Eosinophilic lung diseases: a clinical, radiologic, and pathologic overview

Mimickers of novel coronavirus disease 2019 (COVID-19) on chest CT: spectrum of CT and clinical features

COVID-19 (coronavirus disease 2019) is a recently emerged pulmonary infection caused by severe acute respiratory syndrome coronavirus (SARS-CoV-2). It started in Wuhan, China, in December 2019 and led to a highly contagious disease. Since then COVID-19 continues to spread, causing exponential morbidity and mortality and threatening economies worldwide. While the primary diagnostic test for COVID-19 is the reverse transcriptase-polymerase chain reaction (RT-PCR) assay, chest CT has proven to be a diagnostic tool of high sensitivity. A variety of conditions demonstrates CT features that are difficult to differentiate from COVID-19 rendering CT to be of low specificity. Radiologists and physicians should be aware of imaging patterns of these conditions to prevent an erroneous diagnosis that could adversely influence management and patients' outcome. Our purpose is to provide a practical review of the conditions that mimic COVID-19. A brief description of the forementioned clinical conditions with their CT features will be included.

Immune checkpoint inhibitors-induced eosinophilic pneumonia: A case report

A 78‐year‐old male with renal cell carcinoma was treated with combined immunotherapy of nivolumab and ipilimumab. After four courses of the treatment, a chest computed tomography (CT) revealed newly formed ground‐glass opacities (GGOs) in both the lower lung lobes; drug‐induced pneumonia was speculated. Eosinophil counts were elevated in both peripheral blood and bronchoalveolar lavage fluid. Both the immune checkpoint inhibitors (ICIs) were discontinued, following which the chest CT findings improved. Based on these findings, a diagnosis of ICI‐induced eosinophilic pneumonia was made. Hence, clinicians should be wary of the risk of eosinophilic pneumonia during ICI‐anticancer therapy.

[Lung imaging in severe asthma]

INTRODUCTION

Asthma is a common disease whose diagnosis does not typically rely on the results of imaging. However, chest CT has gained a key place over the last decade to support the management of patients with difficult to treat and severe asthma.

STATE OF THE ART

Bronchial wall thickening and mild dilatation or narrowing of bronchial lumen are frequently observed on chest CT in people with asthma. Bronchial wall thickening is correlated to the degree of obstruction and to bronchial wall remodeling and inflammation. Diverse conditions which can mimic asthma should be recognized on CT, including endobronchial tumours, interstitial pneumonias, bronchiectasis and bronchiolitis. Ground-glass opacities and consolidation may be related to transient eosinophilic infiltrates, infection or an associated disease (vasculitis, chronic eosinophilic pneumonia). Hyperdense mucous plugging is highly specific for allergic bronchopulmonary aspergillosis.

PERSPECTIVES

Airway morphometry, air trapping and quantitative analysis of ventilatory defects, with CT or MRI, can help to identify different morphological subgroups of patients with different functional or inflammatory characteristics. These imaging tools could emerge as new biomarkers for the evaluation of treatment response.

CONCLUSION

Chest CT is indicated in people with severe asthma to search for additional or alternative diagnoses. Quantitative imaging may contribute to phenotyping this patient group.

COVID-19 and its Mimics: What the Radiologist Needs to Know

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the current outbreak of Coronavirus disease 2019 (COVID-19). Although imaging should not be used for first-line screening or diagnosis, radiologists need to be aware of its imaging features, and those of common conditions that may mimic COVID-19 pneumonia. In this Pictorial Essay, we review frequently encountered conditions with imaging features that overlap with those that are typical of COVID-19 (including other viral pneumonias, chronic eosinophilic pneumonia, and organizing pneumonia), and those with features that are indeterminate for COVID-19 (including hypersensitivity pneumonitis, pneumocystis pneumonia, diffuse alveolar hemorrhage, pulmonary edema, and pulmonary alveolar proteinosis).

COVID-19 mimics on chest CT: a pictorial review and radiologic guide

Chest imaging is often used as a complementary tool in the evaluation of coronavirus disease 2019 (COVID-19) patients, helping physicians to augment their clinical suspicion. Despite not being diagnostic for COVID-19, chest CT may help clinicians to isolate high suspicion patients with suggestive imaging findings. However, COVID-19 findings on CT are also common to other pulmonary infections and non-infectious diseases, and radiologists and point-of-care physicians should be aware of possible mimickers. This state-of-the-art review goal is to summarize and illustrate possible etiologies that may have a similar pattern on chest CT as COVID-19. The review encompasses both infectious etiologies, such as non-COVID viral pneumonia, Mycoplasma pneumoniae, Pneumocystis jiroveci, and pulmonary granulomatous infectious, and non-infectious disorders, such as pulmonary embolism, fat embolism, cryptogenic organizing pneumonia, non-specific interstitial pneumonia, desquamative interstitial pneumonia, and acute and chronic eosinophilic pneumonia.

Ustekinumab associated chronic eosinophilic pneumonia

INTRODUCTION

Ustekinumab-induced eosinophilic pneumonia is rare and to our knowledge, this is the fifth reported case of such an entity.

