What are the demographic and clinical characteristics of Systemic Juvenile Idiopathic Arthritis?
Systemic JIA, formerly known as Still’s disease, is characterized by arthritis, fever, elevated inflammatory markers, and rash. Arthritis in this condition can be absent at onset of fever, and joint involvement can vary from minimal arthritis to polyarthritis. It is a diagnosis of exclusion and other conditions such as infection, malignancy, and Kawasaki disease may present similarly.
- • Peak age of onset: 2 to 5 years.
- • Sex ratio: equal.
- • Case definition according to the Childhood Arthritis & Rheumatology Research Alliance (CARRA) network:
- • Arthritis in one or more joints
- • Fever for at least 2 weeks, with documentation of a quotidian pattern (see Question 5).
- • One or more of the following:
- • Evanescent rash (see Question 3)
- • Generalized lymph node enlargement
- • Hepatomegaly and/or splenomegaly
- • Serositis (pleural/pericardial/peritoneal; present in 10% of patients).