Alterations in smoking habits are associated with acute eosinophilic pneumonia

A Case of Chronic Eosinophilic Pneumonia Associated With the Use of Weight Loss Combination Medication Naltrexone-Bupropion

Chronic eosinophilic pneumonia (CEP) is not a commonly encountered pulmonary disease that presents with bilateral pulmonary infiltrates accompanied by peripheral and bronchoalveolar lavage (BAL) eosinophilia. Recovery is rapid with systemic steroids but has frequent recurrences. We present a case with the classic presentation of CEP that appears to be related to a weight loss medication called naltrexone-bupropion. This case is unique in that this drug combination does not appear to have an established link to CEP, though literature reveals possible association with its individual components. Understanding the mechanism underlying this link may help to better understand CEP as a disease process.

Acute eosinophilic pneumonia-like syndrome post-initiation of vortioxetine

A man in his mid-30s presented to the emergency department with a 1-week history of fatigue, loss of appetite, fever and productive (yellow) cough. This progressed to requiring admission to intensive care needing a oxygen therapy via high-flow nasal cannula for acute hypoxaemic respiratory failure. He had recently started vortioxetine for major depressive disorder, and his acute symptoms correlated with an increase in the dose of vortioxetine. For more than 20 years, rare but consistent reports of serotonergic medications have been implicated in eosinophilic pulmonary conditions. During this same period, serotonergic medications have become a mainstay solution for a wide range of depressive symptoms and disorders. This is the first report of an eosinophilic pneumonia-like syndrome occurring while consuming the novel serotonergic medication vortioxetine.

Eosinophilic Lung Diseases

The eosinophilic lung diseases may manifest as chronic eosinophilic pneumonia, acute eosinophilic pneumonia, or as the Löffler syndrome (generally of parasitic etiology). The diagnosis of eosinophilic pneumonia is made when both characteristic clinical-imaging features and alveolar eosinophilia are present. Peripheral blood eosinophils are generally markedly elevated; however, eosinophilia may be absent at presentation. Lung biopsy is not indicated except in atypical cases after multidisciplinary discussion. The inquiry to possible causes (medications, toxic drugs, exposures, and infections especially parasitic) must be meticulous. Idiopathic acute eosinophilic pneumonia may be misdiagnosed as infectious pneumonia. Extrathoracic manifestations raise the suspicion of a systemic disease especially eosinophilic granulomatosis with polyangiitis. Airflow obstruction is frequent in allergic bronchopulmonary aspergillosis, idiopathic chronic eosinophilic pneumonia, eosinophilic granulomatosis with polyangiitis, and hypereosinophilic obliterative bronchiolitis. Corticosteroids are the cornerstone of therapy, but relapses are common. Therapies targeting interleukin 5/interleukin-5 are increasingly used in eosinophilic lung diseases.

Smoking-Related Interstitial Lung Diseases

Smoking-related interstitial lung diseases (ILDs) are a group of heterogeneous, diffuse pulmonary parenchymal disease processes associated with tobacco exposure. These disorders include pulmonary Langerhans cell histiocytosis, respiratory bronchiolitis-associated ILD, desquamative interstitial pneumonia, acute eosinophilic pneumonia, and combined pulmonary fibrosis and emphysema. This review summarizes the current evidence of pathogenesis, clinical manifestations, diagnostic approach, prognosis, and treatment modalities for these diseases. We also discuss the interstitial lung abnormalities incidentally detected in radiologic studies and smoking-related fibrosis identified on lung biopsies.

Electronic Cigarette or Vaping-Associated Lung Injury Manifested as Acute Eosinophilic Pneumonia: A Case Report

Electronic cigarette or vaping-associated lung injury (EVALI) is a disease defined by lung injuries caused by e-cigarette use. It predominantly manifests in forms of organized pneumonia or diffuse alveolar damage but rarely as acute eosinophilic pneumonia (AEP). This report describes a 34-year-old male with acute respiratory symptoms and a vaping history of only nicotine. Chest CT revealed peripheral distributing multiple patchy consolidations and ground-glass opacities dominant in both lower lobes, bilateral diffuse interlobular septal thickening, and bilateral pleural effusion without cardiomegaly. Bronchoalveolar lavage fluids showed increased eosinophilia levels, while infectious laboratory results were all negative, enabling the diagnosis of both AEP and EVALI. Herein, we report a rare case of only-nicotine vaping EVALI manifested as AEP.

Vaping Associated Acute Eosinophilic Pneumonia: A Clinical and Radiologic Mimicker of COVID-19

Acute eosinophilic pneumonia (AEP) is a rare cause of respiratory failure. It is primarily a disease of smokers, either a new smoker or an existing one with a recent increase in cigarette consumption. Other risk factors include toxic gas exposure, inhalational illicit drugs, and smoking marijuana. AEP has also been reported in patients with e-cigarette or vaping associated lung injury (EVALI). We present the case of a 20-year-old male who presented to the hospital with acute respiratory failure. The patient has been vaping heavily for the past three months and started smoking three days before presenting to the emergency department. He was hypertensive, tachycardic, tachypneic, and required high-flow nasal cannula to maintain SpO2 > 92%. His condition deteriorated in the first 24 hours following hospitalization requiring noninvasive positive pressure ventilation. Bronchoalveolar lavage revealed an eosinophil count of 36%. Bronchoalveolar lavage (BAL) cytology revealed lipid-laden macrophages. He was diagnosed with AEP due to EVALI, and the patient was treated with high dose corticosteroid with subsequent improvement. Before the bronchoscopic evaluation, the clinical and radiologic findings were consistent with COVID-19, and the patient was tested twice for SARS-CoV-2 PCR. In the appropriate clinical setting, AEP should be considered in the differential diagnoses of community-acquired pneumonia, acute respiratory distress syndrome (ARDS), and COVID-19, especially in this pandemic era.

