Interstitial lung disease related to smoking: imaging considerations

Why making smoking cessation a priority for rare interstitial lung disease smokers?

This review aims to discuss the complex relationship between smoking and interstitial lung diseases (ILDs), emphasizing the significant morbidity and mortality associated with these conditions. While the etiology of ILDs remains multifactorial, cigarette smoking emerges as a prominent modifiable risk factor implicated in their pathogenesis and progression. This narrative review will provide insight into smoking-associated interstitial lung diseases and personalised approaches to smoking cessation. Epidemiological studies consistently link smoking to ILDs such as idiopathic pulmonary fibrosis (IPF), respiratory bronchiolitis-associated ILD (RB-ILD), and desquamative interstitial pneumonia (DIP), highlighting the urgent need for comprehensive tobacco cessation strategies. Despite the established benefits of smoking cessation, adherence to cessation programs remains challenging due to nicotine addiction, psychological factors, and social influences. The modest success rates of smoking cessation in ILD patients, emphasises the importance of tailored interventions and ongoing support is needed to overcome barriers and to improve outcomes of quitting smoking in this category of vulnerable patients.

Evaluation of respiratory bronchiolitis nodules with maximum intensity projection images

OBJECTIVE

Respiratory bronchiolitis is a disease associated with heavy smoking. Computed tomography in this disease often shows symmetrical and bilaterally ill-defined circumscribed centriacinar micronodular involvement in the upper-middle lobes. The maximum intensity projection method is a kind of image processing method and provides a better evaluation of nodules and vascular structures. Our study aimed to show whether maximum intensity projection images increase the diagnostic accuracy in the detection of micronodules in respiratory bronchiolitis.

METHODS

Two radiologists with different experiences (first reader: 10-year radiologist with cardiothoracic radiology experience and second reader: nonspecific radiologist with 2 years of experience) reviewed images of patients whose respiratory bronchiolitis diagnosis was supported by clinical findings. The evaluation was done independently of each other. Both conventional computed tomography images and maximum intensity projection images of the same patients were examined. The detection rates on conventional computed tomography and maximum intensity projection images were then compared.

RESULTS

A total of 53 patients were evaluated, of whom 48 were men and 5 were women. The first reader detected centriacinar nodules in 42 (79.2%) patients on conventional computed tomography and centriacinar nodules in all 53 (100%) patients on maximum intensity projection images. The second reader detected centriacinar nodules in 12 (22.6%) patients on conventional computed tomography images and in 48 (90.6%) patients on maximum intensity projection images. For the less experienced reader, the detection rate of micronodules in respiratory bronchiolitis in maximum intensity projection images increased statistically significantly (p<0.001).

CONCLUSION

Maximum intensity projection images in respiratory bronchiolitis increase the detectability of micronodules independently of the experience of the radiologist.

Urban-Rural Disparities in Pulmonary Hypertension-Related Mortality Between 2004 and 2019: A Call to Improve Access to Specialty Care Centers for Rural Residents in the United States

As rural-urban pulmonary hypertension (PH)-related mortality trends have not been reported past 2011, it is important to update the literature to provide guidance for necessary initiatives geared at minimizing barriers to social determinants of health. We extracted PH-related data between 2004 and 2019 from the Centers for Disease Control and Prevention Wide-Ranging OnLine Data for Epidemiologic Research (CDC WONDER). Crude-mortality rate and age-adjusted mortality rate (AAMR) were determined. Associated annual percent changes and average annual percentage changes (AAPCs) were computed using Joinpoint Regression Program trend analysis software. A total of 353, 916 PH-related deaths occurred in the study population within the United States between 2004 and 2019 out of 3,326,222,482 total deaths. The overall rural PH-related AAMR was 10.75 per 100,000 individuals. The overall urban PH-related AAMR was 9.70 per 100,000 individuals. Both rural and urban county subgroups demonstrated increases in AAMR during the study period. Notably, 8.5% of specialty centers are in rural counties while 91.5% of centers are located in urban counties. Given the crucial role of early treatment at specialty centers in PH disease courses, we highlight higher mortality rates among rural county individuals. Specialty center accessibility for these patients must improve.

Smoking-related interstitial lung disease

Exposure to smoke is associated with the development of diseases of the airways and lung parenchyma. Apart from chronic obstructive pulmonary disease (COPD), in some individuals, tobacco smoke can also trigger mechanisms of interstitial damage that result in various pathological changes and pulmonary fibrosis. A causal relation has been established between tobacco smoke and a group of entities that includes respiratory bronchiolitis-associated interstitial lung disease (RB-ILD), desquamative interstitial pneumonia (DIP), Langerhans cell histiocytosis (LCH), and acute eosinophilic pneumonia (AEP). Smoking is considered a risk factor for idiopathic pulmonary fibrosis (IPF); however, the role and impact of smoking in the development of this differentiated clinical entity, which has also been called combined pulmonary fibrosis and emphysema (CPFE) as well as nonspecific interstitial pneumonia (NIP), remains to be determined. The definition of smoking-related interstitial fibrosis (SRIF) is relatively recent, with differentiated histological characteristics. The likely interconnection between the mechanisms involved in inflammation and pulmonary fibrosis in all these processes often results in an overlapping of clinical, radiological, and histological features in the same patient that can sometimes lead to radiological patterns of interstitial lung disease that are impossible to classify. For this reason, a combined approach to diagnosis is recommendable. This combined approach should be based on the joint interpretation of the histological and radiological findings while taking the clinical context into consideration. This paper aims to describe the high-resolution computed tomography (HRCT) findings in this group of disease entities in correlation with the clinical manifestations and histological changes underlying the radiological pattern.

