Adult-onset Still's disease
Adult-onset Still's disease is a form of Still's disease, a rare systemic autoinflammatory disease characterized by the classic triad of 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 extremely 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 kidneys may occasionally cause severe life-threatening complications. It is treated first with corticosteroids such as prednisone. Medications that block the action of interleukin-1, such as Anakinra, can be effective treatments when standard steroid treatments are insufficient.
Signs and symptoms
The disease typically presents with joint pain, high fevers, a salmon-pink macular or maculopapular rash, enlargement of the liver and spleen, swollen lymph nodes, and a neutrophil-predominant increased white blood cell count in the blood. Tests for rheumatoid factor and anti-nuclear antibodies are usually negative and serum ferritin is markedly 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 life-threatening complications, including hemophagocytic lymphohistiocytosis, IVDC, fulminant hepatitis, or disabling conditions such as aseptic meningitis and sensorineural hearing loss.Pathophysiology
The cause of adult-onset Still's disease is unknown, but it presumably involves interleukin-1, since medications 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.| Major criteria | Minor criteria |
| Fever of at least 39 °C for at least one week | Sore throat |
| Arthralgias or arthritis for at least two weeks | Lymphadenopathy |
| Nonpruritic salmon-colored rash | Hepatomegaly or splenomegaly |
| Leukocytosis, with granulocyte predominance | Abnormal liver function tests |
| Negative tests for antinuclear antibody and rheumatoid factor |
Classification
People with AOSD generally experience one of two patterns in the disease:- a debilitating pattern of fevers, pain, and other systemic symptoms, or
- a somewhat less aggressive pattern, in which the main symptom is arthritis and chronic joint pain.
Treatment
Adult-onset Still's disease is treated with anti-inflammatory medications. Steroids such as prednisone are used to treat severe symptoms of Still's. Other commonly used medications include hydroxychloroquine, penicillamine, azathioprine, methotrexate, etanercept, anakinra, tocilizumab cyclophosphamide, adalimumab, rituximab, and infliximab.Newer medications target interleukin-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. On June 2020 FDA approved Ilaris for the treatment of AOSD, this is the first FDA approved treatment for AOSD. Canakinumab is another anti-IL1 drug which selectively binds IL-1β and rilonacept which blocks both IL-1A and IL-1β. The monoclonal anti-IL6 antibody tocilizumab is another treatment option as effective as anakinra.
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.