Allergic Bronchopulmonary Aspergillosis: A Perplexing Clinical Entity

Abstract

In susceptible individuals, inhalation of Aspergillus spores can affect the respiratory tract in many ways. These spores get trapped in the viscid sputum of asthmatic subjects which triggers a cascade of inflammatory reactions that can result in Aspergillus-induced asthma, allergic bronchopulmonary aspergillosis (ABPA), and allergic Aspergillus sinusitis (AAS). An immunologically mediated disease, ABPA, occurs predominantly in patients with asthma and cystic fibrosis (CF). A set of criteria, which is still evolving, is required for diagnosis. Imaging plays a compelling role in the diagnosis and monitoring of the disease. Demonstration of central bronchiectasis with normal tapering bronchi is still considered pathognomonic in patients without CF. Elevated serum IgE levels and Aspergillus-specific IgE and/or IgG are also vital for the diagnosis. Mucoid impaction occurring in the paranasal sinuses results in AAS, which also requires a set of diagnostic criteria. Demonstration of fungal elements in sinus material is the hallmark of AAS. In spite of similar histopathologic features, co-existence of ABPA and AAS is still uncommon. Oral corticosteroids continue to be the mainstay of management of allergic aspergillosis. Antifungal agents play an adjunctive role in ABPA as they help reduce the fungal load. Saprophytic colonization in cavitary ABPA may lead to aspergilloma formation, which could increase the severity of the disease. The presence of ABPA, AAS, and aspergilloma in the same patient has also been documented. All patients with Aspergillus-sensitized asthma must be screened for ABPA, and AAS should always be looked for.

Allergic aspergillosis of the respiratory tract

“…Perihilar or pseudohilar infiltrates may simulate hilar adenopathy in ABPA. These infiltrates are found in 40-77% of patients [91,96], and are seen surrounding the secretion-filled dilated central bronchi. True hilar adenopathy, which resolved on therapy, was also documented in ABPA in adults [99,100], as well as a single report in a 3.5-year-old child [86].…”

“…3), toothpaste shadows and gloved finger shadows should raise the possibility of ABPA. Wine glass shadows were observed in 27% of 113 patients from India [91]. Lobar or segmental collapse is not uncommon.…”

“…These opacities usually appear and disappear in different areas of the lung over a period of time and are also known as transient pulmonary infiltrates (figs 1 and 2). In a review of 1340 chest radiographs from 113 patients with ABPA, fleeting shadows were observed in 89% [91]. These changes, usually seen in either the acute or exacerbation stage of the disease, indicate the presence of an active disease process.…”

“…When these opacities keep recurring at the same sites they are described as recurrent fixed shadows [98]. Consolidation or non-homogeneous infiltrations are the most commonly observed patterns, described in up to 91% of patients with ABPA [91,[95][96][97]. Perihilar or pseudohilar infiltrates may simulate hilar adenopathy in ABPA.…”

“…The symptomatic presentation however, appears to bear little or no relationship to the severity or chronicity of the disease, as a third of the patients may be relatively asymptomatic despite extensive radiological lesions [90]. In an analysis of 113 patients with ABPA [91], 70 of whom were males, the mean age of the patients was 32 years while the mean age of asthma onset was 21 years. Cough (99%) and breathlessness (99%) were the commonest symptoms, followed by expectoration (98%), wheezing (97%) and haemoptysis (41%).…”