Effects of continuous positive airway pressure on stridor in multiple system atrophy-sleep laryngoscopy.

The presence of stridor in patients with multiple system atrophy (MSA) is associated with poor prognosis, mainly due to a high risk of complete airway obstruction at night. Continuous positive airway pressure (CPAP) therapy has been proposed as a treatment of MSA-associated stridor, but, until now, there has been no visual documentation of the effect of CPAP on laryngeal patency during nonpharmacologically induced spontaneous sleep of a patient with MSA. We present a video-laryngoscopic documentation of a 57-year-old woman with MSA who was evaluated for nocturnal stridor. Direct laryngoscopy during sleep without pharmacologic sedation documented inspiratory adduction of the vocal cords with downward displacement of the larynx. Application of CPAP resulted in improvement of stridor, distension of the hypopharynx, abduction of vocal cords, and reduction of the downward displacement of the larynx. We discuss the possible mechanisms of action of CPAP in MSA-associated stridor.