Transient wheeze. Eosinophilic bronchobronchiolitis in acute eosinophilic pneumonia

Idiopathic Chronic Eosinophilic Pneumonia Evolving to Pulmonary Fibrosis: A Retrospective Analysis

BACKGROUND

Patients with idiopathic chronic eosinophilic pneumonia (ICEP) may have pulmonary fibrosis.

OBJECTIVES

To investigate the predictors of pulmonary fibrosis in ICEP, to describe the timeline of pulmonary fibrosis after ICEP diagnosis, and to detail the radiologic pattern of fibrosis.

METHODS

A retrospective computer-assisted search was performed to identify patients with ICEP seen at Mayo Clinic in Rochester, Minnesota, from January 1, 1997, through September 1, 2019. Patients with follow-up chest computed tomography (CT) beyond 12 months after the ICEP diagnosis were included in the study. Demographic, clinical, radiologic, and histopathologic characteristics were analyzed. Proportional hazards regression was used to assess the predictors of pulmonary fibrosis.

RESULTS

We identified 62 patients (mean [SD] age at ICEP diagnosis, 60 [13] years; female sex, 37 [60%]). Cough (87%) and shortness of breath (85%) were the most common presenting symptoms. Of patients, 27 (44%) had a history of smoking and 27 (44%) had a history of asthma. During follow-up, 23 patients (37%) had CT evidence of pulmonary fibrosis, of whom 16 patients (70%) had a CT pattern inconsistent with usual interstitial pneumonia. In 29% of the patients, the CT evidence of pulmonary fibrosis developed within 2 years after ICEP. Age and male sex were predictors of pulmonary fibrosis. Of note, a history of asthma decreased the likelihood of pulmonary fibrosis.

CONCLUSIONS

Development of pulmonary fibro-sis is not uncommon in patients with ICEP, especially older men, and is associated with increased risk of death.

Glucocorticoid therapy in respiratory illness: bench to bedside

Each year, hundreds of millions of individuals are affected by respiratory disease leading to approximately 4 million deaths. Most respiratory pathologies involve substantially dysregulated immune processes that either fail to resolve the underlying process or actively exacerbate the disease. Therefore, clinicians have long considered immune-modulating corticosteroids (CSs), particularly glucocorticoids (GCs), as a critical tool for management of a wide spectrum of respiratory conditions. However, the complex interplay between effectiveness, risks and side effects can lead to different results, depending on the disease in consideration. In this comprehensive review, we present a summary of the bench and the bedside evidence regarding GC treatment in a spectrum of respiratory illnesses. We first describe here the experimental evidence of GC effects in the distal airways and/or parenchyma, both in vitro and in disease-specific animal studies, then we evaluate the recent clinical evidence regarding GC treatment in over 20 respiratory pathologies. Overall, CS remain a critical tool in the management of respiratory illness, but their benefits are dependent on the underlying pathology and should be weighed against patient-specific risks.

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.

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.

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.

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.

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.

Eosinophilic Lung Diseases

Eosinophilic lung diseases especially comprise eosinophilic pneumonia or as the more transient Löffler syndrome, which is most often due to parasitic infections. The diagnosis of eosinophilic pneumonia is based on characteristic clinical-imaging features and the demonstration of alveolar eosinophilia, defined as at least 25% eosinophils at BAL. Peripheral blood eosinophilia is common but may be absent at presentation in idiopathic acute eosinophilic pneumonia, which may be misdiagnosed as severe infectious pneumonia. All possible causes of eosinophilia, including drug, toxin, fungus related etiologies, must be thoroughly investigated. Extrathoracic manifestations should raise the suspicion of eosinophilic granulomatosis with polyangiitis.

Idiopathic acute eosinophilic pneumonia: A retrospective case series and review of the literature

Introduction

Idiopathic acute eosinophilic pneumonia (AEP) is characterized by hypoxemia, pulmonary infiltrates and pulmonary eosinophilia. Data is limited and the purpose of this study is to better understand this disorder.

Methods

A search of the computerized patient records from January 1, 1997 to October 15, 2010 for patients with suspicion of “eosinophilic pneumonia” was conducted. Included patients were 18 years or older with an acute febrile illness, hypoxemia, diffuse pulmonary infiltrates on imaging, and pulmonary eosinophilia. Patients were excluded with other known causes of pulmonary eosinophilia.

