Systemic-onset juvenile idiopathic arthritis

Systemic juvenile idiopathic arthritis (or the juvenile onset form of Still's disease^[1]) is a type of juvenile idiopathic arthritis (JIA) with extra-articular manifestations like fever and rash apart from arthritis. It was originally called systemic-onset juvenile rheumatoid arthritis or Still's disease.

Predominantly extra-articular manifestations like high

Systemic JIA is characterized by arthritis, fever, which typically is higher than the low-grade fever associated with polyarticular and a salmon pink rash. It accounts for 10-20% of JIA and affects males and females equally, unlike the other two subtypes of JIA, and affects adolescents. It generally involves both large and small joints. Systemic JIA can be challenging to diagnose because the fever and rash come and go. Fever can occur at the same time every day or twice a day (often in late afternoon or evening) with a spontaneous rapid return to baseline (vs. continuous fever of septic arthritis). The rash often occurs with fever. It is a discrete, salmon-pink macules of different sizes. It migrates to different locations on skin, rarely persisting in one location more than one hour. The rash is commonly seen on trunk and proximal extremities or over pressure areas.^{[citation needed]}

Arthritis is often absent in the first weeks or even 6–8 months into the illness. Systemic JIA may have

The cause is unknown but it's thought to be related to environmental, genetic, and hormonal factors.^[citation needed]

A polymorphism in macrophage migration inhibitory factor has been associated with this condition.^[3]

Diagnosis

Rheumatoid factor and ANA tests are generally negative in systemic JIA. Lab findings:

25% of cases progress to severe destructive arthritis.[10] In the United States, mortality is estimated at 4% ^[11] and in Europe, mortality is estimated at 21.7%.^[12]

History

Still's disease is named after