Imaging of asthma and allergic bronchopulmonary mycosis

Ultra-high-resolution computed tomography shows changes in the lungs related with airway hyperresponsiveness in a murine asthma model

In vivo presentation of airway hyper-responsiveness (AHR) at the different time points of the allergic reaction is not clearly understood. The purpose of this study was to investigate how AHR manifests in the airway and the lung parenchyma in vivo following exposure to different stimuli and in the early and late phases of asthma after allergen exposure. Ovalbumin (OVA)-induced allergic asthma model was established using 6-week female BALB/c mice. Enhanced pause was measured with a non-invasive method to assess AHR. The dynamic changes of the airway and lung parenchyma were evaluated with ultra-high-resolution computed tomography (128 multi-detector, 1024 × 1024 matrix) for 10 h. While the methacholine challenge showed no grossly visible changes in the proximal airway and lung parenchyma despite provoking AHR, the OVA challenge induced significant immediate changes manifesting as peribronchial ground glass opacities, consolidations, air-trapping, and paradoxical proximal airway dilatations. After resolution of immediate response, multiple episodes of AHRs occurred with paradoxical proximal airway dilatation and peripheral air-trapping in late phase over a prolonged time period in vivo. Understanding of airflow limitation based on the structural changes of asthmatic airway would be helpful to make an appropriate drug delivery strategy for the treatment of asthma.

Allergic Broncho-Pulmonary Aspergillosis

Allergic broncho-pulmonary aspergillosis (ABPA) is an immunologically mediated lung disease that usually occurs in people with a diagnosis of asthma or cystic fibrosis. It is a noninvasive lung disease caused by colonization of the airways with Aspergillus fumigatus. In people who are susceptible, Aspergillus leads to an exaggerated immune response and ultimately pulmonary inflammation and lung damage. Patients with ABPA typically present with poorly controlled asthma, recurrent pulmonary infiltrates, and bronchiectasis. Diagnosis of ABPA is established based on a combination of clinical manifestations as well as laboratory and radiological evaluations. Delay in diagnosis can result in airway destruction and pulmonary fibrosis, which may result in significant morbidity and mortality. This article discusses the clinical characteristics, diagnosis, and management of patients with ABPA. It aims to serve as a tool for pediatricians to aid in early recognition of this debilitating disease and consider referral, facilitating early diagnosis and treatment. [Pediatr Ann. 2021;50(5):e214-e221.].

Current Approach in the Diagnosis and Management of Allergic Bronchopulmonary Aspergillosis in Children With Cystic Fibrosis

Allergic bronchopulmonary aspergillosis (ABPA) is a complex pulmonary disorder characterized by a hypersensitivity reaction to Aspergillus fumigatus, and almost always seen in patients with cystic fibrosis (CF) and asthma. Fungal hyphae leads to an ongoing inflammation in the airways that may result in bronchiectasis, fibrosis, and eventually loss of lung function. Despite the fact that ABPA is thought to be more prevalent in CF than in asthma, the literature on ABPA in CF is more limited. The diagnosis is challenging and may be delayed because it is made based on a combination of clinical features, and radiologic and immunologic findings. With clinical deterioration of a patient with CF, ABPA is important to be kept in mind because clinical manifestations mimic pulmonary exacerbations of CF. Early diagnosis and appropriate treatment are important in preventing complications related to ABPA. Treatment modalities involve the use of anti-inflammatory agents to suppress the immune hyperreactivity and the use of antifungal agents to reduce fungal burden. Recently, in an effort to treat refractory patients or to reduce adverse effects of steroids, other treatment options such as monoclonal antibodies have started to be used. Intensive research of these new agents in the treatment of children is being conducted to address insufficient data.

