High-resolution nerve ultrasound and corneal confocal microscopy in taxane-induced polyneuropathy.

BACKGROUND AND PURPOSE: The role of high-resolution nerve ultrasound (HRUS) and corneal confocal microscopy (CCM) in the early detection of taxane-induced polyneuropathy (TIPN) is unclear. The present prospective longitudinal controlled observational pilot study estimates the role of HRUS and CCM in the early diagnosis of TIPN in breast cancer patients. METHODS: Fifteen breast cancer patients receiving paclitaxel and 15 healthy age matched controls were included. Visits before and 3 weeks, 8 weeks and 6 months after treatment included clinical examination, the total neuropathy score, nerve conduction studies (NCS), monocular CCM including corneal nerve fibre length, density and branching and HRUS of bilateral median, ulnar, radial, tibial, peroneal and sural nerves. Patients were compared between different visits and to healthy controls. RESULTS: Total neuropathy score increased from 2.2 at baseline to 5.8 (p < 0.001) at week 8. NCS showed a decreased sensory amplitude in the sural, radial, ulnar and median nerve after 6 months (p < 0.001). HRUS revealed a significant increase of cross-sectional area in the sural nerve (p = 0.004), the median nerve (p = 0.003) at the carpal tunnel and the ulnar nerve in the forearm (p = 0.006) after 6 months. CCM showed no changes at different visits. CONCLUSIONS: Corneal confocal microscopy and HRUS do not detect early signs of TIPN during the paclitaxel treatment period. HRUS and NCS might detect congruent signs of an axonal, predominantly sensory polyneuropathy after 6 months. The clinical examination remains the most sensitive tool in the early detection of TIPN in breast cancer patients.

Nitrous-oxide-induced polyneuropathy and subacute combined degeneration of the spine: clinical and diagnostic characteristics in 70 patients, with focus on electrodiagnostic studies.

BACKGROUND AND PURPOSE: Nitrous oxide (N2 O) induced neurological symptoms are increasingly encountered. Our aim is to provide clinical and diagnostic characteristics with a focus on electrodiagnostic studies. METHODS: Patients with neurological sequelae due to N2 O presenting in our hospital between November 2018 and December 2021 reporting clinical and diagnostic data were retrospectively reviewed. RESULTS: Seventy patients (median 22 years) were included. Median N2 O usage was 4 kg/week during 12 months. Patients' history revealed a higher rate of sensory symptoms compared to motor (97% vs. 57%) and 77% walking difficulties. Clinical diagnosis was polyneuropathy (PNP) in 44%, subacute combined degeneration (SCD) of the spine in 19%, both in 37%. Median vitamin B12 level was low (159 pmol/L), normal in 16%. The median methylmalonic acid was increased (2.66 µmol/L). Electrodiagnostic abnormalities were observed in 91%, with 72% fulfilling axonal PNP criteria, 20% showing mild to intermediate slowing. One patient fulfilled demyelinating PNP criteria not related to N2 O abuse (Charcot-Marie-Tooth type 1a). More prominent motor nerve conduction abnormalities were found; lower limbs were more affected. In 64% with normal conduction, myography showed signs of axonal loss. Magnetic resonance imaging showed cervical myelopathy in 58% involving generally five to six segments. CONCLUSIONS: Nitrous oxide (N2 O) leads to neurological symptoms by causing PNP and/or SCD primarily involving the legs. Distinguishing PNP and SCD clinically was shown to be insufficient. Electrodiagnostic studies showed axonal PNP. Demyelinating PNP due to N2 O abuse was not present in our cohort. Therefore, further diagnostic work-up is warranted if demyelinating features are present.

Multifocal motor neuropathy is not associated with altered innate immune responses to endotoxin.

