Electrophysiological features of Guillain-Barré syndrome in Mongolian adult patients

Abstract

The Guillain-Barré syndrome (GBS) is a rare but severe disorder that affects peripheral nerves and is classified into several subtypes based on clinical presentation and electrophysiological abnormalities. Incidence and predominant subtypes of GBS differ geographically. The diagnosis is made upon clinical features and confirmed by nerve conduction studies (NCSs) which can differentiate subtypes such as demyelinated and axonal. Demyelinating subtypes in Europe and North America and axonal subtypes in Asia are predominant. Electrophysiological subtypes have not been determined in Mongolia. Therefore, we aimed to determine common electrophysiological subtypes of Guillain-Barré syndrome in Mongolia. In our study, 75 patients referred to Reflex Neurological Clinic between 2016 and 2019 were retrospectively reviewed. After excluding the cases by the criteria, patients were classified as demyelinating, axonal, normal and equivocal subtypes based on Hadden criteria. We compared the electrophysiological features of axonal and demyelinating subtypes. SPSS-23 was used for statistical analysis. The results are expressed in averages (standard deviations) and percentages (numbers). The difference between the mean and the group of variables was calculated using the T-test and the Chi-square test. Patients were 44% male (33), and the mean age was 46.4±15.1. There was no significant association between seasonal factors and electrophysiological subtypes. Among 75 patients with Guillain-Barré syndrome, a nerve conduction study was performed in the first week on 36% of patients, 33.3% in the 2nd week, and others in the 3rd-4th week after symptom onset. Electrophysiology subtypes were classified as demyelinating (65.3%), axonal (20%), within the normal range (5.4%) and equivocal (9.3%) based on Hadden criteria. The absence of F-waves on electrophysiological examination was higher in patients within 14 days of the disease onset, whereas non-sensory changes were higher in patients after 14 days. We conclude that acute inflammatory demyelinating neuropathy (AIDP) was the most frequent subtype of GBS in Mongolia.