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.

[Inhaled marijuana and the lung, a toxic cocktail?]

Unlike the well-documented effects of tobacco smoke on the lung, the effects of cannabis smoke remain controversial, the main bias consisting in co-consumption of tobacco. That said, the composition of joint smoke is close to that of cigarettes, containing many compounds that are carcinogenic and/or alter the respiratory epithelium. Confirmed respiratory effects in chronic cannabis smokers include aggravated chronic bronchitis symptoms, a cumulative effect with tobacco on COPD and emphysema occurrence, an increased risk of bullous emphysema, and pneumothorax with heightened risk of recurrence after pleural symphysis. Recent prospective studies have shown a negative impact on lung function, with not only damage to the airways, but also DLCO alteration and an accelerated drop in FEV1. Finally, cannabis smoking is very common among young patients with lung cancer. Its consumption could lead to a different lung cancer profile, potentially more undifferentiated and less accessible to targeted therapy. Questioning about cannabis consumption must be systematic and targeted medical care should be offered.

Raucherassoziierte interstitielle Lungenerkrankungen

Klinisches Problem

Raucherassoziierte interstitielle Lungenerkrankungen umfassen heterogene pulmonale Pathologien, deren korrekte Diagnostik prognostische und therapeutische Konsequenzen hat. In diesem Artikel werden die gängigsten raucherassoziierten interstitiellen Lungenerkrankungen beschrieben sowie eine strukturierte Herangehensweise präsentiert, welche den diagnostischen Arbeitsprozess erleichtern kann.

Empfehlungen für die Praxis

Die Computertomographie (CT) besitzt einen hohen Stellenwert in der Diagnose der raucherassoziierten interstitiellen Lungenerkrankungen und kann dazu beitragen, Lungenbiopsien zu verhindern. Um eine hohe diagnostische Genauigkeit zu erreichen, sollten standardisierte Untersuchungsprotokolle sowie eine strukturierte Herangehensweise in der Befundung zur Anwendung kommen. In den entzündlich dominierten Stadien der respiratorischen Bronchiolitis (RB), der respiratorischen Bronchiolitis mit interstitieller Lungenerkrankung (RB-ILD) sowie der desquamativen interstitiellen Pneumonie (DIP) haben die Beendigung des Rauchens sowie Steroide den größten therapeutischen Effekt. Bei fibrotischen Veränderungen (z. B. im Rahmen einer idiopathischen pulmonalen Fibrose [IPF]) können antifibrotische Therapien mit Pirfenidon und Nintedanib zum Einsatz kommen. Patienten mit dem Verdacht auf raucherassoziierte interstitielle Lungenerkrankung sollten in multidisziplinären Boards abgeklärt und behandelt werden.

Acute eosinophilic pneumonia following aromatherapy with essential oil

Essential oils are liquid extracts of various plants with potential health benefits and are often used in aromatherapy. Contact allergy, including skin irritation, is a well-known side effects of these extracts. A Japanese woman visited our emergency department complaining of dyspnea, cough, and fever. Two weeks earlier, she had started aromatherapy using a humidifier and essential oil. Based on clinical and imaging findings, and the results of bronchoalveolar lavage, we diagnosed acute eosinophilic pneumonia due to inhalation of essential oil. Her symptoms resolved after steroid therapy. This case makes the clinicians aware the possibility of acute eosinophilic pneumonia induced by aromatherapy using essential oil.

Diagnostic index for acute eosinophilic pneumonia without bronchoscopy in military smokers

BACKGROUND/AIMS

Acute eosinophilic pneumonia (AEP) is common among military smokers; however, bronchoscopy is required for the diagnosis. We aimed to derive and validate a scoring system to diagnose AEP without bronchoscopy.

METHODS

We conducted a retrospective study including patients diagnosed with AEP or any other pneumonia among military smokers hospitalized in the Armed Forces Capital Hospital from 15 November 2016 through 25 December 2019. The patients were divided into derivation and validation groups according to their admission day. Patient symptoms, laboratory findings, and computed tomography findings were candidate variables. Least absolute shrinkage and selection operator (LASSO) regression was used to calculate the scores for each variable.

RESULTS

Among 414 patients, AEP was confirmed in 54 of 279 patients (19.4%) in the derivation group and in 18 of 135 patients (13.3%) in the validation group. Ten variables were selected using LASSO regression: new-onset or a recently increased smoking (≤ 4 weeks) (8 points), interlobular septal thickening (5 points), absence of sputum (3 points), ground glass opacity (3 points), acute onset (≤ 3 days) (2 points), dyspnea (2 points), chest pain (2 points), leukocytosis (2 points), bronchovascular bundle thickening (2 points), and bilateral involvement (2 points). The area under the receiver-operating characteristic curve of the score to diagnose AEP was 0.997 (95% confidence interval, 0.992 to 1.000) in the derivation group and 0.985 (95% confidence interval, 0.965 to 1.000) in the validation group.

CONCLUSION

We introduce a scoring system that can distinguish AEP from other types of pneumonia in military smokers without the need for bronchoscopy.