OBJECTIVE: Antibody- and complement-mediated peripheral nerve inflammation are central in the pathogenesis of MMN. Here, we studied innate immune responses to endotoxin in patients with MMN and controls to further our understanding of MMN risk factors and disease modifiers. METHODS: We stimulated whole blood of 52 patients with MMN and 24 controls with endotoxin and collected plasma. With a multiplex assay, we determined levels of the immunoregulating proteins IL-1RA, IL-1ß, IL-6, IL-10, IL-21, TNF-α, IL-8 and CD40L in unstimulated and LPS-stimulated plasma. We compared baseline and stimulated protein levels between patients and controls and correlated concentrations to clinical parameters. RESULTS: Protein level changes after stimulation were comparable between groups (p > 0.05). IL-1RA, IL-1ß, IL-6 and IL-21 baseline concentrations showed a positive correlation with monthly IVIg dosage (all corrected p-values < 0.016). Patients with anti-GM1 IgM antibodies showed a more pronounced IL-21 increase after stimulation (p 0.048). CONCLUSIONS: Altered endotoxin-induced innate immune responses are unlikely to be a susceptibility factor for MMN.

[Mechanisms of platinum-induced peripheral neuropathy in cancer patients]. / Polineiropatiya, indutsirovannaya primeneniem preparatov platiny u onkologicheskikh bol'nykh.

Chemoinduced polyneuropathy (CIPNP) is a common side-effect of chemotherapy, significantly impairing quality of life in patients treated for cancer. Platinum preparations are the most commonly used chemotherapeutic agents used in the treatment of ovarian, testicular, breast, lung and colon cancers. Clinical examination reveals restrictions on the motor, sensory and autonomic functions of the upper and lower extremities, which occur at different stages of antitumor treatment, seriously complicating the treatment of the underlying disease. Pain and sensory disturbances may persist for months or even years after chemotherapy is completed. Thus, CIPNP is a major problem because it is impossible to predict which patients will develop neurological symptoms, to estimate their timing of manifestation, which can occur at any time during the course of chemotherapy, there is no early indication to reduce the dose of the cytotoxic drug, and there are no drugs that effectively prevent or alleviate the course of neuropathy. This review focuses on neurotoxicity with the use of platinum drugs, including the frequency of occurrence, risk factors, cumulative doses, various pathogenetic mechanisms for the development of CIPNP, clinical features and variants of the neurophysiological picture.

Acute/subacutae demyelinating polyneuropathy in Parkinson's Disease patients on levodopa-carbidopa intestinal gel therapy: systematic review with new case report.

Polyneuropathy (PNP) is a known complication of levodopa-carbidopa intestinal gel (LCIG) therapy of advanced Parkinson's Disease (PD). The overall prevalence of PNP in PD is estimated to be 42.1% (as shown in a review by Romagnolo et al. 2018), and the most common type is chronic axonal polyneuropathy. There is a group of acute/subacute onset demyelinating polyneuropathies, which is far less common, although it seems to be an important factor leading to the rapid discontinuation of LCIG treatment. In this systematic review, we present data on demyelinating polyneuropathy with acute/subacute onset; we identified nine papers including prospective assessments and case reports, with detailed information on 15 patients. In all patients, despite treatment with corticosteroids, intravenous immunoglobulins (IVIG) or plasma exchange (PE), the LCIG therapy was terminated. We also present a case of subacute demyelinating polyneuropathy with effective treatment and continuation of LCIG therapy.

Clinical feature and sural biopsy study in nitrous oxide-induced peripheral neuropathy.

OBJECTIVE: The objective was to analyze the clinical characteristics and pathological characteristics of sural biopsy in nitrous oxide (N2O) -induced peripheral neuropathy. METHODS: We recruited 18 patients with N2O abuse-induced neurological disorders and reported their demographic data, clinical manifestations, laboratory examinations, and nerve conduction studies. Seven patients underwent sural nerve biopsy pathologic examination. RESULTS: All 18 patients had polyneuropathy, the nerve conduction results showed significant reductions in motor and sensory amplitudes, slowing of conduction velocities, and prolongation of latencies in most tested nerves compared to the controls. Toluidine blue staining of semi-thin sections of sural nerve biopsy showed decreased myelinated nerve fiber density, increased thin myelinated nerve fiber density, and axonal regeneration. Electron microscopy showed axonal degeneration and nerve regeneration. CONCLUSION: The main manifestations of peripheral nerve damage caused by the abuse of N2O are lower limb weakness and distal sensory disorder. The nerve conduction study results demonstrated that mixed axonal and demyelinating neuropathy was the most common type of neuropathy. Sural biopsy showed the main pathological change was chronic axonal degeneration.

Successful utilization of high frequency spinal cord stimulation for HIV and chemotherapy induced polyneuropathy.