Lung Hyperlucency: A Clinical-Radiologic Algorithmic Approach to Diagnosis

Areas of diminished lung density are frequently identified both on routine chest radiographs and chest CT examinations. Colloquially referred to as hyperlucent foci of lung, a broad range of underlying pathophysiologic mechanisms and differential diagnoses account for these changes. Despite this, the spectrum of etiologies can be categorized into underlying parenchymal, airway, and vascular-related entities. The purpose of this review is to provide a practical diagnostic algorithmic approach to pulmonary hyperlucencies incorporating clinical history and characteristic imaging patterns to narrow the differential.

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.

Novel imaging approaches in adult asthma and their clinical potential

Currently, imaging in asthma is confined to chest radiography and CT. The emergence of new imaging techniques and tremendous improvement of existing imaging methods, primarily due to technological advancement, has completely changed its research and clinical prospects. In research, imaging in asthma is now being employed to provide quantitative assessment of morphology, function and pathogenic processes at the molecular level. The unique ability of imaging for non-invasive, repeated, quantitative, and in vivo assessment of structure and function in asthma could lead to identification of 'imaging biomarkers' with potential as outcome measures in future clinical trials. Emerging imaging techniques and their utility in the research and clinical setting is discussed in this review.

Miliary nodules: An unusual presentation of allergic bronchopulmonary aspergillosis

Allergic bronchopulmonary aspergillosis (ABPA) is an immune-mediated inflammatory disease caused by hypersensitivity to Aspergillus fumigatus. A wide spectrum of plain radiographic appearances has been described in ABPA, though none are pathognomonic of ABPA. The common radiological abnormalities encountered are fleeting pulmonary opacities, bronchiectasis, and mucoid impaction. Uncommon radiological findings encountered in ABPA include pulmonary masses, perihilar opacities simulating hilar adenopathy, and pleural effusions. However, miliary nodules as a radiological presentation of ABPA are very rare and only one case has been reported in literature. It is often misdiagnosed and mismanaged as tuberculosis; thus, the clinician should be vigilant enough to diagnose this very rare entity.

Allergic bronchopulmonary aspergillosis in asthma: epidemiological, clinical and therapeutic issues

Allergic bronchopulmonary aspergillosis (ABPA) is a complex pulmonary disorder caused by immunologic reactions to antigens released by Aspergillus fumigatus, a ubiquitous fungi colonizing the tracheobronchial tree of asthmatic patients. The clinical presentation is usually poorly controlled asthma, recurrent pulmonary opacities and bronchiectasis. The prevalence of ABPA in asthma clinics may be as high as 13% with a global burden of almost 5 million patients. A. fumigatus-specific IgE level is the most sensitive test in diagnosis of ABPA, and all asthmatic patients should be routinely screened with A. fumigatus-specific IgE levels for early diagnosis. The goals of managing ABPA include control of asthma, prevention and treatment of acute exacerbations, and preventing the development or progression of bronchiectasis. Glucocorticoids are the treatment of choice with itraconazole reserved for those with recurrent exacerbations and glucocorticoid-dependent disease. There is a dire need for newer treatment approaches including oral antifungal agents and immunomodulatory therapy.

Management of allergic bronchopulmonary aspergillosis: a review and update

Since the first description of allergic bronchopulmonary aspergillosis (ABPA) in the 1950s there have been numerous studies that have shed light on the characteristics and immunopathogenesis of this disease. The increased knowledge and awareness have resulted in earlier diagnosis and treatment of patients with this condition. This article aims to provide a summary and updates on ABPA by reviewing the results of recent studies on this disease with a focus on articles published within the last 5 years. A systematic search of PubMed/Medline with keywords of ABPA or allergic bronchopulmonary aspergillosis was performed. All selected articles were reviewed with a focus on findings of articles published from December 2006 to December 2011. The relevant findings are summarized in this paper.

