OBJECTIVETo identify clinical features and diagnostic tests that would alert the otolaryngologist to consider myasthenia gravis (MG) in the differential diagnosis of dysphonia, we reviewed the clinical characteristics of MG whose initial symptom is dysphonia.

METHODS31 patients who presented with dysphonia as their initial and primary complaint are reported, their symptoms and signs are observed and analyzed.

RESULTSPatients with dysphonia as their initial symptom of MG may complain of vocal fatigue, difficulty sustaining or projecting their voices, breathy voice or intermittent hoarseness. These symptoms are characterized by fluctuating weakness and abnormal fatigability. Flexible fibroendoscopic examination revealed that patients had incomplete adduction of the vocal folds, fatigue of the tensors of the vocal fold, incomplete glottic closure, vocal cord paralysis, saliva pooling over the bilateral or unilateral pyriform sinus. Neostigmine test revealed dramatic improvement in all patients. Serum levels of anti-Ach-R antibodies were tested in 19 cases, only 5 cases were abnormality. All patients had improved after treatment

CONCLUSIONSVoice changes can be the first sign of early MG. Based on fluctuating weakness or weak voice at the end of the day, a positive neostigmine test, significantly higher circulating antibody to acetylcholine receptor, a diagnosis of MG could definitively be made.