We present a case of a 53-year-old male who presented with functionally limiting bilateral lower extremity neuropathic pain secondary to multiple subtypes of small fiber neuropathy. He had failed management with multiple conservative measures including oral medications, physical therapy and desensitization techniques. He ultimately underwent placement of a spinal cord stimulator and continued to experience 80% improvement of his pain, as well as improved function and quality of life at 5 month follow-up. To our knowledge, this is the first reported case of successful treatment of multiple subtypes of small fiber neuropathy with spinal cord stimulator.

We report a case of a 53-year-old male who presented with multiple subtypes of small fiber neuropathy, characterized by abnormal sensation and nerve pain in his distal lower extremities, which was making performing his activities of daily living challenging. He had failed multiple conservative measures including oral medications, physical therapy and desensitization techniques. The patient then underwent a trial with a spinal cord stimulator, which includes placing a device in the spinal canal that can alleviate pain by providing low levels of electrical current. At the 5 month follow-up, he continued to report 80% improvement of his pain as well as improved function and quality of life. This is the first reported use of spinal cord stimulator in a patient with multiple subtypes of small fiber neuropathy.

Peripheral polyneuropathy and acute psychosis from chronic nitrous oxide poisoning: A case report with literature review.

RATIONALE: Nitrous oxide (NO) is a commonly used drug in medical practice, restoration, and the automobile industry. Recreational abuse is an emerging public health problem owing to its accessibility and drug properties. PATIENT CONCERNS: A 25-year-old male was hospitalized with acute psychosis and lower-extremity sensorimotor proprioceptive ataxia due to nitrous oxide abuse. DIAGNOSIS: Laboratory studies confirmed a vitamin B12 deficiency. Magnetic resonance imaging of the spinal cord showed normal findings. Electrophysiological testing confirmed length-dependent sensorimotor polyneuropathy, with a predominant motor component and axonal degeneration. INTERVENTION AND OUTCOMES: Abstinence from toxic substances was suggested, and vitamin B12 substitution was introduced. The patient was lost to follow up. LESSONS: Nitrous oxide toxicity is multisystemic and is thought to result from vitamin B12 inactivation. Recent case reports postulated direct paranodal lesions resulting from nitrous oxide consumption. Neurological, neuropsychiatric, and hematological toxicities are among those explored in this case report. Correction of the functional vitamin B12 status and nitrous oxide abstinence are essential in the treatment process.

Peripheral neuropathies after BRAF and/or MEK inhibitor treatment: A pharmacovigilance study.

Reports suggested the potential occurrence of peripheral neuropathies (PN) in patients treated with BRAF (BRAFi) and/or MEK inhibitors (MEKi) for BRAF-activated tumours. We aimed to better characterize these PN. We queried the French pharmacovigilance database for all cases of PN attributed to BRAFi and/or MEKi. Fifteen patients were identified. Two main clinical PN phenotypes were seen. Six patients presented a length-dependent, axonal polyneuropathy: symptoms were mostly sensory and affecting the lower limbs; management and outcome were variable. Nine patients developed a demyelinating polyradiculoneuropathy: symptoms affected the four limbs and included hypoesthesia, weakness and ataxia; cranial nerves were involved in four cases; most patients received intravenous immunoglobulins or glucocorticoids, with variable outcome; one patient was rechallenged with a different BRAFi/MEKi combination with a rapid relapse in symptoms. In conclusion, patients under BRAFi/MEKi therapy may develop treatment-induced PN. Two main phenotypes can occur: a symmetric, axonal, length-dependent polyneuropathy and a demyelinating polyradiculoneuropathy.

Multifocal motor neuropathy after SARS-CoV-2 vaccination: a causal or coincidental association?

Multifocal motor neuropathy (MMN) is an immune-mediated and acquired demyelinating motor polyneuropathy. Several cases of polyneuropathy associated with severe acquired respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination have been reported. However, MMN has not been reported as a complication of SARS-CoV-2 vaccination. In this study, we report a case of MMN with progressive muscle weakness following the second dose of the Pfizer-BioNTech mRNA vaccine. It was diagnosed by clinical evaluation and electroneuromyography. SARS-CoV-2 vaccination is increasing rapidly all over the world. Some cases of polyneuropathy, especially Guillain-Barré syndrome, have been reported after vaccination. This is the first case report of MMN after SARS-CoV-2 vaccination.

