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Background: Acute hepatitis E virus (HEV) infection has recently emerged as a potential trigger for acute dysimmune neuropathies, but prospective controlled studies are lacking. Aims: To compare the frequency of concomitant acute HEV infection in patients with neuralgic amyotrophy (NA), Guillain–Barré syndrome (GBS), and Bell's palsy with a matched control population. Methods: Swiss multicenter, prospective, observational, matched case–control study over 3 years (September 2019–October 2022). Neurological cases with NA, GBS, or Bell's palsy were recruited within 1 month of disease onset. Healthy controls were matched for age, sex, geographical location, and timing of blood collection. Diagnostic criteria for acute hepatitis E were reactive serum anti‐HEV IgM and IgG assays (ELISA test) and/or HEV RNA detection in serum by real‐time polymerase chain reaction (RT‐PCR). RT‐PCR was performed on sera to confirm IgM positivity. Results: We included 180 patients (59 GBS, 51 NA, 70 Bell's palsy cases) and corresponding matched controls (blood donors) with median age 51 years for both groups and equal gender distribution. Six IgM+ cases were detected in the NA, two in the GBS, and none in the Bell's palsy group. Two controls were anti‐HEV IgM‐positive. At disease onset, most cases with acute HEV infection had increased liver enzymes. A moderate association (p = 0.027, Fisher's exact test; Cramér's V = −0.25) was observed only between acute HEV infection and NA. Conclusion: This prospective observational study suggests an association between concomitant acute HEV infection and NA, but not with GBS or Bell's palsy. [ABSTRACT FROM AUTHOR]

Skeletal muscle channelopathies (SMCs) are a heterogenous group of disorders, caused by mutations in skeletal ion channels leading to abnormal muscle excitability, resulting in either delayed muscle relaxation (myotonia) which characterizes non-dystrophic myotonias (NDMs), or membrane transient inactivation, causing episodic weakness, typical of periodic paralyses (PPs). SMCs include myotonia congenita, paramyotonia congenita, and sodium-channel myotonia among NDMs, and hyper-normokalemic, hypokalemic, or late-onset periodic paralyses among PPs. When suspecting an SMC, a structured diagnostic approach is required. Detailed personal and family history and clinical examination are essential, while neurophysiological tests should confirm myotonia and rule out alternative diagnosis. Moreover, specific electrodiagnostic studies are important to further define the phenotype of de novo cases and drive molecular analyses together with clinical data. Definite diagnosis is achieved through genetic testing, either with Sanger sequencing or multigene next-generation sequencing panel. In still unsolved patients, more advanced techniques, as exome-variant sequencing or whole-genome sequencing, may be considered in expert centers. The diagnostic approach to SMC is still mainly based on clinical data; moreover, definite diagnosis is sometimes complicated by the difficulty to establish a proper genotype–phenotype correlation. Lastly, further studies are needed to allow the genetic characterization of unsolved patients. [ABSTRACT FROM AUTHOR]

Hereditary transthyretin‐related (hATTR) amyloidosis is a rare disease, causing a disabling and life‐threatening axonal length‐dependent polyneuropathy. Monitoring of disease progression and treatment response is difficult. We aimed to determine if serum neurofilament light chain (sNfL) is a reliable and early biomarker of peripheral neuropathy in hATTR amyloidosis. We prospectively included 20 hATTR patients, 14 symptomatic and 6 asymptomatic. Patients were assessed at baseline and 1 year, including a full clinical examination with disease severity and functional scores, electrochemical skin conductance measurement with Sudoscan and nerve conduction studies, and sNfL level. hATTR patient sNfL were also compared with sNfL of 4532 healthy controls of a reference database by calculating age and BMI‐adjusted Z scores. At baseline, median sNfL concentration was 3.6‐fold higher in symptomatic than asymptomatic hATTR patients (P =.003), and this difference was also found in our under 60‐years‐old patients (P =.003). There was no significant difference of sNfL concentration between asymptomatic patients and healthy controls (Z‐score of −0.29), but a significant difference between symptomatic patients and healthy controls (Z‐score of 2.52). We found a significant correlation between sNfL levels and most clinical and electrophysiological disease severity scores, the strongest correlation being with the NIS score. sNfL seems to be a reliable biomarker of peripheral neuropathy severity in hATTR amyloidosis and can distinguish between asymptomatic and symptomatic patients. sNfL could also become a reliable biomarker to establish disease onset and treatment response. [ABSTRACT FROM AUTHOR]

Purpose of Review: This review highlights recent developments in the field of muscle ultrasound (MUS) for the diagnosis and follow up of muscle disorders., Recent Findings: The diagnostic screening capacity of quantitative grayscale analysis is still sufficient to assess children suspected of a neuromuscular disorder. A combination of visual and quantitative assessment is advised for optimal interpretation. MUS was more sensitive but less specific than MRI for detecting pathology in limb girdle dystrophies and inflammatory myopathies. New techniques such as shearwave elastography and artificial intelligence algorithms for automated image segmentation show promise but need further development for use in everyday practice.Muscle ultrasound has high correlations with clinical measures of function in skeletal and respiratory muscles and the orofacial region, in most of the myopathies and dystrophies studied. Over time, imaging changes precede changes in clinical status, making them attractive for biomarker use in trials. In Duchenne muscular dystrophy MUS was also responsive to the effects of steroid treatment., Summary: Muscle ultrasound is a sensitive technique to diagnose and follow up of skeletal, facial and respiratory muscles in neuromuscular disorders. Its role is both complementary to and partially overlapping with that of MRI., (Copyright © 2024 The Author(s). Published by Wolters Kluwer Health, Inc.)

