Adult-onset Still's disease (AOSD) is a rare systemic inflammatory disease characterized by the classic triad of persistent high spiking fevers, joint pain and a distinctive salmon-colored bumpy rash. The disease is considered a diagnosis of exclusion. Levels of the iron-binding protein ferritin may be elevated with this disorder. AOSD may present in a similar manner to other inflammatory diseases and to autoimmune diseases, which must be ruled out before making the diagnosis. Prognosis is usually favorable but manifestations of the disease affecting the lungs, heart, or kidney may occasionally cause severe life-threatening complications. It is treated first with steroids such as prednisone. Drugs that block the action of Interleukin-1, particularly IL-1β, are effective treatments.
Signs and symptoms
The disease typically presents with joint pain, high fevers, a salmon-pink rash, enlargement of the liver and spleen, swollen lymph nodes, and an increased white blood cell count in the blood. Tests for rheumatoid factor and anti-nuclear antibodies are usually negative and serum ferritin is elevated. Patients experiencing a flare-up from Adult-onset Still's disease usually report extreme fatigue, swelling of the lymph nodes, and less commonly fluid accumulation in the lungs and heart. In rare cases, AOSD can cause aseptic meningitis and sensorineural hearing loss.
Pathophysiology
The cause of adult-onset Still's disease is unknown, but it presumably involves interleukin-1 (IL-1), since drugs that block the action of IL-1β are effective treatments. Interleukin-18 is expressed at high levels.
Diagnosis
The diagnosis is clinical, not based upon serology. At least seven sets of diagnostic criteria have been devised, however the Yamaguchi criteria have the highest sensitivity. Diagnosis requires at least five features, with at least two of these being major diagnostic criteria.
Treatment
One set of 21 adult-onset Still's disease patients were divided into four types, according to clinical course patterns. These included monocyclic systemic disease, polycyclic systemic disease, chronic articular monocyclic systemic disease, and chronic articular polycyclic systemic disease. Chronic articular disease and polyarticular disease were at higher risk to develop disabling arthritis.
Adult-onset Still's disease is treated with anti-inflammatory drugs. Steroids such as prednisone are used to treat severe symptoms of Still's. Other commonly used medications include hydroxychloroquine, penicillamine, azathioprine, methotrexate, etanercept, anakinra, cyclophosphamide, adalimumab, rituximab, and infliximab.
Newer drugs target interleukin-1 (IL-1), particularly IL-1β. A randomized, multicenter trial reported better outcomes in a group of 12 patients treated with anakinra than in a group of 10 patients taking other disease-modifying antirheumatic drugs. Other anti-IL1β drugs are being developed, including canakinumab and rilonacept.
The condition "juvenile-onset Still's disease" is now usually grouped under juvenile rheumatoid arthritis. However, there is some evidence that the two conditions are closely related.
Epidemiology
Adult-onset Still's Disease is rare and has been described all over the world. The number of new cases of AOSD per year is estimated to be 0.16 new cases per 100,000 population. Prevalence is estimated at 1.5 cases per 100,000-1,000,000 population. There is a bimodal age distribution with one peak incidence between ages 15â€"25 and a second peak between ages of 36â€"46 years.
History
Still's disease is named after English physician Sir George Frederic Still (1861â€"1941). It was characterized by EG Bywaters in 1971.