Radiologic Review With Pathology Correlation of E-Cigarette or Vaping Product Use-associated Lung Injury

More than 2000 cases of vaping-associated lung injury have been reported in a recent outbreak, including >40 deaths. Although chest imaging is integral in the evaluation of these patients and is often abnormal, the spectrum of findings and the role of imaging in the diagnosis are not widely appreciated. The aim of this review is to highlight the imaging findings of vaping-associated lung injury. Basilar-predominant ground-glass opacities and/or consolidations, often with areas of subpleural or lobular sparing, are the most common pattern, and many other patterns are known to occur. Radiologists are encouraged to become familiar with the different imaging patterns of vaping-associated lung injury. The diagnosis should be considered in patients who have vaped within 90 days of onset of symptoms and present with bilateral lung opacities.

Smoking-associated interstitial lung disease: update and review

INTRODUCTION

Smoking-associated interstitial lung disease manifests as several heterogeneous disorders involving the airways, pleura, and lung parenchyma with various radiological patterns. The clinical history, radiologic, and pathologic findings are important to distinguish these more uncommon diseases. A multidisciplinary approach is recommended for diagnosis and to manage these conditions appropriately.

AREAS COVERED

This review provides an overview of the epidemiology, risk factors, pathogenesis, clinical features, diagnosis, and treatment of acute eosinophilic pneumonia, e-cigarettes, or vaping associated lung injury, respiratory bronchiolitis interstitial lung disease, desquamative interstitial pneumonitis, pulmonary Langerhans cell histiocytosis, idiopathic pulmonary fibrosis, and combined pulmonary fibrosis emphysema.

EXPERT OPINION

Cigarette smoking is associated with a variety of pathologic conditions that affect the airways and lungs. E-cigarette use and vaping present new challenges to the clinician. Consensus between the clinical, radiographic, and pathologic findings is important in identifying and differentiating between the various entities to properly diagnose smoking-related interstitial lung diseases discussed in this review.

Possible Mechanisms of Eosinophil Accumulation in Eosinophilic Pneumonia

Eosinophilic pneumonia (EP), including acute EP and chronic EP, is characterized by the massive pulmonary infiltration of eosinophils into the lung. However, the mechanisms underlying the selective accumulation of eosinophils in EP have not yet been fully elucidated. We reported that bronchoalveolar lavage fluid (BALF) from EP patients induced the transmigration of eosinophils across endothelial cells in vitro. The concentrations of eotaxin-2 (CCL24) and monocyte chemotactic protein (MCP)-4 (CCL13), which are CC chemokine receptor (CCR) 3 ligands, were elevated in the BALF of EP patients, and anti-CCR3 monoclonal antibody inhibited the eosinophil transmigration induced by the BALF of EP patients. The concentration of macrophage inflammatory protein 1β (CCL4), a CCR5 ligand that induces eosinophil migration, was increased in the BALF of EP patients. Furthermore, the concentration of interleukin (IL) 5 was increased in the BALF of EP patients, and it has been reported that anti-IL-5 antibody treatment resulted in remission and the reduction of glucocorticoid use in some cases of chronic EP. The concentrations of lipid mediators, such as leukotriene (LT) B₄, damage-associated molecular pattern molecules (DAMPs), such as uric acid, or extracellular matrix proteins, such as periostin, were also increased in the BALF of EP patients. These findings suggest that chemokines, such as CCR3/CCR5 ligands, cytokines, such as IL-5, lipid mediators, such as LTB₄, DAMPs, and extracellular matrix proteins may play roles in the accumulation or activation of eosinophils in EP.

Radiologic, Pathologic, Clinical, and Physiologic Findings of Electronic Cigarette or Vaping Product Use-associated Lung Injury (EVALI): Evolving Knowledge and Remaining Questions

Proposed as a safer alternative to smoking, the use of electronic cigarettes has not proven to be innocuous. With numerous deaths, there is an increasing degree of public interest in understanding the symptoms, imaging appearances, causes of, and treatment of electronic cigarette or vaping product use-associated lung injury (EVALI). Patients with EVALI typically have a nonspecific clinical presentation characterized by a combination of respiratory, gastrointestinal, and constitutional symptoms. EVALI is a diagnosis of exclusion; the patient must elicit a history of recent vaping within 90 days, other etiologies must be eliminated, and chest imaging findings must be abnormal. Chest CT findings in EVALI most commonly show a pattern of acute lung injury on the spectrum of organizing pneumonia and diffuse alveolar damage. The pathologic pattern found depends on when in the evolution of the disease process the biopsy sample is taken. Other less common forms of lung injury, including acute eosinophilic pneumonia and diffuse alveolar hemorrhage, have also been reported. Radiologists and pathologists help play an important role in the evaluation of patients suspected of having EVALI. Accurate and rapid identification may decrease morbidity and mortality by allowing for aggressive clinical management and glucocorticoid administration, which have been shown to decrease the severity of lung injury in some patients. In this review, the authors summarize the current state of the art for the imaging and pathologic findings of this disorder and outline a few of the major questions that remain to be answered.

Association between peripheral blood/bronchoalveolar lavage eosinophilia and significant oxygen requirements in patients with acute eosinophilic pneumonia

Background

We investigated the association between a combination of two markers, peripheral (PEC) and bronchoalveolar lavage (BAL) eosinophil percentage (BEP), and oxygen requirements in patients with acute eosinophilic pneumonia (AEP).

Methods

We retrospectively reviewed the medical records of patients with AEP treated at the Armed Forces Capital Hospital between May 2012 and May 2017. We used correlation analyses to assess the association between PEC/BEP and clinical outcomes in AEP patients. Receiver operating characteristic (ROC) curve analyses were used to calculate the cut-off value for BEP that categorised patients requiring a significant oxygen supply. The BAL/blood eosinophil (BBE) score was introduced to stratify patients with peripheral eosinophilia and elevated BEP. Clinical characteristics and outcomes were compared between the different groups. Multiple logistic regression was performed for significant oxygen requirements using two different models using age, C-reactive protein (CRP), smoking duration, and BBE score (model 1) and age, CRP, BEP, and PEC (model 2).

