Plastic bronchitis: Three cases caused by influenza B virus Yamagata lineage

Outcomes and Risk Factor Analysis of Plastic Bronchitis Among 321 Children with Influenza Pneumonia After Bronchoscopy Examination

Background

Plastic bronchitis (PB) is a rare and severe lung disease. It can be triggered by influenza virus infection, which is a common respiratory infection in children. Bronchoscopy can aid in the early detection and treatment of PB. However, the outcomes and risk for PB development in pediatric patients with influenza virus infection are not fully understood.

Methods

Data from 321 children diagnosed with influenza virus pneumonia who underwent bronchoscopy examinations between 1st January, 2009 and 31st December, 2020 were retrospectively analyzed to assess the outcomes and risk factors associated with PB development.

Results

This study included 97 girls and 224 boys with influenza virus pneumonia with a median age of 42 months. Among them, 36 patients (11.2%) were categorized as having PB based on bronchoscopy findings. PB patients had significantly longer fever durations (p=0.010) and higher risks of developing severe conditions including respiratory failure (p<0.001), acute respiratory distress syndrome (p<0.001), and air-leak syndrome (p<0.001) compared to non-PB patients. Conventional treatment including the use of neuraminidase inhibitors and antibiotics did not differ between the PB and non-PB patients, but PB patients required more anti-inflammatory treatment (p=0.019) and ventilator support (p<0.001). Combined univariate and multivariate analyses suggested that radiographic findings, including mediastinal emphysema (p=0.012) and lung consolidation (p=0.012), as well as increased levels of neutrophils (p=0.026), aspartate aminotransferase (p=0.004), and lactate dehydrogenase (p<0.001), were identified as risk factors for PB development in patients with influenza virus pneumonia. Although PB patients required more intensive care and had longer hospital stays, they all recovered well after treatment.

Conclusion

Influenza virus infection is linked to PB development in children. Identifying risk factors and early intervention such as bronchoscopy can improve the prognosis of children with PB.

Clinical features and risk factors of plastic bronchitis caused by refractory Mycoplasma pneumoniae pneumonia in children: a practical nomogram prediction model

Early assessment of refractory Mycoplasma pneumoniae pneumonia (RMPP) with plastic bronchitis (PB) allows timely removal of casts using fiberoptic bronchoscopic manipulation, which relieves airway obstruction and limit sequelae development. This study aimed to analyze clinical data for risk factors and develop a nomogram for early predictive evaluation of RMPP with PB. The clinical data of 1-14 year-old patients with RMPP were retrospectively analyzed. Patients were classified into a PB or non-PB group. The general characteristics, clinical symptoms, laboratory test results, imaging findings, and microscopic changes of the two groups were compared. A statistical analysis of the risk factors for developing PB was performed, and a nomogram model of risk factors was constructed. Of 120 patients with RMPP included, 68 and 52 were in the non-PB and PB groups, respectively. Using multivariate logistic regression analysis, fever before bronchoscopy, extrapulmonary complications, pleural effusion, cough duration, and lactate dehydrogenase (LDH) levels were identified as risk factors. A nomogram was constructed based on the results of the multivariate analysis. The area under the receiver operating characteristic curve value of the nomogram was 0.944 (95% confidence interval: 0.779-0.962). The Hosmer-Lemeshow test displayed good calibration of the nomogram (p = 0.376, R2 = 0.723).

CONCLUSION

The nomogram model constructed in this study based on five risk factors (persistent fever before bronchoscopy, extrapulmonary complications, pleural effusion, cough duration, and LDH levels) prior to bronchoscopy can be used for the early identification of RMPP-induced PB.

WHAT IS KNOWN

• Refractory Mycoplasma pneumoniae pneumonia (RMPP) in children has been increasingly reported and recognized, which often leads to serious complications. • Plastic bronchitis (PB) is considered to be one of the causes of RMPP, and bronchoscopic treatment should be improved as soon as possible to remove plastic sputum thrombus in bronchus.

WHAT IS NEW

• This study determined the risk factors for RMPP-induced PB. • The nomogram model constructed in this study prior to bronchoscopy can be used for the early identification of RMPP-induced PB, which facilitate the early bronchoscopic removal of casts, thereby promoting recovery and reducing cases with poor RMPP prognosis.