Allergic bronchopulmonary aspergillosis: Lessons for the busy radiologist

The probability of a radiologist interpreting a disease correctly is not only influenced by their training and experience but also on the knowledge of a particular entity. This editorial reviews certain myths and realities associated with radiological manifestations of allergic bronchopulmonary aspergillosis (ABPA). ABPA is a hypersensitivity disorder against the antigens of Aspergillus fumigatus. Although commonly manifesting with central bronchiectasis (CB), the disorder can present without any abnormalities on high-resolution computed tomography (HRCT) of the chest, so-called serologic ABPA (ABPA-S). HRCT of the chest should not be used in screening or in the initial diagnostic work up of asthmatics, as asthma without ABPA can manifest with findings of CB. High-attenuation mucus (HAM) is the pathognomonic sign of ABPA and is very helpful in the diagnosis of ABPA complicating asthma and cystic fibrosis. Instead of classifying ABPA based on the presence and absence of CB into ABPA-CB and ABPA-S respectively, ABPA should be classified as ABPA-S, ABPA-CB and ABPA-CB-HAM. The classification scheme based on HAM not only identifies an immunologically severe disease but also predicts a patient with increased risk of recurrent relapses.

Asthma: an imaging update

Significant advances continue in the subjective and quantifiable imaging features of asthma. Radiologists need to be aware of not only the general features, but also potential asthma mimics as well as complications.

Allergic bronchopulmonary aspergillosis

Allergic bronchopulmonary aspergillosis (ABPA) is an immunologic pulmonary disorder caused by hypersensitivity to Aspergillus fumigatus. Clinically, a patient presents with chronic asthma, recurrent pulmonary infiltrates, and bronchiectasis. The population prevalence of ABPA is not clearly known, but the prevalence in asthma clinics is reported to be around 13%. The disorder needs to be detected before bronchiectasis has developed because the occurrence of bronchiectasis is associated with poorer outcomes. Because many patients with ABPA may be minimally symptomatic or asymptomatic, a high index of suspicion for ABPA should be maintained while managing any patient with bronchial asthma whatever the severity or the level of control. This underscores the need for routine screening of all patients with asthma with an Aspergillus skin test. Finally, there is a need to update and revise the criteria for the diagnosis of ABPA. This review summarizes the advances in the diagnosis and management of ABPA using a systematic search methodology.

Allergic bronchopulmonary aspergillosis: a unique presentation in a pediatric patient

Infection by the Aspergillus species of fungus can result in a variety of clinically and radiographically unique pulmonary diseases. The specific disease manifested is most dependent upon the immunocompetency of the infected individual. Allergic bronchopulmonary aspergillosis (ABPA) is most commonly seen in patients with asthma and cystic fibrosis. Since its original description in 1952, much has been published describing the radiographic manifestations of this disease. In this article, we present the unusual case of a 13-year-old whose initial radiographic presentation was that of a dense lobar consolidation. Additionally, we highlight the contributory role of the radiologist in guiding the appropriate clinical work-up and treatment of this disease.

High-attenuation mucus plugs on MDCT in a child with cystic fibrosis: potential cause and differential diagnosis

High-attenuation mucus plugging is a rare finding in both adults and children. When it occurs, the field of differential diagnoses is typically quite small and includes acute hemorrhage, aspiration of radiodense material, and allergic bronchopulmonary aspergillosis (ABPA). The last of these three diagnoses is the most difficult to make, although ABPA is more commonly seen in children with cystic fibrosis (CF) or asthma. ABPA is radiographically characterized by recurrent mucus plugging, atelectasis, and central bronchiectasis. Thus far, high-attenuation mucus plugs have only been reported in adults. We report a rare case of a child with CF who had high-attenuation mucus plugs and atelectasis that raised the possibility of ABPA. We discuss the differential diagnoses of this finding and the role of multidetector CT in these children.

Air trapping at CT: high prevalence in asymptomatic subjects with normal pulmonary function

PURPOSE

To determine the degree and extent of air trapping at computed tomography (CT) in subjects with normal pulmonary function test results.

