Study objectives: To evaluate patients for vocal cord
dysfunction (VCD) in a military population presenting with symptoms of
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.
underwent direct visualization of vocal cords with flexible
laryngoscopy before and after exercise to evaluate for presence of
inspiratory vocal cord adduction.
results: Complete evaluation for all patients consisted of
spirometry with flow-volume loops, lung volumes, diffusing capacity,
and maximum voluntary ventilation at rest; chest radiograph;
methacholine bronchoprovocation testing; and a maximal cardiopulmonary
exercise test with expiratory gas analysis. Fifteen percent of patients
studied prospectively were found to have VCD, whereas all control
subjects were negative for VCD. There was minimal difference in
pulmonary function testing between VCD-positive and VCD-negative
patients, whereas control subjects had higher spirometric values.
Twenty percent of VCD-positive patients had abnormal flow-volume loops
compared with 14% of patients without VCD, but after methacholine,
60% of VCD-positive patients developed abnormal flow-volume loops. In
the VCD-positive group, 60% had a positive methacholine response, but
there was less decrease in FEV1/FVC ratio compared with
either VCD-negative patients or control subjects.
Conclusions: Paradoxical inspiratory vocal cord closure is
a frequent occurrence in patients with symptoms of exertional dyspnea
and should be strongly considered in their