Electrophysiological diagnosis of Guillain–Barré syndrome subtype: could a single study suffice?

TLDR

Serial electrophysiology is considered essential for accurate Guillain–Barré syndrome diagnosis, but it is unclear whether adapted criteria could allow a single study to suffice. In a retrospective review of 365 patients, the authors compared existing diagnostic criteria with newly developed modified criteria that use sensitive and specific cut‑offs for demyelination and incorporate recent axonal electrophysiology knowledge. The modified criteria yielded diagnostic rates and subtype shifts comparable to serial studies, with a single nerve‑conduction study proving especially useful when performed within seven days of symptom onset.

Abstract

<h3>Background</h3> Serial electrophysiology has been suggested as essential for accurate diagnosis in Guillain–Barré syndrome (GBS). However, whether more adapted electrophysiological criteria may allow a single study to be sufficient is unknown. <h3>Methods</h3> We retrospectively reviewed records of 365 consecutive patients with GBS from Birmingham, UK, and Garches, France, admitted between 1998 and 2013. Electrophysiology was analysed using existing criteria as well as a set of modified criteria, developed using sensitive and specific cut-off values for demyelination and incorporating new knowledge on electrophysiology of axonal GBS. We compared diagnostic rates and classification changes using modified criteria with published literature relating to serial studies. <h3>Results</h3> With existing criteria, we found similar proportions of acute inflammatory demyelinating polyradiculoneuropathy (AIDP) (71.5% vs 72%; p=1), axonal GBS (17.5% vs 14.7%; p=0.62) and equivocal forms (9.9% vs 13.3%; p=0.41) to the previous studies considered. With modified criteria, we identified comparable rates of AIDP (56.2% vs 58.7%; p=0.70), axonal GBS (35.1% vs 36%; p=0.89) and equivocal forms (7.7% vs 5.3%; p=0.63) with a single nerve conduction study as compared with when serial electrophysiology was used in previous analyses. We observed an identical diagnostic shift from AIDP to axonal GBS with modified criteria as that described with serial studies (21.5% vs 18.5%; p=0.72). Classification changes with modified criteria correlated significantly with performing of electrophysiology ≤7 days after symptom onset (p=0.045), indicating their greater usefulness in earlier disease stages. <h3>Conclusions</h3> A single electrophysiological study may suffice to establish the ultimate electrodiagnosis of GBS subtype if the proposed modified electrodiagnostic criteria are used.