Results

Of 195 patients with pulmonary eosinophilia, 8 patients had “definite” or “probable” and 4 patients had “possible” idiopathic AEP. Three patients were categorized as “probable” idiopathic AEP due to exceeding expected maximal 30-day symptom duration and/or a maximal recorded temperature less than 38 °C. Four patients were defined as “possible” idiopathic AEP given histories of polymyalgia rheumatica, eczema or allergic rhinitis. Of the 8 included patients, 63% were male with a median age of 53. Median duration of symptoms was 21 days. Median nadir oxygen saturation was 83%. Median eosinophil count on bronchoalveolar lavage was 36%. Two patients required intubation. Two patients were current smokers, one of whom had reported a change in smoking habits. All patients were treated with steroids (median of two months).

Conclusions

As diagnostic methods and pharmacologic knowledge improve, the number of patients meeting criteria for idiopathic AEP remains small. Much remains to be learned about this truly rare condition, and current criteria may exclude milder presentations of the disease.

Acute eosinophilic pneumonia

Acute eosinophilic pneumonia is a severe and rapidly progressive lung disease that can cause fatal respiratory failure. Since this disease exhibits totally different clinical features to other eosinophilic lung diseases (ELD), it is not difficult to distinguish it among other ELDs. However, this can be similar to other diseases causing acute respiratory distress syndrome or severe community-acquired pneumonia, so the diagnosis can be delayed. The cause of this disease in the majority of patients is unknown, even though some cases may be caused by smoke, other patients inhaled dust or drugs. The diagnosis is established by bronchoalveolar lavage. Treatment with corticosteroids shows a rapid and dramatic positive response without recurrence.

The definitive diagnostic process and successful treatment for ABPM caused by Schizophyllum commune: a report of two cases

BACKGROUND

Although mucoid impaction of the bronchi (MIB) is a well-known manifestation in allergic bronchopulmonary mycosis (ABPM), when unknown samples or plural eumycetes are cultured from bronchial materials, several problems are encountered which can affect the definitive diagnostic process or successful treatment.

CASE SUMMARY

The definitive diagnostic process of two patients [a 58-(Case 1) and a 70-(Case 2) year-old female] with MIB was: 1) to identify the existence of any allergic respiratory disorder, 2) to detect the fungi obtained from bronchial materials, with use of the 28S rDNA sequencing and analysis, 3) to investigate whether the detected fungus was a probable etiologic antigen, and 4) to make the final diagnosis based on the results of the inhalation examinations using the antigenic solution of the fungi. As a treatment strategy, bronchial toilet and low dose itraconazole therapy were planned according to the clinical manifestations of each patient.

DISCUSSION

The two patients with MIB were successfully diagnosed as ABPM caused by Schizophyllum commune (Sc-ABPM) accompanied with hyperattenuating mucoid impaction. The reliability of some allergological makers as a substitution for the bronchoprovocation test should be clarified in near future. Clinical manifestations demonstrated in our cases suggested that the allergic reaction such as eosinophilic bronchoalveolitis spreading around the mucus plug was a primary lesion underlying the Sc-ABPM. The success of the treatment for Sc-ABPM will be achieved by the strategy targeting to fundamental condition and by the control of the disease recurrence by means of effective environmental management.

Deterioration of asthma in a patient with diffuse panbronchiolitis (DPB) after macrolide therapy

Diffuse panbronchiolitis (DPB), an important cause of progressive obstructive lung disease in the Far East, is a distinctive sinobronchial syndrome with characteristic radiologic and histologic features. Asthma is a chronic inflammatory disease characterized by airway narrowing. The major inflammatory cells involved in the pathogenesis of asthma are type 2 helper T (Th2) cells, eosinophils, and mast cells. The authors' patient was diagnosed with DPB and asthma. Although macrolide therapy led to the disappearance of the radiologic abnormalities indicating centrilobular nodular lesions, the respiratory symptoms and pulmonary function worsened. Administration of inhaled corticosteroids improved the respiratory symptoms and pulmonary function. To the authors' knowledge, no case of DPB with asthma has been reported in the English-language literature.

Acute eosinophilic pneumonia: A case report and review of the literature

OBJECTIVES

Since its original description in 1989, clinicians have documented many cases of acute eosinophilic pneumonia (AEP), but information regarding the appropriate timing of diagnostic testing and treatment continues to be lacking. As a cause of respiratory failure in relatively young individuals, AEP is one of the few diagnoses that will often dramatically alter the intensivist's current therapy. Evidence for effective therapy is anecdotal and may even suggest that the traditional treatment with steroids offers limited benefit. This review uses a patient with AEP to emphasize certain aspects of this illness and discusses the current literature regarding its features, diagnosis, and treatment.

