Autonomic Dysfunction in Myasthenia Gravis: A Case–Control Study Using COMPASS-31 and Electrophysiological Measures

<title>Abstract</title> <p>Background Myasthenia gravis (MG) is a well-characterized autoimmune disorder of the neuromuscular junction, primarily affecting voluntary muscles. Although autonomic nervous system (ANS) involvement is not considered a classical feature, increasing evidence suggests that autonomic dysfunction may be present in a subset of patients. Objective To investigate the prevalence and characteristics of autonomic dysfunction in MG patients using symptom-based and electrophysiological assessments. Methods This case–control study included 51 MG patients and 51 age- and sex-matched healthy controls. Autonomic symptoms were assessed using the Composite Autonomic Symptom Score-31 (COMPASS-31). Objective autonomic evaluation included sympathetic skin response (SSR), heart rate variability (R-R interval variation), and orthostatic blood pressure measurements. Results MG patients demonstrated significantly higher COMPASS-31 total and domain scores compared to controls (p &lt; 0.001). Gastrointestinal, bladder, vasomotor, secretomotor, pupillomotor, and orthostatic domains were all affected. No statistically significant differences were observed in SSR or R-R interval variability. Diastolic blood pressure values were significantly higher in MG patients in both supine and standing positions. No significant differences were found across MG subtypes. Conclusion Autonomic dysfunction is more prevalent in MG patients than previously recognized, particularly at the symptomatic level. These findings highlight the need for routine autonomic evaluation in MG management.</p>