Abstract Details

Electropathological characteristics and electroclinical patterns of Guillain Barré Syndrome in South Wales

This small observational study aims to highlight the electropathological characteristics and electroclinical patterns of Guillain-Barré Syndrome (GBS) in the population of South Wales. Out of a series of 34 patients diagnosed with GBS over the last 30 months in the University Hospital of Wales and the wider area around Cardiff, 17 cases (50%) showed a predominantly or purely motor demyelinating or axonal neuropathy in their nerve conduction studies. After following up a few complicated GBS cases with repeated studies, we observed chronic nerve changes in all of them, but in fact only some of them progressed to chronic forms of demyelinating or axonal neuropathies.

As recent studies suggest, the very early changes (within a few days) we see in the amplitude, duration or area, onset or peak latency of the CMAPs do not necessarily reflect loss of myelin, but may be the result of an immunologic attack at key motor axonal parts (the Nodes of Ranvier) affecting saltatory conduction, resulting in slowing or failure of conduction and motor blocks. Chronic changes with reduction, dispersion or attenuation of the CMAPs do not necessarily reflect ongoing demyelination but may be the result of axonal loss and remyelination with dysmyelination, as many patients clinically improve without that always being reflected in their nerve conduction studies.  In these cases, EMG may be invaluable in assessing the degree of axonal loss or recovery, demyelination/remyelination and muscle denervation/reinnervation.   

Acknowledging the selection bias of our study in following up only a few complicated cases, our impressions are that: (1) in electropathological terms, predominantly motor and sensorimotor demyelinating GBS variants (AIDP) account for significant proportions of GBS cases in Wales; (2) atypical (Miller-Fisher, Bifacial and Pharyngeal-Cervical-Brachial syndromes) and axonal GBS variants, i.e. acute motor axonal neuropathy (AMAN) and acute motor-sensory axonal neuropathy (AMSAN) may not be as rare in Wales as previously thought; (3) apart from its value for early diagnostic purposes, distinguishing the various electroclinical patterns at present makes no significant difference in terms of treatment, management and outcomes; however, we do not know how useful this might be in the future in designing trials and assessing the effects of more targeted alternative regimens; (4) acute axonal or “demyelinating” changes may be seen as early as 48 hours from clinical onset; a follow-up NCS/EMG study, at least for the complicated cases, may be useful in classifying them or assessing progression to chronic disease and indicating longer-term prognosis.

TitleForenamesSurnameInstitutionLead AuthorPresenter
DrNickTsarouchasCardiff University Hospital of Wales
Reference
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