DATA SOURCES

A PubMed search from 1989 to 2008 was conducted using the search terms acute eosinophilic pneumonia, respiratory failure, eosinophilic lung disease, bronchoalveolar lavage, and smoking.

DATA EXTRACTION

Twenty-two articles were included in this review and ranged from case reports to randomized controlled trials. These studies demonstrate our current knowledge of this disease and, more importantly, emphasize areas in which we are lacking.

CONCLUSIONS

The diagnostic criteria and treatment of AEP is currently based on data from limited case series. Although these criteria are rigid, a wide variation in symptoms, diagnostic findings, and treatments reported further emphasizes our lack of knowledge regarding the pathophysiology of this illness. Important questions remain regarding this disease, including predisposing factors in patients with AEP and the benefit of treating with steroids.

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

Eosinophilic lung diseases are a diverse group of pulmonary disorders associated with peripheral or tissue eosinophilia. They are classified as eosinophilic lung diseases of unknown cause (simple pulmonary eosinophilia [SPE], acute eosinophilic pneumonia [AEP], chronic eosinophilic pneumonia [CEP], idiopathic hypereosinophilic syndrome [IHS]), eosinophilic lung diseases of known cause (allergic bronchopulmonary aspergillosis [ABPA], bronchocentric granulomatosis [BG], parasitic infections, drug reactions), and eosinophilic vasculitis (allergic angiitis, granulomatosis [Churg-Strauss syndrome]). The percentages of eosinophils in peripheral blood and bronchoalveolar lavage fluid are essential parts of the evaluation. Chest computed tomography (CT) demonstrates a more characteristic pattern and distribution of parenchymal opacities than does conventional chest radiography. At CT, SPE and IHS are characterized by single or multiple nodules with a surrounding ground-glass-opacity halo, AEP mimics radiologically hydrostatic pulmonary edema, and CEP is characterized by nonsegmental airspace consolidations with peripheral predominance. ABPA manifests with bilateral central bronchiectasis with or without mucoid impaction. The CT manifestations of BG are nonspecific and consist of a focal mass or lobar consolidation with atelectasis. The most common CT findings in Churg-Strauss syndrome include sub-pleural consolidation with lobular distribution, centrilobular nodules, bronchial wall thickening, and interlobular septal thickening. The integration of clinical, radiologic, and pathologic findings facilitates the initial and differential diagnoses of various eosinophilic lung diseases.

Flavored Cigar Smoking Induces Acute Eosinophilic Pneumonia

Two cases of acute eosinophilic pneumonia (AEP) following smoking of flavored cigars were analyzed for characteristic features. None of our patients had a history of smoking flavored cigars/cigarettes in the past. One of them had never smoked, and the second patient was an ex-smoker who quit 17 years ago. Both patients presented with community-acquired pneumonia-like symptoms that did not respond to treatment with antibiotics. Their chest radiographs revealed bilateral diffuse infiltrates. The diagnosis of AEP was established based on the clinical picture, BAL that revealed an average eosinophil count > 45%, and immediate clinical improvement after introducing corticosteroids. All other possible causes were excluded during the initial workup.

Eosinophilic pneumonia induced by daptomycin

We present a case of drug-induced eosinophilic pneumonia resulting from intravenous daptomycin being used as therapy for recurrent methicillin-sensitive Staphlococcus aureus endocarditis. The patient developed hypoxic respiratory failure requiring intubation and mechanical ventilation. Daptomycin therapy was discontinued immediately, and the patient improved significantly after the administration of intravenous corticosteroids allowing for extubation 3 days later.