Plastic bronchitis associated with influenza B virus infection: A case report

Plastic bronchitis (PB) is a severe acute respiratory disease that develops as a result of the formation of branching mucus plugs in the bronchial tree. PB is known as a complication of influenza A virus infection, but some cases have been associated with influenza B virus infections. This patient was a 3-year-old boy with no history of allergic disease who developed PB requiring ventilator management after influenza B virus infection. He was hospitalized and managed with ventilator support because of acute respiratory failure. Influenza B virus infection was diagnosed via rapid antigen test and real-time reverse-transcription polymerase chain reaction (RT-PCR). A bronchoscopy performed after a chest X-ray and computed tomography confirmed the presence of extensive atelectasis in the right lung field and mucus plugs in the right bronchus. The patient’s respiratory condition improved rapidly after removal of the plugs. Quantitative real-time RT-PCR performed with nasal and aspirated sputum samples obtained at hospitalization revealed a higher viral RNA load in the upper rather than in the lower respiratory tract. Viral replication in the lower respiratory was not found to be a major contributor toward mucus plug formation. The finding of increased serum IgE in the absence of a history of allergic disease suggests that an allergic reaction contributed to the formation of mucus plugs.

Management of Plastic Bronchitis Using α-Chymotrypsin: A Novel Treatment Modality

Plastic bronchitis (PB) is a rare pediatric respiratory disease, characterized by the formation of obstructive casts in the bronchial tract that causes partial or extensive airway obstruction, leading to obstructive dyspnea mimicking a foreign body in the trachea. The clinical presentation and radiologic examination of plastic bronchitis are nonspecific, and the confirmation of the diagnosis is only possible via the direct observation of the casts via bronchoscopy or expectorating. So far, no effective treatment for PB has been demonstrated in controlled clinical trials, and presently, there are no reports regarding the use of α-chymotrypsin as a treatment modality. α-Chymotrypsin, as a mucolytic agent, liquefies the mucus and decreases the viscosity of sputum by acting directly on mucus. Here, we report a PB case that is associated with influenza A virus infection, developing in an eight-year-old boy. The diagnosis of PB was confirmed via cast observation following its removal via bronchoscopy. Specifically, the casts were successfully removed via bronchoscopy coupled with endotracheal instilled α-chymotrypsin. Thereafter, the patient gradually improved and successfully extubated. In the clinical follow-up, the patient was asymptomatic and without recurrent casts. Therefore, α-chymotrypsin may be one modality of treatment to remove casts in PB.

[Clinical features of influenza with plastic bronchitis in children]

OBJECTIVE

To study the clinical features of influenza with plastic bronchitis (PB) in children, and to improve the awareness of the diagnosis and treatment of PB caused by influenza virus.

METHODS

A retrospective analysis was performed for the clinical data of 70 children with lower respiratory influenza virus infection from October 2018 to October 2019. According to the presence or absence of PB, they were divided into an influenza+PB group with 12 children and a non-PB influenza group with 58 children. Related clinical data were collected for the retrospective analysis, including general information, clinical manifestations, laboratory examination, imaging findings, treatment, and prognosis.

RESULTS

In the influenza+PB group, most children experienced disease onset at the age of 1-5 years, with the peak months of January, February, July, and September. Major clinical manifestations in the influenza+PB group included fever, cough, and shortness of breath. The influenza+PB group had significantly higher incidence rates of shortness of breath and allergic diseases such as asthma than the non-PB influenza group (P<0.05). Of the 12 children in the influenza+PB group, 7(58%) had influenza A virus infection and 5 (42%) had influenza B virus infection, among whom 1 had nephrotic syndrome. For the children in the influenza+PB group, major imaging findings included pulmonary consolidation with atelectasis, high-density infiltration, pleural effusion, and mediastinal emphysema. Compared with the non-PB influenza group, the influenza+PB group had a significantly higher proportion of children who were admitted to the pediatric intensive care unit (P<0.05). Bronchoscopic lavage was performed within 1 week after admission, and all children were improved and discharged after anti-infective therapy and symptomatic/supportive treatment.

CONCLUSIONS

Influenza with PB tends to have acute onset and rapid progression, and it is important to perform bronchoscopy as early as possible. The possibility of PB should be considered when the presence of shortness of breath, allergic diseases such as asthma or nephrotic syndrome in children with influenza.