Laryngeal Dysfunction Manifesting as Chronic Refractory Cough and Dyspnea: Laryngeal Physiology in Respiratory Health and Disease

• Published in: Chest Vol. 166; no. 1; p. 171
• Main Authors: Sundar, Krishna M, Stark, Amanda, Morris, Michael J
• Format: Journal Article
• Language: English
• Published: United States 01.07.2024
• Subjects: vocal cord dysfunction; chronic cough; dysphonia
• ISSN: 1931-3543; 1931-3543
• DOI: 10.1016/j.chest.2024.03.026

Laryngeal dysfunction as a cause of chronic refractory cough (CRC) and episodic dyspnea is often missed, which results in unnecessary testing and delays in diagnosis. Understanding laryngeal roles in breathing and airway protection can help to appreciate the propensity to laryngeal dysfunction with aging, chronic lung disease, and sleep apnea. The human larynx is a complex muscular structure that is responsible for multiple roles of breathing, vocalization, coughing, and swallowing. To undertake these activities, the larynx has a high density of sensory and motor innervation. In addition to common embryological origins with the pharynx and esophagus, with which many laryngeal activities are shared, somatomotor and autonomic pathways regulate emotional, cognitive, and complex motor sequence-planning activities within the larynx. Due to its unique location, the larynx is susceptible to infectious and gastroesophageal reflux-related insults. Couple this with key roles in regulation of airflow and mediation of airway protective reflexes, it is not surprising that neuropathic abnormalities and muscle dysfunction frequently develop. The expression of laryngeal dysfunction as hypersensitivity to mechanical, thermal, chemical, and other stimuli leads to exaggerated airway protective reflexes (laryngeal adductor reflex and cough reflex) manifesting as dyspnea and cough. Pulmonologists should incorporate assessment of laryngeal dysfunction during evaluation of CRC and dyspnea. Recognition of laryngeal hypersensitivity in patient with CRC can identify patients who may benefit from cough suppression therapies. Similarly, timely identification of inducible laryngeal obstruction may not only resolve episodic dyspnea but lessen the need for unnecessary testing and treatments.