Results

Among the 338 patients, 99.7% were male, and their mean age was 20.4 ± 1.4 years. Only 0.6% of patients were never smokers and the mean number of smoking days was 26.2 ± 25.4. Correlation analyses revealed that both the PaO₂/FiO₂ ratio and duration of oxygen supply were associated with BEP. ROC curve analyses indicated a cut-off level of 41.5%. Patients with a high BBE score had favourable outcomes in terms of hypoxemia, hospital days, intensive care unit admission, oxygen supply days, and steroid treatment days. Multiple logistic regression revealed that BEP and BBE score tended to be associated with significant oxygen requirements.

Conclusions

In this study, we revealed that both peripheral and BAL eosinophilia is associated with favourable outcomes in AEP patients.

Vaping Is Not Safe: A Case of Acute Eosinophilic Pneumonia following Cannabis Vapor Inhalation

There is a well-established association between inhalational exposures and acute eosinophilic pneumonia (AEP). The most reported exposure is cigarette smoking. Here, we present a case of progressive shortness of breath and nonproductive cough in a college student with no significant medical history, approximately 10 days after inhaling cannabis aerosols on two separate occasions. He was started on empiric antibiotics and bronchodilators without improvement. He was diagnosed with AEP based on peripheral eosinophilia and high-resolution CT image results. He made rapid recovery on intravenous glucocorticoids. Vaping has gained popularity among young adults mainly due to the perception that it is a safe alternative to smoking. This case shows that there may be a false sense of security with vaping. Vaping poses a yet-to-be quantified public health threat, which requires further studies.

Mimics of Acute Respiratory Distress Syndrome

Acute respiratory distress syndrome (ARDS) was first described in 1967 by Ashbaugh and colleagues. Acute respiratory distress syndrome is a clinical syndrome, not a disease, and has no ideal definition or gold standard diagnostic test. There are multiple causes and different pathways of pathogenesis as well as various histological findings. Given these variations, there are many clinical entities that can get confused with ARDS. These entities are discussed in this article as "Mimics of ARDS." It imperative to correctly identify ARDS and distinguish it from other diseases to implement correct management strategy.

Pediatric Acute Respiratory Distress Syndrome and Hypersensitivity Pneumonitis Related to E-cigarette Vaping

In recent years, electronic cigarettes (e-cigs) have been falsely advertised as safe alternatives to conventional smoking. We report a case involving a 16-year-old female who presented with fever, nonproductive cough, and shortness of breath after vaping e-cig/tetrahydrocannabinol dab pen. Her symptoms rapidly deteriorated and met diagnostic criteria for pediatric acute respiratory distress syndrome. Chest radiograph revealed extensive patchy airspace disease and computed tomography scan showed bilateral ground glass opacities. Bronchoalveolar lavage fluid revealed increased neutrophils, lymphocytosis, but absent eosinophilia. After the results of a comprehensive workup for infectious etiology returned negative, she was diagnosed with hypersensitivity pneumonitis and started on systemic corticosteroids.

Eosinophilic pneumonia: A review of the previous literature, causes, diagnosis, and management

Eosinophilic pneumonia (EP) is a rare disorder, comprising several heterogeneous diseases. Two major types of EP are acute eosinophilic pneumonia (AEP) and chronic eosinophilic pneumonia (CEP), both of which are characterized by marked accumulation of eosinophils in lung tissues and/or BAL fluid. AEP and CEP share some similarities in terms of pathophysiology, radiological findings, and treatment response to corticosteroids. However, they distinctly differ in etiology, clinical manifestations, and the nature of disease course. Especially, although AEP and CEP respond well to corticosteroids, relapse frequently occurs in patients with CEP, but rarely in those with AEP. Although CEP occasionally persists and becomes corticosteroid dependent, most patients with AEP completely recover. This article reviews previous studies and discusses the etiology, clinical manifestations, and treatment of AEP and CEP.

Acute Eosinophilic Pneumonia. Causes, Diagnosis, and Management

Acute eosinophilic pneumonia (AEP) is an uncommon acute respiratory illness of varying severity that includes presentation as acute respiratory distress syndrome with fatal outcome. AEP may be idiopathic, but identifiable causes include smoking and other inhalational exposures, medications, and infections. The pathogenesis of AEP is poorly understood but likely varies depending on the underlying cause. Airway epithelial injury, endothelial injury, and release of IL-33 are early events that subsequently promote eosinophil recruitment to the lung; eosinophilic infiltration and degranulation appear to mediate subsequent lung inflammation and associated clinical manifestations. Crucial for the diagnosis are the demonstration of pulmonary eosinophilia in the BAL fluid and the exclusion of other disease processes that can present with acute pulmonary infiltrates. Although peripheral blood eosinophilia at initial presentation may be a clue in suggesting the diagnosis of AEP, it may be absent or delayed, especially in smoking-related AEP. Optimal management of AEP depends on the recognition and elimination of the underlying cause when identifiable. The cessation of the exposure to the inciting agent (e.g., smoking), and glucocorticoids represent the mainstay of treating AEP of noninfectious origin. If AEP is recognized and treated in a timely manner, the prognosis is generally excellent, with prompt and complete clinical recovery, even in those patients manifesting acute respiratory failure.