Extrinsic allergic alveolitis with eosinophil infiltration induced by 1,1,1,2-tetrafluoroethane (HFC-134a): a case report

A 22-year-old woman was admitted with symptoms of dyspnea and fever with pulmonary infiltrates noted on her chest X-ray study. She developed these symptoms in the workplace; her job included the removal of body hair using a diode-laser with 1,1,1,2-tetrafluoroethane (HFC134a, an alternative to chlorofluorocarbon) as a coolant. A chest X-ray examination revealed ground-glass opacities in the lower lung fields, and a chest computed tomographic study showed diffuse centrilobular opacities. An examination of the bronchoalveolar lavage fluid revealed increased lymphocytes with a slight increase in the number of eosinophils. An examination of the transbronchial biopsy specimens revealed eosinophil infiltration. A peripheral blood eosinophilia was also seen. The patient's symptoms, chest X-ray findings, and arterial blood gas analysis all returned to normal within a week. A challenge test of 1,1,1,2-tetrafluoroethane (HFC134a) inhalation was performed, which resulted in an elevation of body temperature, the development of a cough, and laboratory data indicating increased inflammation. We then determined the patient's diagnosis to be extrinsic allergic alveolitis with eosinophil infiltration, caused by HFC134a.

Idiopathic acute eosinophilic pneumonia

Idiopathic acute eosinophilic pneumonia (IAEP) is a rare disease but of clinical importance because of its good prognosis if treated promptly and appropriately. The etiology remains unknown and the temporal relationship between IAEP and a history of resent onset of cigarette smoking has been described. We report a typical case of a 21-year-old male with recent onset of smoking, who presented with acute febrile hypoxemic respiratory failure. High-resolution chest computed tomography scan revealed patchy ground glass opacity and ill-defined nodules, diffuse interlobar and interlobular septal thickening, and bilateral small amount of pleural effusion, which mimicked congestive heart failure except that the heart size was within normal limits. Bronchoalveolar lavage (BAL) was performed soon after the patient was admitted and remarkable eosinophilia was noted in BAL fluid. Clinical condition and chest radiographs improved dramatically after corticosteroid treatment. Because effective treatment and prompt institution of therapy can obviate unnecessary morbidity and mortality, IAEP should be kept in mind when treating patients presenting with diffuse parenchymal lung disease and acute respiratory failure. In that case, BAL is valuable and should be performed as soon as possible.

Eosinophilic pneumonias

Eosinophilic pneumonias (EP) encompass a wide spectrum of lung diseases characterized by peripheral blood eosinophilia (>1 x 10(9) eosinophils/l) and/or alveolar eosinophilia (>25%). Blood eosinophilia may be lacking, as in the early phase of idiopathic acute EP, or in patients already taking oral corticosteroids. EP may present with varying severity, ranging from almost asymptomatic infiltrates to the acute respiratory distress syndrome necessitating mechanical ventilation. Possible causes of EP must be thoroughly investigated, especially drugs and the variety of parasitic infections (considering history of travel or residence in areas of endemic parasitic infection). However, chronic EP remains idiopathic in many cases. When present, extrathoracic manifestations lead to suspect Churg-Strauss syndrome (CSS) or the hypereosinophilic syndrome (HES), the prognosis of which is dominated by cardiac involvement. Apart from the treatment of specific causes when possible, corticosteroids remain the cornerstone of symptomatic treatment for eosinophilic disorders, usually with a dramatic response, but frequent relapses when tapering or after stopping the treatment. The adjunction of immunosuppressants to corticosteroids is necessary in patients with CSS and poor prognosis factors. Imatinib has recently proven effective in the treatment of the myeloproliferative variant of the HES.

Clinicopathological differences between acute and chronic eosinophilic pneumonia

OBJECTIVE

Considerable confusion exists regarding the proper classification of idiopathic eosinophilic pneumonia (IEP). Furthermore, there are no reports describing the clinicopathological differences between the various forms of eosinophilic pneumonias.

METHODOLOGY

The histological findings in acute eosinophilic pneumonia (AEP) and chronic eosinophilic pneumonia (CEP) were examined and the clinical and radiological features were contrasted with them.

RESULTS

Radiologically, ground glass opacity and interlobular septal thickening were characteristic of the AEP cases, while air space consolidation was seen in all CEP cases. Histologically, interstitial oedema and fibrin deposition were prominent in the AEP cases. Type II cells were detached from the alveolar walls, although the basal lamina was predominantly intact. In CEP, in addition to cellular infiltration, there was prominent intraluminal fibrosis. Disruption of the basal lamina was observed and nests of intraluminal fibrosis were directly adjacent and connected to the alveolar walls.

CONCLUSIONS

An essential histological difference between AEP and CEP is the severity of basal lamina damage and the amount of subsequent intraluminal fibrosis. In AEP particularly, these findings explain the radiographical findings, as well as the rapid and complete improvement noted in such cases.

