Systemic-onset juvenile idiopathic arthritis, or Still disease, is the systemic form of juvenile idiopathic arthritis. It is characterized by severe concomitant symptoms. Typically, the disease begins at the age of 3 to 5 years. Symptoms include fever, which oscillates throughout the day and night, with peak temperatures and above 39°C. These fever tips are associated with transient cutaneous efflorescences and diffuse erythematous or urticarial lesions.
Arthritis is a prerequisite for a diagnosis, although it may also occur later in the course of the disease. The number of affected joints is different (mono-, oligo- or polyarthritis). In an almost symmetrical arrangement, both small and large joints are affected.
This characteristic diagnostic triad may be expanded with the occurrence of enlarged lymph nodes and hepatosplenomegaly. Also possible are complications of the internal organs (pericarditis, pleural effusion, serous peritonitis). Causal therapy is not available due to unknown etiology.
Symptomatic first-line therapy is NSAIDs. If therapy resistance is high, glucocorticoids should be given. Disease-modifying antirheumatic drugs (methotrexate, biotherapeutics) may be used for corticosteroid resistance or for increased disease activity. In some case,s intra-articular injections may be recommended. The differential diagnosis may include fever associated with infection, connective tissue disease (especially lupus), acute leukemia, and other autoinflammatory diseases.
In about half of the case,s symptoms disappear before reaching adulthood. In the other cases, arthritis continues, with or without fever and skin symptoms. Severe sequelae exist in 20% of the cases, which include delayed growth, bone and cartilage erosions with functional limitations, and a risk of osteopenia.