Shoulder pain or paresis should be assessed carefully, as there are many possible causes, which can be osteoarticular, degenerative, inflammatory, or neurological. Weakness or pain can be related to cervicobrachialgia, plexitis, or focal mononeuropathy. The clinical picture should identify any muscular or mechanical origin of paresis responsible for pseudo-paretic functional limitation. Neurogenic scapulalgia with functional deficit implies the compression or entrapment of a nerve trunk including the axillary, long thoracic, accessory, suprascapular, or dorsal scapular nerves. Nerve conduction study and myography together with medical imaging help to identify the relevant etiology. Treatment mostly includes pain relief and physiotherapy, but surgery is rarely necessary., Competing Interests: Les auteurs n’ont déclaré aucun conflit d’intérêts en relation avec cet article.

Muscle diseases or myopathies have heterogeneous clinical presentations and etiologies. The principal sign is muscular weakness, whose distribution can help diagnostic orientation. Exercise intolerance, even without weakness at rest, can indicate an underlying myopathy. An isolated CK elevation can have multiple causes, but its persistence after a period of rest can point towards a subclinical myopathy. Isolated myalgia, especially at rest, are usually not associated with muscle disease. If the suspicion of myopathy is high, the patient will be assessed by a neurologist trained in muscle disorders, with correlation of clinical and neurophysiological findings, muscle imaging and, if indicated, muscle biopsy and genetic analysis. Cardiac and respiratory assessments are mandatory if a myopathy is suspected., Competing Interests: Les auteurs n’ont déclaré aucun conflit d’intérêts en relation avec cet article.

chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) has been widely described during the last quarter of the twentieth century. The last 20 years have seen decisive progress in its understanding. The diagnostic criteria have been simplified and the steps of the diagnostic process have been clarified. The phenotypic contours of the disease are now well known, as are the diagnostic pitfalls. From a pathophysiological point of view, the discovery of autoantibodies directed against nodal and paranodal proteins has been a major advance, although it concerns only a minority of patients. These discoveries have a major impact on the therapeutic management of these patients, often suffering from a very active form of the disease. The next 20 years will surely see a further deepening of knowledge about this fascinating disease., Competing Interests: Le Pr Magy déclare avoir ou avoir eu au cours des 5 dernières années des liens d’intérêts pour invitation à des congrès, hospitalité, participation à des boards ou activités de conseil avec les laboratoires suivants : Alnylam, CSL Behring, Grifols, LFB, Pfizer. Le Pr Echaniz Laguna déclare recevoir ou avoir reçu ponctuellement des rémunérations des laboratoires CSL Behring, Grifols, LFB, Santhera, en contrepartie de sa participation à des conférences, des réunions de formation, la rédaction d’articles de formation médicale continue ou d’activités de conseil. Les autres auteurs n’ont déclaré aucun conflit d’intérêts en relation avec cet article.

Hereditary neuropathies have been the subject of recent major therapeutic advances. Treatments based on antisense oligonucleotides (ASO) and small interfering RNA (siRNA) have been developed and are now commercially available to treat hereditary transthyretin amyloidosis (hTTR) and porphyria. More recently, a CRISPR-Cas9 genomic editing treatment targeting the TTR gene has been developed and is being tested in patients with hTTR. Based on their success in hTTR and porphyria, innovative treatments targeting mRNA and DNA are being evaluated in other hereditary neuropathies, including Charcot-Marie-Tooth disease (CMT)., Competing Interests: Le Pr Echaniz-Laguna déclare recevoir ou avoir reçu ponctuellement des rémunérations des laboratoires Alnylam, Pfizer, en contrepartie de sa participation à des conférences, des réunions de formation, la rédaction d’articles de formation médicale continue ou d’activités de conseil. Le Pr Magy déclare avoir ou avoir eu au cours des 5 dernières années des liens d’intérêts pour invitation à des congrès, hospitalité, participation à des boards ou activités de conseil avec les laboratoires suivants : Alnylam, Pfizer. La Dre Théaudin déclare avoir ou avoir eu au cours des 5 dernières années des liens d’intérêts pour invitation à des congrès, hospitalité, participation à des boards ou activités de conseil avec les laboratoires suivants : Alnylam, Sobi. Les autres auteurs n’ont déclaré aucun conflit d’intérêts en relation avec cet article.

