Neuropathies related to hepatitis E virus infection: A prospective, matched case-control study.

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.

Neuromuscular ultrasound standardized scanning techniques and protocols: Expert panel recommendations.

Neuromuscular ultrasound has become an integral part of the diagnostic workup of neuromuscular disorders at many centers. Despite its growing utility, uniform standard scanning techniques do not currently exist. Scanning approaches for similar diseases vary in the literature creating heterogeneity in the studies as reported in several meta-analysis. Moreover, neuromuscular ultrasound experts including the group in this study have different views with regards to technical aspects, scanning protocols, and the parameters that should be assessed. Establishing standardized neuromuscular scanning protocols is essential for the development of the subspeciality to ensure uniform clinical and research practices. Therefore, we aimed to recommend consensus-based standardized scanning techniques and protocols for common neuromuscular disorders using the Delphi approach. A panel of 17 experts participated in the study, which consisted of three consecutive electronic surveys. The first survey included voting on six scanning protocols addressing the general scanning technique and five common categories of suspected neuromuscular disorders. The subsequent surveys focused on refining the protocols and voting on new steps, rephrased statements, or areas of non-agreement. A high degree of consensus was achieved on the general neuromuscular ultrasound scanning technique and the scanning protocols for focal mononeuropathies, brachial plexopathies, polyneuropathies, amyotophic lateral sclerosis, and muscle diseases. In this study, a group of neuromuscular ultrasound experts developed six consensus-based neuromuscular ultrasound scanning protocols that may serve as references for clinicians and researchers. The standardized protocols could also aid in achieving high-quality uniform neuromuscular ultrasound practices.

Lower Motoneuron Dysfunction Impacts Spontaneous Motor Recovery in Acute Cervical Spinal Cord Injury.

Paresis after spinal cord injury (SCI) is caused by damage to upper and lower motoneurons (LMNs) and may differentially impact neurological recovery. This prospective monocentric longitudinal observational study investigated the extent and severity of LMN dysfunction and its impact on upper extremity motor recovery after acute cervical SCI. Pathological spontaneous activity at rest and/or increased discharge rates of motor unit action potentials recorded by needle electromyography (EMG) were taken as parameters for LMN dysfunction and its relation to the extent of myelopathy in the first available spine magnetic resonance imaging (MRI) was determined. Motor recovery was assessed by standardized neurological examination within the first four weeks (acute stage) and up to one year (chronic stage) after injury. Eighty-five muscles of 17 individuals with cervical SCI (neurological level of injury from C1 to C7) and a median age of 54 (28-59) years were examined. The results showed that muscles with signs of LMN dysfunction peaked at the lesion center (Χ2 [2, n = 85] = 6.6, p = 0.04) and that the severity of LMN dysfunction correlated with T2-weighted hyperintense MRI signal changes in routine spine MRI at the lesion site (Spearman ρ = 0.31, p = 0.01). Muscles exhibiting signs of LMN dysfunction, as indicated by pathological spontaneous activity at rest and/or increased discharge rates of motor unit action potentials, were associated with more severe paresis in both the acute and chronic stages after SCI (Spearman ρ acute = -0.22, p = 0.04 and chronic = -0.31, p = 0.004). Moreover, the severity of LMN dysfunction in the acute stage was also associated with a greater degree of paresis (Spearman ρ acute = -0.24, p = 0.03 and chronic = -0.35, p = 0.001). While both muscles with and without signs of LMN dysfunction were capable of regaining strength over time, those without LMN dysfunctions had a higher potential to reach full strength. Muscles with signs of LMN dysfunction in the acute stage displayed increased amplitudes of motor unit action potentials with chronic-stage needle EMG, indicating reinnervation through peripheral collateral sprouting as compensatory mechanism (Χ2 [1, n = 72] = 4.3, p = 0.04). Thus, LMN dysfunction represents a relevant factor contributing to motor impairment and recovery in acute cervical SCI. Defined recovery mechanisms (peripheral reinnervation) may at least partially underlie spontaneous recovery in respective muscles. Therefore, assessment of LMN dysfunction could help refine prediction of motor recovery after SCI.

