Postinfectious bronchiolitis obliterans in children: lessons from bronchiolitis obliterans after lung transplantation and hematopoietic stem cell transplantation

Postinfectious bronchiolitis obliterans (PIBO) is an irreversible obstructive lung disease characterized by subepithelial inflammation and fibrotic narrowing of the bronchioles after lower respiratory tract infection during childhood, especially early childhood. Although diagnosis of PIBO should be confirmed by histopathology, it is generally based on history and clinical findings. Irreversible airway obstruction is demonstrated by decreased forced expiratory volume in 1 second with an absent bronchodilator response, and by mosaic perfusion, air trapping, and/or bronchiectasis on computed tomography images. However, lung function tests using spirometry are not feasible in young children, and most cases of PIBO develop during early childhood. Further studies focused on obtaining serial measurements of lung function in infants and toddlers with a risk of bronchiolitis obliterans (BO) after lower respiratory tract infection are therefore needed. Although an optimal treatment for PIBO has not been established, corticosteroids have been used to target the inflammatory component. Other treatment modalities for BO after lung transplantation or hematopoietic stem cell transplantation have been studied in clinical trials, and the results can be extrapolated for the treatment of PIBO. Lung transplantation remains the final option for children with PIBO who have progressed to end-stage lung disease.

[Delayed convulsion after lidocaine instillation for bronchoscopy]

INTRODUCTION

Lidocaine toxicity usually appears rapidly and is directly correlated with plasma concentrations of the drug.

CASE REPORT

We report a case of a late neurologic toxicity occurring after instillation of lidocaine during fibre-optic bronchoscopy. A patient with bronchiolitis obliterans underwent a diagnostic bronchoscopy. She received multiples instillations of Xylocaine(®) 2% (lidocaine). Three and a half hours later, she had a tonic-clonic seizure. Seven hours later, this recurred. Lidocaine plasma levels were in the toxic range at the time of the first seizure (18.32μg/mL) with a significant decrease in the concentration noted 24hours later.

CONCLUSION

The slow absorption of lidocaine into the blood from the bronchial tree explains the delayed neurologic toxicity. Our observation is a reminder that complications can occur due to high doses of lidocaïne administrated by instillation. Thus, if the recommended dose of lidocaine is exceeded, it is essential to monitor patients closely for a prolonged period, especially those with fibrosing lung disease in order to avoid possible late toxicity.

Characterization of naturally occurring airborne diacetyl concentrations associated with the preparation and consumption of unflavored coffee

Diacetyl, a suspected cause of respiratory disorders in some food and flavorings manufacturing workers, is also a natural component of roasted coffee. We characterized diacetyl exposures that would plausibly occur in a small coffee shop during the preparation and consumption of unflavored coffee. Personal (long- and short-term) and area (long-term) samples were collected while a barista ground whole coffee beans, and brewed and poured coffee into cups. Simultaneously, long-term personal samples were collected as two participants, the customers, drank one cup of coffee each per h. Air sampling and analyses were conducted in accordance with OSHA Method 1012. Diacetyl was detected in all long-term samples. The long-term concentrations for the barista and area samples were similar, and ranged from 0.013⿿0.016 ppm; long-term concentrations for the customers were slightly lower and ranged from 0.010⿿0.014 ppm. Short-term concentrations ranged from below the limit of detection (<0.0047 ppm)⿿0.016 ppm. Mean estimated 8 h time-weighted average (8 h TWA) exposures for the barista ranged from 0.007⿿0.013 ppm; these values exceed recommended 8 h TWA occupational exposure limits (OELs) for diacetyl and are comparable to long-term personal measurements collected in various food and beverage production facilities. The concentrations measured based on area sampling were comparable to those measured in the breathing zone of the barista, thus exceedances of the recommended OELs may also occur for coffee shop workers who do not personally prepare coffee (e.g., cashier, sanitation/maintenance). These findings suggest that the practicality and scientific basis of the recommended OELs for diacetyl merit further consideration.

Effects of home-based respiratory muscle training in children and adolescents with chronic lung disease

OBJECTIVE

Respiratory muscle weakness is a functional repercussion of chronic lung disease (CLD). The objective of this study was to assess the effects of home-based respiratory muscle training (RMT) in children and adolescents with CLD or neuromuscular disease (NMD).

