A Challenging Diagnosis of Fluctuating Dyspnea: Myasthenia Gravis.

Isolated respiratory muscles weakness is an unusual presentation of Myasthenia Gravis (MG). We present a case of 49-year-old male with undiagnosed MG who presented with fluctuating dyspnea on exertion and at rest. There was no peripheral muscle involvement, diagnostic tests and standard electromyography was normal, and the serologic tests were negative.