Background-From October 2013 to April 2014, French Polynesia experienced the largest Zika virus (ZIKV) outbreak ever described at that time. During the same period, an increase in GuillainBarré syndrome (GBS) was reported, suggesting a possible association between ZIKV and GBS.

Guillain-Barré syndrome is the most common and most severe acute paralytic neuropathy, with about 100,000 people developing the disorder every year worldwide. Under the umbrella term of Guillain-Barré syndrome are several recognisable variants with distinct clinical and pathological features. The severe, generalised manifestation of Guillain-Barré syndrome with respiratory failure affects 20-30% of cases. Treatment with intravenous immunoglobulin or plasma exchange is the optimal management approach, alongside supportive care. Understanding of the infectious triggers and immunological and pathological mechanisms has advanced substantially in the past 10 years, and is guiding clinical trials investigating new treatments. Investigators of large, worldwide, collaborative studies of the spectrum of Guillain-Barré syndrome are accruing data for clinical and biological databases to inform the development of outcome predictors and disease biomarkers. Such studies are transforming the clinical and scientific landscape of acute autoimmune neuropathies.

Guillain–Barré syndrome (GBS) is a rare, but potentially fatal, immune-mediated disease of the peripheral nerves and nerve roots that is usually triggered by infections. The incidence of GBS can therefore increase during outbreaks of infectious diseases, as was seen during the Zika virus epidemics in 2013 in French Polynesia and 2015 in Latin America. Diagnosis and management of GBS can be complicated as its clinical presentation and disease course are heterogeneous, and no international clinical guidelines are currently available. To support clinicians, especially in the context of an outbreak, we have developed a globally applicable guideline for the diagnosis and management of GBS. The guideline is based on current literature and expert consensus, and has a ten-step structure to facilitate its use in clinical practice. We first provide an introduction to the diagnostic criteria, clinical variants and differential diagnoses of GBS. The ten steps then cover early recognition and diagnosis of GBS, admission to the intensive care unit, treatment indication and selection, monitoring and treatment of disease progression, prediction of clinical course and outcome, and management of complications and sequelae.

This review charts the progress of anti-glycolipid antibodies in neuropathy, from their original discovery 20 years ago in immunoglobulin M paraproteinaemic neuropathy through to current discoveries mapping their relationship to subtypes of Guillain-Barré syndrome. Antibodies to >20 different glycolipids have now been associated with a wide range of clinically identifiable acute and chronic neuropathy syndromes. Particular progress has been achieved in understanding the link between acute motor axonal neuropathy and antibodies to GM1, GD1a, GM1b and GalNAc-GD1a, and between the cranial, bulbar and sensory variants of GBS and antibodies to the disialylated gangliosides GQ1b, GT1a, GD1b and GD3. In addition to clinical and serological studies, the origins and measurement of anti-glycolipid antibodies and their relationships to similar carbohydrate structures on infectious organisms, particularly Campylobacter jejuni, are discussed in the context of a molecular mimicry hypothesis. The structure and nomenclature of relevant glycolipids are outlined, along with information on their localization in nerve, and the influence this has on clinical phenotypes. Major advances have been made in animal modelling of anti-glycolipid antibody-associated diseases, both in vitro and in vivo. This has advanced our understanding of the role of anti-GQ1b antibodies in Miller Fisher syndrome with particular respect to the motor nerve terminal as a potential site of injury, and led to the creation of rabbit models of anti-GD1b and anti-GM1 antibody-mediated sensory and motor neuropathy, respectively. With such information in place, it will now be possible to determine the precise mechanisms by which antibodies injure the different compartments of peripheral nerve and establish how a range of immunomodulating therapies, including current treatments, exert their therapeutic effects. Despite these very significant advances, considerable gaps in our knowledge persist, and it is likely that other pathogenic pathways operate in inflammatory neuropathy that are unrelated to glycolipid antibodies, although these are outside the scope of this review.

This multicenter, randomized, double-blind, crossover trial compared a six week course of oral prednisolone tapering from 60 mg to 10 mg daily with intravenous immunoglobulin (IVIg) 2.0 g/kg given over one to two days for treating chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). Twenty-four of the thirty-two randomized patients completed both treatment periods. Both treatments produced significant improvements in the primary outcome measure, change in an 11-point disability scale two weeks after randomization. There was slightly, but not significantly, more improvement after IVIg than with prednisolone, the mean difference between the groups in change in disability grade being 0.16 (95% CI = -0.35 to 0.66). There were also slightly, but not significantly, greater improvements favoring IVIg in the secondary outcome measures: time to walk 10 meters after two weeks and improvement in disability grade after six weeks. Results may have been biased against IVIg by the eight patients who did not complete the second arm of the trial. A serious adverse event (psychosis) attributable to treatment occurred in one patient while on prednisolone and in none with IVIg.