Acquired Tracheobronchomegaly Mimicking Mounier-Kuhn Syndrome Following Prolonged Mechanical Ventilation in Severe COVID-19 ARDS: A Fatal Case

Background: Mounier–Kuhn syndrome (MKS) is a rare congenital disorder characterized by marked dilation of the trachea and main bronchi due to a deficiency of elastic and smooth muscle tissue. However, prolonged mechanical ventilation and severe acute respiratory distress syndrome (ARDS), particularly in COVID-19, may induce acquired tracheobronchial remodeling that mimics MKS morphologically.

Case presentation: We report the case of a 67-year-old female patient with severe SARS-CoV-2 pneumonia requiring intubation and prolonged mechanical ventilation. Despite viral clearance, her course was complicated by invasive pulmonary aspergillosis, nosocomial infections, vasoplegic shock, continuous renal replacement therapy, and prolonged ventilatory dependency. After 93 days of intensive care, she developed barotrauma with tension pneumothorax and bronchopleural fistula. High-resolution computed tomography demonstrated extensive pulmonary fibrosis, microcystic changes, pneumomediastinum, and marked tracheobronchial dilation (trachea 34.9 mm; right main bronchus 21.0 mm; left main bronchus 17.3 mm), fulfilling morphometric criteria for MKS. There was no prior history of
chronic respiratory disease. Given the temporal evolution and absence of pre-existing airway pathology, findings were consistent with acquired tracheobronchomegaly secondary to prolonged ARDS
and mechanical stress. Due to irreversible fibrosis and refractory respiratory failure, therapeutic effort
was limited. The patient died after 96 days of hospitalization.

Conclusion: This case illustrates an acquired post-COVID tracheobronchomegaly phenotype mimicking MKS. Prolonged ventilation, inflammatory injury, and barotrauma may contribute to central airway remodeling in long-term ARDS survivors. Recognition of this entity is essential for prognosis and management.

Keywords: Tracheobronchomegaly, COVID-19, ARDS, mechanical ventilation, airway remodeling, barotrauma