Electrophysiological studies versus high-resolution nerve ultrasound in diagnosis of Guillain–Barré syndrome

Guillain–Barré syndrome (GBS) is polyneuropathy characterized by inflammation and immune-mediated processes that is classified into many subtypes based on electrophysiological and pathological criteria. The diagnosis of GBS can be confirmed using electrophysiological studies. However, electrophysiological studies may be normal when carried out early within 1 week in the course of the disease (Berciano et al. in J Neurol 264:221–236, 2017). One of the most useful imaging modalities for peripheral nerve diseases is ultrasonography (US). Nerve US in combination with electrophysiological studies provides an appropriate method in evaluating diseased peripheral nerves. This study aimed to enhance the reliability of early GBS diagnosis by correlating the findings of electrophysiological studies and nerve ultrasound. The nerve conduction studies (NCSs) in 37 GBS patients and 37 controls combined with cross-sectional area (CSA) assessment with US within the first 3 days of onset of symptoms and on day 14 after disease onset were evaluated.

At presentation, patients and controls did not differ significantly in NCS parameters (p ≥ 0.05) except for a significantly longer F-wave minimum latency in the median, ulnar, and tibial nerves in patients (p < 0.001). While on day 14 all NCS parameters differed significantly in patients in comparison to controls (p < 0.001) with exception of the sural nerve parameters (p ≥ 0.05). Except for the sural nerve (p ≥ 0.05), all the examined nerves' CSAs were considerably higher in patients at presentation and on day 14 in comparison to the controls (p < 0.001). The subtypes of Guillain–Barré syndrome either demyelinating, axonal or mixed axonal and demyelinating did not significantly differ regarding the CSAs of all the examined nerves either at presentation or on day 14 (p > 0.05).

Electrophysiological results in GBS are crucial in diagnosing the disease and understanding its pathophysiology, but serial NCSs are required. Ultrasound shows structural aspects of the nerve, so ultrasonography is a reliable tool which can be used in diagnosis and follow-up of early GBS. As a result, combining the two investigations has a complementary effect in the diagnosis and prognosis of GBS.