More on the Pathology of Vaping-Associated Lung Injury

Bronchoalveolar Lavage (BAL) and Pathologic Assessment of Electronic Cigarette or Vaping Product Use-associated Lung Injury (EVALI): The EVALI-BAL Study, A Multicenter Cohort

BACKGROUND

E-cigarette or vaping-use related acute lung injury (EVALI) is a spectrum of radiographic and histologic patterns consistent with acute to subacute lung injury. However, limited data exist characterizing bronchoalveolar lavage (BAL) findings. The goal of this study is to further define the pathologic findings from BAL and biopsy samples of subjects with EVALI across 7 institutions.

METHODS

A multicentered registry of patients admitted with EVALI who underwent flexible bronchoscopy with BAL+/-transbronchial biopsy from July 2019 to April 2021 was compiled for retrospective evaluation from 7 academic institutions throughout the United States. Radiographic and cytopathologic findings and frequencies were correlated with the substance vaped.

RESULTS

Data from 21 subjects (42.9% women) who were predominantly White (76.2%) with a median age of 25 years (range, 16 to 68) with EVALI were included in this study. Sixteen patients (76.2%) reported use of tetrahydrocannabinol; the remainder used nicotine. BAL was performed in 19 of the 21 subjects, and transbronchial lung biopsy was performed in 7 subjects. BAL findings revealed neutrophilic predominance (median, 59.5%, range, 3.1 to 98) in most cases. Ten BAL samples demonstrated pulmonary eosinophilia ranging from 0.2% to 49.1% with one subject suggesting a diagnosis of acute eosinophilic pneumonia associated with the use of e-cigarettes. Lipid-laden macrophages were noted in 10 of 15 reports (66.7%). Transbronchial biopsy most frequently demonstrated patterns of organizing pneumonia (57.1%).

CONCLUSION

EVALI-associated BAL findings typically demonstrate a spectrum of nonspecific inflammatory changes, including neutrophilia, lipid-laden macrophages, and in some cases eosinophilia.

Nicotine self-administration and ERK signaling are altered in RasGRF2 knockout mice

Ras/Raf/MEK/ERK (Ras-ERK) signaling has been demonstrated to play a role in the effects of drugs of abuse such as cocaine and alcohol, but has not been extensively examined in nicotine-related reward behaviors. We examined the role of Ras Guanine Nucleotide Releasing Factor 2 (RasGRF2), an upstream mediator of the Ras-ERK signaling pathway, on nicotine self-administration (SA) in RasGRF2 KO and WT mice. We first demonstrated that acute nicotine exposure (0.4 mg/kg) resulted in an increase in phosphorylated ERK1/2 (pERK1/2) in the striatum, consistent with previous reports. We also demonstrated that increases in pERK1/2 resulting from acute (0.4 mg/kg) and repeated (0.4 mg/kg, 10 daily injections) exposure to nicotine in WT mice were not present in RasGRF2 KO mice, confirming that RasGRF2 at least partly regulates the activity of the Ras-ERK signaling pathway following nicotine exposure. We then performed intravenous nicotine SA (0.03 mg/kg/infusion for 10 days) in RasGRF2 KO and WT mice. Consistent with a previous report using cocaine SA, RasGRF2 KO mice demonstrated an increase in nicotine SA relative to WT controls. These findings suggest a role for RasGRF2 in the reinforcing effects of nicotine, and implicate the Ras-ERK signaling pathway as a common mediator of the response to drugs of abuse.

The vaping product use associated lung injury: is this a new pulmonary disease entity?

In the summer of 2019, an epidemic of e-cigarette or vaping product use associated lung injury (EVALI) broke out in the United States of America. EVALI is a lung disease that can be severe and life-threatening. It should be emphasized that EVALI is not a clinical diagnosis, but surveillance case definition. Due to the profile of users of such devices, the pathology mainly affects young adults, although cases of EVALI have been reported in almost all age groups, from teenage children to seniors. The worst prognosis is in patients over 35 years of age, with accompanying diseases. A significant number of patients declared the use of products containing tetrahydrocannabinol (THC). The most likely factor responsible for the occurrence of EVALI is vitamin E acetate, which is sometimes added to liquids necessary for the use of electronic cigarette type devices, especially those liquids that contain THC. Nevertheless, it is possible that other substances used in liquids may also be a causative factor. Typical for EVALI are respiratory, gastrointestinal and systemic symptoms, while in imaging tests, a characteristic feature of EVALI is the presence of opacities on the chest radiogram and ground-glass clouds on computed tomography scans. In the course of this disease, respiratory failure often occurs (58%). In the vast majority of cases oxygen substitution is necessary. Currently, the best treatment of EVALI is considered to be the administration of systemic glucocorticosteroids. Over 90% of patients with EVALI required hospitalization, while the mortality rate was about 2.42%. Median age of the fatalities was 51 years. The aim of this review is to summarise the available information on EVALI and to consider possible causative factors and pathomechanism.

