Characterization of Autonomic Involvement in Various Subtypes of Guillain-Barré Syndrome and Association With Electrophysiological Parameters.

Introduction/aims: About two-thirds of patients with Guillain-Barré Syndrome (GBS) have autonomic dysfunction. The aim of this study was to characterize autonomic system involvement in various subtypes of GBS and its association with electrophysiological parameters.

Methods: This was a prospective cross-sectional study in which patients with GBS underwent autonomic function testing and nerve conduction studies along with the routine clinical history and examination. Involvement of various domains of the autonomic system was recorded by the Composite Autonomic Symptom Score-31 (COMPASS-31) at admission. Patients were classified into Miller Fisher syndrome (clinically) or demyelinating and axonal subtypes.

Results: Between June 2021 and December 2022, 68 patients completed the study. At baseline, 79% had dysfunction on laboratory autonomic function tests, while only 25% had abnormal scores on COMPASS-31. Sympathetic dysfunction was the predominant abnormality, accounting for 85.7% of patients in the acute inflammatory demyelinating polyneuropathy group and 68.2% (15/22) of patients in the axonal group (acute motor axonal neuropathy and acute motor sensory axonal neuropathy). There was no association of any pattern of autonomic dysfunction with the subtype of GBS or degree of axonal involvement.

Discussion: Autonomic dysfunction detected by standardized autonomic function tests can be present even in GBS patients with no dysautonomic symptoms. These tests can be done as early as first week after admission. Such patients may require close monitoring in intensive care units for clinical dysautonomia. Further longitudinal studies on this group of patients may help to identify the incidence of clinically significant autonomic dysfunction and their long-term prognosis.