Allergic bronchopulmonary fungal disease caused by Saccharomyces cerevisiae

We describe a patient who presented with dry cough, low-grade fever, and focal patchy shadow of pulmonary infiltrates. Remarkably, the prospective etiological agent, Saccharomyces cerevisiae was purely and repeatedly cultured from her sputum. Allergic bronchopulmonary mycosis (ABPM) was diagnosed based on clinical, serological, and pathological criteria. Although the patient described here satisfied only three of the criteria, the conclusion that the allergic bronchopulmonary disease in our case was induced by S. cerevisiae was made based on the following evidence: 1) S. cerevisiae was repeatedly isolated from the patient's sputum, 2) anti-S. cerevisiae antibody was detected in her serum, and 3) bronchoprovocation test to S. cerevisiae antigen was positive. We present here a case of allergic bronchopulmonary fungal disease caused by S. cerevisiae antigen.

Idiopathic acute eosinophilic pneumonia: a study of 22 patients

Idiopathic acute eosinophilic pneumonia (IAEP) is characterized by acute febrile respiratory failure associated with diffuse radiographic infiltrates and pulmonary eosinophilia. We conducted a multicenter retrospective study to characterize this rare clinical entity further and to improve its diagnostic criteria. A total of 13 male and 9 female patients (mean age: 29 +/- 15.8 years) presented with severe hypoxemia (Pa(O2)/fraction of inspired oxygen ratio = 156 +/- 74.1) requiring mechanical ventilation in 14 cases. Bronchoalveolar lavage was performed on all patients and showed 54.4 +/- 19.2% eosinophils on differential cell count, but no open-lung biopsies were done. No clinical differences were found between patients seen at less than 7 days (n = 15) or at 7 to 31 days (n = 7) from the onset of IAEP. A total of 12 patients met the clinical criteria of acute lung injury, and eight of these patients met the criteria for acute respiratory distress syndrome. All patients recovered, either spontaneously (6) or on corticosteroid treatment (16). No relapses occurred. We conclude that: (1) diagnostic criteria of IAEP are compatible with a duration of symptoms for up to 1 month, but the response to corticosteroid treatment is not diagnostic because of possible spontaneous recovery; (2) IAEP should be considered as differential diagnosis of acute lung injury or acute respiratory distress syndrome; (3) bronchoalveolar lavage eosinophilia obviates the need for lung biopsy in IAEP.

Isolated chronic cough with sputum eosinophilia caused by Humicola fuscoatra antigen: the importance of environmental survey for fungus as an etiologic agent

We report here a 35-year-old man with isolated chronic cough associated with sputum eosinophilia in which Humicola fuscoatra (H. fuscoatra) antigen was an etiologic agent. He was admitted for the diagnosis and the treatment of his severe nonproductive cough. Although 80% of the nucleated cells in his induced sputum were eosinophils, he did not have bronchial hyperresponsiveness to methacholine or heightened bronchomotor tone. Bronchodilator therapy was not effective against his coughing. His cough worsened on his return home, suggesting the existence of some etiologic agent in his house. H. fuscoatra was isolated from his house, and the bronchoprovocation test with H. fuscoatra antigen was positive: i.e., development of coughing and decrease in capsaicin cough threshold (capsaicin concentration causing five or more coughs) from the prechallenge value of 31.3 microM to 1.95 microM at 6 and 48 hr, respectively, after the challenge. In addition, repeated environmental survey for fungi was suggestive of the importance of H. fuscoatra in the sputum eosinophilia. This is the first report concerning chronic cough with sputum eosinophilia caused by allergic reaction to H. fuscoatra antigen.

Acute eosinophilic pneumonia associated with antidepressant agents

Acute eosinophilic pneumonia is a severe syndrome characterized by fever, lung infiltrates, blood eosinophilia and respiratory failure. We describe a case of acute eosinophilic pneumonia associated with clomipramine and sertraline. A 40-year-old woman was admitted to the emergency department with 37.9 degrees C and respiratory rate of 35 respirations per minute. Blood analysis showed PaO2 = 57.6 mm Hg and HCO3- = 21.7 mmol/l and 12.2% eosinophils. Chest X-ray showed infiltrates in both lower lobes. She was taking clomipramine 25 mg bid for the last 4 weeks and sertraline 50 mg/day for the last week. Other causes of acute eosinophilic pneumonia such as parasitic and fungal infections or collagen diseases were discarded. Both antidepressant were stopped and the patient became afebrile and asymptomatic. A week later the patient was discharged from hospital. Physicians should be aware of this adverse antidepresant reaction which may result in severe pulmonary symptoms.

