Welcome to the WCN 2023 Interactive Program

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CIDP is an inflammatory neuropathy with different subtypes. The EAN/PNS CIDP criteria were recently revised (2021) and neurofascin-155 neuropathy (NF155), and chronic immune sensory polyradiculopathy (CISP) were no longer considered as CIDP subtypes. NF155-IgG4 neuropathy presents at a young age with distal and lower limb predominant weakness. Patients have positive sensory symptoms, sensory ataxia, action tremor and cranial nerve involvement. The CSF protein is markedly elevated. Nerve biopsies show paranodal myelin thickening without onion-bulbs. NF155-IgG4 neuropathy is IVIG refractory but may respond to other immunotherapies (such as rituximab). CISP has isolated inflammatory demyelination of sensory roots with normal nerve conductions (NCS). CISP-plus is a non-pure form. We studied 44 CISP-plus and 28 CISP cases and found large fiber sensory loss and gait ataxia in both but mild distal weakness only in CISP-plus. NCS were normal in CISP and mildly abnormal in all CISP-plus. Elevated CSF protein, slowing of somatosensory evoked potentials and MRI root enhancement occurred in both. Nerve biopsies in CISP-plus and CISP cases showed loss of large myelinated nerve fibers, increased segmental demyelination, and onion-bulbs. Immunotherapy resulted in marked improvement of gait ataxia in both. In conclusion, NF155-IgG4 neuropathy and CISP/CISP-plus are inflammatory neuropathies previously classified as CIDP. The pathology and treatment response of NF155-IgG4 neuropathy is different from CIDP whereas those of CISP/ CISP-plus are similar to CIDP. By not classifying CISP/CISP-plus as forms of CIDP, the revised CIDP criteria are potentially opening a risk for CISP/CISP-plus patients to be denied medical coverage with immunotherapy.

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In the 21^st century Zika virus, chikungunya and then MERS and SARS-1 sensitised the world to the potential occurrence of acute inflammatory neuropathies associated with viral infections. When COVID-19 started to overwhelm communities and hospital services case reports and series of cases of GBS associated with COVID-19 started to appear. Small series generated potential incidences of GBS which would result in an epidemic of GBS. In larger studies no measurable increase in GBS occurred, and no new forms of GBS emerged to identify any significant association of GBS with COVID-19. Furthermore, despite postulation no pathogenic mechanism has been identified.

COVID-19 vaccinations have saved millions of lives worldwide and continues to be administered. With a worldwide vaccination programme for billions, and on the background of concerns for GBS generated from influenza vaccination in the 1970s, active surveillance for vaccination associated GBS was carried out by governments, pharma and medics. Whilst mRNA vaccines are not associated with GBS, the adenoviral vectored vaccines do seem to be associated with a small but clear peak of GBS in the 42 days after vaccinations, of about 5.7 cases per million doses. We explore the potential mechanisms and implications for future vaccines and pharmaceuticals.

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Using a series of case vignettes, I would illustrate

1. The challenges in the clinical diagnosis of inflammatory neuropathies such as chronic inflammatory demyelinating polyneuroradiculopathy (CIDP), multi-focal motor neuropathy (MMN) and vasculitic nuropathy. The emphasis would be on clinical examination tips that would benefit in parts of the world where the specific diagnostic tests for these conditions, namely electrophysiologic expertise and the resources to test for diagnostic antibodies such as anti GM1 IgM antibody, are not routinely available. Common pitfalls leading to over and under diagnosis of these conditions would be highlighted.

2. Treatment options, both in developed as well as under-resourced parts of the word. This runs the gamut of immunotherapy- corticosteroids, intravenous immunoglobulins, plasma exchange (including small volume plasma exchange), rituximab and steroid sparing drugs such as mycophenolate.

3. Recent ideas on para-nodopathy and how they are pertinent to understand the clinical, electrodiagnostic and therapeutic features of MMN and subtypes of CIDP such as those associated with neurofascin antibodies.