COVID-19 related concerns of people with long-term respiratory conditions: a qualitative study.

BACKGROUND: The COVID-19 pandemic is having profound psychological impacts on populations globally, with increasing levels of stress, anxiety, and depression being reported, especially in people with pre-existing medical conditions who appear to be particularly vulnerable. There are limited data on the specific concerns people have about COVID-19 and what these are based on. METHODS: The aim of this study was to identify and explore the concerns of people with long-term respiratory conditions in the UK regarding the impact of the COVID-19 pandemic and how these concerns were affecting them. We conducted a thematic analysis of free text responses to the question "What are your main concerns about getting coronavirus?", which was included in the British Lung Foundation/Asthma UK (BLF-AUK) partnership COVID-19 survey, conducted between the 1st and 8th of April 2020. This was during the 3rd week of the UK's initial 'social distancing measures' which included advice to stay at home and only go outside for specific limited reasons. RESULTS: 7039 responses were analysed, with respondents from a wide range of age groups (under 17 to over 80), gender, and all UK nations. Respondents reported having asthma (85%), COPD (9%), bronchiectasis (4%), interstitial lung disease (2%), or 'other' lung diseases (e.g. lung cancer) (1%). Four main themes were identified: (1) vulnerability to COVID-19; (2) anticipated experience of contracting COVID-19; (3) pervasive uncertainty; and (4) inadequate national response. CONCLUSIONS: The COVID-19 pandemic is having profound psychological impacts. The concerns we identified largely reflect contextual factors, as well as their subjective experience of the current situation. Hence, key approaches to reducing these concerns require changes to the reality of their situation, and are likely to include (1) helping people optimise their health, limit risk of infection, and access necessities; (2) minimising the negative experience of disease where possible, (3) providing up-to-date, accurate and consistent information, (4) improving the government and healthcare response.

Clinical features and radiographic findings in cats with eosinophilic, neutrophilic, and mixed airway inflammation (2011-2018).

BACKGROUND: Idiopathic inflammatory airway disease (IAD) in cats often is described as asthmatic (eosinophilic) or bronchitic (neutrophilic), but this designation requires collection of airway fluid and it fails to consider cats with mixed airway inflammation. OBJECTIVE: To identify clinical features that would differentiate inflammatory disease types. ANIMALS: Forty-nine cats with nonspecific airway inflammation identified by bronchoscopic bronchoalveolar lavage (BAL) between 2011 and 2018 were evaluated. METHODS: This is a retrospective study. Cats were categorized by BAL differential cytology as having eosinophilic (eosinophils >20% with neutrophils <14%, or eosinophils >50%), mixed (eosinophils 20%-50% and neutrophils >14% or discordant inflammation from 2 BAL sites), or neutrophilic (neutrophils >14% and eosinophils <20%) inflammation. Type and duration of presenting complaints, signalment, body condition score, respiratory rate, CBC results, bronchoscopy, BAL results (% recovery, total nucleated cell count, differential cell count), and radiographic findings were compared among groups. RESULTS: Idiopathic IAD was diagnosed in 49 cats, with BAL eosinophilic inflammation in 23, mixed inflammation in 14, and neutrophilic inflammation in 12. Cough was the predominant presenting complaint with no difference in duration of signs among groups (median, 5.5 months). Respiratory rate and effort also did not differ. Cats with eosinophilic inflammation were significantly younger (4.4 ± 3.3 years) than those with neutrophilic (8.0 ±5.6 years) or mixed inflammation (7.5 ± 4.0 years; P = .03). Results of CBC and interpretation of radiographic findings did not differ among groups. CONCLUSIONS AND CLINICAL IMPORTANCE: Substantial overlap exists in clinical and radiographic findings in cats with various forms of idiopathic airway inflammation.

Importance of coding co-morbidities for APR-DRG assignment: Focus on cardiovascular and respiratory diseases.