Nonresolving or slowly resolving pneumonia

Given the variability in rate of radiographic resolution, it remains controversial to decide when to initiate an invasive diagnostic work-up for nonresolving or slowly resolving pulmonary infiltrates. In immunocompetent patients who present with classical features of CAP (i.e., fever, chills, productive cough, new pulmonary infiltrate), clinical response to therapy is the most important determinant for further diagnostic studies. Within the first few days, persistence or even progression of infiltrates on chest radiographs is not unusual. Defervescence, diminished symptoms, and resolution of leukocytosis strongly support a response to antibiotic therapy, even when chest radiographic abnormalities persist. In this context, observation alone is reasonable, and invasive procedures can be deferred. Serial radiographs and clinical examinations dictate subsequent evaluation. In contrast, when clinical improvement has not occurred and chest radiographs are unchanged or worse, a more aggressive approach is warranted. In this setting, we advise fiberoptic bronchoscopy with BAL and appropriate cultures for bacteria, legionella, fungi, and mycobacteria. When endobronchial anatomy is normal and there is no purulence to suggest infection, TBBs should be done to exclude noninfectious causes (discussed earlier) or infections attributable to mycobacteria or fungi. An aggressive approach is also warranted in patients who are clinically stable or improving when the rate of radiographic resolution is delayed. As discussed earlier, what constitutes excessive delay is controversial, and depends upon the acuity of illness, specific pathogen, extent of involvement (i.e., lobar versus multilobar), comorbidities, and diverse host factors. Stable infiltrates even 2 to 4 weeks after institution of antibiotic therapy does not mandate intervention provided patients are improving clinically. Invasive techniques can also be deferred when unequivocal, albeit incomplete, radiographic resolution can be demonstrated. Lack of at least partial radiographic resolution by 6 weeks, even in asymptomatic patients, however, deserves consideration of alternative causes (e.g., endobronchial obstructing lesions, or noninfectious causes). Fiberoptic bronchoscopy with BAL and TBBs has minimal morbidity and is the preferred initial invasive procedure for detecting endobronchial lesions or substantiating noninfectious causes. The yield of bronchoscopy depends on demographics, radiographic features, and pre-test likelihood. In the absence of specific risk factors, the incidence of obstructing lesions (e.g., bronchogenic carcinomas, bronchial adenomas, obstructive foreign body) is low. Bronchogenic carcinoma is rare in nonsmoking, young (< 50 years) patients but is a legitimate consideration in older patients with a history of tobacco abuse. Non-neoplastic causes (e.g., pulmonary vasculitis, hypersensitivity pneumonia, etc.) should be considered when specific features are present (e.g., hematuria, appropriate epidemiologic exposures). Ancillary serologic tests or biopsies of extrapulmonary sites are invaluable in some cases. In rare instances, surgical (open or VATS) biopsy is necessary to diagnose refractory or non-resolving "pneumonias."

Bronchoalveolar lavage cell findings in three types of eosinophilic pneumonia: acute, chronic and drug-induced eosinophilic pneumonia

There are clinically different types of eosinophilic pneumonia (EP) but no study to date has compared pulmonary inflammatory cells between different types of EP, such as acute eosinophilic pneumonia (AEP), chronic eosinophilic pneumonia (CEP) and drug-induced eosinophilic pneumonia (drug-EP). The present study compared bronchoalveolar lavage fluid (BALF) cell findings to elucidate whether the profiles of the pulmonary inflammatory cells were different among the three types of EP. Clinical records of 28 patients with EP, consisting of eight AEP patients, 10 CEP patients and 10 drug-EP patients, were examined retrospectively. The differential cell counts, the CD4+/CD8+ ratio of lymphocytes, the percentage of HLA-DR+ in CD4+ and CD8+ lymphocytes, and the mean number of nuclear segmentations in cosinophils in BALF were compared among the three types of EP. The numbers of total cells, lymphocytes, neutrophils and eosinophils in BALF from patients with AEP were increased compared with those from normal subjects, and patients with CEP and drug-EP. The CD4+/CD8+ ratio of the BALF lymphocytes in patients with AEP, which exceeded 1.0 in all patients, was significantly higher than that in normal subjects. The percentages of HLA-DR+ cells in CD8+ lymphocytes in BALF from patients with CEP were significantly higher than those from patients with AEP and drug-EP. There was no significant difference in the mean number of nuclear segmentations in eosinophils in BALF among the three types of EP. The BALF cell findings in patients with EP showed some characteristics in accordance with type of EP. It is suggested that pulmonary neutrophils and lymphocytes, rather than eosinophils, may be related to the pathogenesis of the different types of EP.

