An Alternate Method of Classifying Allergic Bronchopulmonary Aspergillosis Based on High-Attenuation Mucus

Abstract

Background and AimAllergic bronchopulmonary aspergillosis (ABPA) is classified radiologically based on the findings of central bronchiectasis (CB) and other radiologic features (ORF). However, the long-term clinical significance of these classifications remains unknown. We hypothesized that the immunological activity and outcomes of ABPA could be predicted on HRCT chest finding of high-attenuation mucus (HAM), a marker of inflammatory activity. In this study, we evaluate the severity and clinical outcomes of ABPA with different radiological classifications.MethodsPatients were classified based on CT chest findings as: (a) serologic ABPA (ABPA-S) and ABPA-CB; (b) ABPA-S, ABPA-CB, and ABPA-CB-ORF; and, (c) ABPA-S, ABPA-CB and ABPA-CB-HAM. The clinical, spirometric and serological (total and A fumigatus specific IgE levels, eosinophil count) severity of the disease and clinical outcomes in various classifications were analyzed.ResultsOf the 234 (123 males, 111 females; mean age, 34.1 years) patients, 55 (23.5%) had normal HRCT, 179 (76.5%) had CB, 49 (20.9%) had HAM, and 27 (11.5%) had ORF. All immunological markers were consistently higher in the HAM classification, while in other classifications these findings were inconsistent. On multivariate analysis, the factors predicting frequent relapses were presence of HAM (OR 7.38; 95% CI, 3.21–17.0) and CB (OR 3.93; 95% CI, 1.63–9.48) after adjusting for ORF.ConclusionsThe classification scheme based on HAM most consistently predicts immunological severity in ABPA. Central bronchiectasis and HAM are independent predictors of recurrent relapses in ABPA. Hence, HAM should be employed in the radiological classification of ABPA.

Chest radiographic and computed tomographic manifestations in allergic bronchopulmonary aspergillosis

“…Varicose bronchiectasis was considered to be moderate dilatation of the bronchus with irregular bronchial walls showing a beaded appearance. Cystic bronchiectasis was defined as marked saccular dilatation, which appears as a cluster of air-filled cysts [32] ; (2) CB was defined using two different criteria, depending on whether the bronchiectasis was confined to the medial half (point midway between hilum and chest wall) or the medial two-thirds of the lung [33] ; (3) the presence of high attenuation mucus (HAM) was considered if the mucus was visually denser than the paraspinal skeletal muscle [23,34,35] ; (4) centrilobular nodules were considered to be present if the nodules were distributed primarily within the center of the secondary pulmonary lobule with or without a tree-in-bud pattern [36] ; (5) presence of parenchymal abnormalities including consolidation, parenchymal scarring, bullae, atelectasis and pneumothorax were also noted. The criteria used to define these appearances were as described by Webb et al [31] ; and (6) patients were classified radiologically as ABPA-S, ABPA-CB and ABPA-CB-HAM based on the presence or absence of CB and HAM [35] .…”

Treatment options in severe fungal asthma and allergic bronchopulmonary aspergillosis

“…Only one published trial, stratified or otherwise, distinguished ABPA patients without bronchiectasis (''ABPAserologic'') from those with bronchiectasis [120,150]; those with hyperattenuating mucoid impaction have not been compared with those without impaction, despite apparent differences in severity of immunopathology and prognosis [13,151].…”

Allergic Bronchopulmonary Aspergillosis : An interesting presentation

“…[18] Agarwal et al included a new subtype known as ABPA-HAM (highly attenuated mucous). [19] The best thing about ABPA is its response to oral corticosteroids, which further necessitates an earlier diagnosis. Oral corticosteroids suppress both the immune response as well as the inflammation.…”