Acute Airway Obstruction: An Unusual Presentation of Posttransplant Lymphoproliferative Disorder in a Renal Transplant Recipient.

Posttransplant lymphoproliferative disorder is a life-threatening complication after solid-organ transplants. In adults, recipients of heart transplants have the highest risk, whereas renal transplant recipients have the lowest risk among all solid-organ transplants. The most common site for posttransplant lymphoproliferative disorders are gastrointestinal tract followed by the graft itself. Airway involvement in posttransplant lymphoproliferative disorder is rarely encountered. We report a case of a 26-year-old renal allograft recipient who presented to the emergency room with airway obstruction necessitating an emergency tracheostomy. Imaging revealed a left tonsillar mass extending into the nasopharynx and retropharyngeal space causing complete oropharyngeal occlusion. Endoscopic biopsy from nasopharyngeal mass showed a diffuse large B-cell lymphoma and was Ebstein-Barr virus positive. Reduction in immunosuppression and treatment with posttransplant lymphoproliferative disorder-1 risk-stratified approach resulted in complete remission.

Ventilated Patients With COVID-19 Show Airflow Obstruction.

OBJECTIVE: Many patients with coronavirus disease 2019 (COVID-19) need mechanical ventilation secondary to acute respiratory distress syndrome. Information on the respiratory system mechanical characteristics of this disease is limited. The aim of this study is to describe the respiratory system mechanical properties of ventilated COVID-19 patients. DESIGN, SETTING, AND PATIENTS: Patients consecutively admitted to the medical intensive care unit at the University of Iowa Hospitals and Clinics in Iowa City, USA, from April 19 to May 1, 2020, were prospectively studied; final date of follow-up was May 1, 2020. MEASUREMENTS: At the time of first patient contact, ventilator information was collected including mode, settings, peak airway pressure, plateau pressure, and total positive end expiratory pressure. Indices of airflow resistance and respiratory system compliance were calculated and analyzed. MAIN RESULTS: The mean age of the patients was 58 years. 6 out of 12 (50%) patients were female. Of the 21 laboratory-confirmed COVID-19 patients on invasive mechanical ventilation, 9 patients who were actively breathing on the ventilator were excluded. All the patients included were on volume-control mode. Mean [±standard deviation] ventilator indices were: resistive pressure 19 [±4] cmH2O, airway resistance 20 [±4] cmH2O/L/s, and respiratory system static compliance 39 [±16] ml/cmH2O. These values are consistent with abnormally elevated resistance to airflow and reduced respiratory system compliance. Analysis of flow waveform graphics revealed a pattern consistent with airflow obstruction in all patients. CONCLUSIONS: Severe respiratory failure due to COVID-19 is regularly associated with airflow obstruction.

Necrotizing tracheobronchitis causing airway obstruction complicated by pandemic 2009 H1N1 influenza: A case report.

RATIONALE: Influenza is an infection caused by the influenza virus, and its symptoms are mostly mild and self-limiting. However, influenza can cause severe or fatal complications in high-risk patients. Although tracheobronchitis is one of the common complications of influenza, necrotizing tracheobronchitis is very rare. Herein, we describe a case of necrotizing tracheobronchitis causing airway obstruction complicated by pandemic 2009 H1N1 influenza. PATIENT CONCERNS: A 60-year-old man presented with fever and dyspnea. On arrival at the emergency room (ER), the patient received oxygen 4 L/minute via a nasal prolong owing to mild hypoxemia. And invasive mechanical ventilation was needed 5 hours after arrival at the ER due to progressive hypoxemia. DIAGNOSES: Fiberoptic bronchoscopy was performed owing to bloody secretion in the endotracheal tube and revealed diffuse tracheobronchitis with necrotic and hemorrhagic materials obstructing the trachea and bronchus. The pandemic 2009 H1N1 influenza virus was detected from the bronchial washing sample; no other microorganism was detected. INTERVENTION: He received peramivir plus oseltamivir and broad-spectrum antibiotics. OUTCOMES: The bloody secretion continued. He developed cardiac arrest due to airway obstruction on the 6th day of admission. After cardiac arrest, his condition progressed to multi-organ failure, and the patient died on the 10th day of admission. LESSONS: We suggest that necrotizing tracheobronchitis be considered in patients with influenza who present with unexplained hypoxemia.

