Systemic juvenile idiopathic arthritis (formerly called Still's disease or systemic onset juvenile rheumatoid arthritis) is a subset of juvenile idiopathic arthritis (JIA). Adult-onset Still's disease (AOSD) is probably the same or similar disease when it begins in patients ≥16 years of age. Systemic JIA is classified as a subset of JIA, but the pathophysiology is most consistent with an autoinflammatory disorder. (See "Classification of juvenile arthritis", section on 'Systemic arthritis'.)
The treatment options for systemic JIA are discussed in this review. The clinical manifestations, diagnosis, complications, and prognosis of systemic JIA are discussed separately, as are oligoarticular JIA and polyarticular JIA. (See "Systemic juvenile idiopathic arthritis: Clinical manifestations and diagnosis" and "Systemic juvenile idiopathic arthritis: Course, prognosis, and complications" and "Oligoarticular juvenile idiopathic arthritis" and "Polyarticular juvenile idiopathic arthritis: Clinical manifestations and diagnosis" and "Classification of juvenile arthritis".)
Nonsteroidal antiinflammatory drugs (NSAIDs) alone are effective for many children with systemic juvenile idiopathic arthritis (sJIA) . Second line agents, such as glucocorticoids or methotrexate, are used if NSAIDs are ineffective. Biologic agents, such as monoclonal antibodies to interleukin-1 (IL-1) or IL-6, are effective in reducing clinical symptoms in patients with disease refractory to conventional therapy and more limited data suggest they are also beneficial when used early in the care of ill children with systemic JIA (ie, instead of glucocorticoids) once the diagnosis is confirmed.
The initiation of any therapy in sJIA including NSAIDs, but probably not glucocorticoids, has been associated anecdotally with a transiently elevated risk of life-threatening macrophage activation syndrome (MAS). Accordingly, careful monitoring is essential. Since glucocorticoids represent a poor long-term therapeutic option because of associated toxicity, additional disease-modifying drugs are required in many patients to avoid the aggressive and often permanently disabling consequences of unremitting disease. Although the following discussion is an attempt to give useful guidelines, difficult cases of systemic JIA should be referred to an experienced pediatric rheumatologist. (See "Treatment and prognosis of hemophagocytic lymphohistiocytosis".)
The administration of live-viral vaccines and other standard childhood immunizations in patients with JIA is discussed in detail separately. (See "Oligoarticular juvenile idiopathic arthritis", section on 'Immunizations'.)