Novel Autoantibodies in Idiopathic Small Fiber Neuropathy.

OBJECTIVE: Small fiber neuropathy (SFN) is clinically and etiologically heterogeneous. Although autoimmunity has been postulated to be pathophysiologically important in SFN, few autoantibodies have been described. We aimed to identify autoantibodies associated with idiopathic SFN (iSFN) by a novel high-throughput protein microarray platform that captures autoantibodies expressed in the native conformational state. METHODS: Sera from 58 SFN patients and 20 age- and gender-matched healthy controls (HCs) were screened against >1,600 immune-related antigens. Fluorescent unit readout and postassay imaging were performed, followed by composite data normalization and protein fold change (pFC) analysis. Analysis of an independent validation cohort of 33 SFN patients against the same 20 HCs was conducted to identify reproducible proteins in both cohorts. RESULTS: Nine autoantibodies were screened with statistical significance and pFC criteria in both cohorts, with at least 50% change in serum levels. Three proteins showed consistently high fold changes in main and validation cohorts: MX1 (FC = 2.99 and 3.07, respectively, p = 0.003, q = 0.076), DBNL (FC = 2.11 and 2.16, respectively, p = 0.009, q < 0.003), and KRT8 (FC = 1.65 and 1.70, respectively, p = 0.043, q < 0.003). Further subgroup analysis into iSFN and SFN by secondary causes (secondary SFN) in the main cohort showed that MX1 is higher in iSFN compared to secondary SFN (FC = 1.61 vs 0.106, p = 0.009). INTERPRETATION: Novel autoantibodies MX1, DBNL, and KRT8 are found in iSFN. MX1 may allow diagnostic subtyping of iSFN patients. ANN NEUROL 2022;91:66-77.

Small fiber neuropathy: Swiss cohort characterization.

INTRODUCTION/AIM: There is currently insufficient clinical and epidemiological data concerning small fiber neuropathy (SFN). This research analyzes data from medical records to determine epidemiology, demographics, clinical characteristics and etiology of SFN. METHODS: This is a retrospective, observational study of sequential patients diagnosed with definite SFN (typical clinical features, normal nerve conduction studies, abnormal epidermal nerve fiber density) from the end of November 2016 to the middle of July 2019 at the Cantonal Hospital Lucerne, central Switzerland. RESULTS: A total of 84 patients (64.3% female) with a mean age of 54.7 y were analyzed. Symptoms had been present in patients for an average of 4.8 y when entering the study. A length dependent clinical pattern was seen in 79.8%. All patients had sensory discomfort. Etiology could not be determined in 35.7% of patients, who were diagnosed with idiopathic SFN; 34.5% of patients had an apparently autoimmune SFN, followed by14.3% of patients with metabolic causes. The estimated incidence was at least 4.4 cases/100.000 inhabitants/y. The minimum prevalence was 131.5 cases/100.000 inhabitants. DISCUSSION: This study indicates significant incidence and prevalence rates of SFN in Switzerland. SFN can vary greatly in its symptoms and severity. Extensive work-up resulted in two thirds of the patients being assigned an etiological association. The largest group of patients could not be etiologically defined, underlining the importance of further research on etiologic identification. We expect increased awareness of the developing field of SFN.

Neuromuscular ultrasound competency assessment: Consensus-based survey.

Neuromuscular ultrasound is a rapidly evolving specialty with direct application for patient care. Competency assessment is an essential standard needed to ensure quality for practitioners, particularly for those newly acquiring skills with the technique. Our aim was to survey experts' opinions regarding physician competency assessment of neuromuscular ultrasound and to identify minimal competency of knowledge and skills. The opinions of 18 experts were obtained through the Delphi method using two consecutive electronic surveys. A high degree of consensus was achieved on items regarding framework and the conduct of neuromuscular ultrasound assessment and the knowledge and skills that a candidate needs to attain minimal competency in neuromuscular ultrasound. In this study, a group of neuromuscular ultrasound experts developed a general framework for neuromuscular ultrasound competency assessment and recommended testable areas of knowledge and skills suitable for establishing minimal competency.

