye condition, uveitis occurring, and regular checks are required.

There are a number of other conditions in which persisting arthritis may be seen. These include:

This is by no means an inclusive list. For information on these and other conditions, please contact Arthritis Victoria on 8531 8000 or FreeCall 1800 011 041.