Three children with plastic bronchitis associated with 2009 H1N1 influenza virus infection

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.

Histological characteristics of matrix metalloproteinase-9 and tissue inhibitor of metalloproteinases-1 in asthmatic murine model during A(H1N1)pdm09 infection

Pandemic influenza virus A(H1N1)pdm09 infection occurred in healthy children and young adults, but asthmatic patients presented more rapid progression of respiratory distress and plastic bronchitis. To investigate the pathogenesis of worsening respiratory symptoms after A(H1N1)pdm09 infection, we focused on matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinases-1 (TIMP-1). MMP-9 and TIMP-1 levels in bronchoalveolar lavage fluid and serum from mice with and without asthma were evaluated after A(H1N1)pdm09 or seasonal A(H1N1) infection. MMP-9 levels were more elevated in Asthma/A(H1N1)pdm09-infected mice than in non-Asthma/A(H1N1)pdm09-infected mice on both 3 and 7 days post-infection. Immunohistochemical findings in this pneumonia model showed that MMP-9 and TIMP-1 positive cells were observed in blood vessels and bronchus of lung tissue in severe pathological findings of pneumonia with asthma. Microscopically, shedding cells and secretions were conspicuous in the trachea on days 3 and 7 post-infection, in the A(H1N1)pdm09-infected mice with asthma. Our results suggest that MMP-9 and TIMP-1 expressions are related to severe pneumonia in the A(H1N1)pdm09 infection with asthma, leading to cause epithelial cell shedding.

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.

Plastic bronchitis associated with influenza A virus in children with asthma

Plastic bronchitis (PB) is a rare and potentially fatal disease characterized by acute progressive dyspnea caused by bronchial casts in the bronchial tree. We analyzed two children with asthma and PB who presented with high fever, cough and dyspnea. Both cases showed acute onset and rapid disease progression. Laboratory examination revealed that both children were infected with influenza A virus. Emergency fiberoptic bronchoscopy was performed within 20 hours of admission. Immediately after removing the bronchial casts, their dyspnea symptoms improved significantly, and they recovered after comprehensive treatment with antiviral drugs, antibiotics and glucocorticoids. When children with asthma have acute progressive and difficult-to-relieve dyspnea after infection with influenza A virus, clinicians should be aware of the possibility of PB and perform bronchoscopy as soon as possible to facilitate early diagnosis and treatment and improve patient prognosis.

[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.

Clinical characteristics of influenza virus-induced lower respiratory infection during the 2015 to 2016 season

Background

Influenza A(H1N1)pdm09 virus infections often manifest severe respiratory symptoms, particularly in patients with a past history of allergic disease. Most of these findings were reported during the 2009 pandemic. The purpose of this study was to detail the clinical characteristics of influenza virus-induced lower respiratory infection (LRI) during the A(H1N1)pdm09-predominant 2015–2016 season.

Methods

We retrospectively reviewed the clinical characteristics of influenza-induced LRI cases in children admitted to a tertiary children's hospital. Molecular diagnostic evaluation was performed on samples obtained from the most severe cases.

Results

We identified 66 patients with influenza-associated hospitalization and included 21 patients with influenza virus-induced LRI for analyses. Twelve patients (57%) were admitted to the pediatric intensive care unit, seven (33%) required mechanical ventilation, and three (14%) required extracorporeal membrane oxygenation. Plastic bronchitis (PB) was identified in six patients (29%), among whom a past medical history of asthma or food allergy were noted in all six patients. A past history of allergic disease was more common among patients with, than among those without, PB (p = 0.009). A(H1N1)pdm09 was detected from all the PB cases, and phylogenetic analyses of the hemagglutinin and neuraminidase genes demonstrated that this virus belonged to subclades 6B.1 and 6B.2. In the six PB cases, we found one patient with H275Y mutation in neuraminidase.

Conclusion

Allergic disease was a risk factor for developing PB due to influenza A(H1N1)pdm09 infection during the 2015–16 season.