Clinical features of fatal severe fever with thrombocytopenia syndrome that is complicated by invasive pulmonary aspergillosis.

INTRODUCTION: Severe fever with thrombocytopenia syndrome (SFTS) has been prevalent in parts of Asia during recent years. However, SFTS with invasive pulmonary aspergillosis (IPA) is rare, and it is important to understand its clinical features. MATERIALS AND METHODS: Total four cases of SFTS with IPA are reviewed and detailing the disease progression, treatment options, and prognosis were summarized and analyzed. RESULTS: The patients with SFTS-associated IPA first presented with fever, gastrointestinal symptoms, thrombocytopenia, leukopenia, and multiple organ failure. After 1-2 weeks, the patients developed mild polypnea and wheezing rales, and quickly developed dyspnea and respiratory failure. Tracheal intubation was usually performed, but did not relieve the intractable airway spasm and pulmonary ventilation failure. Bronchoscopy confirmed that the antifungal treatment was ineffective and the aspergillosis had worsened. All patients died of type 2 respiratory failure caused by continued airway obstruction and spasticity. CONCLUSIONS: Given the high mortality rate in this series, there is a need for increased awareness of SFTS-associated IPA. Additional examinations should be performed in these cases, and early-stage antifungal treatment with organ support may be helpful.

Local dornase alfa treatment reduces NETs-induced airway obstruction during severe RSV infection.

Respiratory syncytial virus (RSV) infection is characterised by airway obstruction with mucus plugs, containing DNA networks in the form of neutrophil extracellular traps (NETs). We investigated the effect of dornase alfa on histopathological NETs-induced airway obstruction and viral load in an age-relevant calf model of severe bovine RSV disease. As compared with the control animals, dornase alfa treatment resulted in a strong reduction of NETs-induced airway obstruction. Viral load in the lower respiratory tract was not different between the two groups. We conclude that NETs form a relevant target for treatment of airway obstruction in severe RSV disease.

Long-term follow-up and outcome in patients with recurrent respiratory laryngeal papillomatosis.

INTRODUCTION: Recurrent respiratory papillomatosis is characterized by wart-like lesions of the upper airway and is most frequently caused by human papillomavirus (HPV). The disease has significant impact on quality of life due to potential airway obstruction, dysphonia and the need for serial surgeries. The main objective of this study was to describe patient characteristics and long-term follow-up data in a Danish cohort with the disease. METHODS: The study was a longitudinal retrospective cohort-study using data from electronic medical records and a pathology database. RESULTS: A total of 61 adult and four juvenile patients were identified. The male-to-female ratio was 2.4. In the adult population, the mean age at onset was 45 years. The median number of surgeries was four (interquartile range: 2.8). The mean follow-up time was 8.7 years (range: 7 days-30 years). Three cases of malignant transformation were observed. In the juvenile population, the mean age of onset was 8.5 years (range: 3-12 years). The mean follow-up time was 11.5 years (range: 2-23 years), and the number of surgeries per year at risk was one/year. CO2-laser and microdebrider were the surgical techniques usually employed. 43% of histopathologic analyses could detect HPV infection (subtype 6 or 11). CONCLUSIONS: More males than females suffer from respiratory papillomatosis; age of onset was either in childhood or in mid-life. Use of CO2-laser or microdebrider was the preferred surgical approach in this cohort. FUNDING: none. TRIAL REGISTRATION: not relevant.

Proliferative laryngitis with airway obstruction in an adult: Consider herpes.