CASE STUDY

A 60-year-old female was admitted with worsening shortness of breath and a nonproductive cough for 4 months. Her past medical history was significant for Crohn's disease and psoriatic arthritis that was previously managed with adalimumab and switched to ustekinumab 2 months before symptoms. Initial diagnostic workup showed 10% peripheral eosinophilia and a CT chest showed numerous 5 mm nodules scattered throughout the lungs along with some peripheral reticulations. Her BAL fluid analysis showed abnormally high eosinophil count (67%), greatly limiting her potential diagnoses to eosinophilic pneumonia, EGPA, and tropical pulmonary eosinophilia (TPE). AEP typically causes more severe disease with a rapid onset, and there was low suspicion for TPE based on history, leaving EGPA and CEP. Based on her negative autoimmune serology, a negative biopsy of the nasal mucosa (no vasculitis/granulomata or eosinophils), and negative infectious workup, the patient was diagnosed with CEP secondary to ustekinumab and the drug was stopped. She was started on high dose prednisone and after a prolonged taper over 5 months, her symptoms and nodules and reticulations on her CT scan resolved.

DISCUSSION

This case exemplifies the importance of identifying drug-induced lung diseases which in many cases might not have a strong temporal association with the symptom onset. It also highlights that some drugs owing to their long elimination half-time can remain in the system for a prolonged period and continues to cause symptoms despite their cessation and require prolonged treatment and reassurance.

CONCLUSION

The association of eosinophilic pneumonia with ustekinumab, a drug used in the treatment of psoriasis and other autoimmune diseases, is rare and there is a paucity of literature regarding this association.

A Characteristic Chest Radiographic Pattern in the Setting of the COVID-19 Pandemic

PURPOSE

To determine the utility of chest radiography in aiding clinical diagnosis of coronavirus disease 2019 (COVID-19) utilizing reverse-transcription polymerase chain reaction (RT-PCR) as the standard of comparison.

MATERIALS AND METHODS

A retrospective study was performed of persons under investigation for COVID-19 presenting to this institution during the exponential growth phase of the COVID-19 outbreak in New Orleans (March 13-25, 2020). Three hundred seventy-six in-hospital chest radiographic examinations for 366 individual patients were reviewed along with concurrent RT-PCR tests. Two experienced radiologists categorized each chest radiograph as characteristic, nonspecific, or negative in appearance for COVID-19, utilizing well-documented COVID-19 imaging patterns. Chest radiograph categorization was compared against RT-PCR results to determine the utility of chest radiography in diagnosing COVID-19.

RESULTS

Of the 366 patients, the study consisted of 178 male (49%) and 188 female (51%) patients with a mean age of 52.7 years (range, 17 to 98 years). Of the 376 chest radiographic examinations, 37 (10%) exhibited the characteristic COVID-19 appearance; 215 (57%) exhibited the nonspecific appearance; and 124 (33%) were considered negative for a pulmonary abnormality. Of the 376 RT-PCR tests evaluated, 200 (53%) were positive and 176 (47%) were negative. RT-PCR tests took an average of 2.5 days ± 0.7 to provide results. Sensitivity and specificity for correctly identifying COVID-19 with a characteristic chest radiographic pattern was 15.5% (31/200) and 96.6% (170/176), with a positive predictive value and negative predictive value of 83.8% (31/37) and 50.1% (170/339), respectively.

CONCLUSION

The presence of patchy and/or confluent, bandlike ground-glass opacity or consolidation in a peripheral and mid to lower lung zone distribution on a chest radiograph obtained in the setting of pandemic COVID-19 was highly suggestive of severe acute respiratory syndrome coronavirus 2 infection and should be used in conjunction with clinical judgment to make a diagnosis.© RSNA, 2020.

[Radiological manifestations of pulmonary diseases in COVID-19]

CLINICAL ISSUE

Since its emergence in late 2019, the disease caused by the novel coronavirus, termed COVID-19, has been declared a pandemic by the World Health Organization. Reference standard for the diagnosis of COVID-19 is a positive reverse transcription polymerase chain reaction (RT-PCR) test. While the RT-PCR shows a high specificity, its sensitivity depends on the duration of symptoms, viral load, quality of the sample, and the assay used.

STANDARD RADIOLOGICAL METHODS

Chest radiography and computed tomography (CT) of the chest are the imaging modalities primarily used for assessment of the lung manifestations, extent, and complications of COVID-19 pneumonia.

PERFORMANCE

Sensitivity and specificity of chest radiography is low. While sensitivity of CT for detecting COVID-19 pneumonia is high-averaging around 90%-its specificity is low-between 25 and 33%.

PRACTICAL RECOMMENDATIONS

Indications for imaging in patients with suspected or diagnosed COVID-19 infection should be carefully considered to minimize the risk of infection for medical personnel and other patients. Imaging, particularly CT, can assess disease extent, complications, and differential diagnoses. COVID-19 pneumonia typically presents with bilateral, subpleural areas of ground glass opacifications with or without consolidations. During the course of the disease features resembling organizing pneumonia can occur. Follow-up examinations after recovery from COVID-19 pneumonia should focus on fibrotic changes of the lung parenchyma.

Practical guide for pediatric pulmonologists on imaging management of pediatric patients with COVID-19

Understanding of coronavirus disease 2019 is rapidly evolving with new articles on the subject daily. This flood of articles can be overwhelming for busy practicing clinicians looking for key pieces of information that can be applied in daily practice. This review article synthesizes the reported imaging findings in pediatric Coronavirus disease 2019 (COVID-19) across the literature, offers imaging differential diagnostic considerations and useful radiographic features to help differentiate these entities from COVID-19, and provides recommendations for requesting imaging studies to evaluate suspected cases of pediatric COVID-19.

The role of HRCT in Tropical Pulmonary Eosinophilia

PURPOSE

To determine the pattern of pulmonary involvement in clinically confirmed patients of tropical pulmonary eosinophilia (TPE).