Limb Hypothermia for the Prevention of Chemotherapy-Induced Peripheral Neuropathy - Modality for Optimal Cooling.

Chemotherapy-induced peripheral neuropathy (CIPN) is a common dose-limiting adverse effect of neurotoxic chemotherapeutic agents. Recent studies have suggested clinical utility of limb hypothermia in reducing CIPN. However, conventional cooling methods such as ice packs are unable to provide thermoregulated cooling and cause frostbites. Cooling modalities offering thermoregulation have been developed for sports injury and orthopaedic indications, but not explored for preventing CIPN. This study aims to determine the safety, tolerability and optimal parameters of three cooling modalities for delivery of limb hypothermia in healthy subjects, prior to testing in cancer patients for prevention of CIPN. Healthy subjects underwent limb hypothermia by either: continuous-flow cooling, cryocompression or frozen gloves. Skin temperatures and tolerance scores were monitored. Overall, 58 subjects underwent limb hypothermia. No adverse events were observed barring transient erythema. Both continuous-flow cooling and cryocompression are feasible, safe and tolerable methods for delivery of limb hypothermia. Cryocompression achieved lower skin temperatures than continuous-flow cooling with similar safety profiles. Frozen gloves were minimally tolerated. Cryocompression may provide greater efficacy in preventing CIPN, with clinical trials currently underway.

Safety and tolerability of cryocompression as a method of enhanced limb hypothermia to reduce taxane-induced peripheral neuropathy.

PURPOSE: Severe peripheral neuropathy is a common dose-limiting toxicity of taxane chemotherapy, with no effective treatment. Frozen gloves have shown to reduce the severity of neuropathy in several studies but comes with the incidence of undesired side effects such as cold intolerance and frostbite in extreme cases. A device with thermoregulatory features which can safely deliver tolerable amounts of cooling while ensuring efficacy is required to overcome the deficiencies of frozen gloves. The role of continuous-flow cooling in prevention of neurotoxicity caused by paclitaxel has been previously described. This study hypothesized that cryocompression (addition of dynamic pressure to cooling) may allow for delivery of lower temperatures with similar tolerance and potentially improve efficacy. METHOD: A proof-of-concept study was conducted in cancer patients receiving taxane chemotherapy. Each subject underwent four-limb cryocompression with each chemotherapy infusion (three hours) for a maximum of 12 cycles. Cryocompression was administered at 16 °C and cyclic pressure (5-15 mmHg). Skin surface temperature and tolerance scores were recorded. Neuropathy was assessed using clinician-graded peripheral sensory neuropathy scores, total neuropathy score (TNS) and nerve conduction studies (NCS) conducted before (NCSpre), after completion (NCSpost) and 3 months post-chemotherapy (NCS3m). Results were retrospectively compared with patients who underwent paclitaxel chemotherapy along with continuous-flow cooling and controls with no hypothermia. RESULTS: In total, 13 patients underwent 142 cycles of cryocompression concomitant with chemotherapy. Limb hypothermia was well tolerated, and only 1 out of 13 patients required an intra-cycle temperature increase, with no early termination of cryocompression in any subject. Mean skin temperature reduction of 3.8 ± 1.7 °C was achieved. Cryocompression demonstrated significantly greater skin temperature reductions compared to continuous-flow cooling and control (p < 0.0001). None of the patients experienced severe neuropathy (clinician-assessed neuropathy scores of grade 2 or higher). NCS analysis showed preservation of motor amplitudes at NCS3m in subjects who underwent cryocompression, compared to the controls who showed significant deterioration (NCS3m cryocompression vs. NCS3m control: ankle stimulation: 8.1 ± 21.4%, p = 0.004; below fibula head stimulation: 12.7 ± 25.6%, p = 0.0008; above fibula head stimulation: 9.4 ± 24.3%, p = 0.002). Cryocompression did not significantly affect taxane-induced changes in sensory nerve amplitudes. CONCLUSION: When compared to continuous-flow cooling, cryocompression permitted delivery of lower temperatures with similar tolerability. The lower skin surface temperatures achieved potentially lead to improved efficacy in neurotoxicity amelioration. Larger studies investigating cryocompression are required to validate these findings.