[Cadmium polyneuropathy: a rare, but not less important, cause of peripheral neuropathy]. / Polineuropatía por cadmio: una causa infrecuente, pero no menos importante, de neuropatía periférica.

INTRODUCTION: Cadmium is an important heavy metal in neurobiology, with potential neurotoxic effects, often in the form of polyneuropathy (PNP). CASE REPORT: We present an exceptional case of PNP due to cadmium of toxic-occupational origin, specifically a 47-year-old man, aeronautical mechanic, with a 5-year clinical picture, consisting of a tingling sensation having a 'glove and stocking' distribution of symptoms and bimanual manipulative clumsiness. The neurological examination revealed bilateral achilles hyporeflexia and protopathic-thermal-algesic exteroceptive hypoesthesia in hands and feet. The following complementary rests were requested: toxic-metabolic-infectious-vitamin profile, full craniospinal MRI, electroneurographic-electromyographic study (ENG-EMG) of the upper and lower limbs, PET-CT body and 24-hour video-electroencephalogram. The results were consistent with an axonal, distal, symmetric sensory-motor PNP, of moderate intensity, chronic evolution, with active denervation, of toxic-occupational origin due to cadmium. The patient continued on sick leave to cease exposure to cadmium, initiating intensive multimodal neurorehabilitation program, with serial analytical determinations of toxins and new ENG-EMG studies every 6 months. With normalization of the altered values ??and complete clinical restitution at one-year follow-up. CONCLUSIONS: This case highlights the importance of including the toxicological determination of cadmium in case of suspicion of a PNP of toxic-occupational origin, once ruled out other etiologies, in order to early interrupt occupational exposure, as it is a potentially reversible cause of peripheral neuropathy. Currently there is no specific pharmacological treatment against cadmium tested in humans. Randomized clinical trials carried out in these patients are warranted to develop an anti-cadmium drug in refractory cases despite the end of exposure.

TITLE: Polineuropatía por cadmio: una causa infrecuente, pero no menos importante, de neuropatía periférica.Introducción. El cadmio es un metal pesado importante en neurobiología, con potenciales efectos neurotóxicos, frecuentemente en forma de polineuropatía. Caso clínico. Presentamos un caso excepcional de polineuropatía por cadmio de origen tóxico-ocupacional, en concreto, un varón de 47 años, mecánico aeronáutico, con un cuadro de cinco años de evolución, consistente en sensación de hormigueo 'en guante y calcetín' y torpeza manipulativa bimanual. En la exploración destacaba una hiporreflexia aquílea bilateral, y una hipoestesia exteroceptiva protopático-térmico-algésica en las manos y los pies. Se solicitó analítica general completa con perfil tóxico-metabólico-infeccioso-vitamínico, resonancia magnética craneomedular completa, estudio electroneurográfico-electromiográfico de los miembros superiores e inferiores, tomografía por emisión de positrones-tomografía axial computarizada body y videoelectroencefalograma de 24 horas. Los resultados fueron compatibles con una polineuropatía sensitivomotora axonal, distal, simétrica, de intensidad moderada, de evolución crónica y desnervación activa, de origen tóxico-ocupacional por cadmio. El paciente prosiguió la baja laboral para cesar la exposición al cadmio, iniciando neurorrehabilitación intensiva multimodal, y determinaciones analíticas seriadas de tóxicos y nuevos estudios electroneurográficos-electromiográficos cada seis meses, con normalización de los valores alterados y restitución clínica ad integrum al año. Conclusiones. Este caso enfatiza la importancia de incluir la determinación toxicológica del cadmio ante la sospecha de una polineuropatía de origen tóxico-ocupacional, descartadas otras etiologías, para interrumpir precozmente dicha exposición laboral, al ser una causa potencialmente reversible de neuropatía periférica. Actualmente no existe un tratamiento farmacológico específico frente al cadmio demostrado en seres humanos. Urgen ensayos clínicos aleatorizados en estos pacientes, para desarrollar un fármaco frente al cadmio en casos refractarios pese a finalizar la exposición.