METHOD

An observational study on 13 patients with clinically confirmed TPE was performed to determine the CT scan appearances.

RESULTS

The predominant CT scan finding is the presence widespread ill-defined bronchocentric nodules, which need to be differentiated from other conditions.

CONCLUSION

The pattern of lung involvement on a CT scan can give a clue to the diagnosis of TPE in the correct clinical context. Radiologists in tropical countries should have a high index of suspicion for this diagnosis when reading scans showing widespread ill-defined bronchocentric nodules.

Chronic Eosinophilic Pneumonia in an Airbrush Painter With Poor Response to Systemic Steroids

Airbrush paints contain low-molecular-weight chemicals that can cause occupational asthma, respiratory sensitization, and hypersensitivity pneumonitis; however, its relationship to chronic eosinophilic pneumonia (CEP) has never been reported. In this article, we are presenting a unique association between CEP and prolonged exposure to acrylic airbrush paints. Unlike the vast majority of CEP patients who exhibit an excellent response to systemic steroids, our patient did not respond to systemic steroids. We believe that his prolonged exposure to airbrush paints and the evolution of organizing pneumonia might have contributed to the unsatisfactory response to systemic steroids, prolonged hypoxia, and the overall worse prognosis. There are no current data that correlate acrylic paints to the development of CEP; our report is the first to introduce a probe to further investigate this association.

Noninfectious Granulomatous Diseases of the Chest

Granulomas are pathologically defined as focal aggregations of activated macrophages, Langerhans cells, and lymphocytes. Granulomas form in the lungs when the immune system barricades the substances it perceives as foreign but is unable to remove. Granulomas manifest with numerous imaging appearances in thoracic radiology, and their presence is a nonspecific finding. Granulomatous lung diseases comprise multiple entities with variable clinical manifestations and outcomes. Their imaging findings are rarely specific and can mimic malignancies, often triggering an extensive diagnostic workup. Radiologists must be familiar with the clinical manifestations and imaging findings of these entities to generate appropriate differential diagnoses. This review describes the imaging manifestations of various noninfectious, necrotizing, and nonnecrotizing granulomatous diseases that primarily affect the thorax. ©RSNA, 2020.

Chemotherapy-induced pulmonary complications in cancer: Significance of clinicoradiological correlation

Chemotherapy while revolutionizing cancer management by improving survival and quality of life; is also associated with several adverse effects. Lung is the most common organ affected in chemotherapy-related complications, due to either drug toxicity or more commonly due to infections caused by immunosuppression and less commonly due to immune-mediated injury. Radiology, when used in combination with clinical and lab data, can help reach the specific diagnosis or narrow down the differentials. The common radiological patterns of drug toxicity include pulmonary interstitial and airway infiltrates, diffuse alveolar damage, nonspecific interstitial pneumonia, eosinophilic pneumonia, cryptogenic organizing pneumonia, pulmonary hemorrhage, edema and hypertension. Cancer patients are immunosuppressed due to the underlying malignancy itself or due to therapy and are prone to a gamut of opportunistic infections including viral, bacterial, fungal and mycobacterial pathogens. Immune reconstitution inflammatory syndrome (IRIS), a well-known complication in HIV, is now being increasingly recognized in non-HIV patients with immunosuppression. Engraftment syndrome is specifically seen following hematopoietic stem cell transplant during neutrophil recovery phase. Pulmonary involvement is frequent, causing a radiological picture of noncardiogenic pulmonary edema. Thus, radiology in combination with clinical background and lab parameters helps in detecting and differentiating various causes of pulmonary complications. This approach can help alter potentially toxic treatment and initiate early treatment depending on the diagnosis.

Chronic airspace disease: Review of the causes and key computed tomography findings

Chronic airspace diseases are commonly encountered by chest, body or general radiologists in everyday practice. Even though there is significant overlap in the imaging findings of different causes of chronic airspace disease, some key clinical, laboratory and imaging findings can be used to guide the radiologist to the correct diagnosis. The goal of this article is to review and compare these features.

International Expert Consensus Statement on Chest Imaging in Pediatric COVID-19 Patient Management: Imaging Findings, Imaging Study Reporting, and Imaging Study Recommendations

Coronavirus disease 2019 (COVID-19) has quickly spread since it was first detected in December 2019 and has evolved into a global pandemic with over 1.7 million confirmed cases in over 200 countries around the world at the time this document is being prepared. Owing to the novel nature of the virus and the rapidly evolving understanding of the disease, there is a great deal of uncertainty surrounding the diagnosis and management of COVID-19 pneumonia in pediatric patients. Chest imaging plays an important role in the evaluation of pediatric patients with COVID-19; however, there is currently little information available describing imaging manifestations of COVID-19 in pediatric patients and even less information discussing the utilization of imaging studies in pediatric patients. To specifically address these concerns, a group of international experts in pediatric thoracic imaging from five continents convened to create a consensus statement describing the imaging manifestations of COVID-19 in the pediatric population, discussing the potential utility of structured reporting during the COVID-19 pandemic, and generating consensus recommendations for utilization of chest radiographs and CT in the evaluation of pediatric patients with COVID-19. The results were compiled into two structured reporting algorithms (one for chest radiographs and one for chest CT) and eight consensus recommendations for the utilization of chest imaging in pediatric COVID-19 infection. © RSNA, 2020.