Pulmonary inflammation and cytokine dynamics of bronchoalveolar lavage fluid from a mouse model of bronchial asthma during A(H1N1)pdm09 influenza infection

Asthmatic patients present more rapid progression of respiratory distress after A(H1N1)pdm09 influenza infection than after seasonal infection. Here, we sought to clarify the pathophysiology of early deterioration in asthmatic patients after A(H1N1)pdm09 infection. Cytokine levels and virus titres in bronchoalveolar lavage fluid from mice with and without asthma after A(H1N1)pdm09 or seasonal H1N1 infection were examined. In asthma/A(H1N1)pdm09 mice, IL-6 and TNF-α levels peaked at 3 days post-infection and were higher than those in all other groups. IFN-γ levels in asthma/A(H1N1)pdm09 mice at 3 days post-infection were higher than in all other mice at any time point, whereas at 7 days post-infection, the levels were lowest in asthma/A(H1N1)pdm09 mice. Virus titres in asthma/A(H1N1)pdm09 mice were highest at 3 days post-infection, and decreased by 7 days post-infection, although the levels at this time point were still higher than that in any other group. Histopathological examination showed more inflammatory cell infiltration and lung tissue destruction in the asthma/A(H1N1)pdm09 group than in any other group. The distinct cytokine profiles in A(H1N1)pdm09-infected asthmatic mice indicated excessive inflammation and virus replication within a few days after infection. Thus, bronchial asthma could be a more exacerbating factor for pandemic influenza infection than for seasonal influenza infection.

Plastic bronchitis arising from solitary influenza B infection: A report of two cases in children

Plastic bronchitis (PB) is characterized by thick, inspissated, tracheobronchial casts. It is classified as either inflammatory or acellular based on the content of the endobronchial casts. PB has never been reported in a healthy child with solitary influenza B infection. This study is a retrospective case series of two children who presented to our institution in acute respiratory distress. Emergency rigid bronchoscopy was performed with extraction of casts from the L mainstem bronchus in both patients. Influenza B was the only isolate identified. In otherwise healthy children with respiratory distress, influenza B-mediated inflammatory PB must be considered in the differential diagnosis.

Plastic bronchitis associated with influenza virus infection in children: a report on 14 cases

BACKGROUND

Plastic bronchitis (PB) is a rare disease characterized by formation of bronchial casts. It is usually associated with congenital heart disease, sickle cell disease, lymphoma, and lung diseases such as asthma and pneumonia.

OBJECTIVES

To report 14 cases of PB with influenza A or influenza B infection.

METHODS

We analyzed the clinical manifestations, bronchoscopic and histologic findings, clinical courses, and outcomes.

RESULTS

These cases indicate that PB is a life-threatening complication of severe influenza. Plastic bronchitis should be considered in the diagnosis of children with acute respiratory distress such as lung atelectasis accompanied by influenza.

CONCLUSIONS

Diagnosis should be made by bronchial endoscopy and histopathology, and bronchial casts removed as early as possible.

Cytokine profile of bronchoalveolar lavage fluid from a mouse model of bronchial asthma during seasonal H1N1 infection

BACKGROUND

Several studies support the role of viral infections in the pathogenesis of asthma exacerbation. However, several pediatricians believe that influenza virus infection does not exacerbate bronchial asthma, except for influenza A H1N1 2009 pandemic [A(H1N1)pdm09] virus infection. We previously reported that A(H1N1)pdm09 infection possibly induces severe pulmonary inflammation or severe asthmatic attack in a mouse model of bronchial asthma and in asthmatic children. However, the ability of seasonal H1N1 influenza (H1N1) infection to exacerbate asthmatic attacks in bronchial asthma patients has not been previously reported, and the differences in the pathogenicity profiles, such as cytokine profiles, remains unclear in bronchial asthma patients after A(H1N1)pdm09 and H1N1 infections.

METHODS

The cytokine levels and viral titers in the bronchoalveolar lavage (BAL) fluid from mice with and without asthma after H1N1 infection (A/Yamagata and A/Puerto Rico strains) were compared.

