Risk factors for plastic bronchitis in children with community-acquired pneumonia: a retrospective bronchoscopy-based study

To investigate the pathogen distribution and clinical characteristics of pediatric community-acquired pneumonia (CAP) based on bronchoscopy findings, and to analyze the risk factors for plastic bronchitis (PB). A retrospective analysis was conducted on the clinical data of 761 children with community-acquired pneumonia (CAP) who underwent bronchoscopy in our hospital from January to December 2024. Based on the presence or absence of plastic casts observed under bronchoscopy, the children were divided into a plastic bronchitis (PB) group (n = 100) and a non-PB group (n = 661). Etiological results, clinical manifestations, laboratory findings, and prognostic indicators were collected for both groups. Univariate and multivariate logistic regression analyses were performed to identify independent risk factors for the development of plastic bronchitis. Among the 761 children, the overall pathogen detection rate was 72.4% (551/761). Single pathogen infections were identified in 470 cases (61.8%), among which Mycoplasma pneumoniae (MP) was the most prevalent (356 cases, accounting for 75.7% of single infections), followed by Haemophilus influenzae (44 cases, 9.4%) and Streptococcus pneumoniae (37 cases, 7.9%). Mixed infections were observed in 85 cases (11.2%), with the most common combinations being S. pneumoniae + H. influenzae (17 cases), MP + H. influenzae (14 cases), and S. pneumoniae + MP (13 cases). A total of 100 children (13.1%) were classified into the plastic bronchitis (PB) group and 661 (86.9%) into the non-PB group. Compared to the non-PB group, children in the PB group were significantly older 60 months vs. 36 months, had a higher proportion of left-sided pneumonia (23.0% vs. 11.2%), a lower proportion of bilateral pneumonia (55.0% vs. 67.0%), a lower rate of hospital stay ≤1 week (18.0% vs. 31.8%), and a higher rate of requiring ≥2 bronchoscopic procedures (30.0% vs. 8.9%); all differences were statistically significant (P < 0.05). Multivariate logistic regression analysis revealed that older age (OR = 1.009, 95% CI: 1.003–1.015, P = 0.002), left-sided pneumonia (OR = 2.114, 95% CI: 1.080–4.138, P = 0.029), and isolated Mycoplasma pneumoniae infection (OR = 1.781, 95% CI: 1.015–2.868, P = 0.018) were independent risk factors for the development of plastic bronchitis. Conversely, the non-PB group had a significantly higher rate of hospital stay ≤1 week compared to the PB group (OR = 0.390, 95% CI: 0.225–0.677, P = 0.001). Mycoplasma pneumoniae was the predominant pathogen among children with CAP in this cohort. Older age, left-sided pneumonia, and M. pneumoniae infection were identified as independent risk factors for PB. Early recognition of these factors may facilitate timely bronchoscopic intervention and improve clinical outcomes.