Adult-onset Still disease

Last revised by Subhan Iqbal on 22 Feb 2023

Adult-onset Still disease (AOSD) is a rare multisystem inflammatory disorder and was originally thought to be a variant of Still disease, a pediatric arthropathy.

Still disease in adults is rare affecting around 1.5 per 100,000 people, it occurs in a bimodal distribution with one peak around the age of 15-25 years old and another around the age of 35-45 years old 1. It affects females more than males 2.

Adult-onset Still disease classically is described as a triad of:

Less common are:

Elevated inflammatory markers (e.g. CRP), leukocytosis, thrombocytosis and elevated ferritin more than 1000 (an acute phase protein) are common 3,10.

The cause of adult-onset Still disease is unknown but genetic, environmental and infectious factors may play a role 3,4. Elevated levels of various cytokines are seen in adult-onset Still disease. Interleukin-18-induced activation of macrophages and neutrophils appears to be important in Still disease. Interleukin-1-β also seems to be important in Still disease causing neutrophil production and diapedesis 5

The Yamaguchi criteria is probably the most commonly used and sensitive scoring system for diagnosing adult-onset Still disease 6.

Adult-onset Still disease is a seronegative disease meaning a negative rheumatoid factor and antinuclear antibodies are commonly found.

Pericapitate and trapezoid-metacarpal joint space narrowing without radiocarpal involvement is characteristic 7. This pattern is rarer in rheumatoid arthritis.

Steroids are commonly used to achieve remission of acute disease. Disease modifying antirheumatic drugs (DMARDs) may be used to maintain remission 3.

Three main patterns of disease have been described:

  1. single acute episode before a period of lifelong remission

  2. acute symptomatic episodes separated by months-years of no symptoms

  3. chronic articular disease causing joint destruction 3

Adult-onset Still disease was described first in 1971, by the renowned British rheumatologist Eric George Lapthorne​ Bywaters (1910-2003) 8, who thought the disease resembled the systemic form of juvenile idiopathic arthritis a.k.a. Still disease 1.

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