An analysis of clinical manifestations and therapeutic outcomes in pediatric connective tissue disease-associated interstitial lung disease

Abstract Background Pediatric connective tissue disease-associated interstitial lung disease (CTD-ILD) is a rare but serious condition with limited clinical data; this study aimed to evaluate its clinical features, treatment strategies, and outcomes. Methods A single-center retrospective study included 50 pediatric CTD-ILD patients with complete follow-up data from June 2018 to February 2024. Collected variables included age at CTD-ILD diagnosis (years), sex, underlying CTD, respiratory symptoms, chest HRCT findings, pulmonary function parameters (VC, FVC, FEV₁, FEV₁/FVC%, TLC, DLco), treatment regimens, and outcomes. All patients underwent HRCT, and follow-up data were obtained from electronic medical records. Results The median onset age was 10 years, with a female-to-male ratio of 4.56:1. Systemic lupus erythematosus (27/50, 54.00%) was the most common underlying disease, followed by MCTD and pSS. Nearly one-third of the patients (18/50, 36.0%) were asymptomatic; the most common symptom was cough (17/50, 34.0%), followed by dyspnea (8/50, 16.0%) and hypoxemia (6/50, 12.0%), while hemoptysis was rare (1/50, 2.0%). On HRCT, ground-glass opacities were the most common finding (25/50, 50.0%), followed by reticulation (11/50, 22.0%). All patients received corticosteroids for induction; CTX was used in 24/50 (48.0%) and MMF in 23/50 (46.0%). During maintenance, MMF was used in 45/50 (90.0%) of cases. Pulmonary function improved significantly at six and 12 months (P < 0.05), and HRCT showed radiological improvement in all patients with no progression at 1 year. Conclusion Pediatric CTD-ILD often has an insidious onset with non-specific respiratory symptoms. Chest HRCT and pulmonary function testing are important tools for early evaluation and detection. In our cohort, treatment with corticosteroids and immunosuppressants was associated with improvements in lung function and imaging findings, supporting the potential benefit of early recognition and timely management.