Allergic Bronchopulmonary Aspergillosis Aided by Bronchoalveolar Lavage: A Case Report

This protocol establishes a clear primary goal: to develop a structured, actionable diagnostic workflow that enables accurate differentiation of allergic bronchopulmonary aspergillosis (ABPA) from other chronic respiratory diseases with similar presentations in young patients with refractory respiratory symptoms. In this population, ABPA is frequently misdiagnosed due to non-classical clinical features, leading to avoidable delays in targeted therapy and persistent diagnostic uncertainty in routine clinical practice. The diagnostic workflow is designed as an integrated, multi-step approach incorporating comprehensive clinical assessment, high-resolution computed tomography (HRCT), bronchoscopy, and bronchoalveolar lavage fluid (BALF) analysis, including galactomannan assay, alongside targeted next-generation sequencing (tNGS) to detect Aspergillus fumigatus sequence reads. These components function as adjunctive tools within a holistic framework, guiding clinicians through the sequential evaluation of atypical ABPA cases. To demonstrate clinical applicability, the workflow was implemented in a 22-year-old male patient with a 10-year history of recurrent cough and sputum production, who had been initially misdiagnosed with infectious bronchiectasis and was unresponsive to antibacterial therapy. Application of the workflow enabled integration of serial HRCT findings, BALF testing, tNGS results for Aspergillus fumigatus sequence reads, and baseline serological data, ultimately leading to a definitive diagnosis of ABPA. This protocol highlights that a multimodal diagnostic strategy can enhance diagnostic confidence in young patients with refractory respiratory symptoms and elevated serum IgE levels, reducing diagnostic ambiguity and facilitating timely initiation of targeted anti-inflammatory and antifungal therapy to improve clinical outcomes.