RESULTS

The interleukin (IL)-6, IL-10, tumor necrosis factor (TNF)-α, IL-5, interferon (IFN)-α, IFN-β, and IFN-γ levels were significantly higher in the BAL fluids from the control/H1N1 mice than from the asthmatic/H1N1 mice. The viral titers in the BAL fluid were also significantly higher in the control/H1N1mice than in the asthmatic/H1N1 mice infected with either A/Yamagata or A/Puerto Rico.

CONCLUSIONS

A(H1N1)pdm09 infection, but not H1N1 infection, can induce severe pulmonary inflammation through elevated cytokine levels in a mouse model of asthma.

Analysis of bronchoalveolar lavage fluid in a mouse model of bronchial asthma and H1N1 2009 infection

BACKGROUND

Bronchial asthma is known as a risk factor of admission to the intensive care unit. However, the mechanism by which pandemic 2009 H1N1 (A(H1N1)pdm09) infection increases the severity of symptoms in patients with bronchial asthma is unknown; therefore, we aimed at determining this mechanism.

METHODS

Inflammatory cell levels in the bronchoalveolar lavage (BAL) fluid from the non-asthma/mock, non-asthma/A(H1N1)pdm09, asthma/mock, and asthma/A(H1N1)pdm09 groups were determined using BALB/c mice. Cell infiltration levels, cytokine levels, and viral titers were compared among the groups.

RESULTS

Neutrophil, monocyte, interleukin (IL)-5, IL-6, IL-10, IL-13, and tumor necrosis factor (TNF)-α levels were significantly higher in the BAL fluid from the non-asthma/A(H1N1)pdm09 and asthma/A(H1N1)pdm09 groups than in the mock groups (p<0.05 for neutrophils and monocytes; p<0.01 for the rest). The number of eosinophils and CD8(+) lymphocytes and the level of transforming growth factor beta 1 (TGF-β1) in BAL fluid in the asthma/A(H1N1)pdm09 group were significantly higher among all groups (p<0.05 for eosinophils and CD8(+) lymphocytes; p<0.01 for TGF-β1). The levels of IL-6, IL-10, IL-13, and TNF-α were significantly higher in the asthma/A(H1N1)pdm09 group than in the non-asthma/A(H1N1)pdm09 group (p<0.05 for IL-6 and IL-10; p<0.01 for IL-13 and TNF-α). The level of IFN-γ in the asthma/A(H1N1)pdm09 group was significantly lower than that in the non-asthma/A(H1N1)pdm09 group (p<0.05). The viral titers in the BAL fluids were higher in the asthma/A(H1N1)pdm09 group than in the non-asthma/A(H1N1)pdm09 group (p<0.05). Histopathological examination showed more severe infiltration of inflammatory cells and destruction of lung tissue in the asthma/A(H1N1)pdm09 group than in the non-asthma/A(H1N1)pdm09 group.

CONCLUSIONS

Severe pulmonary inflammation induced by elevated levels of cytokines, combined with increased viral replication due to decreased IFN-γ levels, may contribute to worsening respiratory symptoms in patients with bronchial asthma and A(H1N1)pdm09 infection.

Recurrent plastic bronchitis in a child with 2009 influenza A (H1N1) and influenza B virus infection

Plastic bronchitis is an uncommon disorder characterized by the formation of bronchial casts. It is associated with congenital heart disease or pulmonary disease. In children with underlying conditions such as allergy or asthma, influenza can cause severe plastic bronchitis resulting in respiratory failure. A review of the literature showed nine cases of plastic bronchitis with H1N1 including this case. We report a case of a child with recurrent plastic bronchitis with eosinophilic cast associated with influenza B infection, who had recovered from plastic bronchitis associated with an influenza A (H1N1) virus infection 5 months previously. To the best of our knowledge, this is the first case of recurrent plastic bronchitis related to influenza viral infection. If patients with influenza virus infection manifest acute respiratory distress with total lung atelectasis, clinicians should consider plastic bronchitis and early bronchoscopy should be intervened. In addition, management for underlying disease may prevent from recurrence of plastic bronchitis.

