Clinical features of laryngeal myasthenia gravis: A case series.

BACKGROUND: Myasthenia gravis (MG) is an autoimmune disease. Dysarthria, dysphagia, and difficulty swallowing as exclusive initial and primary complaints in MG (laryngeal MG) are rare and seldom reported. METHODS: Here we review and analyze the largest series of laryngeal MG patients. RESULTS: A total of 30 patients with laryngeal MG as primary manifestation were found in 20 case reports/series. Dysarthria was the most frequent primary symptom (14/30), followed by dysphagia (11/30), slurred speech (4/30) and dysphonia (1/30). Sixty-three percent visited the otolaryngology department first. Only 23.33% of patients were diagnosed with MG at the first clinic visit. Forty-five percent laryngeal MG patients were acetylcholine receptor (AChR) antibody positive, 52.9% showed decremental response in the repetitive nerve stimulation (RNS) test, and 92.6% were positive in the neostigmine/edrophonium test. Fluctuating weakness was examined in 16 of 30 patients and observed in 14/16 patients. CONCLUSION: Laryngeal MG is a rare and possibly under-diagnosed condition. The patients can present with dysarthria, dysphagia, or difficulty swallowing. Fluctuation in severity of disease by neostigmine/edrophonium test is a typical feature for MG patients. AChR antibody and RNS tests should be included to evaluate the pathologic changes in the neuromuscular junction.