Pictorial Review of Thoracic Parasitic Diseases: A Radiologic Guide

Parasitoses are infectious diseases of global distribution, with predominance in areas of poor sanitation. Parasites cause damage through direct tissue injury and the inflammatory response generated by their migration and establishment in various organs. Thoracic involvement by parasitic disease can generate both specific and nonspecific clinical, laboratorial, and radiologic manifestations, which often makes their diagnosis challenging. The correct diagnosis is crucial for definition of treatment, which sometimes requires rapid intervention. Based on a literature review of the last few decades, this article aimed to characterize the main radiologic findings related to thoracic manifestations of parasitic diseases, correlating them with radiographic and tomographic images of patients with confirmed diagnosis of such pathologies. The included parasitic diseases are malaria, Chagas disease, toxoplasmosis, amoebiasis, ascariasis, toxocariasis, strongyloidiasis, dirofilariasis, cysticercosis, echinococcosis, schistosomiasis, and paragonimiasis.

Pneumonia

This chapter describes the imaging patterns of pneumonia (lobar, lobular, interstitial, round) and its complications (abscess, empyema, pneumatocele); bacterial, fungal, and viral infections; and the many manifestations of pulmonary tuberculosis.

Acute Lung Injury and Non-infectious Pneumonias

Lung injury can occur secondary to a myriad of causes, including infection, immunologic disorders, drug toxicity, or inhalational injury among others. Although the list of causative agents is long, the lung’s response to injury is limited resulting in similar patterns of disease irrespective of the cause. From a pathological perspective, acute lung injury refers to a group of entities that present with acute or subacute disease. These conditions are characterized by particular histological patterns including diffuse alveolar damage, acute fibrinous and organizing pneumonia, organizing pneumonia, and eosinophilic pneumonia and clinically correspond to the varying degrees of acute respiratory distress syndrome (Patel et al, Chest 125:197–202, 2004; Beasley et al, Arch Pathol Lab Med 126:1064–1070, 2002; Avecillas et al, Clin Chest Med 27:549–557, 2006; Cottin, Cordier, Semin Respir Crit Care Med 33:462–475, 2012; Ferguson et al, Intensive Care Med 38:1573–1582, 2012). In most cases, the underlying cause will not be apparent from the histological findings requiring close correlation with clinical history and laboratory findings to determine the etiology. Nevertheless, careful search for infectious organisms with application of histochemical and immunohistochemical stains should be performed in all cases in order to identify cases that benefit from more targeted treatment.

Infectious Lung Disease

Infectious diseases are one of the main causes of morbidity and mortality worldwide. With new pathogens continuously emerging, known infectious diseases reemerging, increasing microbial resistance to antimicrobial agents, global environmental change, ease of world travel, and an increasing immunosuppressed population, recognition of infectious diseases plays an ever-important role in surgical pathology. This becomes particularly significant in cases where infectious disease is not suspected clinically and the initial diagnostic workup fails to include samples for culture. As such, it is not uncommon that a lung biopsy becomes the only material available in the diagnostic process of an infectious disease. Once the infectious nature of the pathological process is established, careful search for the causative agent is advised. This can often be achieved by examination of the hematoxylin and eosin-stained sections alone as many organisms or their cytopathic effects are visible on routine staining. However, ancillary studies such as histochemical stains, immunohistochemistry, in situ hybridization, or molecular techniques may be needed to identify the organism in tissue sections or for further characterization, such as speciation.

Severe mononeuritis multiplex in a patient with eosinophilic granulomatosis with polyangiitis

Eosinophilic granulomatosis with polyangiitis (EGPA) is a systemic vasculitis characterised by bronchial asthma, hypereosinophilia, and systemic vasculitis. History of asthma with blood eosinophilia and multiorgan involvement are the important clues to suspect EGPA. In the original paper by Churg and Strauss cardiac, gastrointestinal tract, renal, and neurological involvement were noted more frequently. The pattern of neurological involvement may be mononeuritis multiplex, and symmetrical and asymmetrical polyneuropathy. Mononeuritis multiplex was present in 78.1% while cranial nerves were involved in only 4.1% of cases. Glucocorticosteroids and immunosuppressants, especially cyclophosphamide, have considerably improved the prognosis and overall survival rates in patients with systemic vasculitis, including eosinophilic granulomatosis with polyangiitis. The authors present a clinical case of eosinophilic granulomatosis with polyangiitis with severe mononeuritis multiplex. The case reflects the successful application of a cyclophosphamide regime as a remission inducer.

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.

Transient Asymptomatic Pulmonary Opacities During Osimertinib Treatment and its Clinical Implication

INTRODUCTION

Osimertinib is an oral, potent, irreversible third-generation EGFR tyrosine kinase inhibitor approved for the treatment of T790M-positive NSCLC patients who failed first- or second-generation EGFR tyrosine kinase inhibitors. Interstitial lung disease (ILD) is a rare complication with osimertinib, occurring in 1% to 3% of patients. Recently, a relatively high incidence of transient asymptomatic pulmonary opacities (TAPOs), which are different from ILD, has been described. However, its clinical implication has not been fully determined yet.

METHODS

We retrospectively analyzed 74 EGFR T790M mutant NSCLC patients treated with osimertinib. Serial computed tomographic findings were reviewed by a thoracic radiologist independently, and TAPO was classified according to its radiologic pattern. We also analyzed the correlation of TAPO with clinical outcomes.

