Imaging-based assessment of lung function in a population cooking indoors with biomass fuel: a pilot study

Biomass fuels (wood) are commonly used indoors in underventilated environments for cooking in the developing world, but the impact on lung physiology is poorly understood. Quantitative computed tomography (qCT) can provide sensitive metrics to compare the lungs of women cooking with wood vs. liquified petroleum gas (LPG). We prospectively assessed (qCT and spirometry) 23 primary female cooks (18 biomass, 5 LPG) with no history of cardiopulmonary disease in Thanjavur, India. CT was obtained at coached total lung capacity (TLC) and residual volume (RV). qCT assessment included texture-derived ground glass opacity [GGO: Adaptive Multiple Feature Method (AMFM)], air-trapping (expiratory voxels ≤ -856HU) and image registration-based assessment [Disease Probability Measure (DPM)] of emphysema, functional small airways disease (%AirTrapDPM), and regional lung mechanics. In addition, within-kitchen exposure assessments included particulate matter <2.5 μm(PM2.5), black carbon, β-(1, 3)-d-glucan (surrogate for fungi), and endotoxin. Air-trapping went undetected at RV via the threshold-based measure (voxels ≤ -856HU), possibly due to density shifts in the presence of inflammation. However, DPM, utilizing image-matching, demonstrated significant air-trapping in biomass vs. LPG cooks (P = 0.049). A subset of biomass cooks (6/18), identified using k-means clustering, had markedly altered DPM-metrics: greater air-trapping (P < 0.001), lower TLC-RV volume change (P < 0.001), a lower mean anisotropic deformation index (ADI; P < 0.001), and elevated % GGO (P < 0.02). Across all subjects, a texture measure of bronchovascular bundles was correlated to the log-transformed β-(1, 3)-d-glucan concentration (P = 0.026, R = 0.46), and black carbon (P = 0.04, R = 0.44). This pilot study identified environmental links with qCT-based lung pathologies and a cluster of biomass cooks (33%) with significant small airways disease.NEW & NOTEWORTHY Quantitative computed tomography has identified a cluster of women (33%) cooking with biomass fuels (wood) with image-based markers of functional small airways disease and associated alterations in regional lung mechanics. Texture and image registration-based metrics of lung function may allow for early detection of potential inflammatory processes that may arise in response to inhaled biomass smoke, and help identify phenotypes of chronic lung disease prevalent in nonsmoking women in the developing world.

Domestic mixed-dust pneumoconiosis: A case report and literature review

Background

Mixed-dust pneumoconiosis (MDP) is a controversial disease with respect to diagnostic criteria. Usually, it is regarded as an occupational disease, but cases due to domestic exposure have been reported. In domestic settings, different dust sources may contribute individually or collectively to the pathogenesis.

Case presentation

A 56-year-old woman presented with chest nodularity on chest X-ray examination that had not resolved after 6 months of tuberculosis (TB) treatment. Her history showed significant exposure to mixed dusts caused by grinding grains with stones and the use of biomass fuel.

Conclusion

In residential settings, sufficient exposure to a variety of dusts, primarily silica-based dusts as well as those containing other less-fibrogenic materials, such as carbon, silicates and iron, have been shown to cause mixed-dust pneumoconiosis. In settings where the incidence of TB is very high, such as South Africa, the diagnosis of MDP might be overlooked due to the similarities of both diseases in their radiological presentations, especially when a detailed history of domestic exposure is omitted.

Gujjar Lung: An Unusual Case Report and Systematic Review of Literature

We report a 65 year old female patient who had presented with dry cough and shortness of breath for the last 5 years and had also received anti-tubercular therapy but without any benefit. Evaluation revealed the presence of obstructive airway disease with nodular opacities in bilateral lungs. Histopathological examination including electron microscopy was suggestive of domestically acquired pneumoconiosis.A diagnosis of Gujjar lung was made based on history of exposure to wood smoke, characteristic histological and radiological features. Anti-tubercular therapy was stopped and bronchodilators were initiated along with removal from source of exposure to which she showed significant improvement. We also did a systematic review of literature pertaining to Gujjar lung.