BACKGROUND: The All Patient-Refined Diagnosis-Related Groups (APR-DRGs) system has adjusted the basic DRG structure by incorporating four severity of illness (SOI) levels, which are used for determining hospital payment. A comprehensive report of all relevant diagnoses, namely the patient's underlying co-morbidities, is a key factor for ensuring that SOI determination will be adequate. OBJECTIVE: In this study, we aimed to characterise the individual impact of co-morbidities on APR-DRG classification and hospital funding in the context of respiratory and cardiovascular diseases. METHODS: Using 6 years of coded clinical data from a nationwide Portuguese inpatient database and support vector machine (SVM) models, we simulated and explored the APR-DRG classification to understand its response to individual removal of Charlson and Elixhauser co-morbidities. We also estimated the amount of hospital payments that could have been lost when co-morbidities are under-reported. RESULTS: In our scenario, most Charlson and Elixhauser co-morbidities did considerably influence SOI determination but had little impact on base APR-DRG assignment. The degree of influence of each co-morbidity on SOI was, however, quite specific to the base APR-DRG. Under-coding of all studied co-morbidities led to losses in hospital payments. Furthermore, our results based on the SVM models were consistent with overall APR-DRG grouping logics. CONCLUSION AND IMPLICATIONS: Comprehensive reporting of pre-existing or newly acquired co-morbidities should be encouraged in hospitals as they have an important influence on SOI assignment and thus on hospital funding. Furthermore, we recommend that future guidelines to be used by medical coders should include specific rules concerning coding of co-morbidities.

The burden of air pollution and weather condition on daily respiratory deaths among older adults in China, Jinan from 2011 to 2017.

The health effects of short-term exposure to air pollutants on respiratory deaths and its modifiers such as meteorological indexes have been widely investigated. However, most of the previous studies are limited to single pollutants or total respiratory deaths, and their findings are inconsistent.To comprehensively examine the short-term effects of air pollutants on daily respiratory mortality.Our analysis included 16,931 nonaccidental respiratory deaths (except lung cancer and tuberculosis) among older adults (>65 years) from 2011 to 2017 in Jinan, China. We used a generalized additive Poisson models adjusted for meteorology and population dynamics to examine the associations between air pollutants (particulate matter with an aerodynamic diameter of b2.5µm [PM2.5], particulate matter with an aerodynamic diameter of b10µm [PM10], SO2, NO2, O3) and daily mortality for the total patients, males, females, chronic airway diseases, pneumonia patients, and rest patients in Jinan.Outdoor air pollution was significantly related to mortality from all respiratory diseases especially from chronic airway disease in Jinan, China. The effects of air pollutants had lag effects and harvesting effects, and the effects estimates usually reached a peak at lag 1 or 2 day. An increase of 10 µg/m or 10 ppb of PM2.5, PM10, SO2, NO2, and O3 corresponds to increments in mortality caused by chronic airway disease of 0.243% (95% confidence interval [CI]: -0.172-0.659) at lag 1 day, 0.127% (95% CI: -0.161-0.415) at lag 1 day, 0.603% (95% CI: 0.069-1.139) at lag 3 day, 0.649% (95% CI: -0.808-2.128) at lag 0 day and 0.944% (95% CI: 0.156-0.1598) at lag 1 day, respectively. The effects of air pollutants were usually greater in females and varied by respiratory subgroups. Spearman correlation analysis suggested that there was a significant association between meteorological indexes and air pollutants.Sex, age, temperature, humidity, pressure, and wind speed may modify the short-term effects of outdoor air pollution on mortality in Jinan. Compared with the other pollutants, O3 had a stronger effect on respiratory deaths among the elderly. Moreover, chronic airway diseases were more susceptible to air pollution. Our findings provided new evidence for new local environmental and health policies making.

[Different Prevalences of Pneumological Disease Patterns in Outpatient and Inpatient Care]. / Unterschiedliche Häufigkeiten pneumologischer Krankheitsbilder in der ambulanten und stationären Medizin.