Amyotrophic lateral sclerosis (ALS) is the most common motor neuron disease of the adult age. It is an aggressive condition with a mean disease duration of only 3 to 5 years, characterized by progressive weakness and atrophy of limb, bulbar, and respiratory muscles. In general, death is caused by chronic hypoventilation due to respiratory insufficiency. No causal treatment is known today, but the two therapeutic agents authorized in Switzerland for the treatment of ALS can slow disease progression significantly. Other important therapeutic strategies include invasive/non-invasive ventilation, pain therapy, as well as physio-, ergo- and speech therapy on a regular basis., Competing Interests: Les auteurs n’ont déclaré aucun conflit d’intérêts en relation avec cet article.

Muscle cramps are very common and can reduce quality of life. There are multiple causes, including some physiological conditions, metabolic, endocrine, vascular disorders or neuromuscular diseases. Adequate management first requires differentiating cramps from other muscular phenomena. In most cases, the investigations are limited to a comprehensive history and clinical examination, but a biological, radiological and/or electrophysiological work-up may be useful. Treatment, when needed, is most often symptomatic and is unfortunately based on little evidence., Competing Interests: Les auteurs n’ont déclaré aucun conflit d’intérêts en relation avec cet article.

Small fiber neuropathies affect small, poorly myelinated sensory Aδ and amyelinated C autonomic fibers. Neuropathic pain is often the main symptom. Positive diagnosis is based on the presence of deficient thermo-algesic sensory signs and/or dysautonomic signs with normal neurography. Several tests help to confirm the involvement of small fibers, ranging from simple tests such as the sympathetic skin response to skin biopsy, which measures the density of intraepidermal nerve fibers. The availability of these different tests varies greatly from one center to another. There are multiple etiologies, from rare genetic causes to the more frequent acquired dysimmune or metabolic causes. However, in more than half of the cases, no etiology is identified., Competing Interests: Les auteurs n’ont déclaré aucun conflit d’intérêts en relation avec cet article.

In 2021, we assisted to the publication of new diagnostic criteria, classifications, and guidelines (CIDP, brain tumors, auto-immune encephalitis). Several studies helped to define the pharmacological management of focal and generalized epileptic seizures and epilepsy in pregnant women. The availability of biomarkers and the approval of immunotherapies are modifying the landscape of dementia management. Endovascular interventions without previous thrombolysis seems to be effective in anterior circulation acute ischemic stroke (AIS) and severe posterior circulation AIS. Neurologic complications of Sars-CoV-2 infection were further studied, as well as the efficacy of vaccines in immunosuppressed patients. New molecules and techniques show promising results for the treatment of migraine and cluster headache., Competing Interests: Les auteurs n’ont déclaré aucun conflit d’intérêts en relation avec cet article.

In the wake of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, an increasing number of patients with neurological disorders, including Guillain-Barré syndrome (GBS), have been reported following this infection. It remains unclear, however, if these cases are coincidental or not, as most publications were case reports or small regional retrospective cohort studies. The International GBS Outcome Study is an ongoing prospective observational cohort study enrolling patients with GBS within 2 weeks from onset of weakness. Data from patients included in this study, between 30 January 2020 and 30 May 2020, were used to investigate clinical and laboratory signs of a preceding or concurrent SARS-CoV-2 infection and to describe the associated clinical phenotype and disease course. Patients were classified according to the SARS-CoV-2 case definitions of the European Centre for Disease Prevention and Control and laboratory recommendations of the World Health Organization. Forty-nine patients with GBS were included, of whom eight (16%) had a confirmed and three (6%) a probable SARS-CoV-2 infection. Nine of these 11 patients had no serological evidence of other recent preceding infections associated with GBS, whereas two had serological evidence of a recent Campylobacter jejuni infection. Patients with a confirmed or probable SARS-CoV-2 infection frequently had a sensorimotor variant 8/11 (73%) and facial palsy 7/11 (64%). The eight patients who underwent electrophysiological examination all had a demyelinating subtype, which was more prevalent than the other patients included in the same time window [14/30 (47%), P = 0.012] as well as historical region and age-matched control subjects included in the International GBS Outcome Study before the pandemic [23/44 (52%), P = 0.016]. The median time from the onset of infection to neurological symptoms was 16 days (interquartile range 12-22). Patients with SARS-CoV-2 infection shared uniform neurological features, similar to those previously described in other post-viral GBS patients. The frequency (22%) of a preceding SARS-CoV-2 infection in our study population was higher than estimates of the contemporaneous background prevalence of SARS-CoV-2, which may be a result of recruitment bias during the pandemic, but could also indicate that GBS may rarely follow a recent SARS-CoV-2 infection. Consistent with previous studies, we found no increase in patient recruitment during the pandemic for our ongoing International GBS Outcome Study compared to previous years, making a strong relationship of GBS with SARS-CoV-2 unlikely. A case-control study is required to determine if there is a causative link or not., (© The Author(s) (2021). Published by Oxford University Press on behalf of the Guarantors of Brain.)