In this case report we present the case of a 9-year-old girl who developed myalgia after she was diagnosed with Juvenile Idiopathic Arthritis (JIA), which was treated with etanercept and methotrexate. The primary diagnosis JIA was based on symmetric polyarthritis without signs of systemic involvement. Six months later myalgia, hypertension, fever and angiographic abnormalities led to the diagnosis of juvenile systemic polyarteritis nodosa (PAN). Juvenile PAN is a rare inflammatory disease affecting small to medium-sized muscular arteries. Due to a wide range of affecting organs it causes a variable clinical presentation. Diagnosis can be difficult, because disease symptoms at the onset of disease are nonspecific and often mimick other inflammatory diseases. Even though juvenile PAN is a rare disease it should be included in any differential diagnosis in patients with undetermined systemic symptoms or inflammatory disorders.
Polyarteritis nodosa, Juvenile Idiopathic Arthritis, Myalgia, Etanercept, Biologicals