BACKGROUND: Evaluating the focus of treatment in pneumological inpatient and outpatient care is of special interest due to its impact on physician, patient and research. This work describes differences and commonalities in the focus of treatment of current pneumological inpatient and outpatient care and discusses their impact on patient, physician and research. METHODS: This study compares the inpatient and outpatient sector based on the prevalence of ICD codes of a pneumological specialist clinic (5.211 cases of 2016) and the most prevalent ICD-10 codes of pneumology practices in the third quarter 2016, published by the Association of Statutory Health Insurance Physicians North Rhine ("Kassenärztliche Vereinigung Nordrhein", 142.431 cases). RESULTS: Whereas the proportion of many pneumological disease patterns treated in physicians' practices and hospitals is similar, the relative frequencies of specific diseases differ considerably between the two. Treatment of allergic conditions such as allergic rhinopathy and bronchial asthma is mostly done on an outpatient basis while respiratory insufficiency and lung carcinoma constitute domains of pneumological inpatient care. CONCLUSION: Despite many commonalities in the focus of treatment in pneumological inpatient and outpatient care, there are also substantial differences between the two. These affect medical training, the conduct of clinical studies, and in particular, patient care. In order to maintain a high level of medical care in all areas of pneumology a close exchange between inpatient and outpatient sector seems crucial. In the end, the availability of medical expertise across both sectors will benefit all: physicians, patients and medical science.

Precision medicine in united airways disease: A "treatable traits" approach.

United airways disease (UAD) is the concept that the upper and lower airways, which are anatomically and immunologically related, form a single organ. According to this concept, upper and lower airway diseases are frequently comorbid because they reflect manifestations of a single underlying disease at different sites of the respiratory tract. Allergic asthma-allergic rhinitis is the archetypal UAD, but emerging data indicate that UAD is a heterogeneous condition and consists of multiple phenotypes (observable clinical characteristics) and endotypes (pathobiologic mechanisms). The UAD paradigm also extends to myriad sinonasal diseases (eg, chronic rhinosinusitis with or without nasal polyps) and lower airway diseases (eg, bronchiectasis, chronic obstructive pulmonary disease). Here, we review currently known phenoendotypes of UAD and propose a "treatable traits" approach for the classification and management of UAD, wherein pathophysiological mechanisms and factors contributing to disease are identified and targeted for treatment. Treatable traits in UAD can be analyzed according to a framework comprising airway inflammation (eosinophilic, neutrophilic), impaired airway mucosal defense (impaired mucociliary clearance, antibody deficiency), and exogenous cofactors (allergic sensitizers, tobacco smoke, microbes). Appreciation of treatable traits is necessary in advancing the effort to deliver precise treatments and achieve better outcomes in patients with UAD.

ISHLT Consensus Statement on adult and pediatric airway complications after lung transplantation: Definitions, grading system, and therapeutics.

Airway complications remain a major cause of morbidity and mortality after cardiothoracic transplantation. The reported incidence of airway ischemic complications varies widely, contributed to by the lack of a universally accepted grading system and standardized definitions. Furthermore, the majority of the existing classification systems fail to integrate the wide range of possible bronchial complications that may develop after lung transplant. Hence, a Working Group was created by the International Society for Heart and Lung Transplantation with the aim of elaborating a universal definition of adult and pediatric airway complications and grading system. One such area of focus is to understand the problem in the context of a more standardized consensus of classifying airway ischemia. This consensus definition will have major clinical, therapeutics, and research implications.

Computed tomographic findings in subjects who died from respiratory disease in the National Lung Screening Trial.