Transitions in hookah (Waterpipe) smoking by U.S. sexual minority adults between 2013 and 2015: the population assessment of tobacco and health study wave 1 and wave 2

BACKGROUND

Tobacco smoking using a hookah (i.e., waterpipe) is a global epidemic. While evidence suggests that sexual minorities (SM) have higher odds of hookah use compared to heterosexuals, little is known about their hookah use patterns and transitions. We sought to examine transitions between hookah smoking and use of other tobacco and electronic (e-) products among SM adults aged 18 years of age and older versus their heterosexual counterparts.

METHODS

We analyzed nationally representative data of ever and current hookah smokers from Wave 1 (2013-2014; ever use n = 1014 SM and n = 9462 heterosexuals; current use n = 144 SM and n = 910 heterosexuals) and Wave 2 (2014-2015; ever use n = 901 SM and n = 8049 heterosexuals; current use n = 117 SM and n = 602 heterosexuals) of the Population Assessment of Tobacco and Health Study. Comparisons between groups and gender subgroups within SM identity groups were determined with Rao-Scott chi-square tests and multivariable survey-weighted multinomial logistic regression models were estimated for transition patterns and initiation of electronic product use in Wave 2.

RESULTS

Ever and current hookah smoking among SM adults (ever use Wave 1: 29% and Wave 2: 31%; current use Wave 1: 4% and Wave 2: 3%) was higher than heterosexuals (ever use Wave 1: 16% and Wave 2: 16%; current use Wave 1: 1% and Wave 2: 1%; both p < 0.0001). Among SM adults who reported hookah use at Wave 1, 46% quit hookah use at Wave 2; 39% continued hookah use and did not transition to other products while 36% of heterosexual adults quit hookah use at Wave 2 and 36% continued hookah use and did not transition to other products. Compared with heterosexuals, SM adults reported higher use of hookah plus e-products (Wave 2 usage increased by 65 and 83%, respectively).

CONCLUSIONS

Compared to heterosexuals, in addition to higher rates of hookah smoking, higher percentages of SM adults transitioned to hookah plus e-product use between 2013 and 2015. Results have implications for stronger efforts to increase awareness of the harmful effects of hookah as well as vaping, specifically tailored among SM communities.

Vitamin E acetate as linactant in the pathophysiology of EVALI

The recent identification of Vitamin E acetate as one of the causal agents for the e-cigarette, or vaping, product use associated lung injury (EVALI) is a major milestone. In membrane biophysics, Vitamin E is a linactant and a potent modulator of lateral phase separation that effectively reduces the line tension at the two-dimensional phase boundaries and thereby exponentially increases the surface viscosity of the pulmonary surfactant. Disrupted dynamics of respiratory compression-expansion cycling may result in an extensive hypoxemia, leading to an acute respiratory distress entailing the formation of intraalveolar lipid-laden macrophages. Supplementation of pulmonary surfactants which retain moderate level of cholesterol and controlled hypothermia for patients are recommended when the hypothesis that the line-active property of the vitamin derivative drives the pathogenesis of EVALI holds.

Guidance on the Clinical Management of Electronic Cigarette or Vaping-Associated Lung Injury

In the summer of 2019, there was a rise in clusters of adolescents and young adults in the United States reporting to emergency departments with acute respiratory distress related to use of e-cigarette (electronic cigarette) or vaping. The number of patients with e-cigarette or vaping-associated lung injury continued to rise through the summer before peaking in September 2019. Through the efforts of state and federal public health agencies, officials were able to define the condition, identify the relationship of the respiratory injury to tetrahydrocannabinol-containing products, and stem the rise in new cases. In this report, we present a comprehensive review of the clinical characteristics and features of patients with e-cigarette or vaping-associated lung injury and guidelines for patient care and management to inform and navigate clinicians who may encounter these patients in their clinical practice.

E-cigarette or Vaping Product Use Associated Lung Injury Among Three Young Adults: A Retrospective Case Series From Delaware

Background: E-cigarette or vaping associated lung injury (EVALI) is a lung disease associated with an inflammatory response to the vaping fluid. Currently, diagnosis remains elusive without definitive biomarkers.

