Very early electrodiagnostic findings in Guillain‐Barré syndrome

Abstract

Electrodiagnostic studies play a key role in the evaluation of patients with Guillain‐Barré syndrome (GBS). However, at early stages patients may not meet current neurophysiologic criteria. We report electrodiagnostic findings for 18 patients with suspected GBS within 4 days of clinical onset. Fifteen patients (83%) showed abnormality in the motor nerve conduction study. Prolonged distal motor latency (DML) was the most frequent demyelinating parameter (seen in 55% of patients). Abnormal late responses were noted in 14 patients (77%). Electrodiagnostic study of cranial nerves was abnormal in eight (44%), and motor nerve conduction velocity was abnormal in only six patients (23%). The study shows a predominant motor neuropathy pattern followed by a sural‐sparing pattern; no patients showed a strictly normal electrodiagnostic study. Reduced distal compound muscle action potential and prolonged DML in the demyelinating range were associated with severity of GBS on admission. After the electrodiagnostic study, 5 patients (27%) already fulfilled electrodiagnostic criteria for acute inflammatory demyelinating polyneuropathy (AIDP), 1 (5%) for the axonal variant of GBS, and 13 (72%) were classified as equivocal. We conclude that exhaustive electrodiagnostic studies of patients with suspected GBS in very early stages are useful in the diagnosis and management of the condition.