RESULTS

Among 74 patients, TAPOs were found in 15 (20.3%). The median time to TAPO development was 24.0 weeks (range, 1 to 72 weeks) and the median duration of TAPO was 6.0 weeks (range, 5 to 24 weeks) during continued osimertinib treatment. The most common radiological patterns of TAPO include cryptogenic organizing pneumonia and/or simple eosinophilic pneumonia. There was no significant difference in patient characteristics between TAPO-positive and -negative groups. The duration of exposure to osimertinib was significantly longer in TAPO-positive than -negative groups (25.0 months versus 13.0 months, p = 0.009). The median progression-free survival and the median overall survival was numerically longer in TAPO-positive than -negative groups (22 months versus 15 months for progression-free survival, p = 0.293; 37 months versus 24 months for overall survival, p = 0.059), respectively.

CONCLUSIONS

TAPOs are frequently observed with osimertinib treatment and may be mistaken for isolated pulmonary progression or drug-induced ILD. Given the lack of serious clinical deterioration, it is reasonable to continue osimertinib with regular computed tomographic-scan follow-up. For further clinical validation of TAPOs, long-term follow-up and large studies are warranted.

Idiopathic acute eosinophilic pneumonia

A 44-year-old asthmatic male patient presented to the health centre with a 3-week history of coryzal symptoms, persistent productive sputum and shortness of breath. The chest X-ray (CXR) revealed symmetrical, perihilar airspace shadowed with peribronchial cuffing and bilateral reticular markings. The patient did not improve despite treatment, and hence a high resolution CT (HRCT) scan of the thorax was recommended. The HRCT showed smooth interlobular septal thickening, central perihilar soft tissue thickening and patches of ground glass changes. Both the CXR and HRCT findings, along with the symptoms and eosinophilia counts, were suggestive of idiopathic acute eosinophilic pneumonia (IAEP) which was confirmed on bronchoalveolar lavage. The patient was successfully treated with steroids. This case highlights the symptoms, diagnosis, management and treatment of IAEP. A rapid diagnosis of this rare disease is essential since it can be completely cured with correct management but can be fatal if left untreated. Once properly treated, this disease does not recur.

Approach to Peribronchovascular Disease on CT

Diseases that are predominantly peribronchovascular in distribution on computed tomography by definition involve the bronchi, adjacent vasculature, and associated lymphatics involving the central or axial lung interstitium. An understanding of diseases that can present with focal peribronchovascular findings is useful for establishing diagnoses and guiding patient management. This review will cover clinical and imaging features that may assist in differentiating amongst the various causes of primarily peribronchovascular disease.

A Woman with Asthma and Peripheral Ground-Glass Opacities

Eosinophilic lung disease is a heterogeneous group of disorders that reveal eosinophil involved lung tissue often in patients with asthma or atopy. Classification and diagnostic criteria of eosinophilic lung disease are not well-established; however, peripheral ground-glass opacity is typical on chest computed tomography. Another etiology of this same radiographic finding reported in the literature is silicone embolism syndrome. Here, we present a 43-year-old female with poorly controlled severe persistent asthma presenting with difficulty breathing. Computed tomography showed peripherally dominant ground-glass opacity. Peripheral blood, bronchoalveolar lavage fluid analysis, and transbronchial biopsy did not find eosinophilia. Serial bronchoalveolar lavage of the demonstrated increasingly blood-tinged fluid. The patient required mechanical ventilation upon admission. After further questioning the patient revealed that she had frequently received injectable cosmetics at non-licensed establishments. Initially, due to past medical history, presentation, and radiographic findings, eosinophilic pneumonia was suspected. However, after a review of the patient's social history and risk factors, silicone embolisms syndrome became a likely diagnosis. The patient had good clinical response to high dose steroid therapy.

Elevated Levels of Intelectin-1, a Pathogen-binding Lectin, in the BAL Fluid of Patients with Chronic Eosinophilic Pneumonia and Hypersensitivity Pneumonitis

Objective Human intelectin-1 (hITLN-1) binds to galactofuranosyl residues, which are present in the microbial cell wall, but which are absent in mammalian tissues, and has been suggested to play an immunological role against microorganisms. However, the involvement of hITLN-1 in the pathogenesis of diffuse pulmonary diseases remains unknown. The aim of this study was to compare the hITLN-1 concentrations in the bronchoalveolar lavage (BAL) fluid of patients with diffuse pulmonary diseases. Methods The cell components and concentrations of hITLN-1 were analyzed in the BAL fluid of 8 patients with idiopathic chronic eosinophilic pneumonia (ICEP), 3 patients with drug-induced eosinophilic pneumonia, 4 patients with hypersensitivity pneumonitis (HP), 11 patients with sarcoidosis, 9 patients with cryptogenic organizing pneumonia, and 5 patients with idiopathic fibrosing interstitial pneumonia (fibrosing nonspecific interstitial pneumonia or usual interstitial pneumonia). Results The hITLN-1 concentrations in the BAL fluid of patients with ICEP and HP were higher than in those with other diseases. In the ICEP group, no significant difference was observed in the hITLN-1 concentrations of patients with or without a history of bronchial asthma. Conclusion The results of the present study suggest that hITLN-1 may be involved in the pathogenesis of ICEP and HP, and that an increase in the hITLN-1 concentration in the BAL fluid may represent a new biomarker for these diseases.

Chronic Airspace Diseases

Airspace disease can be acute or chronic and commonly present as consolidation or ground-glass opacity on chest imaging. Consolidation or ground-glass opacity occurs when alveolar air is replaced by fluid, pus, blood, cells, or other material. Airspace disease is considered chronic when it persists beyond 4-6 weeks after treatment. These can be secondary to certain infectious, inflammatory, or neoplastic conditions. Computed tomography of the chest is usually performed in this set of patients to identify characteristic imaging findings. Familiarity with the differential diagnosis and characteristic imaging findings for chronic airspace disease is very important for guiding patient's management in a timely fashion.