Case presentation: Herein, we describe three cases of EVALI among 18- to 21-year-old patients ranging from mild to severe. All cases presented with a combination of respiratory, gastrointestinal, and constitutional symptoms. Oxygen support and level of medical care varied based on disease severity. Bilateral pulmonary opacities were observed on chest imaging in each case. Additionally, each case had markedly elevated inflammatory markers, specifically C-reactive protein (CRP). None of these patients improved with intravenous (IV) antibiotics and all required IV corticosteroid therapy to achieve clinical improvement.

Conclusion: EVALI should be suspected among young, otherwise healthy patients who present with new-onset hypoxia, non-specific gastrointestinal symptoms, and endorse a history of vaping. Though considered a diagnosis of exclusion, diagnosing EVALI requires thorough history taking. Inflammatory studies, CRP, and erythrocyte sedimentation rate (ESR) should be considered adjunctive biomarkers to aid clinicians when the diagnosis remains unclear. Corticosteroids are the mainstay of treatment and patients should have close follow-up whether or not they require hospitalization.

Lipid laden macrophages and electronic cigarettes in healthy adults

Background

An outbreak of E-cigarette or Vaping Product Use-Associated Lung Injury (EVALI) with significant morbidity and mortality was reported in 2019. While most patients with EVALI report vaping tetrahydrocannabinol (THC) oils contaminated with vitamin E acetate, a subset report only vaping with nicotine-containing electronic cigarettes (e-cigs). Whether or not e-cigs cause EVALI, the outbreak highlights the need for identifying long term health effects of e-cigs. EVALI pathology includes alveolar damage, pneumonitis and/or organizing pneumonia, often with lipid-laden macrophages (LLM). We assessed LLM in the lungs of healthy smokers, e-cig users, and never-smokers as a potential marker of e-cig toxicity and EVALI.

Methods

A cross-sectional study using bronchoscopy was conducted in healthy smokers, e-cig users, and never-smokers (n = 64). LLM, inflammatory cell counts, and cytokines were determined in bronchial alveolar fluids (BAL). E-cig users included both never-smokers and former light smokers.

Findings

High LLM was found in the lungs of almost all smokers and half of the e-cig users, but not those of never-smokers. LLM were not related to THC exposure or smoking history. LLM were significantly associated with inflammatory cytokines IL-4 and IL-10 in e-cig users, but not smoking-related cytokines.

Interpretation

This is the first report of lung LLM comparing apparently healthy smokers, e-cig users, and never-smokers. LLM are not a specific marker for EVALI given the frequent positivity in smokers; whether LLMs are a marker of lung inflammation in some e-cig users requires further study.

Funding

The National Cancer Institute, the National Heart, Lung, and Blood Institute, the Food and Drug Administration Center for Tobacco Products, the National Center For Advancing Translational Sciences, and Pelotonia Intramural Research Funds

Pulmonary Injury Resulting from Vaping or e-Cigarette Use: Imaging Appearances at Presentation and Follow-up

Electronic cigarette or vaping product use-associated lung injury most frequently presents with an acute lung injury pattern at CT, manifesting as multifocal ground-glass opacity and/or consolidation, typically multifocal and multilobar, possibly with subpleural sparing. Areas of organization, manifesting as contracting consolidation, mild architectural distortion, intralobular lines, lobular distortion, and traction bronchiectasis may occur as the illness evolves. A CT appearance resembling hypersensitivity pneumonitis, reflecting the exquisitely bronchiolocentric micronodular lesions of organizing pneumonia and acute lung injury seen at histopathologic findings in these patients, may be encountered. Less common CT appearances include organizing pneumonia or acute eosinophilic pneumonia patterns, the latter consisting of multifocal opacity and smooth interlobular septal thickening, possibly with small effusions, but without clinical evidence of volume overload. Patients may present with pneumothorax or pneumomediastinum, or these conditions may develop during their illness course. Most patients improve clinically and at imaging on follow-up, particularly following exposure cessation and corticosteroid therapy, but the time course to improvement is variable and most likely related to the severity of the lung injury. Radiologists should be familiar with the imaging manifestations of vaping-associated pulmonary injury, and the possibility of this condition should be considered when the imaging findings reviewed in this article are encountered. © RSNA, 2020.

E-cigarette or Vaping Product Use-Associated Lung Injury Presenting as Sub-Acute Hypoxemia Without Increased Work of Breathing

A 15-year-old male with a history of mild intermittent asthma presented with fatigue, coughing, vomiting and anorexia which was progressive in nature over the past month. The patient was found to have evolving chest x-ray infiltrates bilaterally, and hypoxemia without accessory muscle use. The patient was placed on non-invasive continuous positive airway pressure (CPAP) for hypoxemia. A CT scan showed bilateral infiltrates in a pattern consistent with E-cigarette or Vaping product use-Associated Lung Injury (EVALI). Upon further history taking, the patient admitted to electronic cigarette (e-cigarette) use with a new tetrahydrocannabinol (THC) cartridge prior to the onset of symptoms. The patient was started on methylprednisolone after which his oxygen requirement improved. This case highlights the need to continue to be diligent regarding the use of e-cigarettes in the pediatric population, and be aware of the constitutional symptoms that are associated with their use.

