Adult-onset Still disease

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

Epidemiology

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 . It affects females more than males .

Clinical presentation

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

high fevers
arthralgia
salmon-colored rash

Less common are:

sore throat
hepatic dysfunction
splenomegaly
lymphadenopathy

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

Pathology

The cause of adult-onset Still disease is unknown but genetic, environmental and infectious factors may play a role . 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 .

Diagnostic criteria

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

Markers

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

Radiographic features

Plain radiograph

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

Treatment and prognosis

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

Three main patterns of disease have been described:

single acute episode before a period of lifelong remission

acute symptomatic episodes separated by months-years of no symptoms

chronic articular disease causing joint destruction

History and etymology

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