Vocal cord paralysis in myasthenia gravis with anti-MuSK antibodies

Abstract

About 20% of patients with generalized myasthenia gravis (MG) have undetectable serum antibodies to the nicotinic acetylcholine receptor (AChR). These patients are referred to as having seronegative MG. Recently, it has been demonstrated that about 50% of patients with generalized seronegative MG have antibodies to the surface membrane enzyme muscle-specific tyrosine kinase (MuSK) in Caucasian populations and a high frequency of respiratory crises.1 Here, we report a case of MG with anti-MuSK antibodies presenting with vocal cord paralysis, facial muscle weakness, and bulbar palsy. A 56-year-old man showed mild upper limb muscle weakness and fatigue on swallowing and chewing that worsened at the end of days in April 2000. He was admitted to our hospital in February 2001. Neurologic examination revealed mild muscle weakness and atrophy of his proximal muscles in the neck, shoulder, upper arm, and thigh. Nasal voice and dysphagia and facial muscle weakness were also observed, There was no ptosis or diplopia. Although repetitive …