Excessive Dynamic Airway Collapse: An Unusual Cause of Refractory Cough

Abstract

Expiratory central airway collapse (ECAC) is characterized by excessive narrowing of the central airways during expiration. Excessive dynamic airway collapse (EDAC), a subtype of ECAC, involves inward bulging of the posterior membranous tracheal wall with preserved cartilaginous rings and its clinical presentation closely mimics asthma and chronic obstructive pulmonary disease. EDAC is frequently underdiagnosed with spirometry and chest imaging and often requires dynamic bronchoscopy, which remains the diagnostic gold standard. We report a 63-year-old non-smoker female with hypothyroidism, treated pulmonary tuberculosis, coronary artery disease status post percutaneous transluminal coronary angioplasty, and obstructive airway disease, who presented with a three-month history of troublesome productive cough, exertional dyspnea (mMRC grade 2). Physical examination revealed bilateral polyphonic wheeze. Spirometry showed a mixed ventilatory defect with moderate obstruction and no reversibility. Despite treatment with bronchodilators and antibiotics, symptoms persisted. High-resolution computed tomography of the chest findings was not helpful in making a sound diagnosis and warranted further evaluation. Cardiac evaluation was normal. Flexible bronchoscopy performed under conscious sedation revealed significant expiratory collapse of the posterior tracheal wall, confirming EDAC. This finding explained the patient’s refractory symptoms and poor response to conventional therapy. Continuous positive airway pressure was initiated as a pneumatic stenting measure, resulting in significant symptomatic improvement. This case shows that dynamic airway disorders should be considered in patients with persistent cough and wheeze, and that bronchoscopy plays a key role in making an early and accurate diagnosis and guiding proper treatment.