The primary symptoms of laryngeal disease are hoarseness and stridor. Hoarseness is caused by an abnormal vibration of the vocal folds. The voice is breathy when too much air passes incompletely apposed vocal folds, as in unilateral vocal fold paralysis or vocal fold mass. The voice is harsh when the vocal folds are stiff and vibrate irregularly, as is the case in laryngitis or malignancy. Heavy, edematous vocal folds produce a rough, low-pitched vocal quality. Stridor (a high-pitched, typically inspiratory, sound) is the result of turbulent airflow from a narrowed upper airway. Airway narrowing at or above the vocal folds produces inspiratory stridor. Airway narrowing below the vocal fold level produces either expiratory or biphasic stridor. The timing and rapidity of onset of stridor are critically important in determining the seriousness of the airway problem. All cases of stridor should be evaluated by a specialist and rapid-onset stridor should be evaluated emergently.
Evaluation of an abnormal voice begins with obtaining a history of the circumstances preceding its onset and an examination of the airway. Any patient with hoarseness that has persisted beyond 2 weeks should be evaluated by an otolaryngologist with laryngoscopy. Especially when the patient has a history of tobacco use, laryngeal cancer or lung cancer (leading to paralysis of a recurrent laryngeal nerve) must be strongly considered. In addition to structural causes of dysphonia, laryngoscopy can help identify functional problems with the voice, including vocal fold paralysis, muscle tension dysphonia, and spasmodic dysphonia.
et al. Emerging techniques in assessment and treatment of muscle tension dysphonia. Curr Opin Otolaryngol Head Neck Surg. 2017 Dec;25(6):447–52.
et al. Effect of botulinum toxin and surgery among spasmodic dysphonia patients: a systematic review. Otolaryngol Head Neck Surg. 2017 Feb;156(2):238–54.