Guidelines for neuromuscular ultrasound training.

Neuromuscular ultrasound has become an essential tool in the diagnostic evaluation of various neuromuscular disorders, and, as such, there is growing interest in neuromuscular ultrasound training. Effective training is critical in mastering this modality. Our aim was to develop consensus-based guidelines for neuromuscular ultrasound training courses. A total of 18 experts participated. Expert opinion was sought through the Delphi method using 4 consecutive electronic surveys. A high degree of consensus was achieved with regard to the general structure of neuromuscular ultrasound training; the categorization of training into basic, intermediate, and advanced levels; the learning objectives; and the curriculum for each level. In this study, a group of neuromuscular ultrasound experts established consensus-based guidelines for neuromuscular ultrasound training. These guidelines can be used in the development of the specialty and the standardization of neuromuscular ultrasound training courses and workshops.

Preventive hypothermia as a neuroprotective strategy for paclitaxel-induced peripheral neuropathy.

Chemotherapy-induced peripheral neuropathy (CIPN) is a severe adverse effect that occurs secondary to anticancer treatments and has no known preventive or therapeutic strategy. Therapeutic hypothermia has been shown to be effective in protecting against central and peripheral nervous system injuries. However, the effects of therapeutic hypothermia on CIPN have rarely been explored. We induced lower back hypothermia (LBH) in an established paclitaxel-induced CIPN rat model and found that the paclitaxel-induced impairments observed in behavioral, electrophysiological, and histological impairments were inhibited by LBH when applied at an optimal setting of 24°C to the sciatic nerve and initiated 90 minutes before paclitaxel infusion. Lower back hypothermia also inhibited the paclitaxel-induced activation of astroglia and microglia in the spinal cord and macrophage infiltration into and neuronal injury in the dorsal root ganglia and sciatic nerves. Furthermore, LBH decreased the local blood flow and local tissue concentrations of paclitaxel. Finally, in NOD/SCID mice inoculated with cancer cells, the antiproliferative effect of paclitaxel was not affected by the distal application of LBH. In conclusion, our findings indicate that early exposure to regional hypothermia alleviates paclitaxel-induced peripheral neuropathy. Therapeutic hypothermia may therefore represent an economical and nonpharmaceutical preventive strategy for CIPN in patients with localized solid tumors.

Evaluation of radial nerve continuity early after humeral shaft fracture fixation using high-resolution nerve ultrasonography: a pilot study of feasibility.

BACKGROUND: This study evaluated the feasibility and reliability of high-resolution ultrasonography (HRUS) of the radial nerve in the early, postoperative period after operative stabilization of humeral shaft fractures. METHODS: This study enrolled patients between September 2015 and April 2018 with a humeral shaft fracture who were assessed with HRUS within 2 weeks after surgery. Based on the ultrasound artifacts, the examiners subjectively defined quality of ultrasound as "bad" or "good." The cross-sectional area of the radial and the posterior interosseous nerve was recorded at predefined locations. The radial nerve was scanned axially in the whole course to identify nerve continuity. RESULTS: Of 44 patients who underwent operations for humeral shaft fracture, HRUS was used to assess 15 patients at an average 4.8 ± 2.6 days (range, 2-11 days) after surgery. The examiners defined ultrasound quality as "good" in 13 of 15 patients (~87%). Primary radial nerve palsy (RNP) was identified in 3 of the 15 patients, and 4 sustained secondary RNP. Nerve continuity was demonstrated by HRUS in every patient. In patients with RNP, nerve continuity was secondarily confirmed by surgical exploration or functional and electrophysiological recovery. CONCLUSION: Early postoperative HRUS of the radial nerve after osteosynthesis of humeral shaft fractures is a feasible and reliable method to identify radial nerve continuity. In case of pathology, this assessment tool can additionally provide valuable information concerning location and etiology of the RNP.