OBJECTIVES/HYPOTHESIS: Few cases of herpes simplex virus (HSV) affecting the larynx have been reported in the literature. Although HSV laryngitis appears to present with nonspecific symptoms, this is a potentially serious condition that can rapidly progress to unnecessary morbidity and mortality if not identified and treated accordingly. We report a case of HSV laryngitis in an individual with well controlled human immunodeficiency virus infection and perform a comprehensive literature review of HSV laryngitis in adults. From this case report and review of the literature, we advocate early diagnostic biopsy of unusual or poorly responsive laryngeal lesions for pathology, culture, and virology studies.

Neutrophil extracellular traps cause airway obstruction during respiratory syncytial virus disease.

Human respiratory syncytial virus (RSV) is the most important cause of severe lower respiratory tract disease (LRTD) in young children worldwide. Extensive neutrophil accumulation in the lungs and occlusion of small airways by DNA-rich mucus plugs are characteristic features of severe RSV-LRTD. Activated neutrophils can release neutrophil extracellular traps (NETs), extracellular networks of DNA covered with antimicrobial proteins, as part of the first-line defence against pathogens. NETs can trap and eliminate microbes; however, abundant NET formation may also contribute to airway occlusion. In this study, we investigated whether NETs are induced by RSV and explored their potential anti-viral effect in vitro. Second, we studied NET formation in vivo during severe RSV-LRTD in infants and bovine RSV-LRTD in calves, by examining bronchoalveolar lavage fluid and lung tissue sections, respectively. NETs were visualized in lung cytology and tissue samples by DNA and immunostaining, using antibodies against citrullinated histone H3, elastase and myeloperoxidase. RSV was able to induce NET formation by human neutrophils in vitro. Furthermore, NETs were able to capture RSV, thereby precluding binding of viral particles to target cells and preventing infection. Evidence for the formation of NETs in the airways and lungs was confirmed in children with severe RSV-LRTD. Detailed histopathological examination of calves with RSV-LRTD showed extensive NET formation in dense plugs occluding the airways, either with or without captured viral antigen. Together, these results suggest that, although NETs trap viral particles, their exaggerated formation during severe RSV-LRTD contributes to airway obstruction.

[THE VALUE OF RECURRENT BRONCHIAL OBSTRUCTION ASSOCIATED WITH RESPIRATORY INFECTIONS IN INFANTS].

It is shown that recurrent bronchial obstruction with nonallergic genesis is a significant problem for young children. Further researches of this disease are needed in order to develop differentiated therapies.

Alveolar macrophages contribute to the pathogenesis of human metapneumovirus infection while protecting against respiratory syncytial virus infection.

Human metapneumovirus (hMPV) and respiratory syncytial virus (RSV) are leading causes of upper and lower respiratory tract infections in young children and among elderly and immunocompromised patients. The pathogenesis of hMPV-induced lung disease is poorly understood. The lung macrophage population consists of alveolar macrophages (AMs) residing at the luminal surface of alveoli and interstitial macrophages present within the parenchymal lung interstitium. The involvement of AMs in innate immune responses to virus infections remains elusive. In this study, BALB/c mice depleted of AMs by intranasal instillation of dichloromethylene bisphosphonate (L-CL2MBP) liposomes were examined for disease, lung inflammation, and viral replication after infection with hMPV or RSV. hMPV-infected mice lacking AMs exhibited improved disease in terms of body weight loss, lung inflammation, airway obstruction, and hyperresponsiveness compared with AM-competent mice. AM depletion was associated with significantly reduced hMPV titers in the lungs, suggesting that hMPV required AMs for early entry and replication in the lung. In contrast, AM depletion in the context of RSV infection was characterized by an increase in viral replication, worsened disease, and inflammation, with increased airway neutrophils and inflammatory dendritic cells. Overall, lack of AMs resulted in a broad-spectrum disruption in type I IFN and certain inflammatory cytokine production, including TNF and IL-6, while causing a virus-specific alteration in the profile of several immunomodulatory cytokines, chemokines, and growth factors. Our study demonstrates that AMs have distinct roles in the context of human infections caused by members of the Paramyxoviridae family.

RSV-encoded NS2 promotes epithelial cell shedding and distal airway obstruction.