Management of plastic bronchitis with topical tissue-type plasminogen activator

Plastic bronchitis or cast bronchitis is a rare disease of unclear etiology characterized by formation of airway casts that can lead to life-threatening airway obstruction. There is currently limited data regarding optimal treatment of plastic bronchitis. Several therapies have been suggested, but recurrences are common and mortality remains high. We report the case of a 6-year-old boy with refractory eosinophilic bronchial casts, unresponsive to low-dose systemic corticosteroids, inhaled corticosteroids, azithromycin, and dornase alfa, who was treated successfully and safely with direct instillation of tissue-type plasminogen activator (tPA) to the obstructing casts during flexible bronchoscopy and inhaled tPA. Our case illustrates that the current therapy for plastic bronchitis remains inadequate. To our knowledge, this case is the first to show that direct instillation of tPA can be used safely for treatment of this disease. The use of tPA via direct administration into the airways during bronchoscopy and via a nebulizer appeared to be a safe and effective therapy for plastic bronchitis and should be considered early in the course of the disease to prevent complications of severe airway obstruction.

Pneumonia induced by swine-origin influenza A (H1N1) infection: chest computed tomography findings in children

PURPOSE

The purpose of this study was to determine the features of chest computed tomography (CT) in children with swine-origin influenza A (H1N1) virus (S-OIV).

MATERIALS AND METHODS

The study population consisted of 16 children with laboratory-confirmed S-OIV infection (12 boys, 4 girls), with an age range of 5-10 years (mean 6.3 years). Pneumonia was suspected in these patients based on clinical features or confirmed by radiography. All subjects underwent CT for close evaluation of pneumonia, including characteristics, distribution, extent, and other findings such as pleural effusion, pneumothorax, and pneumomediastinum.

RESULTS

The predominant CT finding was consolidation plus ground-grass opacity (GGO) (11/16, 69%). The consolidation-dominant pattern was found in 10 of 16 (66%) patients, and 1 (6%) was GGO-dominant. One (6%) had only GGO. In all, 7 of the 16 patients had segmental or lobar consolidation. Abnormal opacities were primarily distributed in the central lung zone (8/16, 50%) and were multifocal (15/16, 94%). Four showed atelectasis (4/16, 25%). Pneumomediastinum was observed in 4 of 16 (25%). One patient had negative radiographic findings but was positive on CT.

CONCLUSION

Multifocal consolidation with central distribution is a common CT finding in children with S-OIV, but there are few GGO-dominant cases. Widespread consolidation (segmental or lobar) is also common.

Analysis of cases of severe respiratory failure in children with influenza (H1N1) 2009 infection in Japan

Influenza (H1N1) 2009 occurred in Mexico in April 2009, quickly spread around the world, and was found in Japan in May. Many pediatric patients experienced encephalopathy, acute respiratory distress syndrome, and severe pneumonia. The subjects of this study were 31 pediatric patients who needed mechanical ventilation due to respiratory failure caused by influenza (H1N1) 2009 as reported to the Emergency Medical Information Center of the Japan Pediatric Society in Kanagawa Prefecture in Japan from August 1 to December 31, 2009. The diagnosis of influenza (H1N1) 2009 infection was based on positive results of a real-time polymerase chain reaction. No patient was diagnosed as having a bacterial infection. The average arterial PaO₂/FiO₂ ratio was significantly decreased to 126. Atelectasis was revealed by chest X-ray in 90.3% of subjects. There was one plastic bronchitis patient. Anti-influenza drugs were used at an average of 14.9 h after onset. Five patients showed abnormal behavior as a complication of encephalopathy. We found that respiratory failure progressed rapidly. The type of respiratory failure was oxygenation failure. It was helpful to attempt to remove more sputum in these cases. Pediatric patients with respiratory failure from influenza (H1N1) 2009 should be carefully monitored for the onset of encephalopathy.