Mechanisms of acute eosinophilic inflammation in a case of acute eosinophilic pneumonia in a 14-year-old girl

BACKGROUND

Acute eosinophilic pneumonia (AEP) is characterized by respiratory distress, eosinophilic infiltration in the lung, acute onset, resolution of symptoms with corticosteroids and the absence of relapse. Studies to identify the pathophysiology of AEP in adults have demonstrated eosinophil activation in the BAL fluid, and the presence of high levels of interleukin 5 (IL-5) in the BAL.

OBJECTIVE

To investigate the pathophysiology of AEP with pleural effusion in a paediatric patient.

METHODS

ECP levels in the BALand pleural fluid was determined by radioimmunoassay. IL-5 and GM-CSF concentrations in the BAL and pleural fluid were measured by Elisa. Immunohistochemistry studies performed on open lung biopsy included a specific ICAM-1 immunostaining and a ECP specific immunostaining (EG2+).

RESULTS

High levels of ECP were found in the BAL (5 microg/L) and pleural fluid (750 microg/L) demonstrating eosinophil activation at these sites. Immunohistochemistry illustrated activated (EG2+) eosinophils in the interalveolar septa and alveolar space and detected increased expression of ICAM-1 on alveolar epithelial cells. High levels of IL-5 were measured in the BAL (1334 pg/mL) and pleural fluid (7014 pg/mL), while elevated concentrations of GM-CSF (150 pg/mL) were found in the BAL.

CONCLUSION

We conclude that in this paediatric patient with AEP activated eosinophils were present in the BAL fluid, in the interalveolar septa and in the pleural space while increased ICAM-1 expression was detected on alveolar epithelial cells, contributing, at least partly, for their adhesive interactions. IL-5 and GM-CSF are likely important to the massive eosinophil recruitment and activation in the lung, while IL-5 is probably related to eosinophil accumulation and activation in the pleural space. Thus, lung generation of eosinophil-active cytokines is central to the pathophysiology of AEP in paediatric patients.

Acute eosinophilic pneumonia. A summary of 15 cases and review of the literature

Idiopathic acute eosinophilic pneumonia (AEP) is an acute febrile illness that may be mistaken for an infectious pneumonia. Patients are often young and otherwise healthy. Clues to considering this disorder in a differential diagnosis include the acuity and severity of the clinical presentation and an initial chest X-ray with diffuse infiltrates, often interstitial, and the presence of Kerley B lines and/or evidence of pleural fluid. The diagnosis can be made through examination of bronchoalveolar lavage fluid in most cases, with careful exclusion of other similar eosinophilic lung disease. Although it can lead to life-threatening respiratory failure, AEP is easily treatable with corticosteroids. This disease has not been reported to recur in any patients to this point.

The effect of the neurokinin antagonist FK-224 on the cough response to inhaled capsaicin in a new model of guinea-pig eosinophilic bronchitis induced by intranasal polymyxin B

Eosinophilic bronchitis without asthma can cause a persistent non-productive cough which is resistant to bronchodilator therapy. To understand the mechanism of the cough in this disorder, an animal model of eosinophilic bronchitis was developed. Guinea-pigs were treated with transnasal administration of polymyxin B or saline twice a week for 3 weeks. The number of eosinophils in bronchoalveolar lavage fluid increased in polymyxin B-treated animals when compared with those treated with saline. In addition, histological examination showed that the number of eosinophils infiltrated into the tracheal epithelium increased; injury to the tracheal epithelium was greater in polymyxin B-treated animals. The numbers of coughs induced by saline and each concentration of capsaicin (10(-18), 10(-16), 10(-14) M) were greater in the polymyxin B-treated animals. FK-224 (a neurokinin receptor antagonist) decreased the heightened cough reflex in this animal model of eosinophilic bronchitis. These findings suggest that neuropeptides, and particularly neurokinins, are involved in the heightened cough receptor sensitivity in eosinophilic bronchitis without asthma. This has implications for better understanding of this disorder and its treatment.