Is Autonomic Dysphagia Involved in Early-Stage Myasthenia Gravis?

As is supposed, dysfunction of the autonomic nervous system may be involved in the pathogenesis of myasthenia gravis (MG). Disorders of the pupillomotor, orthostatic, vasomotor, and gastrointestinal systems may cause symptoms in MG. Among such symptoms, dysphagia has not yet been reported. However, this phenomenon can be a frequent symptom in patients with MG. We have examined 19 patients with class 1–2b MG (by classification of the Myasthenia Gravis Foundation of America) and 19 healthy volunteers. The existence and severity of dysphagia were characterized using clinical screening tests, manometry and endoscopy, electroneuromyography, and electrocardiography. Significant differences were found between groups of patients with dysphagia and with normal swallowing in Eat-10 and fiberoptic endoscopic evaluation of swallowing scores (P=0.001 in both cases). Between these groups, there were also significant differences in the active standing test and sympathetic skin response latencies in the foot (P=0.009 and P=0.033 respectively). In MG patients with dysphagia, this cannot solely be attributed to the parasympathetic system; sympathetic dysfunction was also found to be associated with increased dysphagia severity. It is concluded that the swallowing function should be evaluated in MG with or without dysphagia symptoms, especially in terms of esophageal phase dysfunction.