Clinical manifestations, treatment and prognosis of juvenile idiopathic arthritis with pulmonary involvement in China: a single centre study

Objective In recent years, the distinct clinical presentations and elevated mortality rates of various subtypes of juvenile idiopathic arthritis (JIA) with pulmonary involvement have garnered significant attention. This study aimed to elucidate the clinical characteristics of pulmonary involvement in patients with JIA to improve clinicians' knowledge. Methods This single-centre retrospective study analysed the baseline data, treatment options, follow-up of sixty patients of JIA with pulmonary involvement in China. Patients with interstitial lung disease (ILD) were further classified in accordance with the 2013 American Thoracic Society/European Respiratory Society International multidisciplinary consensus on idiopathic interstitial pneumonia. Results Sixty patients (5.03%) with JIA were complicated with pulmonary involvement. The highest subtype was systemic JIA (sJIA, 63.3%), followed by rheumatoid factor (RF)-positive polyarthritis (pJIA, 25.0%). The incidence of macrophage activation syndrome (MAS) was 21.6%. The most common diagnosis was ILD (90%). Respiratory symptoms/signs were initially experienced by 61.7% of the patients, and respiratory support was required by 21.7%. High-resolution CT classification of sJIA revealed non-specific interstitial pneumonia (NSIP) and organising pneumonia. High-resolution CT classification of pJIA was NSIP and usually interstitial pneumonia (UIP). Patients were treated with NSAIDs, along with glucocorticoids, DMARDs, and biological agents. The survival rates after 1 and 5 years were approximately 93.3% and 90.0%, respectively. Conclusion Patients with JIA with pulmonary involvement present with early onset, high mortality rate. JIA patients should undergo physical examination thoroughly and high-resolution CT scans, lung function tests for evaluating and monitoring the occurrence and development ofpulmonary involvement in early stages to improve prognosis.