Idiopathic acute eosinophilic pneumonia: A rare cause of hypoxic respiratory failure

Idiopathic Acute Eosinophilic Pneumonia (IAEP) is a life-threatening cause of hypoxic respiratory failure. IAEP is challenging to diagnose as it may mimic infectious pneumonia or acute respiratory distress syndrome. Distinguishing IAEP from these alternatives is important; the mainstay of treatment for IAEP is corticosteroids, a therapy which might not otherwise be indicated. Patients treated appropriately usually experience a full recovery. In this case report we describe the presentation, evaluation, and management of a 19-year old male who presented to the emergency department (ED) in respiratory failure from IAEP. The patient was a military trainee who recently moved to the United States from Saudi Arabia. He also recently began smoking cigarettes for the first time, a known risk factor for IAEP. Upon initial presentation, the patient was in respiratory distress and had an oxygen saturation of 82% on room air. His ED diagnostic workup included chest X-ray showing diffuse interstitial thickening and chest computed tomography that demonstrated diffuse nodular opacification of pulmonary parenchyma. The patient was admitted to the intensive care unit (ICU) where bronchoscopy yielded cytology with 30% eosinophilia. The patient ultimately required 3 days of extra corporeal membrane oxygenation (ECMO) due to worsening hypoxic respiratory failure. After both intravenous and outpatient oral steroid treatments, the patient went on to have a full recovery with no ongoing respiratory issues. To our knowledge, this is the first case of IAEP requiring ECMO reported in the emergency medicine literature.

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.

A Review of Smoking-Related Interstitial Fibrosis, Respiratory Bronchiolitis, and Desquamative Interstitial Pneumonia: Overlapping Histology and Confusing Terminology

Smoking-related lung diseases traverse a spectrum of clinicopathologic entities, with cases often comprising a complex mixture of findings. The complexity of the diagnostic process extends beyond the histologic findings to the nomenclature, which is murky from a seemingly unending expansion of terms being applied to a handful of pathologic changes. Here, we focus our review on smoking-related interstitial fibrosis, respiratory bronchiolitis, and desquamative interstitial pneumonia, 3 entities that perhaps show the most histologic overlap and suffer from competing terminology.

Extracorporeal Membrane Oxygenation in Severe Acute Eosinophilic Pneumonia

Acute Eosinophilic Pneumonia (AEP) is a potentially fatal cause of hypoxemic respiratory failure characterized by fever, diffuse bilateral pulmonary infiltrates, and pulmonary eosinophilia. Shown to be associated with a number of environmental exposures and lifestyle choices, AEP has a good prognosis when diagnosed early and treated with corticosteroids. In this clinical case report, we detail the presentation, evaluation, diagnosis, and management of a 40-year old male who presented to the emergency department with dyspnea, chills, and diaphoresis. He had a history of pulmonary embolism 8 years prior but was otherwise healthy, though he had re-started smoking cigarettes a week prior to presentation. Initial chest CT scan revealed widespread mixed groundglass and solid airspace opacities; over the next 12 hours, he rapidly decompensated and after not responding to other invasive mechanical ventilation, was emergently cannulated for veno-venous extracorporeal membrane oxygenation (V-V ECMO). Bronchoalveolar lavage later revealed pulmonary eosinophilia, and after an infectious workup was negative, a diagnosis of AEP was reached and the patient was started on corticosteroids. To our knowledge, this is one of few published cases of AEP requiring V-V ECMO for clinical stabilization, highlighting the utility of this treatment modality in severe disease.

Acute eosinophilic pneumonia following electronic cigarette use

Electronic cigarette (e-cigarette) use, or vaping, is gaining widespread popularity among adults aged 18–35. Vaping is commercially promoted as a safer alternative to traditional cigarette smoking. Previous studies have reported a close relationship between conventional cigarette smoking and acute eosinophilic pneumonia (AEP), but only one case report to date associates vaping with AEP in a male patient. We present the first case of AEP involving a young female after use of e-cigarettes. Clinicians should consider AEP when evaluating young patients with hypoxic respiratory failure and a recent history of e-cigarette use. This case highlights the need for more research into the relationship between e-cigarettes and AEP.

Cigarette smoking-induced acute eosinophilic pneumonia: A case report

RATIONALE

Acute eosinophilic pneumonia (AEP) is a rare pulmonary disease, which is characterized by diffuse pulmonary eosinophilia. The pathogenesis remains unknown. Here we report a patient with AEP following a recently acquired habit of smoking.

PATIENT CONCERNS

A 21-year-old female presented with fever, dry cough, and acute hypoxic respiratory distress for 2 days. Chest computed tomography showed bilateral ground glass opacities, patchy nodules, and pleural effusions. Blood tests showed a gradually raised peripheral eosinophils level.

DIAGNOSES

Bronchoalveolar lavage fluid revealed marked elevation of eosinophils. She was diagnosed with AEP.

INTERVENTIONS

Systemic methylprednisolone was immediately used for treatment.

OUTCOMES

Her clinical symptoms and chest radiographs improved promptly after treatment.

LESSONS

Cigarette smoking might be an underlying triggering factor of AEP. Diffuse alveolar infiltrates and a gradually increasing peripheral eosinophilia should raise the concern especially in recent smoking patients.

Age distribution and seasonality in acute eosinophilic pneumonia: analysis using a national inpatient database

BACKGROUND

Acute eosinophilic pneumonia (AEP) is a rare inflammatory lung disease. Previous studies have shown that most patients with AEP are aged 20 to 40 years, whereas several case studies have included older patients with AEP. These studies also suggested that AEP is more prevalent in summer, but they were limited due to their small sample sizes. We therefore investigated the age distribution and seasonality among patients with AEP using a national inpatient database.