MATERIALS AND METHODS

The study group consisted of 50 subjects with normal pulmonary function, including 26 nonsmokers and 24 smokers (14 current and 10 ex-smokers; 11 mild and 13 heavy smokers). All 50 subjects underwent thin-section CT at which images were obtained during deep inspiration and expiration at three lung levels. The mean expiratory increase in lung attenuation was measured at each level. Air trapping was visually classified into four degrees (none, lobular, mosaic, or extensive), and the extent of air trapping was also semiquantitatively calculated. The visual grade and semiquantitative ratio of air trapping were compared among nonsmokers, current smokers, and ex-smokers and among nonsmokers, mild smokers, and heavy smokers by using the Kruskal-Wallis rank test and the Fisher protected least significant difference test, respectively.

RESULTS

The mean increase in lung attenuation in the three levels at expiration was 111.9 HU +/- 46.3 (SD). The overall frequency of air trapping was 64%. Lobular, mosaic, and extensive air trapping were seen in 10 (20%), 14 (28%) and eight (16%) patients, respectively. There was no significant difference in the visual grade of air trapping among the nonsmokers, current smokers, and ex-smokers (P =.387) or among the nonsmokers, mild smokers, and heavy smokers (P =.231). There was also no significant difference in the semiquantitative ratio of air trapping among nonsmokers, current smokers, and ex-smokers (P =.859) or among nonsmokers, mild smokers, and heavy smokers (P =.897).

CONCLUSION

Various degrees of air trapping, including the mosaic or extensive types, can be observed in subjects with normal pulmonary function and have no correlation with the subject's current smoking status or cigarette consumption.

Allergic bronchopulmonary aspergillosis: a review of a disease with a worldwide distribution

Allergic bronchopulmonary aspergillosis (ABPA), an immunologically mediated lung disease, occurs predominantly in patients with asthma. This chronic relapsing disorder ranges clinically from mild asthma to fatal destructive lung disease and is caused by hypersensitivity to colonized Aspergillus fumigatus (Af). The immunopathogenesis of the disease is yet to be understood clearly. Specific IgE-Af and IgG-Af, the serological markers, contribute to the diagnosis. Radiologically, ABPA is characterized by fleeting pulmonary infiltrates often confused with pulmonary tuberculosis. However, central bronchiectasis on computed tomography is considered to be the hallmark of the disease. Early diagnosis and therapy with prednisolone, the cornerstone of management, could alter the course of the disease and prevent the development of end-stage lung fibrosis.

[Allergic bronchopulmonary aspergillosis in children]

Allergic bronchopulmonary aspergillosis (ABPA) associates the development of aspergillus in bronchus and a predominant immediate hypersensitivity for aspergillus antigens. It complicates an old and severe allergic asthma or cystic fibrosis. Its prevalence is not well known. In children, ABPA prevalence is rare, except in cystic fibrosis where 0.6% to 11% of patients can be affected by the disease. Acute exacerbation of the disease favours the development of bronchiectasis and fibrosis. The diagnosis is suggested by an unexplained aggravation of asthma or, in cystic fibrosis, by wheezing, an unsuccessful antibiotherapy, and a recent modification of the chest X-ray. The diagnosis is based upon the presence of seven major criteria or six major criteria and one minor. The follow-up of biological parameters is important for early diagnosis of exacerbations. Some parameters are very sensitive, ie, precipitins and total serum IgE. Systemic corticotherapy is the usual treatment of exacerbation. The association with inhaled corticotherapy could reduce the duration of systemic treatment. The use of Itraconazole is logical, mainly in cystic fibrosis.

Allergic bronchopulmonary aspergillosis

Allergic bronchopulmonary aspergillosis (ABPA) is a syndrome seen in patients with asthma and cystic fibrosis. It is characterized by chronic colonization of the airways with a ubiquitous fungus, Aspergillus fumigatus. The clinical expression of ABPA results from the complex interaction of chronic colonization of the airways with A fumigatus, host factors allowing this colonization, and the host's genetically determined immune response. Clinically the syndrome is characterized by recurrent episodes of wheezing, mucus production, pulmonary infiltrates, and elevated levels of serum IgE. Many patients develop central bronchiectasis, and a subset will go on to endstage fibrotic lung disease. It is thought that treatment will prevent this progression. The mainstay of therapy remains oral corticosteroids.