We evaluated the prevalence of significant lung abnormalities on computed tomography (CT) in patients who died from a respiratory illness other than lung cancer in the National Lung Screening Trial (NLST).In this retrospective case-control study, NLST participants in the CT arm who died of respiratory illness other than lung cancer were matched for age, sex, pack-years and smoking status to a surviving control. A chest radiologist and a radiology resident blinded to the outcome independently scored baseline CT scans visually and qualitatively for the presence of emphysema, airway wall thickening and fibrotic lung disease. The prevalence of CT abnormalities was compared between cases and controls by using chi-squared tests.In total, 167 participants died from a respiratory cause other than lung cancer. The prevalence of severe emphysema, airway wall thickening and fibrotic lung disease were 28.7% versus 4.8%, 26.9% versus 13.2% and 18.6% versus 0.5% in cases and controls, respectively. Radiological findings were significantly more prevalent in deaths compared with controls (all p<0.001).CT-diagnosed severe emphysema, airway wall thickening and fibrosis were much more common in NLST participants who died from respiratory disease, and CT may provide an additional means of identifying these diseases.

[THE PREVALENCE OF RESPIRATORY SYMPTOMS AMONG RESIDENTS OF THE RUSSIAN FAR NORTH].

Aim: To study the frequency of respiratory symptoms among the reindeer herders of the Yamal region in the Far North of Russia. We conducted a cross-sectional study of the occurrence of respiratory symptoms among 500 subjects of the tundra Nenets population (28.1% of the adult Nenets population in the district), of which 38.3% were men and 61.7% women (average age 40.1 years). All patients were matched for age and occupation. Medical examination was carried out by a pulmonologist with the use of the GARD questionnaire (WHO, 2004) and spirometry. Spirometry was performed with a SpiroUSB device (UK) according to a unified standard and the criteria of ATS/ERS 2005. The frequency of respiratory symptoms among the tundra population was estimated at 71.8%. Cough with expectoration and dyspnea were found in 22.8% of the respondents. 70.0% of the examined subjects worked in the cold, 33% were exposed to the open flame at home, and 34.4% smoked. Respiratory symptoms developed in 16.3% of those working in the cold and in 37% exposed to open fire. The combination of such complaints as cough and sputum production occurred in smokers twice as frequently as in non-smokers (54.1%) (p<0.01).The combination of such complaints as cough and sputum production was twice as likely note in his those who smoked (54.1% vs 20.2%) (p<0.01). The combination of these problems dyspnea was three times more common in the smokers (23,3%vs 7,3%) (p<0.001). At presence at patients of such a factor as work in the cold and the absence of other only 16.3% of them have respiratory symptoms. When using at home the open flame and the absence of other factors leading up 37.0% of the individuals with symptoms of chronic bronchitis. Cough, sputum and dyspnea are formed only among 26.3% of the smokers face when smoking is the only risk factor. If the surveyed residents of all three negative factors respiratory symptoms met at 62.1%. Disorders of respiratory function according to spirometry were not observed in none of the study participants. Respiratory symptoms developed in 62.1% of the subjects exposed to all three risk factors. External respiration indices remain normal in all he examine subjects. It is concluded that residents of the Far North frequently suffer respiratory symptoms without disorders in the external respiratory function. In most cases they associated with three factors (work in the cold, exposure to open fire at home, and smoking). Compensatory stimulation of lung functions may create additional difficulties for diagnostics of bronchial obstruction.

Classifying Chronic Lower Respiratory Disease Events in Epidemiologic Cohort Studies.