METHODS

This was a quasi-experimental study involving children and adolescents with CLD or NMD. Before and after 6 months of home-based RMT, we measured respiratory muscle strength (MIP and MEP), PEF, and peak cough flow (PCF). We made statistical comparisons between the pre-RMT and post-RMT values, as well as evaluating the correlation between the duration and effect of RMT.

RESULTS

The study included 29 patients, with a mean age of 12 years (range, 5-17 years), of whom 18 (62.1%) were male. The CLD group comprised 11 patients (37.9%), and the NMD group comprised 18 (62.1%). The mean duration of the RMT was 60 weeks (range, 46-90 weeks) in the CLD group and 39 weeks (range, 24-89 weeks) in the NMD group. In comparison with the pre-RMT values, the post-RMT values for MIP and MEP were significantly higher in both groups, whereas those for PEF and PCF were significantly higher only in the NMD group. We found no correlation between the duration and the effect of RMT.

CONCLUSIONS

Home-based RMT appears to be an effective strategy for increasing respiratory muscle strength in children and adolescents with CLD or NMD, although it increased the ability to cough effectively only in those with NMD.

Airway inflammation in children and adolescents with bronchiolitis obliterans

BACKGROUND

Airway inflammation plays a major role in the progression of chronic lung diseases. The features of airway inflammation are not well defined among patients with cases of bronchiolitis obliterans (BO) that began in childhood.

OBJECTIVES

To investigate the sputum cell and cytokine profiles of stable cases of BO regarding lung function and the involvement of small airway disease (SAD).

METHODS

Twenty patients with BO (median age=14.5, range=7-23years) and 22 healthy controls (median age=16.5years, range=7-24years) were investigated. Lung function parameters and bronchial reversibility testing as well as sputum cell and cytokine profiles (IL-1β, IL-6, IL-8, TNF-α, IL-5, IFN-γ, and NFκB regulation) were analysed using quantitative RT-PCR and cytometric bead assay (CBA) in induced sputum.

RESULTS

Patients with BO had significantly lower lung function values, including FVC, forced expiratory volume (FEV1), the Tiffeneau index (FEV1/VC), and MEF25, but increased functional residual capacity (RV/TLC) values. Bronchial reversibility was found in five patients (25%). Moreover, airway inflammation (as indicated by total cells, neutrophils, IL-1β, IL-6, IL-8, TNF-α, and NFκB) was significantly increased among patients with BO compared with controls.

CONCLUSIONS

BO is predominantly a neutrophilic disease of the small bronchioles featuring elevated levels of pro-inflammatory cytokines leading to tissue remodelling and fibrosis of the small airways. Future therapies for patients with BO should more efficiently target the small airways.

Chronic respiratory failure due to toxic epidermal necrosis in a 10 year old girl

Toxic epidermal necrosis is a severe mucocutaneous disease with a high mortality rate. A third of the patients surviving the acute phase will develop pulmonary complications. The most frequent complication is bronchiolitis obliterans. Despite well-conducted treatment, in most cases, lung injury often leads to chronic respiratory failure. We describe here the case of a young patient that presented a toxic epidermal necrosis at the age of 3 years. Poor therapeutic compliance result in chronic respiratory failure and after 7 years of follow-up, pulmonary transplant remains the only long-term alternative. Close monitoring of respiratory symptoms in the course of toxic epidermal necrosis, intense treatment as soon as they appear and a long-term follow-up are essential to postpone chronic respiratory failure.

Current research on pediatric patients with bronchiolitis obliterans in Brazil

Bronchiolitis obliterans (BO) is a rare but severe disease, characterized by inflammation and fibrosis of the terminal bronchioles. BO in children usually occurs after a severe lung viral infection. Diagnosis is based on clinical history of acute bronchiolitis followed by persistent obstruction of the airways and characteristic findings in HRCT. There is no consensus on treatment beyond supportive measures, but bronchodilators and corticosteroids are often used. This review describes the clinical and radiological characteristics and outcomes of BO in pediatric patients, with an emphasis on current research in Brazil.

