Difficulties in differential diagnosis of vocal cord dysfunction and asthma

Abstract

Aim. Differential diagnosis of vocal cord dysfunction (VCD) and asthma.Methods. 105 patients with partially controlled asthma were examined. We used specific examinations for VCD: psychological scales , questionnaires for monitoring symptoms of VCD, transnasal fiberoptic laryngoscopy, conventional and electronic lung auscultation with the analysis of the amplitude-frequency characteristics (AFC) of wheezing in the chest and in the region of the larynx on the left and right. Spirometry was performed using Vitalograph ALPHA spirometer (England). The patients were divided into three groups: group 1 included patients with asthma; group 2 included patients with asthma and VCD (asthma-plus syndrome); group 3 included patients with VCD.Results. Conventional auscultation revealed wheezing over the lungs with a decrease in its intensity on the neck surface in group 1. In groups 2 and 3, the maximal wheezing was observed on the anterior surface of the neck and less intense wheezing was heard over the lungs. Electronic auscultation found mid-tonal wheezing over the lungs and over the larynx in group 1; high-pitched wheezing over the larynx and mid-tonal wheezing over the lungs in groups 2 and 3. Score of dyspnea according to the Borg scale was highest in the asthma-plus group – 4,8 (5,2 – 6,5) points, and lowest in the 1st group – 4,2 (3,7 – 4,9) points. The sensation of wheezing is maximal in VCD – 7,1 (6,5 – 7,9) points. The scores of symptoms of VCD were strongly correlated with the intensity of wheezing, dyspnea, and AFC of wheezing. Spirometry was close to normal in the group of patients with VCD; obstructive disorders were noted in groups 1 and 2. Transnasal laryngoscopy demonstrated paradoxical movement of the vocal cords during inspiration in groups 2 and 3. The triggers of episodes of VCD in the subjects were numerous; vocal loads predominated. Specific treatment of VCD in groups 2 and 3 improved the respiratory performance significantly.Conclusion. The primary diagnosis of asthma cannot be made without an examination for VCD. Psychological questionnaires and VCD questionnaires should be used. It is important to use electronic auscultation over the larynx for diagnosis. Correction of treatment in accordance with VCD in patients with asthma can significantly reduce the doses of inhaled and oral corticosteroids.