Isolated dysarthria as the sole manifestation of myasthenia gravis: a case report

Abstract

Myasthenia gravis (MG) is an acquired autoimmune disease. Its clinical manifestations comprise ptosis, diplopia, dysarthria, dysphagia, limb weakness, and in severe cases, respiratory muscle involvement. Dysarthria as an exclusive initial and primary complaint in MG is rare and seldom reported. In this paper, we report a case of type IIIb MG with isolated dysarthria as the only clinical manifestation and we review the relevant literature. The patient was a 62-year-old man who presented with episodes of slurred speech for 20 days that had worsened in the previous 9 days. His medical history comprised hypertension, diabetes mellitus, and coronary heart disease. The initial diagnosis on admission was transient ischemic attack. Careful re-examination of the patient's history revealed that his symptoms mainly involved increasingly worse slurred speech episodes without drinking or swallowing difficulties, and no significant improvement with rest was observed. Electromyography and autoantibody profiling led to a diagnosis of type IIIb MG. His symptoms improved after the oral administration of pyridostigmine bromide 60 mg. Laryngeal MG is important to differentiate from stroke. It is necessary to perform a computerized voice analysis when encountering patients with atypical symptoms of MG.

Keywords: Myasthenia gravis; acoustic analysis; atypical symptoms; case report; isolated dysarthria; laryngeal; late-onset MG.