RATIONALE: One in 12 adults has chronic obstructive pulmonary disease or asthma. Acute exacerbations of these chronic lower respiratory diseases (CLRDs) are a major cause of morbidity and mortality. Valid approaches to classifying cases and exacerbations in the general population are needed to facilitate prevention research. OBJECTIVES: To assess the feasibility, reproducibility, and performance of a protocol to identify CLRD cases and exacerbations triggering emergency department (ED) visits or hospitalizations in cohorts of patients derived from general populations of adults. METHODS: A protocol was developed to classify CLRD cases and severe exacerbations on the basis of review of medical records. ED and inpatient medical records were ascertained prospectively in the Hispanic Community Health Study/Study of Latinos, and inpatient records were retrospectively identified by administrative codes in the Multi-Ethnic Study of Atherosclerosis. "Probable" exacerbations were defined as a physician's diagnosis of CLRD with acute respiratory symptoms. "Highly probable" exacerbations additionally required systemic corticosteroid therapy, and "definite" exacerbations required airflow limitation or evidence of CLRD on imaging studies. Adjudicated results were compared with CLRD cases identified by spirometry and self-report, and with an administrative definition of exacerbations. MEASUREMENTS AND MAIN RESULTS: Protocol-based classification was completed independently by two physicians for 216 medical records (56 ED visits and 61 hospitalizations in the Hispanic Community Health Study/Study of Latinos; 99 hospitalizations in the Multi-Ethnic Study of Atherosclerosis). Reviewer disagreement occurred in 2-5% of cases and 4-8% of exacerbations. Eighty-nine percent of records were confirmed as at least probable CLRD cases. Fifty-six percent of confirmed CLRD cases had airflow limitation on the basis of baseline study spirometry. Of records that described CLRD as the primary discharge diagnosis code, an acute exacerbation was confirmed as at least probable for 96% and as highly probable or definite for 77%. Only 50% of records with CLRD as a secondary code were confirmed, although such records accounted for over half of all confirmed exacerbations. CONCLUSIONS: CLRD cases and severe exacerbations without preceding documentation of airflow limitation are identified frequently in population-based cohorts of persons. A primary discharge diagnosis of CLRD is specific but insensitive for defining exacerbations. Protocol-based classification of medical records may be appropriate to supplement and to validate identification of CLRD cases and exacerbations in general population studies. Clinical trials registered with www.clinicaltrials.gov (NCT00005487 and NCT02060344).

Evaluation of inter-observer agreement when using a clinical respiratory scoring system in pre-weaned dairy calves.

AIM: To determine inter-observer agreement for a clinical scoring system for the detection of bovine respiratory disease complex in calves, and the impact of classification of calves as sick or healthy based on different cut-off values. METHODS: Two third-year veterinary students (Observer 1 and 2) and one post-graduate student (Observer 3) received 4 hours of training on scoring dairy calves for signs of respiratory disease, including rectal temperature, cough, eye and nasal discharge, and ear position. Observers 1 and 2 scored 40 pre-weaning dairy calves 24 hours apart (80 observations) over three visits to a calf-rearing facility, and Observers 1, 2 and 3 scored 20 calves on one visit. Inter-observer agreement was assessed using percentage of agreement (PA) and Kappa statistics for individual clinical signs, comparing Observers 1 and 2. Agreement between the three observers for total clinical score was assessed using cut-off values of ≥4, ≥5 and ≥6 to indicate unhealthy calves. RESULTS: Inter-observer PA for rectal temperature was 0.68, for cough 0.78, for nasal discharge 0.62, for eye discharge 0.63, and for ear position 0.85. Kappa values for all clinical signs indicated slight to fair agreement (<0.4), except temperature that had moderate agreement (0.6). The Fleiss' Kappa for total score, using cut-offs of ≥4, ≥5 and ≥6 to indicate unhealthy calves, was 0.35, 0.06 and 0.13, respectively, indicating slight to fair agreement. CONCLUSIONS AND CLINICAL RELEVANCE: There was important inter-observer discrepancies in scoring clinical signs of respiratory disease, using relatively inexperienced observers. These disagreements may ultimately mean increased false negative or false positive diagnoses and incorrect treatment of cases. Visual assessment of clinical signs associated with bovine respiratory disease needs to be thoroughly validated when disease monitoring is based on the use of a clinical scoring system.

Relationships (II) of International Classification of High-resolution Computed Tomography for Occupational and Environmental Respiratory Diseases with ventilatory functions indices for parenchymal abnormalities.

