Laryngeal Breathing Dystonia (LBD) is a rare disorder characterized by inappropriate adduction of the true vocal cords during inspiration, resulting in stridor and dispnea. However, sometimes it is difficult to recognize the underlying etiology of the stridor, specially in emergencial situations, and LBD may be occasionally misdiagnosed, which makes this disease perhaps more frequent than it has been taught. The diagnosis is further supported by the finding of dystonic features and by exclusion of other causes of paradoxical vocal cord motion. There has been no satisfactory treatment for the disease. Botulinum toxin type A (Botox®) injection into the thyreoarytenoid muscle has been shown to be very effective, but only few cases have been reported. The authors describe the clinical presentation of Laryngeal Breathing Dystonia in two patients with complaints of stridor. Evaluation by laryngoscopy revealed paradoxical vocal cord motion and malacia of the epiglottis. Treatment was attempted by injection of Botox® in the adductor muscles. In this article the diagnostic approach of this disease is evaluated in accordance to the earliest concepts on laryngeal dystonias. Based on the classification system for laryngeal dystonias presented by Koufman and Blabock, the authors propose the recognition of a new subtype of DLR.
dystonia; vocal fold; stridor
