Autonomic Dysfunction After Guillain-Barré Syndrome: Evidence from Comprehensive Autonomic Testing.

Background/Objectives: Guillain-Barré syndrome (GBS) is an acute immune-mediated disorder of the peripheral nervous system. Autonomic involvement in GBS occurs during the acute phase and may persist into the recovery phase. This study aimed to investigate the autonomic nervous system's function in GBS sufferers. Methods: A cross-sectional exploratory study was conducted at the Clinical Neurophysiology Laboratory, Medical School, University of Cyprus. Eligible patients were previously hospitalized with GBS. Autonomic nervous system assessment included the Ewing battery using the Finapres Nova system as well as sudomotor assessment. Results: Seventeen patients were recruited (53% female; mean age 58.7 ± 14.1 years). The mean follow-up time since diagnosis was 15.5 ± 13.2 months (range 1-45 months). At follow-up, 4/17 patients (24%) demonstrated an abnormal heart rate (HR) response to standing, 3/17 patients (18%) exhibited an abnormal systolic blood pressure (BP) response to standing, and 4/17 patients (24%) exhibited an abnormal diastolic BP response to standing. One patient (6%) demonstrated an abnormal HR response during deep breathing, while another showed an abnormal diastolic BP response during the handgrip test. Overall, 6/17 patients (35%) showed abnormal findings in at least one component of the Ewing battery, and 3/17 (18%) fulfilled the criteria for definite generalised dysautonomia. Two patients (12%) demonstrated abnormal sympathetic skin response (SSR) results; both fulfilling the criteria for dysautonomia based on the Ewing battery. Conclusions: Autonomic dysfunction may be present in GBS patients beyond the acute phase, even in the absence of overt autonomic symptoms. Larger prospective studies with serial autonomic assessments are required to better characterise the long-term course and clinical significance of dysautonomia in GBS.