Respiratory insufficiency as the primary presenting symptom of multiple-system atrophy

Background: Respiratory stridor, sleep-disordered breathing, and respiratory insufficiency are part of the clinical spectrum of multiple-system atrophy (MSA). We have encountered cases where these were presenting symptoms, with the diagnosis of MSA being initially unrecognized. Objective: To describe cases in which breathing difficulties were the initial and primary manifestation of MSA. Design: Database review from January 1, 1996, through October 31, 2005. Setting: Mayo Clinic, Rochester, Minn. Patients: All patients diagnosed as having MSA, cross-referenced for apnea, hypopnea, or hypoventilation. On review, we included only cases in which respiratory dysfunction was the primary initial clinical event in MSA, excluding equivocal cases. Interventions: None. Main Outcome Measures: Characteristics and clinical course of patients. Results: Six cases were identified in which substantial respiratory insufficiency occurred as an early, presenting symptom of MSA. Three patients had been examined emergently for acute respiratory distress before the ultimate diagnosis of MSA; the other 3 patients were diagnosed as having obstructive sleep apnea unresponsive to therapy, with bilateral vocal cord paralysis found on ear, nose, and throat examination. Stridor was noted early in the course in all. All patients required tracheostomy, and all eventually developed features consistent with probable MSA. Conclusions: Multiple-system atrophy may occasionally present as primary respiratory failure or dysfunction, with initially mild motor and autonomic symptoms. Otherwise unexplained central respiratory failure, bilateral vocal cord paralysis, stridor, or refractory central sleep apnea should prompt consideration of MSA.