Use of Neuromuscular Ultrasound in the Diagnosis of Disulfiram Polyneuropathy.

ABSTRACT: We present the case of a 37-year-old woman with alcohol use disorder, who developed leg cramping, bilateral foot drop, and hand weakness 3 months after starting disulfiram. This was accompanied by an 18-pound involuntary weight loss. Electrophysiologic findings showed a motor predominant axonal neuropathy. Neuromuscular ultrasound showed normal to small cross-sectional area of all nerves studied. This case is discussed, and the ultrasound findings are compared with another reported case.

Neurofilament proteins as a potential biomarker in chemotherapy-induced polyneuropathy.

BACKGROUNDPaclitaxel chemotherapy frequently induces dose-limiting sensory axonal polyneuropathy. Given that sensory symptoms are challenging to assess objectively in clinical practice, an easily accessible biomarker for chemotherapy-induced polyneuropathy (CIPN) holds the potential to improve early diagnosis. Here, we describe neurofilament light chain (NFL), a marker for neuroaxonal damage, as a translational surrogate marker for CIPN.METHODSNFL concentrations were measured in an in vitro model of CIPN, exposing induced pluripotent stem cell-derived sensory neurons (iPSC-DSNs) to paclitaxel. Patients with breast or ovarian cancer undergoing paclitaxel chemotherapy, breast cancer control patients without chemotherapy, and healthy controls were recruited in a cohort study and examined before chemotherapy (V1) and after 28 weeks (V2, after chemotherapy). CIPN was assessed by the validated Total Neuropathy Score reduced (TNSr), which combines patient-reported symptoms with data from clinical examinations. Serum NFL (NFLs) concentrations were measured at both visits with single-molecule array technology.RESULTSNFL was released from iPSC-DSNs upon paclitaxel incubation in a dose- and time-dependent manner and was inversely correlated with iPSC-DSN viability. NFLs strongly increased in paclitaxel-treated patients with CIPN, but not in patients receiving chemotherapy without CIPN or controls, resulting in an 86% sensitivity and 87% specificity. An NFLs increase of +36 pg/mL from baseline was associated with a predicted CIPN probability of more than 0.5.CONCLUSIONNFLs was correlated with CIPN development and severity, which may guide neurotoxic chemotherapy in the future.TRIAL REGISTRATIONClinicalTrials.gov NCT02753036.FUNDINGDeutsche Forschungsgemeinschaft (EXC 257 NeuroCure), BMBF (Center for Stroke Research Berlin, 01 EO 0801), Animalfree Research, EU Horizon 2020 Innovative Medicines Initiative 2 Joint Undertaking (TransBioLine, 821283), Charité 3R - Replace - Reduce - Refine.

Severe Generalized Weakness, Paraplegia following administration of Oxaliplatin in a patient with refractory T-cell non-Hodgkin lymphoma: A case report.

INTRODUCTION: Oxaliplatin is a third-generation platinum compound that used extensively for the treatment of various types of cancer especially gastrointestinal neoplasms. The main dose-limiting toxicities of oxaliplatin are hematological toxicity and peripheral sensory neuropathy. CASE REPORT: A 42-year-old man with refractory peripheral T-cell lymphoma (PTCL) was admitted to receive GEMOX chemotherapy regimen (gemcitabine, oxaliplatin). Three days after receiving his third cycle of chemotherapy regimen, he was re-admitted to the emergency department with complaint of severe generalized weakness, and paraplegia in the lower extremities. According to clinical and para-clinical findings, chronic sensorimotor polyneuropathy with ongoing axonal loss was confirmed. MANAGEMENT & OUTCOME: Intravenous dexamethasone 8 mg three times daily was started at the time of admission for the patient. Muscle weakness and sensory impairment improved dramatically within 10 days and the patient was able to walk with assistance. DISCUSSION: Several cases of neuropathy following oxaliplatin and only one case with gemcitabine-based chemotherapy regimen have been previously reported. However, motor symptoms are rare unless in the setting of acute neuropathy due to oxaliplatin. The most striking finding of our study was the incidence of a chronic sensorimotor axonaldemyelinating polyneuropathy in a patient who were subjected to oxaliplatin therapy. In conclusion, we report a case of severe generalized weakness and paraplegia following administration of Oxaliplatin.