Exercise-associated Excessive Dynamic Airway Collapse in Military Personnel

Area of Science:

• Pulmonary Medicine
• Military Health
• Diagnostic Imaging

Background:

• Exertional dyspnea in military personnel is challenging to diagnose due to unique deployment factors.
• Common causes include asthma and exercise-induced bronchospasm.
• Excessive dynamic airway collapse (EDAC) has not been previously reported in this population.

Purpose of the Study:

• To describe the clinical and imaging features of military personnel with exertional dyspnea attributed to excessive dynamic collapse of large airways during exercise.

Main Methods:

• 240 active U.S. military personnel with postdeployment exertional dyspnea underwent standardized evaluation.
• Procedures included pulmonary function tests, oscillometry, nitric oxide measurement, methacholine challenge, exercise laryngoscopy, cardiopulmonary exercise testing, and bronchoscopy.
• Imaging involved high-resolution and dynamic computed tomography (CT) with inspiratory and expiratory views.

Main Results:

• Six individuals (five men, one woman) were diagnosed with exercise-associated EDAC.
• Diagnosis criteria included exertional dyspnea, focal expiratory wheezing during exercise, large airway collapse on bronchoscopy, and airway narrowing on expiratory CT.
• Focal expiratory wheezing correlated with bronchoscopic and imaging findings.

Conclusions:

• Excessive dynamic central airway collapse was identified as the sole cause of dyspnea in six military personnel.
• EDAC should be considered in the differential diagnosis for exertional dyspnea in military populations.