High-resolution ultrasound of peripheral neuropathies in rheumatological patients: An overview of clinical applications and imaging findings.

Peripheral neuropathies are surprisingly common and can be associated with a number of conditions, including rheumatological diseases. Whether the co-existence of peripheral neuropathies with rheumatological disorders is coincidental or related to a common pathogenic mechanism, these disabling conditions can affect the outcome of rheumatological patients and should be targeted with specific treatment. The clinical presentation of peripheral neuropathy can be multifaceted and difficult to recognize in polysymptomatic patients. However, physicians adopting state-of-art diagnostic strategies, including nerve imaging, may improve the detection rate and management of neuropathies. In particular, a diagnostic approach relying exclusively on clinical history and nerve conduction studies may not be sufficient to disclose the etiology of the nerve damage and its anatomical location and thus requires integration with morphological studies. High-Resolution Ultrasound (HRUS) is increasingly adopted to support the diagnosis and follow-up of both joint disorders in rheumatology and peripheral neuropathies of different etiologies. In this review, the different types of nerve disorders associated with the most common syndromes of rheumatological interest are discussed, focusing on the distinctive sonographic features.

A case series of parainfectious Guillain-Barré syndrome linked to influenza A (H1N1) virus infection.

Guillain-Barré syndrome (GBS) is an immune-mediated peripheral neuropathy characterized by a typical post-infectious profile. Some post-Zika virus and post-severe acute respiratory syndrome-related coronavirus-2 GBS cases have been reported to occur with very short intervals between the infection and GBS onset. Evaluating 161 GBS patients consecutively admitted to two Italian Regional Hospitals between 2003 and 2019, we found that the only three with an antecedent influenza A (H1N1) virus infection developed GBS within an interval of less than 10 days from the influenza illness. The two of them with a demyelinating subtype promptly recovered without therapy. Overall, the parainfectious cases add heterogeneity to the GBS category, warranting pathogenetic insights.

COVID-19-related and not related Guillain-Barré syndromes share the same management pitfalls during lock down: The experience of Liguria region in Italy.

Recently, during the pandemic infection of the novel SARS-CoV-2, some cases of Guillan-Barré Syndrome (GBS) have been reported. The aim of this work is to report the natural history of patients with GBS, both COVID and not-COVID related, hospitalized in Liguria region, during lock down period, in order to assess clinical features of both groups and possible managements pitfalls due to pandemic emergency. Fifteen GBS patients were admitted to the Hospitals of Liguria, from February 15th to May 3rd 2020, six with SARS-CoV-2 infection and nine without infection. In COVID-19 related GBS five patients presented with classical GBS and one with variant. Two patients presented neurologic symptoms during or shortly after the viral syndrome, suggesting the pattern of a para-infectious profile. Multi-organ involvement, delay in the diagnosis, incomplete work up and start of therapy, were registered in 50% of cases with a GBS-Disability scale ≥4 at follow-up evaluation. In not-COVID-19 related GBS, main problem was diagnostic delay. In three patients the first neurological observation took place after a mean of 33,6 days. Moreover, five patients went to emergency room after an average of 30 days since the onset of neurological symptoms because of fear of contagion. In conclusion, not only SARS-CoV-2 infection can cause GBS, but it can also, due to effects of pandemic on the health organization, affect the outcome of patients with not COVID-19 related GBS.

Diagnostics of anti-MAG antibody polyneuropathy.

This document presents the guidelines for anti-myelin-associated glycoprotein (MAG) antibody testing that have been developed following a consensus process built on questionnaire-based surveys, internet contacts, and discussions at workshops of sponsoring Italian Association of Neuroimmunology (AINI) congresses. The main clinical information on anti-MAG antibody polyneuropathy, indications and limits of anti-MAG antibody testing, instructions for result interpretation, and an agreed laboratory protocol (Appendix) are reported for the communicative community of neurologists and clinical pathologists.

Sphingomyelin as a myelin biomarker in CSF of acquired demyelinating neuropathies.

Fast, accurate and reliable methods to quantify the amount of myelin still lack, both in humans and experimental models. The overall objective of the present study was to demonstrate that sphingomyelin (SM) in the cerebrospinal fluid (CSF) of patients affected by demyelinating neuropathies is a myelin biomarker. We found that SM levels mirror both peripheral myelination during development and small myelin rearrangements in experimental models. As in acquired demyelinating peripheral neuropathies myelin breakdown occurs, SM amount in the CSF of these patients might detect the myelin loss. Indeed, quantification of SM in 262 neurological patients showed a significant increase in patients with peripheral demyelination (p = 3.81 * 10 - 8) compared to subjects affected by non-demyelinating disorders. Interestingly, SM alone was able to distinguish demyelinating from axonal neuropathies and differs from the principal CSF indexes, confirming the novelty of this potential CSF index. In conclusion, SM is a specific and sensitive biomarker to monitor myelin pathology in the CSF of peripheral neuropathies. Most importantly, SM assay is simple, fast, inexpensive, and promising to be used in clinical practice and drug development.