Isolated vocal cord paralysis mimicking respiratory weakness in MuSK myasthenia

Abstract

Vocal cord paralysis is a rare manifestation of myasthenia gravis and challenging to diagnose with presentations other than stridor. We discuss a patient with MuSK myasthenia gravis who had respiratory difficulty due to vocal cord palsy and the diagnostic difficulties encountered in establishing the etiology for the dyspnea. The diagnosis was captured by spirometry flow volume loop showing flattening of the inspiratory portion suggestive of extrathoracic upper airway obstruction. Early diagnosis can prevent the need for tracheostomy and other emergent measures.