Diffuse smoking-related lung diseases: insights from a radiologic-pathologic correlation

Cigarettes are well-recognized risk factors responsible for the emergence of a variety of pathologic conditions affecting both the airways and the lungs. Smoking-related lung diseases can be classified as chronic obstructive pulmonary disease (COPD) and several types of interstitial diseases, such as pulmonary Langerhans cell histiocytosis, bronchiolitis, desquamative interstitial pneumonitis, acute eosinophilic pneumonia, and interstitial fibrosing lung diseases. The evidence of combined lower lung fibrosis and predominant upper lung emphysema is renowned as a distinct clinical entity, named combined pulmonary fibrosis and emphysema. Although computerized tomography permits an adequate classification and distinction of these diseases, the clinical, imaging, and histological features often overlap and coexist in a single patient. Therefore, a combined radiologic and pathologic approach, in the appropriate clinical setting, is useful for best comprehension and distinction of these entities. Our goals are to describe the imaging features in smoking-related lung diseases and how the pathological manifestations translate on high-resolution computerized tomography.

Pathology and radiology correlation of idiopathic interstitial pneumonias

By nature, idiopathic interstitial pneumonias have been diagnosed in a multidisciplinary manner. As classifications have been subject to significant refinement over the last decade, the importance of correlating clinical, radiologic, and pathologic information to arrive at a diagnosis, which will predict prognosis in any given patient, has become increasingly recognized. In 2013, the American Thoracic Society and European Respiratory Society updated the idiopathic interstitial pneumonias classification scheme, addressing the most recent updates in the field. The purpose of this review is to highlight the correlations between radiologic and pathologic findings in idiopathic interstitial pneumonias while using updated classification schemes and naming conventions.

Overlaps and uncertainties of smoking-related idiopathic interstitial pneumonias

Smoking-related interstitial lung disease (ILD) consists of a heterogeneous group of disorders that are considered a distinct entity. The 2013 American Thoracic Society and European Respiratory Society recommendations classified respiratory bronchiolitis (RB)/RB-ILD and desquamative interstitial pneumonia (DIP) as smoking-related idiopathic interstitial pneumonias (IIPs). The overlapping histopathological and radiological patterns of smoking-related IIPs must be considered. Overlap patterns of smoking-related IIPs are not easily classified as a single disorder. The initial radiological manifestation and follow-up changes are heterogeneous, even when diagnosed pathologically as RB or DIP. Therefore, a clinical–radiological–pathological consensus is important in the diagnosis of smoking-related IIPs, and long-term evaluation is essential to monitor the morphological changes in these patients. In this article, we reviewed the clinical, radiological, and pathological findings, and also the changes in radiological manifestations of smoking-related IIPs over time.

Pulmonary Langerhans cell histiocytosis: analysis of 14 patients and literature review

BACKGROUND

Pulmonary Langerhans cell histiocytosis (PLCH) is an orphan disease in respiratory medicine, which most affects adult smokers. The purpose of this article was to discuss the clinical features, especially the radiologic features of PLCH patients during their hospitalization through a retrospective analysis on clinical data. Furthermore, the current literature was also reviewed.

METHODS

Between December 2008 and June 2012, 14 patients with PLCH were assessed at Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China. Among these patients, seven patients were diagnosed through tissue biopsy from the lung and one patient from enlarged cervical lymph nodes; the rest of six patients were diagnosed based on the clinical-radiological data. The data consisting of demographics, clinical presentation, smoking habits, pulmonary function tests (PFTs) and radiographic image from the medical records was analyzed retrospectively.

RESULTS

The average age of patients (11 males and 3 females) was 42.79 (±13.71) years old. All male patients and one female patient had a long smoking history. The common manifestations were cough and exertional dyspnea. Spontaneous pneumothorax was found in three patients. Varieties of pulmonary shadows such as nodular, cystic, patch-like and cord-like were revealed by chest computed tomography (CT) examination. Large Langerhans cells (LCs) were discovered in biopsy tissue by immunohistochemical stains.

CONCLUSIONS

PLCH is still an orphan disease and maybe related to smoking. Clinical symptoms such as cough and exertional dyspnea are non-specific. We shall pay attention to recurrent pneumothorax as clinically it is associated with PLCH. The characteristic radiological manifestation is cystic or nodular shadow in the lungs, which plays crucial roles in diagnosing PLCH.

Action plans for COPD: strategies to manage exacerbations and improve outcomes

COPD is the third-largest killer in the world, and certainly takes a toll on the health care system. Recurrent COPD exacerbations accelerate lung-function decline, worsen mortality, and consume over US$50 billion in health care spending annually. This has led to a tide of payment reforms eliciting interest in strategies reducing preventable COPD exacerbations. In this review, we analyze and discuss the evidence for COPD action plan-based self-management strategies. Although action plans may provide stabilization of acute symptomatology, there are several limitations. These include patient-centered attributes, such as comprehension and adherence, and nonadherence of health care providers to established guidelines. While no single intervention can be expected independently to translate into improved outcomes, structured together within a comprehensive integrated disease-management program, they may provide a robust paradigm.

Respiratory Bronchiolitis-Associated Interstitial Lung Disease in Childhood: New Sequela of Smoking

Childhood interstitial lung diseases are rare disorders of largely unknown etiology characterized by variable types and degrees of parenchymal inflammation. Disease spectrum and prognosis considerably from those in adults. Respiratory bronchiolitis-associated interstitial lung disease (RB-ILD) is a well-described entity occurring almost exclusively in adults who are current heavy cigarette smokers. We describe an 11-year-old boy with failure to thrive, dry cough, and exertional dyspnea for 1 year who was diagnosed with RB-ILD due to heavy passive smoking exposure. Although RB-ILD is well defined in smoking adults, there are no reports in the English literature in nonactive smokers, especially in childhood.