Pathologic features of smoking-related lung diseases, with emphasis on smoking-related interstitial fibrosis and a consideration of differential diagnoses

Smoking-related interstitial fibrosis (SRIF) is frequently-seen and morphologically-distinctive finding in the lung tissue of cigarette smokers. It can be distinguished histologically from the idiopathic interstitial pneumonias and other causes of pulmonary interstitial fibrosis. SRIF is typified by dense thickening of the alveolar septa by thick collagen bundles with a hyalinized appearance, with the common admixture of bands of hyperplastic smooth muscle. Concomitant inflammation is minimal. SRIF predominates in the subpleural and centrilobular parenchyma, and is usually accompanied by the changes of centrilobular emphysema and respiratory bronchiolitis. Most patients with SRIF do not have clinical symptoms of the condition. This article reviews the pathologic features of SRIF and compares them with the appearances of other interstitial lung diseases, some of which are also related to cigarette smoking. Acute eosinophilic pneumonia is another lung disease that has an association with smoking, and its clinicopathologic features are considered here as well.

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.

A case of allergic bronchopulmonary aspergillosis successfully treated with mepolizumab

Background

Allergic bronchopulmonary aspergillosis (ABPA) is an allergic pulmonary disease comprising a complex hypersensitivity reaction to Aspergillus fumigatus. Clinical features of ABPA are wheezing, mucoid impaction, and pulmonary infiltrates. Oral corticosteroids and anti-fungal agents are standard therapy for ABPA, but long-term use of systemic corticosteroids often causes serious side effects.

Case presentation

A 64-year-old woman was diagnosed with ABPA based on a history of bronchial asthma (from 40 years of age), elevated total IgE, the presence of serum precipitating antibodies and elevated specific IgE antibody to A. fumigatus, and pulmonary infiltration. Bronchoscopy showed eosinophilic mucoid impaction. Systemic corticosteroid therapy was initiated, and her symptoms disappeared. Peripheral eosinophilia and pulmonary infiltration recurred five months after cessation of corticosteroid treatment. Systemic corticosteroids were re-initiated and itraconazole was added as an anti-fungal agent. The patient was free of corticosteroids, aside from treatment with a short course of systemic corticosteroids for asthma exacerbation, and clinically stable with itraconazole and asthma treatments for 3 years. In 2017, she experienced significant deterioration. Laboratory examination revealed marked eosinophilia (3017/μL) and a chest computed tomography (CT) scan demonstrated pulmonary infiltration in the left upper lobe and mucoid impaction in both lower lobes. The patient was treated with high-dose inhaled corticosteroid/long-acting beta-agonist, a long-acting muscarinic antagonist, a leukotriene receptor antagonist, and theophylline; spirometry revealed a forced expiratory volume in 1 s (FEV₁) of 1.01 L. An uncontrolled asthma state was indicated by an Asthma Control Test (ACT) score of 18. Mepolizumab, 100 mg every 4 weeks, was initiated for the treatment of severe bronchial asthma with ABPA exacerbation. Bronchial asthma symptoms dramatically improved, and ACT score increased to 24, by 4 weeks after mepolizumab treatment. Peripheral eosinophil count decreased to 174/μL. Spirometry revealed improvement of lung function (FEV₁: 1.28 L). A chest CT scan demonstrated the disappearance of pulmonary infiltration and mucoid impaction.

Conclusions

To our knowledge, this is the first case of ABPA to be treated with mepolizumab. Dramatic improvements were observed in symptoms, lung function, peripheral eosinophil counts, and chest images. Mepolizumab could serve as an alternative treatment with the potential to provide a systemic corticosteroid-sparing effect.

Imaging of Asthma

Asthma is one of the most common diseases of the lung. Asthma manifests with common, although often subjective and nonspecific, imaging features at radiography and high-resolution computed tomography. The primary role of imaging is not to make a diagnosis of asthma but to identify complications, such as allergic bronchopulmonary aspergillosis, or mimics of asthma, such as hypersensitivity pneumonitis. This article reviews the imaging features of asthma as well as common complications and mimics.

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.

Pathology of Antineutrophil Cytoplasmic Antibody–Associated Pulmonary and Renal Disease

Context.—Antineutrophil cytoplasmic antibody (ANCA)–associated vasculitis commonly presents with pulmonary and renal involvement that may present diagnostic challenges.

Objectives.—To highlight the updates in the classification of small vessel vasculitis, present the patterns of pulmonary and renal pathology in which ANCA-associated vasculitis is included in the differential diagnosis, analyze the screening and specific antineutrophil cytoplasmic antibody testing methods in the clinical laboratory, compare and contrast the 3 major ANCA-associated vasculitis diseases, and review the pathophysiologic mechanisms of tissue injury in this setting.

Data Sources.—Data are derived from published literature and clinical experience.

Conclusions.—Although rare, ANCA-associated vasculitis diseases are often considered in the differential diagnosis of many pathologic patterns of pulmonary and renal disease. Histopathologic diagnosis of specific entities in this context nearly always requires correlation of the pathology with clinical and serologic data.