Respiratory syncytial virus (RSV) infection is the major cause of bronchiolitis in young children. The factors that contribute to the increased propensity of RSV-induced distal airway disease compared with other commonly encountered respiratory viruses remain unclear. Here, we identified the RSV-encoded nonstructural 2 (NS2) protein as a viral genetic determinant for initiating RSV-induced distal airway obstruction. Infection of human cartilaginous airway epithelium (HAE) and a hamster model of disease with recombinant respiratory viruses revealed that NS2 promotes shedding of infected epithelial cells, resulting in two consequences of virus infection. First, epithelial cell shedding accelerated the reduction of virus titers, presumably by clearing virus-infected cells from airway mucosa. Second, epithelial cells shedding into the narrow-diameter bronchiolar airway lumens resulted in rapid accumulation of detached, pleomorphic epithelial cells, leading to acute distal airway obstruction. Together, these data indicate that RSV infection of the airway epithelium, via the action of NS2, promotes epithelial cell shedding, which not only accelerates viral clearance but also contributes to acute obstruction of the distal airways. Our results identify RSV NS2 as a contributing factor for the enhanced propensity of RSV to cause severe airway disease in young children and suggest NS2 as a potential therapeutic target for reducing the severity of distal airway disease.

A passive quantitative measurement of airway resistance using depth data.

The Respiratory Syncytial Virus (RSV) is the most common cause of serious lower respiratory tract infections in infants and young children. RSV often causes increased airway resistance, clinically detected as wheezing by chest auscultation. In this disease, expiratory flows are significantly reduced due to the high resistance in patient's airway passages. A quantitative method for measuring resistance can have a great benefit to diagnosis and management of children with RSV infections as well as with other lung diseases. Airway resistance is defined as the lung pressure divided by the airflow. In this paper, we propose a method to quantify resistance through a simple, non-contact measurement of chest volume that can act as a surrogate measure of the lung pressure and volumetric airflow. We used depth data collected by a Microsoft Kinect camera for the measurement of the lung volume over time. In our experimentation, breathing through a number of plastic straws induced different airway resistances. For a standard spirometry test, our volume/flow estimation using Kinect showed strong correlation with the flow data collected by a commercially-available spirometer (five subjects, each performing 20 breathing trials, correlation coefficient = 0.88, with 95% confidence interval). As the number of straws decreased, emulating a higher airway obstruction, our algorithm was sufficient to distinguish between several levels of airway resistance.

Critical role of TLR4 in human metapneumovirus mediated innate immune responses and disease pathogenesis.

Human metapneumovirus (hMPV) is one of the main causes of acute respiratory tract infections in children, elderly and immunocompromised patients. The mammalian Toll-like receptors (TLR) were identified as critical regulators of innate immunity to a variety of microbes, including viruses. We have recently shown that hMPV-induced cytokine, chemokine and type I interferon secretion in dendritic cells occurs via TLR4, however, its role in hMPV-induced disease is unknown. In this study, wild-type(WT) and TLR4-deficient mice (TLR4⁻/⁻) were infected with hMPV and examined for clinical disease parameters, such as body weight loss and airway obstruction, viral clearance, lung inflammation, dendritic cell maturation, T-cell proliferation and antibody production. Our results demonstrate that absence of TLR4 in hMPV-infected mice significantly reduced the inflammatory response as well as disease severity, shown by reduced body weight loss and airway obstruction and hyperresponsiveness (AHR), compared to WT mice. Levels of cytokines and chemokines were also significantly lower in the TLR4⁻/⁻ mice. Accordingly, recruitment of inflammatory cells in the BAL, lungs, as well as in lymph nodes, was significantly reduced in the TLR4⁻/⁻ mice, however, viral replication and clearance, as well as T-cell proliferation and neutralizing antibody production, were not affected. Our findings indicate that TLR4 is important for the activation of the innate immune response to hMPV, however it does play a role in disease pathogenesis, as lack of TLR4 expression is associated with reduced clinical manifestations of hMPV disease, without affecting viral protection.

Adjuvant antiviral therapy for recurrent respiratory papillomatosis.