Biopsy-verified bronchiolitis obliterans and other noninfectious lung pathologies after allogeneic hematopoietic stem cell transplantation

Bronchiolitis obliterans (BO) is a serious complication of allogeneic hematopoietic stem cell transplantation (HSCT). Lung biopsy is the gold standard for diagnosis. This study describes the course of BO and assesses the congruity between biopsy-verified BO and a modified version of the National Institutes of Health's consensus criteria for BO syndrome (BOS) based exclusively on noninvasive measures. We included 44 patients transplanted between 2000 and 2010 who underwent lung biopsy for suspected BO. Of those, 23 were diagnosed with BO and 21 presented other noninfectious pulmonary pathologies, such as cryptogenic organizing pneumonia, diffuse alveolar damage, interstitial pneumonia, and nonspecific interstitial fibrosis. Compared with patients with other noninfectious pulmonary pathologies, BO patients had significantly lower values of forced expiratory volume in 1 second (FEV1), FEV1/forced vital capacity, and maximal mid-expiratory flow throughout follow-up, but there was no difference in the change in pulmonary function from the time of lung biopsy. The BO diagnosis was not associated with poorer overall survival. Fifty-two percent of patients with biopsy-verified BO and 24% of patients with other noninfectious pulmonary pathology fulfilled the BOS criteria. Pathological BO diagnosis was not superior to BOS criteria in predicting decrease in pulmonary function beyond the time of biopsy. A lung biopsy may provide a characterization of pathological patterns that can extend our knowledge on the pathophysiology of HSCT-related lung diseases.

Evaluation of four α-diketones for toll-like receptor-4 (TLR-4) activation in a human transfected cell line

Toll-like receptor-4 (TLR-4) activity is upregulated in persons with fibrotic lung diseases secondary to chronic inflammatory conditions like Crohn's disease and rheumatoid arthritis. We hypothesized that α-diketones associated with fixed obstructive lung disease may activate TLR-4. We utilized a human embryonic kidney cell assay (HEK293) with human TLR-4 receptors to test for potential activation effects of 2,3-butandeione, 2,3-pentanedione, 2,3-hexanedione, and 2,3-heptanedione at test concentrations of 1, 10, 100, and 1000 µM. The assay detects NF-κB-induced expression of secreted alkaline phosphatase measured after 16 h incubation by a UV-VIS Spectrometer at 650 nm. Escherichia coli K12 lipopolysaccharide (LPS) at 0.5 ng/mL served as a positive control and was added with each test compound to evaluate combined effects. None of the tested α-diketones were found to exhibit cytotoxicity, agonism, or synergistic effects with LPS in the human TLR-4 assay up to 1000 µM. Screening of 2,3-butanedione for agonist activity using the HEK assay with mouse TLR-4 receptors exhibited cytotoxicity at 1000 µM, but no agonist activity. We conclude that the tested α-diketones at relatively high concentrations in vitro do not exhibit TLR-4 agonist or synergistic activity and, therefore, apparently do not directly induce inflammasome activation through this pathway in humans or mice.

Postinfectious bronchiolitis obliterans in children: the South American contribution

Postinfectious bronchiolitis obliterans (PIBO) is an infrequent chronic lung that causes irreversible obstruction and, or, obliteration of the smaller airways. This review particularly focuses on more than 30 studies from South America.

CONCLUSION

The initial PIBO event occurs in the early years of life and is strongly associated with adenovirus infection and the need for mechanical ventilator support. Treatment requires a multidisciplinary strategy. Multicentre studies are needed to determine progression, optimal management and long-term follow-up.

An autopsy case of unicentric Castleman's disease associated with bronchiolitis obliterans

A 34-year-old woman visited the hospital suffering from enanthema of the tongue, hair loss, and nonproductive cough. Corticosteroid administration slightly resolved the enanthema and hair loss, but not the nonproductive cough. She was transferred to another hospital for the resection of a retroperitoneal mass, which was histopathologically diagnosed as unicentric, hyaline vascular type Castleman’s disease. She was then referred to our hospital due to progressive dyspnea and was diagnosed as having bronchiolitis obliterans based on computed tomography scan findings and a lung function test, while paraneoplastic pemphigus was clinically considered for her enanthema. After her death from respiratory failure in spite of corticosteroid administration, autopsy confirmed constrictive bronchiolitis in the lung. Mucocutaneous lesions, clinically considered as paraneoplastic pemphigus, were histologically different from pemphigus. The constrictive bronchiolitis and other pathological findings, including nonviral chronic hepatitis and interstitial nephritis, confirmed the diagnosis of paraneoplastic autoimmune multiorgan syndrome associated with the Castleman’s disease.

