Bronchiolitis from nitrous fumes

Short-term association among meteorological variation, outdoor air pollution and acute bronchiolitis in children in a subtropical setting

OBJECTIVES

To examine the association among acute bronchiolitis-related hospitalisation in children, meteorological variation and outdoor air pollution.

METHODS

We obtained the daily counts of acute bronchiolitis-related admission of children≤2 years old from all public hospitals, meteorological data and outdoor air pollutants' concentrations between 1 January 2008 and 31 December 2017 in Hong Kong. We used quasi-Poisson generalised additive models together with distributed lag non-linear models to estimate the associations of interest adjusted for confounders.

RESULTS

A total of 29 688 admissions were included in the analysis. Increased adjusted relative risk (ARR) of acute bronchiolitis-related hospitalisation was associated with high temperature (ambient temperature and apparent temperature) and was marginally associated with high vapour pressure, a proxy for absolute humidity. High concentration of NO₂ was associated with elevated risk of acute bronchiolitis admission; the risk of bronchiolitis hospitalisation increased statistically significantly with cumulative NO₂ exposure over the range 66.2-119.6 µg/m³. For PM₁₀, the significant effect observed at high concentrations appears to be immediate but not long lasting. For SO₂, ARR increased as the concentration approached the 75th percentile and then decreased though the association was insignificant.

CONCLUSIONS

Acute bronchiolitis-related hospitalisation among children was associated with temperature and exposure to NO₂ and PM₁₀ at different lag times, suggesting a need to adopt sustainable clean air policies, especially to target pollutants produced by motor vehicles, to protect young children's health.

Occupational and environmental bronchiolar disorders

Occupational and environmental causes of bronchiolar disorders are recognized on the basis of case reports, case series, and, less commonly, epidemiologic investigations. Pathology may be limited to the bronchioles or also involve other components of the respiratory tract, including the alveoli. A range of clinical, functional, and radiographic findings, including symptomatic disease lacking abnormalities on noninvasive testing, poses a diagnostic challenge and highlights the value of surgical biopsy. Disease clusters in workplaces and communities have identified new etiologies, drawn attention to indolent disease that may otherwise have been categorized as idiopathic, and expanded the spectrum of histopathologic responses to an exposure. More sensitive noninvasive diagnostic tools, evidence-based therapies, and ongoing epidemiologic investigation of at-risk populations are needed to identify, treat, and prevent exposure-related bronchiolar disorders.

Pathology of small airways disease

CONTEXT

The term small airways disease encompasses a generally poorly understood group of lung diseases that may arise primarily within the small airways or secondarily from diseases primarily affecting the bronchi or lung parenchyma. Their histology may be confusing; however, because treatments and prognoses vary, correct pathologic diagnosis is important.

OBJECTIVE

To present a nonexhaustive review of the pathology of primary and secondary small airways diseases, including small airways disease related to tobacco; to various other exposures, including mineral dusts; to diseases involving other areas of the lung with secondary bronchiolar involvement; and to recently described bronchiolitic disorders.

DATA SOURCES

Current literature is reviewed.

CONCLUSIONS

Small airways diseases include a wide variety of diseases of which the pathologist must consider. Uncommon conditions such as diffuse idiopathic neuroendocrine cell hyperplasia and diffuse panbronchiolitis may show relatively specific diagnostic features histologically; however, most small airways diseases exhibit nonspecific histologic features. Conditions not considered primary pulmonary diseases, such as collagen vascular diseases, bone marrow transplantation, and inflammatory bowel disease, must also be considered in patients with small airways changes histologically. Clinical and radiologic correlation is important for obtaining the best possible diagnosis.

Asthma on the job: work-related factors in new-onset asthma and in exacerbations of pre-existing asthma

Occupational asthma (OA) can be defined as variable airways narrowing causally related to exposure in the working environment to airborne dusts, gases, vapours or fumes. There are many agents in the work-place that can induce asthma or cause substantial deterioration in pre-existing asthma. It has been estimated that 5-15% of adult-onset asthma can be attributed to occupational exposures. Hence adult patients, especially those with new-onset asthma, must be investigated with regard to occupational risk factors for disease. The prognosis for OA is improved if the causal exposure is controlled either by controlling the exposure at the workplace or by moving the patient out of the workplace.

Bronchiolitis obliterans

Bronchiolitis obliterans in the adult patient is a relatively uncommon and vexing clinical entity. This confusion results because this pathologic finding occurs in a variety of diverse clinical settings. Bronchiolitis obliterans is a fibrotic process that primarily affects the small conducting airways. The lesion results from damage to the bronchiolar epithelium and the repair process leads to excessive proliferation of granulation tissue. The alveoli adjacent to the small airway are almost always involved; however, a considerable portion of the interstitium is usually spared. The findings in these patients may physiologically and radiographically mimic chronic obstructive pulmonary disease (COPD). On the other hand, some of the processes associated with bronchiolitis obliterans result in restrictive or mixed restrictive and obstructive ventilatory defects; consequently, they may be confused with other diffuse infiltrative lung disorders. This review will focus principally on bronchiolitis obliterans in adults, which, until recently, was considered rare. There has been heightened interest in this process in adults because of its association with the connective tissue diseases, its development following toxic fume exposure, its occurrence as a result of chronic graft versus host reactions, and the increasing recognition of patients with idiopathic forms of the disease that have an insidious onset often confused with more common problems such as COPD or idiopathic pulmonary fibrosis.

Dysfunction of small airways following pulmonary injury due to nitrogen dioxide

Serial physiologic studies were performed to characterize both the immediate and delayed effects of a single occupational exposure to nitrogen dioxide in a nonsmoker. During the initial acute stage of pulmonary edema, the abnormal static pressure-volume curve and decreased static compliance corresponded to a reduction in pulmonary volume. During the delayed acute stage, elastic recoil and properties of resistance to flow were normal, but dynamic compliance was reduced and dependent on respiratory frequency, and oxygen transport was abnormal during exercise, which is consistent with dysfunction of the small airways.

Silo-filler's disease

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The effects of continuous high level nitrogen dioxide on hamsters

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Bronchiolitis fibrosa obliterans

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