The International Classification of High-Resolution Computed Tomography (HRCT) for Occupational and Environmental Respiratory Diseases (ICOERD) is used to screen and diagnose respiratory illnesses. Using univariate and multivariate analysis, we investigated the relationship between subject characteristics and parenchymal abnormalities according to ICOERD, and the results of ventilatory function tests (VFT). Thirty-five patients with and 27 controls without mineral-dust exposure underwent VFT and HRCT. We recorded all subjects' occupational history for mineral dust exposure and smoking history. Experts independently assessed HRCT using the ICOERD parenchymal abnormalities (Items) grades for well-defined rounded opacities (RO), linear and/or irregular opacities (IR), and emphysema (EM). High-resolution computed tomography showed that 11 patients had RO; 15 patients, IR; and 19 patients, EM. According to the multiple regression model, age and height had significant associations with many indices ventilatory functions such as vital capacity, forced vital capacity, and forced expiratory volume in 1 s (FEV1). The EM summed grades on the upper, middle, and lower zones of the right and left lungs also had significant associations with FEV1 and the maximum mid-expiratory flow rate. The results suggest the ICOERD notation is adequate based on the good and significant multiple regression modeling of ventilatory function with the EM summed grades.

Relationships (I) of International Classification of High-resolution Computed Tomography for Occupational and Environmental Respiratory Diseases with the ILO International Classification of Radiographs of Pneumoconioses for parenchymal abnormalities.

The International Classification of High-resolution Computed Tomography (HRCT) for Occupational and Environmental Respiratory Diseases (ICOERD) has been developed for the screening, diagnosis, and epidemiological reporting of respiratory diseases caused by occupational hazards. This study aimed to establish a correlation between readings of HRCT (according to the ICOERD) and those of chest radiography (CXR) pneumoconiotic parenchymal opacities (according to the International Labor Organization Classification/International Classification of Radiographs of Pneumoconioses [ILO/ICRP]). Forty-six patients with and 28 controls without mineral dust exposure underwent posterior-anterior CXR and HRCT. We recorded all subjects' exposure and smoking history. Experts independently read CXRs (using ILO/ICRP). Experts independently assessed HRCT using the ICOERD parenchymal abnormalities grades for well-defined rounded opacities (RO), linear and/or irregular opacities (IR), and emphysema (EM). The correlation between the ICOERD summed grades and ILO/ICRP profusions was evaluated using Spearman's rank-order correlation. Twenty-three patients had small opacities on CXR. HRCT showed that 21 patients had RO; 20 patients, IR opacities; and 23 patients, EM. The correlation between ILO/ICRP profusions and the ICOERD grades was 0.844 for rounded opacities (p<0.01). ICOERD readings from HRCT scans correlated well with previously validated ILO/ICRP criteria. The ICOERD adequately detects pneumoconiotic micronodules and can be used for the interpretation of pneumoconiosis.

[Advances in pediatric thoracic surgery during the past 50 years].

Surgical strategies and treatment for pediatric airway and lung diseases have advanced significantly, especially in the fields of subglottic stenosis, congenital tracheal stenosis, congenital cystic lung lesions, and endoscopic surgery, during the past 50 years. Pediatricians, pathologists, and pediatric surgeons have engaged in continuous discussions at scientific meetings to establish standard terminology and operative indications and to refine surgical techniques such as laryngoplasty, sliding tracheoplasty, lobectomy under thoracotomy and thoracoscopy. The modified Myer-Cotton grading system for subglottic stenosis was proposed and proved to be useful in selecting reconstructive operative techniques. The addition of aortopexy to sliding tracheoplasty was also confirmed to be effective in maintaining a wide postoperative tracheal lumen. The disease entities of each type of cystic lung lesion were clarified, and the clinical and etiological importance of bronchial/bronchiolar atresia was emphasized. A classification of congenital cystic lung disease was proposed based on anatomic and embryologic considerations. In this classification, congenital pulmonary airway anomaly was introduced to replace congenital cystic adenomatoid malformation of the lung. Intralobar sequestration of the lung must be located in the lower lobe in this definition and classification.

