Acute Respiratory Failure Associated with Severe Obstructive Sleep Apnea as an Early Manifestation of Multiple System Atrophy: A Case Report.

Sleep-related breathing disorders are common in patients with multiple system atrophy (MSA), typically presenting as laryngeal stridor due to vocal cord abductor paralysis; however, severe respiratory impairment in the early stage is rare. We report the case of an 81-year-old woman with MSA who developed acute respiratory failure associated with severe obstructive sleep apnea syndrome (OSAS) preceding stridor. The patient required intubation. Although extubation was successful after six days, nocturnal hypercapnia persisted, necessitating noninvasive ventilation. Polysomnography confirmed the diagnosis of OSAS, while laryngoscopy revealed mild bilateral vocal cord abductor paresis without stridor. This case highlights that life-threatening respiratory failure may precede the development of laryngeal stridor in patients with MSA.