Myasthenia Gravis and Upper Airway Obstruction

¹ From the Department of Pulmonary and Critical Care Medicine, The Johns Hopkins Hospital, Baltimore

Respiratory impairment in myasthenia gravis is usually attributed to weakness of the diaphragm and thoracic chest wall muscles, and is rarely attributed to upper airway obstruction. Myasthenia gravis is characterized by weakness of the striated muscles and usually affects those innervated by the bulbar cranial nerves. Weakness of these bulbar and upper airway muscles can lead to upper airway obstruction. To our knowledge, there are only five case reports in the literature associating upper airway obstruction with myasthenia gravis. Therefore, we attempted to further define its occurrence in myasthenia gravis patients by reviewing their flow volume loops. We present a case of upper airway obstruction causing respiratory symptoms in a myasthenia gravis patient. We then surveyed a total of 61 patients with myasthenia gravis who were tested in our pulmonary function laboratory between February 1990 and August 1993. Of these 61 patients, 12 had flow volume loops and 7 of these 12 disclosed a pattern of extrathoracic upper airway obstruction. The FVC was 80% or more in five of seven patients. Our data suggest that upper airway obstruction is much more common in patients with myasthenia gravis than previously recognized. In conclusion, we recommend the performance of flow volume loops in patients with myasthenia gravis to evaluate their respiratory impairment.

Key Words: flow volume loop • myasthenia gravis • upper airway obstruction

Submitted on April 19, 1995
Accepted on September 13, 2007

This article has been cited by other articles:

				J. C. Ruckert, M. Walter, and J. M. Muller Pulmonary function after thoracoscopic thymectomy versus median sternotomy for myasthenia gravis Ann. Thorac. Surg., November 1, 2000; 70(5): 1656 - 1661. [Abstract] [Full Text] [PDF]