Improving survival outcomes in lung transplant recipients through early detection of bronchiolitis obliterans: Daily home spirometry versus standard pulmonary function testing

BACKGROUND

Long-term lung transplant success is limited by bronchiolitis obliterans syndrome (BOS), a form of chronic allograft rejection that manifests in the majority of patients by five years post-transplant. Frequent monitoring of pulmonary function measurements through the use of daily home spirometry may have the capability to detect the onset of BOS sooner than standard pulmonary function testing. Early detection of BOS would confer a treatment advantage that may improve survival outcomes for lung transplant recipients.

METHODS

A systematic review of current evidence was used to determine the effectiveness of daily home spirometry as a BOS detection tool, in addition to its impact and survival outcomes. Articles were included in the present systematic review if they were randomized control studies and if their purpose(s) included investigation of spirometry as a BOS detection tool in lung transplant patients.

RESULTS

A primary search of databases yielded 115 unique citations, with an additional four citations identified through a secondary review of the reference lists of retrieved articles. After application of all inclusion and exclusion criteria through abstract and full-text review, eight randomized controlled trials were included in the review.

DISCUSSION

Forced expiratory volume in 1 s (FEV1) has been identified as the most reliable diagnostic tool for detecting the onset of BOS. Two studies compared the use of traditionally scheduled pulmonary function testing with daily home spirometry and found BOS stage 1 to appear 341 days earlier with home spirometry (P<0.001). Other studies that investigated the impact early detection had on survival showed a positive trend toward freedom from BOS and reduced rates of retransplantation, although these results did not reach statistical significance (P<0.07).

CONCLUSION

Daily home spirometry has been shown to lead to earlier detection and staging of BOS when compared with standard pulmonary function testing. Although FEV1 has been shown to be the most sensitive and reliable marker of BOS onset, the impact of earlier staging via home spirometry on survival has not been reliably determined.

Interstitial lung disease in children

Children's interstitial lung disease (ILD) includes a wide range of rare respiratory disorders associated with high morbidity and mortality. Genetic factors, systemic disease processes, nonspecific inflammatory or fibrotic patterns of repair seen in a number of clinical settings are involved in the ILD pathogenesis. Specific disorders more prevalent in young children include diffuse developmental disorders, alveolar growth abnormalities, genetic surfactant disorders, pulmonary interstitial glycogenosis and neuroendocrine cell hyperplasia of infancy. It may be difficult to recognize these entities and this can lead to delayed treatment. The diagnostic approach is based on a combination of history/physical examinations, imaging studies, pulmonary function testing, genetic testing, bronchoalveolar lavage (BAL) and in most cases an open lung biopsy. Although some disease types overlap with those seen in adults, in this review emphasis is placed on entities unique to the pediatric population focusing on clinical characteristics, histologic definitions, radiologic-pathologic correlation and therapeutic strategies.

GERD related micro-aspiration in chronic mustard-induced pulmonary disorder

BACKGROUND AND AIM

Bronchiolitis obliterans (BO) is the main pulmonary involvement resulting from sulfur mustard (SM) gas exposure that was used against Iranian civilians and military forces during the Iran-Iraq war. The present study aimed to investigate the prevalence of gastro-esophageal reflux (GER) and gastric micro-aspiration in SM gas injured patients with chronic pulmonary diseases and recurrent episodes of exacerbations.

MATERIALS AND METHODS

This cross-sectional study was done at Baqiyatallah University of Medical Sciences, Tehran, Iran. Gastric micro-aspiration and GER were assessed in the enrolled patients by assessing bile acids, pepsin and trypsin in their bronchoalveolar lavage fluid.

RESULTS

Our result showed that bile acids were found to be high in 21.4% patients, and low in 53.6% of patients. Only in 16% patients, no bile was detected in the BALF. Trypsin and pepsin were detected in BAL fluid of all patients.

CONCLUSION

Most of BO patients after exposure to SM suffer GER, while none the etiologic factors of GER in post lung transplant BO are present. It would be hypothesized that GER per se could be considered as an aggregative factor for exacerbations in patients. Further studies will provide more advances to better understanding of pathophysiological mechanism regarding GER and BO and treatment.