Initial presentation, etiology and risk factors for adverse outcomes in infection-associated plastic bronchitis in children: a retrospective study

Objective To summarize the pathogen distribution, imaging features, radiologic outcomes, and risk factors for poor prognosis in children with infection-associated plastic bronchitis (PB). Methods This retrospective study included 86 hospitalized children diagnosed with infection-associated PB at Henan Children's Hospital from January 2021 to December 2023. Patients were grouped based on radiologic findings and outcomes into favorable prognosis, poor prognosis, and indeterminate outcome groups. Clinical data and laboratory results were compared between the favorable and poor prognosis groups to identify potential risk factors for adverse outcomes. Results Among 86 children with infection-associated PB, 81 (94.2%) were caused by Mycoplasma pneumoniae (MP), including 29 (35.8%) co-infections. Of the MP-associated cases, 65 (80.2%) showed a good outcome, and 10 (12.3%) had unclear outcomes, while 6 (7.4%) developed adverse outcomes. These included 1 case requiring surgery, 3 with persistent atelectasis, 1 with both atelectasis and bronchiectasis, and 1 with persistent bronchiectasis. Patients with adverse outcomes exhibited significantly higher levels of LDH (788.5 U/L vs. 408 U/L, p = 0.01) and D-dimer (2.20 μg/mL vs. 0.81 μg/mL, p = 0.01) compared to the good-outcome group. The adverse-outcome group also required more bronchoscopic interventions (median 3.5 vs. 2, p < 0.01), higher glucocorticoid doses (methylprednisolone 20 mg/kg/day vs. 5 mg/kg/day, p = 0.01), and more frequent use of low molecular weight heparin (100% vs. 21.5%, p < 0.01) and intravenous immunoglobulin (50% vs. 9.2%, p = 0.02). Conclusion Mycoplasma pneumoniae is the predominant pathogen in infection-associated PB. All patients with poor outcomes were infected with M. pneumoniae. Although most children responded well to treatment, a subset developed long-term complications such as bronchiectasis and atelectasis, even requiring lobectomy. Elevated LDH and D-dimer levels may serve as early biomarkers for predicting unfavorable outcomes.