Features and Clinical Course of Infantile Juvenile Idiopathic Arthritis.

BACKGROUND Juvenile idiopathic arthritis (JIA) is a heterogeneous group of 7 chronic arthritides categories that affects children younger than 16 years. This case series elucidates the characteristics of patients from a single center diagnosed with JIA at younger than 12 months. METHODS We included patients who presented to the rheumatology clinic for JIA with symptom onset at younger than 1 year. Chart review was conducted to complete case report forms that included demographics, historical features, examination features, laboratory results, imaging results, and treatment courses. RESULTS We identified 12 patients who met our inclusion criteria. Eight of our patients were diagnosed with oligoarticular JIA, 3 had polyarticular JIA, and 1 was diagnosed with systemic JIA. Overall, 58% (7/12) of patients had joint contractures at their initial visit. Of the patients with oligoarticular JIA, 50% (4/8) required a disease-modifying antirheumatic drug to achieve disease remission; 12.5% (1/8) required biologic therapy. All of the polyarticular JIA patients had highly positive antinuclear antibodies, as well as elevated inflammatory markers. CONCLUSIONS Children with infantile JIA are overall similar to the larger population of patients with JIA. Disease severity may not be different compared with that of older children with JIA; however, there is likely a larger delay in diagnosis and the presence of contractures, which occurred in more than half of our patients.