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.