BACKGROUND: This is an update of a Cochrane Review originally published in Issue 4, 2005 of The Cochrane Library and previously updated in 2010.Recurrent respiratory papillomatosis is a condition characterised by benign papillomatous (wart-like) growths in the upper airway. It can affect both adults and children causing airway obstruction and voice change. Treatment usually involves repeated surgical debulking of the papillomata. Several agents have been proposed as adjuvants to surgical debulking, including antivirals, administered systemically or injected into the lesions. OBJECTIVES: To assess the effectiveness of antiviral agents as adjuvant therapy in the management of recurrent respiratory papillomatosis in children and adults. SEARCH METHODS: We searched the Cochrane Ear, Nose and Throat Disorders Group Trials Register; the Cochrane Central Register of Controlled Trials (CENTRAL); PubMed; EMBASE; CINAHL; Web of Science; BIOSIS Previews; Cambridge Scientific Abstracts; ICTRP and additional sources for published and unpublished trials. The date of the most recent search was 24 February 2012. SELECTION CRITERIA: Randomised controlled trials. DATA COLLECTION AND ANALYSIS: We identified 143 references from the searches. Forty-three were appropriate for retrieval and assessed for eligibility by the authors. One randomised controlled trial met the inclusion criteria, involving 19 participants. We contacted the authors to obtain additional data to facilitate the review. MAIN RESULTS: The included study was a single-institution, randomised, double-blind, placebo-controlled trial of intralesional cidofovir administered at the time of surgical debulking. Adults (n = 15) and children (n = 4) were included. We judged the study to have a reasonably low risk of bias. After a 12-month trial period, no difference was found between the cidofovir and placebo groups. Both groups showed a significant reduction in disease extent (as assessed at the time of surgery using the Derkay Scoring System), but no significant change in health-related quality of life. AUTHORS' CONCLUSIONS: There is insufficient evidence to support the efficacy of antiviral agents as adjuvant therapy in the management of recurrent respiratory papillomatosis in children or adults. The included randomised controlled trial showed no advantage of intralesional cidofovir over placebo at 12 months. The study was limited by a small sample size and a change in the cidofovir concentration midway through the trial, from 0.3 mg/ml in children and 0.75 mg/ml in adults, to 5 mg/ml in both adults and children. An adequately powered randomised controlled trial of intra-lesional cidofovir, consistently using higher concentrations of cidofovir in comparison with injected placebo, would be required to determine effectiveness convincingly. Future studies must include health-related quality of life and symptom-based outcome measures.

Adjuvant antiviral therapy for recurrent respiratory papillomatosis.

BACKGROUND: This is an update of a Cochrane Review originally published in Issue 4, 2005 of The Cochrane Library.Recurrent respiratory papillomatosis is a condition characterised by benign papillomatous (wart-like) growths in the upper airway. It can affect both adults and children causing airway obstruction and voice change. Treatment usually involves repeated surgical debulking of the papillomata. Several agents have been proposed as adjuvants to surgical debulking, including antivirals, administered systemically or injected into the lesions. OBJECTIVES: To assess the effectiveness of antiviral agents as adjuvant therapy in the management of recurrent respiratory papillomatosis in children and adults. SEARCH STRATEGY: We searched the Cochrane Ear, Nose and Throat Disorders Group Trials Register; the Cochrane Central Register of Controlled Trials (CENTRAL); PubMed; EMBASE; CINAHL; Web of Science; BIOSIS Previews; Cambridge Scientific Abstracts; mRCT and additional sources for published and unpublished trials. The date of the most recent search was 30 September 2009. SELECTION CRITERIA: Randomised controlled trials. DATA COLLECTION AND ANALYSIS: We identified 143 references from the searches. Forty-three were appropriate for retrieval and assessed for eligibility by the authors. One randomised controlled trial met the inclusion criteria, involving 19 participants. We contacted the authors to obtain additional data to facilitate the review. MAIN RESULTS: The included study was a single-institution, randomised, double-blind, placebo-controlled trial of intralesional cidofovir administered at the time of surgical debulking. Adults (n = 15) and children (n = 4) were included. After a 12-month trial period, no difference was found between the cidofovir and placebo groups. Both groups showed a significant reduction in disease extent (as assessed at the time of surgery using the Derkay Scoring System), but no significant change in health-related quality of life. AUTHORS' CONCLUSIONS: There is insufficient evidence to support the efficacy of antiviral agents as adjuvant therapy in the management of recurrent respiratory papillomatosis in children or adults. The included randomised controlled trial showed no advantage of intralesional cidofovir over placebo at 12 months. The study was limited by a small sample size and a change in the cidofovir concentration midway through the trial, from 0.3 mg/ml in children and 0.75 mg/ml in adults, to 5 mg/ml in both adults and children. An adequately powered randomised controlled trial of intra-lesional cidofovir, consistently using higher concentrations of cidofovir in comparison with injected placebo, would be required to determine effectiveness convincingly. Future studies must include health-related quality of life and symptom-based outcome measures.

