Vocal cord dysfunction in patients with exertional dyspnea

Study objectives: To evaluate patients for vocal cord dysfunction (VCD) in a military population presenting with symptoms of exertional dyspnea, Design: Cross-sectional, controlled study. Setting: Pulmonary disease clinic at an army tertiary care center. Patients: Forty military patients with complaints of exertional dyspnea and 12 military asymptomatic control subjects. Intervention: Patients underwent direct visualization of vocal cords with f lexible laryngoscopy before and after exercise to evaluate for presence of inspiratory vocal cord adduction. Measurements and results: Complete evaluation for all patients consisted of spirometry with flow-volume loops, lung volumes, diffusing capacity, and m aximum voluntary ventilation at I,est; chest radiograph; methacholine bronc hoprovocation testing; and a maximal cardiopulmonary exercise test with exp iratory gas analysis. Fifteen percent of patients studied prospectively wer e found to have VCD, whereas all control subjects were negative for VCD, Th ere was minimal difference in pulmonary function testing between VCD-positi ve and VCD-negative patients, whereas control subjects had higher spirometr ic values. Twenty percent of VCD-positive patients had abnormal flow-volume loops compared with 14% of patients without VCD, but after methacholine, 6 0% of VCD-positive patients developed abnormal flow-volume loops. Tn the VC D-positive group, 60% had a positive methacholine response, but there was l ess decrease in FEV1/FVC ratio compared with either VCD-negative patients o r control subjects. Conclusions: Paradoxical inspiratory vocal cord closure is a frequent occur rence in patients with symptoms of exertional dyspnea and should be strongl y considered in their evaluation.