Bronchoalveolar lavage cytokine profile and clinical features as risk predictors of plastic bronchitis in children with Mycoplasma pneumoniae pneumonia

BACKGROUND: Plastic bronchitis (PB), a condition in which mucus plugs block the bronchial tree, is a serious complication of Mycoplasma pneumoniae pneumonia (MPP). This study investigated whether clinical features and cytokine levels in bronchoalveolar lavage fluid (BALF) distinguish MPP from MPP complicated by PB and sought to identify risk factors for PB in children with MPP. METHODS: A total of 128 children 3-14 years of age with MPP who underwent bronchoscopy at Jingmen Central Hospital, China, between 1 April 2023 and 31 March 2024 were enrolled. Patients were divided into a PB and a non-PB group based on bronchoscopy findings. Clinical manifestations and laboratory findings, including BALF cytokine levels, were compared. A risk prediction nomogram for PB was constructed and evaluated. RESULTS: Of 128 children with MPP, 40 (31%) had PB. Multivariate logistic regression analysis showed that clinically severe MPP (OR = 8.78; P = 0.002), systemic inflammatory response syndrome (SIRS) (OR = 2.78; P = 0.049) and elevated BALF interleukin-6 (IL-6) (OR = 1.01; P < 0.001) were independent risk factors for PB. The area under the receiver operating characteristic (ROC) curve (AUC) value for the combination of severe MPP, SIRS and IL-6 was 0.852 (95% confidence interval, 0.77-0.93). A calibration curve showed good agreement between nomogram prediction and actual observations (P = 0.723). A decision curve analysis indicated that the nomogram demonstrated good clinical applicability. CONCLUSION: Pronounced inflammatory responses and increased clinical severity of MPP are associated with PB. A nomogram that integrates clinical features and BALF IL-6 levels may be used for risk assessment and management of PB in MPP after initial bronchoscopy.