Macrophage impairment underlies airway occlusion in primary respiratory syncytial virus bronchiolitis.

Although respiratory syncytial virus (RSV) infection is the most important cause of bronchiolitis in infants, the pathogenesis of RSV disease is poorly described. We studied histopathologic changes in a panel of lung tissue specimens obtained from infants with fatal cases of primary RSV infection. In these tissues, airway occlusion with accumulations of infected, apoptotic cellular debris and serum protein was consistently observed. Similar observations were found after RSV infection in New Zealand black (NZB) mice, which have constitutive deficiencies in macrophage function, but not in BALB/c mice. A deficiency in the number of alveolar macrophages in NZB mice appears to be central to enhanced disease, because depletion of alveolar macrophages in BALB/c mice before RSV exposure resulted in airway occlusion. In mice with insufficient numbers of macrophages, RSV infection yielded an increased viral load and enhanced expression of type I interferon-associated genes at the height of disease. Together, our data suggest that innate, rather than adaptive, immune responses are critical determinants of the severity of RSV bronchiolitis.

Persistent airway obstruction after virus infection is not associated with airway inflammation.

BACKGROUND: This study examined the contribution of airway inflammation to the delayed lung function recovery that occurs in some people following virus-induced asthma exacerbations. METHODS: Subjects (n = 40) were recruited at hospital admission for acute asthma exacerbation. Respiratory virus infection was diagnosed by viral nucleic acid detection and/or cell culture, using induced sputum, nasal, or throat swabs. Data collected included lung function, answers to common cold and asthma control questionnaires, and induced sputum cellular profiles. Subjects were reexamined 4 to 6 weeks postexacerbation and were compared with stable asthmatic subjects (n = 26) who had been recruited from ambulatory care clinics. RESULTS: Persistent airway obstruction, defined as lung function improvement at follow-up (ie, change in FEV1 percent predicted [Delta%FEV1]) of <15%, was observed in 10 subjects (25%). Airway recovery (Delta%FEV1, > or = 15%) was observed in the remaining subjects (30 subjects; 75%). During the acute episode, the airway-recovery group had increased total cell count (p = 0.019), increased number of neutrophils (p = 0.005), and increased percentage of neutrophils (p = 0.0043) compared to the group of stable subjects with asthma. Postexacerbation, the airway-recovery group had reduced numbers of neutrophils and an increased percentage of eosinophils. In contrast, during exacerbation, subjects with persistent airway obstruction showed no differences in inflammatory cell counts compared to stable subjects with asthma, nor did cell counts change postexacerbation. Symptoms improved in both groups postexacerbation. However, in the persistent-airway-obstruction group, asthma remained uncontrolled. CONCLUSION: Persistent airway obstruction and uncontrolled asthma are observed in some people after viral asthma exacerbations. These abnormalities are not associated with inflammatory cell influx into the airway lining fluid during the exacerbation and may reflect the involvement of noncellular elements. Further work should explore other mechanisms leading to incomplete airway recovery.