Musculoskeletal

Juvenile Idiopathic Arthritis

Juvenile idiopathic arthritis (JIA) is persistent inflammatory arthritis beginning before the 16th birthday and lasting at least 6 weeks after other causes have been considered. It is a group of diseases in which silent anterior uveitis, joint damage, growth disturbance and systemic inflammation make early specialist assessment essential.

Definition

Juvenile idiopathic arthritis is arthritis of unknown cause that begins before the 16th birthday and persists for at least 6 weeks, after other causes have been considered. It comprises several clinical phenotypes with different joint, systemic and ocular risks.

First principles

JIA is persistent childhood synovitis, not a single phenotype

JIA is defined by arthritis beginning before age 16 and persisting for at least 6 weeks, with no better explanation. Inflamed synovium produces swelling, warmth, pain, restricted movement and morning stiffness; persistent inflammation can damage cartilage, bone and growth. The six-week definition is useful for classification, but do not delay urgent assessment of a child with a hot joint, systemic illness, malignancy features or severe pain while waiting for duration.

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