# Epidemiology, clinical characteristics, and risk factors of plastic bronchitis caused by severe Mycoplasma pneumoniae pneumonia in children: a retrospective study from Suzhou, China

## TL;DR

This study examines the risk factors and clinical features of plastic bronchitis in children with severe Mycoplasma pneumoniae pneumonia, identifying key indicators for early diagnosis.

## Contribution

The study identifies LDH, pleural effusion, and hospital stay duration as independent predictors of plastic bronchitis in children with severe Mycoplasma pneumoniae pneumonia.

## Key findings

- Plastic bronchitis was most frequently detected in winter, with a peak positivity rate in December.
- LDH, pleural effusion, and length of hospital stay were identified as independent risk factors for PB in SMPP children.
- A combination of these three indicators showed high predictive value with an AUC of 0.911.

## Abstract

We analyzed the prevalence and clinical characteristics of children with plastic bronchitis (PB) caused by severe Mycoplasma pneumoniae (SMPP) and explored its risk factors.

This retrospective study included pediatric patients with SMPP who were admitted to the Respiratory Department of Children’s Hospital of Soochow University and underwent fiberoptic bronchoscopy (FB) treatment between January 1 and December 31, 2024. The SMPP patients were divided into a PB group and a non-PB group according to whether there was a plastic shape under FB. Epidemiological characteristics, general information, clinical manifestations, laboratory findings, imaging features, and treatment regimens were collected and compared between the two groups. Risk factors for PB were identified using logistic regression analysis, and their predictive value was assessed with receiver operating characteristic (ROC) curves.

This study incorporated a total of 510 children diagnosed with SMPP, with 60 and 450 assigned to the PB and non-PB groups, respectively. The epidemic peak of SMPP occurred in summer and autumn; the highest detection rate of PB was recorded in winter (19.30%), with the PB positivity rate peaking in December (32.26%). In the PB group, fever days, runny nose, diminished breath sounds, abnormal liver function, abnormal coagulation function, number of bronchoscopic interventions, neutrophil percentage, C-reactive protein (CRP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), D-dimer, atelectasis, and pleural effusion were all significantly higher compared to the non-PB group (P < 0.05). In the PB group, lymphocyte percentage and platelet count were significantly lower compared to the non-PB group (P < 0.05). Multivariate logistic regression analysis identified LDH, pleural effusion, and length of hospital stay as independent predictors of PB in children. The combination of these three indicators yielded a notably higher predictive value, with an area under the receiver operating characteristics curve (AUC) of 0.911 (95% CI: 0.868∼0.953).

LDH, pleural effusion, and length of hospital stay were independent risk factors for PB in SMPP children. For children suspected of PB, pediatricians should pay close attention to the above indicators, strive for early diagnosis and treatment, and improve prognosis.