The health and social implications of household air pollution and respiratory diseases

Approximately three billion individuals are exposed to household air pollution (HAP) from the burning of biomass fuels worldwide. Household air pollution is responsible for 2.9 million annual deaths and causes significant health, economic and social consequences, particularly in low- and middle-income countries. Although there is biological plausibility to draw an association between HAP exposure and respiratory diseases, existing evidence is either lacking or conflicting. We abstracted systematic reviews and meta-analyses for summaries available for common respiratory diseases in any age group and performed a literature search to complement these reviews with newly published studies. Based on the literature summarized in this review, HAP exposure has been associated with acute respiratory infections, tuberculosis, asthma, chronic obstructive pulmonary disease, pneumoconiosis, head and neck cancers, and lung cancer. No study, however, has established a causal link between HAP exposure and respiratory disease. Furthermore, few studies have controlled for tobacco smoke exposure and outdoor air pollution. More studies with consistent diagnostic criteria and exposure monitoring are needed to accurately document the association between household air pollution exposure and respiratory disease. Better environmental exposure monitoring is critical to better separate the contributions of household air pollution from that of other exposures, including ambient air pollution and tobacco smoking. Clinicians should be aware that patients with current or past HAP exposure are at increased risk for respiratory diseases or malignancies and may want to consider earlier screening in this population.

ERS/ATS workshop report on respiratory health effects of household air pollution

Exposure to household air pollution (HAP) from solid fuel combustion affects almost half of the world population. Adverse respiratory outcomes such as respiratory infections, impaired lung growth and chronic obstructive pulmonary disease have been linked to HAP exposure. Solid fuel smoke is a heterogeneous mixture of various gases and particulates. Cell culture and animal studies with controlled exposure conditions and genetic homogeneity provide important insights into HAP mechanisms. Impaired bacterial phagocytosis in exposed human alveolar macrophages possibly mediates several HAP-related health effects. Lung pathological findings in HAP-exposed individuals demonstrate greater small airways fibrosis and less emphysema compared with cigarette smokers. Field studies using questionnaires, air pollution monitoring and/or biomarkers are needed to better establish human risks. Some, but not all, studies suggest that improving cookstove efficiency or venting emissions may be associated with reduced respiratory symptoms, lung function decline in women and severe pneumonia in children. Current studies focus on fuel switching, stove technology replacements or upgrades and air filter devices. Several governments have initiated major programmes to accelerate the upgrade from solid fuels to clean fuels, particularly liquid petroleum gas, which provides research opportunities for the respiratory health community.

Medical imaging in occupational and environmental lung disease

PURPOSE OF REVIEW

The purpose of this review is to provide an up-to-date summary of developments in medical imaging in the diagnosis, surveillance, treatment, and screening of occupational and environmental lung diseases, focusing on articles published within the past 2 years.

RECENT FINDINGS

Many new exposures resulting in lung disease have been described worldwide; medical imaging, particularly computed tomography (CT), is often pivotal in recognition and characterization of these new patterns of lung injury. Chest radiography remains important to surveillance studies tracking the long-term evolution of disease and effectiveness of air quality regulation. Finally, studies are proving the utility of screening with low-dose CT, and technical advances offer the prospect of further CT dose reduction with ultra-low-dose CT.

SUMMARY

In understanding the best practices and new developments in medical imaging, the occupational and environmental medicine clinician can optimize diagnosis and management of related lung diseases.

Occupational and environmental lung disease

Occupational and environmental lung disease remains a major cause of respiratory impairment worldwide. Despite regulations, increasing rates of coal worker's pneumoconiosis and progressive massive fibrosis are being reported in the United States. Dust exposures are occurring in new industries, for instance, silica in hydraulic fracking. Nonoccupational environmental lung disease contributes to major respiratory disease, asthma, and COPD. Knowledge of the imaging patterns of occupational and environmental lung disease is critical in diagnosing patients with occult exposures and managing patients with suspected or known exposures.

Imaging in occupational and environmental lung disease

PURPOSE OF REVIEW

Work-related and environmental lung disease is increasing over time and new antigens causing pulmonary response are described in medical literature every year with more or less specific imaging findings. The purposes of this review are to highlight the current role of imaging, describe classic as well as uncommon high-resolution computed tomography (HRCT) patterns helpful in guiding diagnosis and update the recent literature on this topic.

RECENT FINDINGS

Recent literature on imaging of occupational and environmental lung disease is scarce and is predominantly based on the HRCT appearance related to specific antigen exposure and on prognostic significance of findings.

SUMMARY

Knowledge of imaging modality potential and radiologic appearance may guide identification, characterization and follow-up of old and new occupational and environmental lung diseases. HRCT plays a key role in this context, having radiation exposure as a major limitation, especially in asymptomatic patients. Low-dose HRCT has the potential to be employed for screening and surveillance of the exposed individuals. However, future research is needed to further this field.