by G. Lee

Created on: May 07, 2008   Last Updated: May 14, 2008

Arthritis in children may occur in a variety of clinical settings, either as the primary disease process or as an articular manifestation of a number of systemic disorders. A variety of conditions may also mimic a juvenile arthritis picture, so assessment of a child with arthritis involves a range of differential diagnoses.

Juvenile arthritis is more common than is usually thought. Studies generally quote figures of 1:1000 children under 16 years of age, and one study from Western Australia reported a prevalence of 1:250 children. In either case, juvenile arthritis is one of the more common chronic diseases of childhood. Also, the arthropathies of childhood, and their impact on the growing child, tend to be quite different from the inflammatory arthropathies of adulthood.

The nomenclature of juvenile arthritis has been both confusing and somewhat political. The terms "juvenile rheumatoid arthritis" (favored in the US) and "juvenile chronic arthritis" (favored in the UK) have been replaced by an equally awkward "juvenile idiopathic arthritis". Designed specifically to improve consistency in clinical trials, it has progressively become more or less the official name for the condition; however, it doesn't lend itself particularly well when giving parents a diagnosis. Some clinicians simply say "Your child has juvenile arthritis".

There are a number of subgroups of the disease, each with some distinctive features. These include pauciarticular (up to 4 joints involved), seronegative polyarticular (5 or more joints in first 6 months, negative rheumatoid factor), seropositive polyarticular (5 or more joints in first 6 months, positive rheumatoid factor), systemic-onset, enthesitis-related arthritis and psoriatic juvenile arthritis. Each individual subgroup of juvenile arthritis are described to some level of detail below.

~ PAUCIARTICULAR-ONSET ARTHRITIS ~
This is the commonest form of juvenile arthritis, and accounts for about 50% of cases. A typical patient will be a previously well 3-year-old girl presenting with swelling of a large joint - knee, ankle. wrist or elbow. It is not uncommon for joints to be surprisingly asymptomatic, so that careful examination of all joints is essential. The finding of an additional site of involvement negates many differentials for a monoarthritis, especially ones in which synovial biopsy is considered necessary. Leg length inequality is common, as a result of stimulation of the adjacent growth plate from the hypervascular inflammatory

• 1
• 2
• 3
• Next Page >>