Cardiopulmonary and Gastrointestinal Manifestations of Eosinophil- associated Diseases and Idiopathic Hypereosinophilic Syndromes: Multimodality Imaging Approach

Eosinophil-associated diseases (EADs) are a diverse group of disorders characterized by an increase in circulating or tissue eosinophils. Cardiopulmonary and gastrointestinal system involvement can be due to primary EAD with no known cause or can be secondary to known systemic disease. The cardiopulmonary spectrum of EADs comprises simple pulmonary eosinophilia, acute eosinophilic pneumonia, chronic eosinophilic pneumonia, Churg-Strauss syndrome, allergic bronchopulmonary aspergillosis, bronchocentric granulomatosis, parasitic infections, and idiopathic hypereosinophilic syndrome. Eosinophilic gastrointestinal disorders include eosinophilic esophagitis, eosinophilic gastroenteritis, and eosinophilic colitis. Diagnosis is often challenging and requires a combination of clinical and imaging features along with laboratory findings. The absolute eosinophil count in peripheral blood and the percentage of eosinophils in bronchoalveolar lavage fluid are crucial in evaluation of various eosinophilic lung diseases. Although chest radiography is the initial imaging modality used in suspected cases of pulmonary EAD, multidetector computed tomography may demonstrate more characteristic pulmonary patterns, nodules, and subtle parenchymal abnormalities. Barium esophagography is used to assess mucosal abnormalities and the length and diameter of esophageal strictures. Magnetic resonance imaging is superior in providing valuable information in select patients, especially in evaluation of cardiac and gastrointestinal system involvement. Many patients require a multimodality imaging approach to enable diagnosis, guide treatment, and assess treatment response. Knowledge of the clinical features and imaging findings of the spectrum of EADs involving the lungs, heart, and gastrointestinal tract permits optimal patient care.

Arterial Carboxyhemoglobin Measurement Is Useful for Evaluating Pulmonary Inflammation in Subjects with Interstitial Lung Disease

Objective The arterial concentration of carboxyhemoglobin (CO-Hb) in subjects with inflammatory pulmonary disease is higher than that in healthy individuals. We retrospectively analyzed the relationship between the CO-Hb concentration and established markers of disease severity in subjects with interstitial lung disease (ILD). Methods The CO-Hb concentration was measured in subjects with newly diagnosed or untreated ILD and the relationships between the CO-Hb concentration and the serum biomarker levels, lung function, high-resolution CT (HRCT) findings, and the uptake in gallium-67 (⁶⁷Ga) scintigraphy were evaluated. Results Eighty-one non-smoking subjects were studied (mean age, 67 years). Among these subjects, (A) 17 had stable idiopathic pulmonary fibrosis (IPF), (B) 9 had an acute exacerbation of IPF, (C) 44 had stable non-IPF, and (D) 11 had an exacerbation of non-IPF. The CO-Hb concentrations of these subjects were (A) 1.5±0.5%, (B) 2.1±0.5%, (C) 1.2±0.4%, and (D) 1.7±0.5%. The CO-Hb concentration was positively correlated with the serum levels of surfactant protein (SP)-A (r=0.38), SP-D (r=0.39), and the inflammation index (calculated from HRCT; r=0.57) and was negatively correlated with the partial pressure of oxygen in the arterial blood (r=-0.56) and the predicted diffusion capacity of carbon monoxide (r=-0.61). The CO-Hb concentrations in subjects with a negative heart sign on ⁶⁷Ga scintigraphy were higher than those in subjects without a negative heart sign (1.4±0.5% vs. 1.1±0.3%, p=0.018). Conclusion The CO-Hb levels of subjects with ILD were increased, particularly during an exacerbation, and were correlated with the parameters that reflect pulmonary inflammation.

[Noninfectious differential diagnoses of pneumonia]

Hintergrund

Bei der Verdachtsdiagnose Pneumonie sind die Kombination aus typischer Klinik, Labor und der Nachweis einer Verdichtung in der Röntgenthoraxaufnahme in der Regel diagnostisch und es wird umgehend mit der Therapie begonnen. Studien haben jedoch gezeigt, dass bei bis zu 5 % der Patienten mit Erstverdacht auf Pneumonie eine andere (pulmonale) Erkrankung zugrunde liegt. Ein frühzeitiges Erkennen und eine Differenzierung von Erkrankungen, die eine Pneumonie vortäuschen, sind für die weitere Behandlung essenziell.

Fragestellung

Übersicht über wesentliche nichtinfektiöse Differenzialdiagnosen der Pneumonie.

Material und Methode

Es wurde eine Literaturrecherche durchgeführt.

Ergebnisse

Da krankhafte Lungenveränderungen oft ähnliche Bilder hervorrufen und anhand der Röntgenthoraxaufnahme oder der CT-Untersuchung nicht zwischen Blut, Transsudat, Exsudat und Zellen differenziert werden kann, ist eine systematische Herangehensweise wesentlich für die Differenzialdiagnose. Dazu werden der zeitliche Verlauf, das prädominante Muster, die Verteilung der Veränderungen, zusätzliche Befunde und die Klinik berücksichtigt.

The Role and Immunobiology of Eosinophils in the Respiratory System: a Comprehensive Review

The eosinophil is a fully delineated granulocyte that disseminates throughout the bloodstream to end-organs after complete maturation in the bone marrow. While the presence of eosinophils is not uncommon even in healthy individuals, these granulocytes play a central role in inflammation and allergic processes. Normally appearing in smaller numbers, higher levels of eosinophils in the peripheral blood or certain tissues typically signal a pathologic process. Eosinophils confer a beneficial effect on the host by enhancing immunity against molds and viruses. However, tissue-specific elevation of eosinophils, particularly in the respiratory system, can cause a variety of short-term symptoms and may lead to long-term sequelae. Eosinophils often play a role in more commonly encountered disease processes, such as asthma and allergic responses in the upper respiratory tract. They are also integral in the pathology of less common diseases including eosinophilic pneumonia, allergic bronchopulmonary aspergillosis, hypersensitivity pneumonitis, and drug reaction with eosinophilia and systemic symptoms. They can be seen in neoplastic disorders or occupational exposures as well. The involvement of eosinophils in pulmonary disease processes can affect the method of diagnosis and the selection of treatment modalities. By analyzing the complex interaction between the eosinophil and its environment, which includes signaling molecules and tissues, different therapies have been discovered and created in order to target disease processes at a cellular level. Innovative treatments such as mepolizumab and benralizumab will be discussed. The purpose of this article is to further explore the topic of eosinophilic presence, activity, and pathology in the respiratory tract, as well as discuss current and future treatment options through a detailed literature review.