Indications for neuromuscular ultrasound: Expert opinion and review of the literature.

Over the last two decades, dozens of applications have emerged for ultrasonography in neuromuscular disorders. We wanted to measure its impact on practice in laboratories where the technique is in frequent use. After identifying experts in neuromuscular ultrasound and electrodiagnosis, we assessed their use of ultrasonography for different indications and their expectations for its future evolution. We then identified the earliest papers to provide convincing evidence of the utility of ultrasound for particular indications and analyzed the relationship of their date of publication with expert usage. We found that experts use ultrasonography often for inflammatory, hereditary, traumatic, compressive and neoplastic neuropathies, and somewhat less often for neuronopathies and myopathies. Usage significantly correlated with the timing of key publications in the field. We review these findings and the extensive evidence supporting the value of neuromuscular ultrasound. Advancement of the field of clinical neurophysiology depends on widespread translation of these findings.

Acute painful autoimmune neuropathy: A variant of Guillain-Barré syndrome.

INTRODUCTION: We present a painful small-fiber neuropathy variant of Guillain-Barré syndrome characterized by antecedent infectious symptoms, hyporeflexia, and albuminocytologic dissociation. METHODS: Two patients received intravenous immunoglobulin, one corticosteroids. RESULTS: The patients subsequently improved. Immunoglobulin G (IgG) antibodies in their acute phase sera strongly bound to murine small nerve fibers, and the binding disappeared during the convalescent phase. Serum transfer to a murine nociceptive model induced transient alteration in thermal pain responses. DISCUSSION: Our case series suggest that an acute transient immune response can be directed against small nerve fibers, and that patients so affected can exhibit features of Guillain-Barré syndrome. Muscle Nerve 57: 320-324, 2018.

[A selection of advances in neuromuscular medicine]. / Neueste Entwicklungen der Neuromuskulären Medizin.

A selection of advances in neuromuscular medicine Abstract. Significant developments in the realm of neuromuscular medicine have occurred in both non-invasive diagnostics as well as treatments. Whole body muscle MRI can detect disease specific patterns and lead to the implementation of direct molecular genetic diagnostics. Bedside neuromuscular ultrasound can assist in diagnosing inflammatory neuropathies even in some cases enabling the omission of nerve biopsy and lumbar puncture. Specific antibodies aid in the classification and management of acquired autoimmune diseases. First effective genetic therapies for monogenetic neuromuscular illnesses are now available for spinal muscular atrophy and familial transthyretin amyloidosis. This overview aims to highlight select new diagnostic and therapeutic achievements in the realm of neuromuscular medicine.

Electrodiagnosis of reversible conduction failure in Guillain-Barré syndrome.

INTRODUCTION: In this study we propose electrodiagnostic criteria for early reversible conduction failure (ERCF) in axonal Guillain-Barré syndrome (GBS) and apply them to a cohort of GBS patients. METHODS: Serial nerve conduction studies (NCS) were retrospectively analyzed in 82 GBS patients from 3 centers. The criteria for the presence of ERCF in a nerve were: (i) a 50% increase in amplitude of distal compound muscle action potentials or sensory nerve action potentials; or (ii) resolution of proximal motor conduction block with an accompanying decrease in distal latencies or compound muscle action potential duration or increase in conduction velocities. RESULTS: Of 82 patients from 3 centers, 37 (45%) had ERCF, 21 (26%) had a contrasting evolution pattern, and 8 (10%) had both. Sixteen patients did not show an amplitude increase of at least 50%. CONCLUSION: Our proposed criteria identified a group of patients with a characteristic evolution of NCS abnormality that is consistent with ERCF. Muscle Nerve 56: 919-924, 2017.