METHODS

Using the Japanese Diagnosis Procedure Combination database, we identified patients with a recorded diagnosis of AEP from 1 July 2010 to 31 March 2015. We examined patient characteristics and clinical practices including age, sex, seasonal variation, length of stay, use of corticosteroids, use of mechanical ventilation, and in-hospital mortality.

RESULTS

During the 57-month study period, we identified 213 inpatients with AEP. The age distribution of AEP peaked twice: at 15 to 24 years and 65 to 79 years. The proportion of patients with AEP was highest in summer for those aged < 40 years, whereas it was distributed evenly throughout the year for those aged ≥ 40 years. The interval from hospital admission to corticosteroid administration and the duration of corticosteroid use were significantly longer in the older than younger age group.

CONCLUSIONS

The age distribution of patients with AEP was bimodal, and seasonality was undetected in older patients. Older patients may be more likely to have delayed and prolonged treatment.

Elevated Periostin Concentrations in the Bronchoalveolar Lavage Fluid of Patients with Eosinophilic Pneumonia

BACKGROUND

Eosinophilic pneumonia (EP) is characterized by massive pulmonary infiltration by eosinophils. Although serum periostin is a novel marker for eosinophil-dominant asthma, the upregulation of periostin in the airway of asthmatics is controversial. In this study, we examined whether periostin concentrations are elevated in the bronchoalveolar lavage fluid (BALF) of patients with EP.

METHODS

BAL was performed in healthy volunteers and in patients with acute eosinophilic pneumonia (AEP), chronic eosinophilic pneumonia (CEP), and sarcoidosis. The periostin concentrations in the BALF were measured.

RESULTS

The periostin concentration in the BALF increased significantly with pulmonary eosinophil ia and was higher in AEP and CEP patients than in healthy volunteers and sarcoidosis patients, even after adjusting the albumin concentration. In pulmonary eosinophilia, the periostin concentration correlated with the eosinophil and lymphocyte counts, the concentration of albumin, and the concentration of cytokines such as IL-5, IL-13, and transforming growth factor β1.

CONCLUSIONS

Although some blood leakage may be involved in the elevation of periostin in the BALF of EP, periostin can be induced locally, at least in part. Therefore, periostin may play a role in the development of EP.

Heat-not-burn cigarettes induce fulminant acute eosinophilic pneumonia requiring extracorporeal membrane oxygenation

Background

Although the cause of acute eosinophilic pneumonia (AEP) has not yet been fully clarified, cigarette smoking is reported to be a risk factor for developing AEP. The heat-not-burn cigarette (HNBC) was developed to reduce the adverse effects of smoke on the user's surroundings. However, the health risks associated with HNBCs have not yet been clarified. We report a successfully treated case of fatal AEP presumably induced by HNBC use.

Presentation of case

A 16-year-old man commenced HNBC smoking two weeks before admission and subsequently suffered from shortness of breath that gradually worsened. The patient was transferred to emergency department and immediately intubated because of respiratory failure. Computed tomography showed mosaic ground-glass shadows on the distal side of both lungs with a PaO₂/F_IO₂ ratio of 76. The patient required veno-venous extracorporeal membrane oxygenation (ECMO) for severe respiratory failure. He was diagnosed with AEP by clinical course and detection of eosinophils in sputum; thus, methylprednisolone was administrated. The patient was weaned off ECMO four days after initiation and extubated the day after. He fully recovered without sequelae.

Conclusion

As far as we know, our patient is the first case of AEP induced by HNBC use successfully treated with ECMO. Emergency physicians must be aware that HNBCs can induce fatal AEP.

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The use of heat-not-burn cigarettes has been increasing in recent years.

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The effects of heat-not-burn cigarettes on health have not yet been clarified.

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Heat-not-burn cigarettes possibly induce acute eosinophilic pneumonia.

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Extracorporeal membrane oxygenation was effective in a patient with a severe case of acute eosinophilic pneumonia.

Smoking-Related Lung Disease

Smoke from cigarettes and other sources may induce a variety of patterns of lung injury. While smoking related lung diseases, in general, have a better prognosis than many other diffuse lung diseases, they may be a cause of significant symptoms and, in some cases, may even require lung transplantation. On histology, the manifestations of these patterns range from reversible inflammation to irreversible emphysema or fibrosis. High-resolution chest CT plays a critical role in the diagnosis of smoking related lung diseases. It has several roles including (1) helping determine diagnosis, (2) assessing the pattern of injury that is present, (3) evaluating the extent and severity of disease, and (4) determining the response to treatment. The practicing radiologist must have a knowledge of the clinical, pathologic, and imaging features of the differnent patterns of lung injury associated with smoke inhalation.

Traction bronchiectasis on high-resolution computed tomography may predict fatal acute eosinophilic pneumonia

BACKGROUND

Most patients with acute eosinophilic pneumonia (AEP) show rapid improvement. However, some cases of AEP prove fatal. The aims of this study were to determine the clinical, radiographic, and pathologic characteristics of patients in whom AEP has a fatal outcome and to identify predictors of a poor prognosis.

METHODS

We retrospectively identified the medical records of all patients diagnosed with AEP at our institution in Japan from July 2005 to July 2013.

RESULTS

There were four deaths among 41 patients diagnosed to have AEP during the study period. All the patients who died were male; three cases were idiopathic and one was medication-related. The median bronchoalveolar lavage eosinophil differential count was 59%. An autopsy was performed on the patient with medication-related AEP who died and the pathologic finding was diffuse alveolar damage with eosinophilic infiltration. Diffuse ground-glass attenuation and traction bronchiectasis (TBE) were identified on high-resolution computed tomography in the four patients with fatal AEP. TBE was observed in six patients (five with idiopathic AEP, one with medication-related AEP), and 67% of these patients died. None of the patients with smoking-related AEP had TBE; all these patients had better responses to treatment and survived.