Eosinophils in COPD Exacerbations Are Associated With Increased Readmissions

BACKGROUND

A subset of patients with COPD demonstrates eosinophilic inflammation either in their sputum or blood. Previous studies regarding the association between increased blood eosinophil levels and poor readmission outcomes are conflicting. The goal of this study was to investigate outcomes following severe COPD exacerbations in patients with higher blood eosinophil levels.

METHODS

With an observational study design, data on hospitalizations for severe COPD exacerbation were retrospectively gathered. Patient health data previous to and up to 1 year following the index hospitalization were included. Patients were stratified into the eosinophilic group if the blood eosinophil level on admission was ≥ 200 cells/μL and/or ≥ 2% of the total WBC count. Clinical outcomes were 12-month COPD-related readmission, 12-month all-cause readmission, length of stay, and time to COPD-related readmission. These outcomes were analyzed by using logistic, negative binomial, and Cox regression models.

RESULTS

A total of 167 patients were included; 55 had eosinophilia. Eosinophilia was associated with an increased risk of 12-month COPD-related readmission (OR, 3.59 [95% CI, 1.65-7.82]; P = .0013), an increased risk of 12-month all-cause readmission (2.32 [95% CI, 1.10-4.92]; P = .0277), and a shorter time to first COPD-related readmission (hazard ratio, 2.74 [1.56-4.83]; P = .0005). The length of stay was not statistically different between eosinophilic and noneosinophilic patients. Sensitivity analyses using different eosinophilia definitions revealed a proportional increase in effect size with increasing eosinophil cell count definitions for predicting 12-month readmissions.

CONCLUSIONS

Blood eosinophil levels can be used as a biomarker in severe COPD exacerbations for predicting higher readmission rates.

Pulmonary infiltration with eosinophilia complicated with mucosa-associated lymphoid tissue lymphoma: A case report

Tissue eosinophilia is rarely observed in cases of non-Hodgkin's lymphoma of B cell origin. The present study describes a rare case of mucosa-associated lymphoid tissue (MALT) lymphoma, which was initially misdiagnosed as eosinophilic pneumonia. The initial diagnosis was formed based on the results of chest radiography, peripheral eosinophilia tests and bronchoalveolar lavage, and the clinical course of the patient. Following administration of methylprednisolone (40 mg/day) for 4 days and oral administration of prednisolone (30 mg/day), the clinical course rapidly improved and the eosinophil count immediately decreased a to normal level. However, abnormal shadows observed on computed tomography (CT) scans of the chest did not diminish. At 6 months after the initiation of treatment, CT-guided percutaneous lung biopsy was performed, and a final diagnosis of primary pulmonary mucosa-associated lymphoid tissue lymphoma was made based on immunohistochemical examination. Primary lung MALT lymphoma remains a rare entity, with an indolent course and a reasonably favorable prognosis, whose diagnosis may be challenging.

Imaging of Diseases of the Large Airways

Imaging of the large airways is key to the diagnosis and management of a wide variety of congenital, infectious, malignant, and inflammatory diseases. Involvement can be focal, regional, or diffuse, and abnormalities can take the form of masses, thickening, narrowing, enlargement, or a combination of patterns. Recognition of the typical morphologies, locations, and distributions of large airways disease is central to an accurate imaging differential diagnosis.

Chronic eosinophilic pneumonia presenting with ipsilateral pleural effusion: a case report

BACKGROUND

Chronic eosinophilic pneumonia is a rare idiopathic interstitial lung disease. The nearly pathognomonic radiographic finding is the peripheral distribution of alveolar opacities. Pleural effusions are rarely seen. We report a case of chronic eosinophilic pneumonia with transudative eosinophilic pleural effusion.

CASE PRESENTATION

A 57-year-old Hispanic woman, a nonsmoker with a history of controlled asthma, presented to the hospital with unresolving pneumonia despite three rounds of antibiotics over a 2-month period. She was later diagnosed with chronic eosinophilic pneumonia based on the presence of peripheral blood eosinophilia, the peripheral distribution of alveolar infiltrates on chest radiograph, and a lung parenchymal biopsy with infiltrates of eosinophils. Upon presentation, our patient had a right-sided moderate-sized pleural effusion. The pleural fluid profile was consistent with a transudative effusion with eosinophil predominance. Our patient responded promptly to oral corticosteroid treatment in a few days. The pulmonary infiltrates and pleural effusion subsided on a 1-month follow-up chest radiograph after starting corticosteroid treatment.

CONCLUSIONS

We report the first case of chronic eosinophilic pneumonia presenting with pneumonia with ipsilateral transudative eosinophilic pleural effusion. Like other cases of chronic eosinophilic pneumonia, early recognition and diagnosis is essential and prompt treatment with corticosteroids is the mainstay of therapy. Pleural effusion resolved without the further need for therapeutic thoracentesis.