P-PN029. Clinical and electrophysiological profile of patients with Guillain-Barré Syndrome with conduction blocks

Abstract

Introduction . Clinical data is limited in patients with Guillain Barre syndrome (GBS) who show conduction block (CB) on nerve conduction study (NCS). We aim to describe the clinical and electrophysiological profiles of GBS with CB. Methods . Between 2017 and 2020, 111 patients fulfilling the National Institute of Neurological Disorders and Stroke (NINDS) criteria for GBS and Brighton level of certainty one or two were seen in a single neurology unit. NCS of three motor (median, ulnar and common peroneal (CP)) and three sensory (median, ulnar and sural) nerves were performed. Definite and probable CBs were defined as proximal/distal latency of 20% of lower limit of normal (LLN). Results . Mean interval from symptom-onset to NCS was 9.4±6.5 days. Twenty patients had CB (one nerve: 15, two nerves: 4, three nerves: 1). This included probable CB in median (n=3), ulnar (n=2) and CP (n=4) nerves, and definite CB in median (n=5), ulnar (n=6) and CP (n=6) nerves. Electrophysiological subtypes included demyelinating (n=11), axonal (n=4) and equivocal (n=5). Demographic and clinical features included M:F of 3:1, mean age of 38.5±19.9 years, facial weakness (n=8), ophthalmoparesis (n=1), respiratory muscle weakness (n=2) and antecedent infection (n=12). At the time of peak neurological deficits, the mean Medical Research Council (MRC) sum score was 35.4±14.9 and Hughes disability score (HDS) was 3.5±0.8. The mean duration of hospital stay was 14.7±15.9 days. At the time of discharge, the mean MRC sum score was 39.8±15.2 and mean HDS was 3.1±0.7. Conclusion . We report CBs across non-entrapment sites in both demyelinating and axonal sub-types of GBS. Interruption of saltatory conduction due to distortion of paranodal myelin leads to reversible conduction failure and rapid recovery as noted in the present study.