A longitudinal study on early hospitalized airway infections and subsequent childhood asthma.

BACKGROUND: Acute airway infections, including bronchiolitis, are common causes of early childhood hospitalization. The development of later asthma may be related to early airway infections in young children. This study is to investigate the relationship between hospitalized airway infections (HAI) in young children (< 3 years old) and later childhood asthma. METHODS: Hospitalized children (< 3 years old) with bronchiolitis or other acute airway infections (other HAI group) from 1997-2000 were retrieved from the National Health Insurance Research Database of Taiwan, and compared to age- and gender-matched subjects with regards to asthma until 10 years of age; and potential comorbidities and medical care conditions. RESULTS: In total, 3,264 children (1,981 with bronchiolitis; 1,283 with other HAIs) were compared to 18,527 controls. The incidence of childhood asthma was higher in the study (16.2%) than the control (11.7%) group, and most cases were diagnosed between 3-5 years old. The hazard ratios were 1.583 (95% CI: 1.414-1.772) and 1.226 (95% CI: 1.053-1.428) for the bronchiolitis and other HAI subgroups, respectively, compared to the control group, and 1.228 (95% CI: 1.075-1.542) in the bronchiolitis subgroup compared to the other HAIs subgroup. A significantly higher odds ratio (1.973, 95% CI: 1.193-3.263) for the children with congenital heart disease (CHD) in the bronchiolitis subgroup was found at an age of 3-5 years compared to the control group. CONCLUSIONS AND CLINICAL RELEVANCE: Young children (< 3 years old) hospitalized due to acute HAIs are at a higher risk of developing childhood asthma at age 3 to 10 years. The parents of children with HAIs at age 0 to 2 years should be informed for the higher risk of developing childhood asthma, especially in children with CHD and bronchiolitis.

Complex airway disease: an approach to assessment and management.

Research into new treatments for airway disease focuses on severe disease because morbidity, mortality, and health-care costs are substantial and the unmet need is greatest. One reason why outcomes are poor in these patients could be that the clinical expression of disease is heterogeneous and difficult to classify. As a result, guideline-based management algorithms fail. Additionally, difficulties with disease classification and misconceptions about the relation between different aspects of severe airway disease have hindered new drug development. A potential solution is to use a new approach to assess severe airway disease, which moves the diagnostic focus from categorisation of patients to identification and characterisation of the main drivers of disease. This approach will help rather than hinder identification of clinically important phenotypes of disease and will facilitate the development of new phenotype-specific treatment options.

[Environmental causes of the distal airways disease. Hypersensitivity pneumonitis and rare causes]. / L'atteinte des voies aériennes distales d'origine environnementale. Pneumopathie d'hypersensibilité et étiologies rares.

Hypersensitivity pneumonitis is one of the most frequent causes of distal airways disease. It is associated with inflammation of the bronchioles, predominantly by lymphocytic infiltrates, and with granuloma formation causing bronchial obstruction. This inflammation explains the clinical manifestations and the airways obstruction seen on pulmonary function tests, most often in the distal airways but proximal in almost 20%. CT scan abnormalities reflect the lymphocytic infiltrates and air trapping and, in some cases, the presence of emphysema. Bronchiolitis induced by chronic inhalation of mineral particles or acute inhalation of toxic gases (such as NO2) are other examples of small airways damage due to environmental exposure. The pathophysiological mechanisms are different and bronchiolar damage is either exclusive or predominant. Bronchiolitis induced by tobacco smoke exposure, usually classified as interstitial pneumonitis, is easily diagnosed thanks to broncho-alveolar lavage. Its prognosis is linked to the other consequences of tobacco smoke exposure including respiratory insufficiency. Finally, the complex lung exposure observed in some rare cases (such as the World Trade Center fire or during wars) may lead to a less characteristic pattern of small airways disease.