CONCLUSIONS

We observed the characteristics of patients with fatal AEP who did not respond to treatment. TBE was observed in all fatal cases and may be associated with a poor prognosis.

Long-term management and persistent impairment of pulmonary function in chronic eosinophilic pneumonia: A review of the previous literature

Chronic eosinophilic pneumonia (CEP) is an inflammatory disease characterized by accumulations of eosinophils in the lung with unknown etiology. Although corticosteroid treatment dramatically resolves these inflammations, relapse is common during the course of the disease. Approximately 50% of patients with CEP experience relapse. Subsequent to persistent disease and repeated relapse, and in cases of combined severe asthma, some CEP patients are administered corticosteroids indefinitely. Similar to patients with severe asthma who are often steroid dependent, a number of CEP patients exhibit prolonged persistent impairment of pulmonary function. Thus, CEP should be considered a potentially chronic disease requiring long-term management, rather than an acute or sub-acute disease requiring short-time therapy only. This review summarizes previous CEP studies, as well as our own cohort data, and discusses the long-term management of CEP with a particular focus on relapse, the prevalence of maintenance therapy, and persistent impairment of pulmonary function.

Acute eosinophilic pneumonia in the deployed military setting

RATIONALE

Acute eosinophilic pneumonia (AEP) is a rare but important cause of severe respiratory failure most typically caused by cigarette smoking, but can also be caused by medications, illicit drugs, infections and environmental exposures. There is growing evidence that disease severity varies and not all patients require mechanical ventilation or even supplemental oxygen.

OBJECTIVES

To compare patients with AEP treated at Landstuhl Regional Medical Center (LRMC) to those in other published series, and to provide recommendations regarding diagnosis and treatment of AEP.

METHODS

A retrospective chart review was completed on forty-three cases of AEP which were identified from March 2003 through March 2010 at LRMC, Germany.

RESULTS

Tobacco smoking was reported by 91% of our patients. Only 33% of patients in our series had a fever (temperature > 100.4 °F) at presentation. Peripheral eosinophilia (>5%) was present in 35% on initial CBC, but was seen in 72% of patients during their hospital course. Hypoxemia, as measured by PaO2/FiO2 ratio, seemed to be less severe in patients with higher levels of bronchoalveolar (BAL) eosinophilia percentage.

CONCLUSIONS

Based on our experience and literature review, we recommend adjustments to the diagnostic criteria which may increase consideration of this etiology for acute respiratory illnesses as well as provide clinical clues we have found particularly helpful. Similar to recent reports of initial peripheral eosinophilia correlating with less severe presentation we found that higher BAL eosinophilia correlated with less severe hypoxemia.

Drug-induced eosinophilic pneumonia: A review of 196 case reports

BACKGROUND AND OBJECTIVE

Eosinophilic pneumonia (EP) is an important subset of patients who present with pulmonary infiltrates and eosinophilia (PIE). EP is classified by chronicity and etiology and drug-induced EP is the main cause of secondary EP. The primary goal of this review was to examine all the case reports published since the syndrome was defined in 1990. It remains unclear whether acute or chronic EP (AEP or CEP) represent different diseases, and the secondary goal of this review is to determine if there are factors that may help distinguish these 2 entities.

METHODS

PubMed (MEDLINE and Medical Subject Headings) was searched for case reports of drug-induced EP or PIE syndrome published between 1990 and 2017. Case reports were only included if the diagnostic criteria for AEP or CEP were fulfilled. For each case, data were extracted pertaining to age, sex, type of medication associated with the disease, time from the onset of symptoms to diagnosis, eosinophil counts in the blood, eosinophil fractions in bronchoalveolar lavage (BAL) fluid, initial chest radiograph and computed tomography results, use of mechanical ventilation, and use of steroid treatment and recurrence.

RESULTS

We found 196 case reports describing drug-induced EP. The leading cause was daptomycin. From our review, we found that AEP is more common in younger patients with no gender preference. Eosinophilia in the blood at the time of diagnosis characterized only the CEP patients (80% in CEP vs. 20% in AEP). Abnormal findings on radiographic imagine was similar in both syndromes. A significant portion of AEP patients (20%) presented with acute respiratory failure requiring mechanical ventilation. Most patients with EP were treated with steroids with a higher rate of relapse observed in patients with CEP.

CONCLUSION

AEP is a much more fulminant and severe disease than the gradual onset and slowly progressive nature of CEP. The pathogenesis of AEP and CEP remains unclear. However, there is significant clinical overlap among AEP and CEP that are associated with drug toxicity, suggesting the possibility that AEP and CEP are distinct clinical presentations that share a common pathogenic pathway.