E-cigarette or vaping product use-associated lung injury in the pediatric population: imaging features at presentation and short-term follow-up

BACKGROUND

Cases of e-cigarette or vaping product use-associated lung injury (EVALI) have rapidly reached epidemic proportions, yet there remain limited reports within the literature on the associated imaging findings.

OBJECTIVE

We describe the most common imaging findings observed on chest computed tomography (CT) and chest radiograph (CXR) at presentation and at short-term follow-up at our major pediatric hospital.

MATERIALS AND METHODS

A retrospective review of the electronic medical records was performed on all patients with suspected EVALI who were treated at a major pediatric hospital and 11 patients were included for analysis. Two board-certified pediatric radiologists then categorized the CXRs as either normal or abnormal, and further performed a systematic review of the chest CTs for imaging findings in the lungs, pleura and mediastinum. Interrater discordance was reconciled by consensus review.

RESULTS

The 11 patients (9 males:2 females) ranged in age from 14 to 18 years. Gastrointestinal and constitutional symptoms were present in all patients, whereas shortness of breath and cough were reported in 5/11 and 6/11 patients, respectively. The CXR was abnormal in 10/11 patients, whereas all chest CTs were abnormal. The most common CT findings included consolidation, ground-glass opacities, interlobular septal thickening, lymphadenopathy and crazy-paving pattern. Almost all patients demonstrated subpleural sparing, and less than half also demonstrated peribronchovascular sparing. There was complete or near-complete resolution of imaging abnormalities in 5/6 patients with a median follow-up duration of 114 days.

CONCLUSION

Pulmonary opacities with subpleural and peribronchovascular sparing was a commonly observed pattern of EVALI in the pediatric population at this institution. A CXR may not be sufficiently sensitive in diagnosing EVALI, and radiologists and clinicians should exercise caution when excluding EVALI based on the lack of a pulmonary opacity. Caution should also be exercised when excluding EVALI solely based on the lack of respiratory symptoms. Despite extensive pulmonary involvement at presentation, findings may resolve on short-term follow-up imaging.

The importance of anti-vaping vigilance-EVALI in seven adolescent pediatric patients in Northeast Ohio

As of 18 February 2020, the e-cigarette or vaping product use-associated lung injury (EVALI) epidemic has claimed the lives of 68 patients in the USA with the total number of reported cases standing at 2807 to date. We present the clinical and radiologic findings, course of illness, and treatment of EVALI in seven adolescent patients in Northeast Ohio. Five of our patients required supplemental oxygen with four requiring intensive care unit care for respiratory support during admission. Three patients were treated with systemic steroids while inpatient. Bilateral opacities were seen on radiographic imaging of all seven of our patients. All patients were discharged alive on room air. However, impaired diffusing capacity of the lungs for carbon monoxide (DLCO) with nonobstructive spirometry was seen in patients that were tested postdischarge. This suggests that although recovery from the acute illness process of EVALI is achieved, there may be long-term impact on lung function in these patients. We recommend close follow-up with a pediatric pulmonologist where spirometry and DLCO can be performed.

Confirmed E-cigarette or vaping product use associated lung injury (EVALI) with lung biopsy; A case report and literature review

BACKGROUND

E-cigarette or vaping has become an increasingly popular alternative to smoking tobacco. In September 2019 multiple cases of confirmed E-cigarette or vaping product use associated lung injury were published. However, there is limited knowledge regarding the pathologic mechanism of this condition.

METHODS

We performed a systematic literature review in PubMed and EMBASE aiming to obtain additional clinical data on confirmed E-cigarette or vaping product use associated lung injury cases with lung biopsy results. With this information we hope to determine whether this condition is related to a histopathological pattern of acute lung injury instead of lipid deposits.

RESULTS

Seven articles were reviewed and a total of 27 cases were included. Imaging findings predominantly showed presence of diffuse bilateral ground glass opacities. A majority of patients had complete resolution of the disease. The most common histopathological pattern was organizing pneumonia present in almost half of the patients. Other frequently occurring patterns included diffuse alveolar damage and acute fibrinous pneumonitis; lipoid pneumonia was found in one case.

CONCLUSION

The underlying pathophysiological mechanism in E-cigarette or vaping product use associated lung injury is most likely acute lung injury related to direct inhalant-mediated parenchymal inflammation.