Current Concepts in Pathogenesis, Diagnosis, and Management of Smoking-Related Interstitial Lung Diseases

Tobacco exposure results in various changes to the airways and lung parenchyma. Although emphysema represents the more common injury pattern, in some individuals, cigarette smoke injures alveolar epithelial cells and other lung cells, resulting in diffuse infiltrates and parenchymal fibrosis. Smoking can trigger interstitial injury patterns mediated via recruitment and inappropriate persistence of myeloid and other immune cells, including eosinophils. As our understanding of the role of cigarette smoke constituents in triggering lung injury continues to evolve, so does our recognition of the spectrum of smoking-related interstitial lung changes. Although respiratory bronchiolitis-interstitial lung disease, desquamative interstitial pneumonia, pulmonary Langerhans cell histiocytosis, and acute eosinophilic pneumonia have a well-established association with tobacco use, its role and impact on idiopathic pulmonary fibrosis, combined pulmonary fibrosis and emphysema, and connective tissue disease-related interstitial lung diseases is still ambiguous. Smoking-related interstitial fibrosis is a relatively newly appreciated entity with distinct histopathologic features but with unclear clinical ramifications. Increased implementation of lung cancer screening programs and utilization of CT scans in thoracic imaging have also resulted in increased identification of "incidental" or "subclinical" interstitial lung changes in smokers, the ensuing impact of which remains to be studied.

Elevated uric acid and adenosine triphosphate concentrations in bronchoalveolar lavage fluid of eosinophilic pneumonia

BACKGROUND

Recent evidence has suggested that the innate immune response may play a role in the development of eosinophilic airway inflammation. We previously reported that uric acid (UA) and adenosine triphosphate (ATP), two important damage-associated molecular pattern molecules (DAMPs), activate eosinophil functions, suggesting that these molecules may be involved in the development of eosinophilic airway inflammation. The objective of this study was to measure the concentrations of DAMPs including UA and ATP in the bronchoalveolar lavage fluid (BALF) of patients with eosinophilic pneumonia (EP).

METHODS

BAL was performed in patients with EP including acute and chronic eosinophilic pneumonia, and in patients with hypersensitivity pneumonia, and sarcoidosis. UA, ATP, and cytokine concentrations in the BALF were then measured.

RESULTS

The UA concentration was increased in the BALF of EP patients. UA concentrations correlated with eosinophil numbers, and with eosinophil-derived neurotoxin and interleukin (IL)-5 concentrations. Furthermore, the ATP concentration was increased in the BALF of EP patients and ATP concentrations correlated with UA concentrations. Moreover, IL-33 was increased in EP patients and IL-33 concentrations correlated with UA and ATP concentrations.

CONCLUSIONS

The UA and ATP concentration was increased in the BALF of EP patients. UA concentrations correlated with eosinophil numbers, and with ATP and IL-33 concentrations. Our findings suggest that DAMPs such as UA and ATP play a role in the pathogenesis of EP.

Acute eosinophilic pneumonia following artenimol-piperaquine exposure

Acute eosinophilic pneumonia (AEP) has been reported following chloroquine or mefloquine exposure, both structurally related to piperaquine. We report a case of AEP with typical CT scan patterns, hypereosinophilia in blood (9.8 109/l), and bronchoalveolar lavage (78% of 600 000 cells/ml), 10 days after artenimol-piperaquine exposure in a 26-year-old man.

A Man in His 20s With Diffuse Lung Opacities and Acute Respiratory Failure After Hookah Smoking

A man in his 20s with no medical history presented with 2 days of progressively worsening shortness of breath accompanied by subjective fevers, chills, body aches, decreased appetite, night sweats, and cough producing nonbloody sputum. He denied childhood lung diseases, allergies, or a family history of lung disease. He did not smoke cigarettes but had smoked hookah in Saudi Arabia before moving to the United States 1 month before presentation and had restarted 2 days before the start of symptoms. He denied travel outside of the northeastern United States. He did not take medications, use illicit drugs, or engage in high-risk behavior.

Acute Eosinophilic Pneumonia: Correlation of Clinical Characteristics With Underlying Cause

BACKGROUND

Acute eosinophilic pneumonia (AEP) is an uncommon disease, often indistinguishable from ARDS or community-acquired pneumonia at initial presentation. AEP can be idiopathic, but identifiable causes include medications and inhalational exposures, including cigarette smoke.

METHODS

Using a computer-assisted search, we retrospectively identified and reviewed the medical records of all patients diagnosed with AEP between January 1, 1998, and June 30, 2016, at our institution. Demographic and clinical data were extracted, including exposures (occupational, environmental, recreational, pharmacologic, and smoking), laboratory and radiologic findings, treatments, hospitalization (including ICU stay), and subsequent clinical course.

RESULTS

Among 36 consecutive patients with AEP, 11 were smoking-related cases, six were medication-related cases and 19 were idiopathic. Smoking-related AEP included six first-time smokers and five ex-smokers who had resumed smoking after a period of abstinence. Patients with smoking-related AEP were younger compared with both medication-related and idiopathic AEP cases (median age: 22 vs 47.5 vs 55 years, respectively; P = .004). Patients with smoking-related AEP were less likely to be associated with peripheral eosinophilia at presentation (36% vs 50% vs 58%; P = .52) but more likely to be hospitalized (100% vs 50% vs 63%; P = .039), including a longer ICU stay, compared with medication-related and idiopathic cases.

CONCLUSIONS

AEP is associated with a good prognosis when recognized and treated promptly. Compared with medication-related and idiopathic AEP, smoking-related AEP was less likely to be associated with peripheral eosinophilia at presentation but was characterized by more severe disease manifestations.

A Review of Clinical and Imaging Findings in Eosinophilic Lung Diseases

OBJECTIVE

The purpose of this article is to review the clinical and imaging findings associated with eosinophilic lung diseases.

CONCLUSION

The spectrum of eosinophilic lung diseases comprises a diverse group of pulmonary disorders that have an association with tissue or peripheral eosinophilia. These diseases have varied clinical presentations and may be associated with several other abnormalities. Characteristic imaging findings are often detected with chest radiography, and CT best shows parenchymal abnormalities. The integration of clinical, radiologic, and pathologic findings facilitates diagnosis and directs appropriate treatment.