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.

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.

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.

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.

Taxane-induced polyneuropathy - current possibilities of prediction and management

Peripheral neurotoxicity is the most typical non-haematological adverse effect of taxanes. Symptoms are dominated by sensory peripheral neuropathy, the incidence and degree of which depend on the cumulative dose level. The impact of neurotoxicity on the patient´s quality of life is significant, therefore it is necessary to consider the selection of therapy and the patient´s pre-existing risk factors for developing neuropathy and to get acquainted with current management options, including genetic prediction of polyneuropathy. This review article reports on a very common complication of cancer therapy that can be encountered at each internist´s outpatient dispensary.

Lithium toxicity with prolonged neurologic sequelae following sleeve gastrectomy: A case report and review of literature

RATIONALE

Lithium is the first-line medication for bipolar disorder, given a narrow therapeutic window of 0.8 to 1.2 mEq/L. Change of lithium pharmacokinetics following bariatric surgery may lead to lithium toxicity, which is particularly concerned.

PATIENT CONCERNS

We presented a 39-year-old man with morbid obesity and bipolar affective disorder for 20 years, who was treated with lithium. He developed serious lithium toxicity following sleeve gastrectomy and prolonged neurologic sequelae.

DIAGNOSES

He suffered from persistent watery diarrhea, general weakness, and then drowsy consciousness. Lithium level was checked immediately to be 3.42 mEq/L and lithium toxicity was diagnosed.

INTERVENTIONS

After 3 courses of hemodialysis, his serum lithium level subsequently declined to 0.63 mEq/L, while his consciousness returned normal. Lithium was replaced by lamotrigine.

OUTCOMES

The patient was discharged thirty-five days after admission, while his serum lithium declined to 0.06 mEq/L. Neurologic sequelae were noted by muscle weakness and pain sensation in both feet. The nerve conduction test revealed sensorimotor polyneuropathy with conduction block. He was advised to keep a passive range of motion exercise.

LESSONS

Although the consensus guideline remains lacking, our report reviewed cases of relevance in the literature and highlighted the awareness of the potential risk of lithium toxicity following bariatric surgery. We suggest close monitoring of the lithium levels and perhaps a dosage adjustment for the postoperative period.

Comparison of high tone therapy and transcutaneous electrical nerve stimulation therapy in chemotherapy-induced polyneuropathy

INTRODUCTION

Chemotherapy-induced peripheral neuropathy (CIPN) is a worldwide concern in patients receiving neurotoxic agents for cancer therapy. High tone external muscle stimulation is a promising therapeutic approach to alleviate symptoms of CIPN.

METHODS

This pilot study aims to investigate whether the application of home-based high-tone external muscle stimulation therapy (HTEMS) improves symptoms of CIPN. The trial is planned as a therapist- and assessor-blinded, 1:1 randomized controlled study. A total of 50 patients with chemotherapy-induced peripheral polyneuropathy will be included. All patients will perform therapy at home. Study participants will be allocated randomly to the HTEMS therapy (intervention group) or to the transcutaneous electrical nerve stimulation (TENS, control group), respectively, following a standardized therapy schedule. Compliance of participants can be verified by reading out the tool box. Outcomes will be evaluated at baseline and after 8 weeks of home-based therapy. The primary outcome includes improvement of CIPN according to the patient-reported EORTC QLQ-CIPN 20 questionnaire. Secondary outcomes are the patient-reported change in health-related quality of life and clinician-reported changes of vibration sensibility, tendon reflexes, temperature sensibility, perception of touch, and strength of the lower leg muscles. Further a safety- and process evaluation will be performed.

DISCUSSION

This pilot RCT aims to evaluate the impact of home-based HTEMS as compared to TENS in CIPN. There is a need for an effective treatment for CIPN and the results of this study are expected to possibly identify a novel and effective treatment strategy in the future.

[Festive use of nitrous oxide: major risks !]

Nitrous oxide is increasingly consumed during parties for its euphoric properties. But unfortunately, in several cases it leads to real addictions. Unfortunately because its use leads to neurological, psychiatric, pulmonary and even death -by hypoxia-. It is important that the medical community be informed. It is important that the medical community be informed that in the face of atypical and poorly explained disorders doctors may think about the use of laughing gas, especially among young students.

A Pilot, Phase II, Randomized, Open-Label Clinical Trial Comparing the Neurotoxicity of Three Dose Regimens of Nab-Paclitaxel to That of Solvent-Based Paclitaxel as the First-Line Treatment for Patients with Human Epidermal Growth Factor Receptor Type 2-Negative Metastatic Breast Cancer

BACKGROUND

This study aimed to characterize the neurotoxicity of three different regimens of nab-paclitaxel compared with a standard regimen of solvent-based (sb) paclitaxel for the first-line treatment of HER2-negative metastatic breast cancer based on the Total Neurotoxicity Score (TNS), a tool specifically developed to assess chemotherapy-induced neurotoxicity.

MATERIALS AND METHODS

This was a randomized, open-label study testing 4-week cycles of 80 mg/m² sb-paclitaxel (PACL80/w) on days 1, 8, and 15; 100 mg/m² nab-paclitaxel on days 1, 8, and 15 (NAB100/w); 150 mg/m² nab-paclitaxel on days 1, 8, and 15 (NAB150/w); and 150 mg/m² nab-paclitaxel on days 1 and 15 (NAB150/2w). In addition to the TNS, neuropathy was assessed using the National Cancer Institute Common Terminology Criteria for Adverse Events (NCI-CTCAE). Tumor response and quality of life were also evaluated.

RESULTS

Neurotoxicity, as evaluated by the TNS, did not significantly differ between the sb-paclitaxel group and any of the nab-paclitaxel groups. The frequency of (any grade) polyneuropathy, as measured by the NCI-CTCAE, was lower in the PACL80/w (n = 7, 50%) and NAB150/2w (n = 10, 62.5%) groups than in the NAB100/w (n = 13, 81.3%) or NAB150/w (n = 11, 78.6%) group. Although the differences were not statistically significant, compared with the other groups, in the NAB150/w group, the time to occurrence of grade ≥2 polyneuropathy was shorter, and the median time to recovery from grade ≥2 polyneuropathy was longer. Dose delays and reductions due to neurotoxicity and impact of neurotoxicity on the patients' experience of symptoms and functional limitations was greater with NAB150/w. Among the seven polymorphisms selected for genotyping, the variant alleles of EPHA5-rs7349683, EPHA6-rs301927, and EPHA8-rs209709 were associated with an increased risk of paclitaxel-induced neuropathy.

CONCLUSION

The results of this exploratory study showed that, regardless of the dose, nab-paclitaxel did not differ from sb-paclitaxel in terms of neurotoxicity as evaluated with the TNS. However, results from NCI-CTCAE, dose delays and reductions, and functional tools consistently indicate that NAB150/w regimen is associated with a greater risk of chemotherapy-induced neuropathy. Thus, our results question the superiority of the TNS over NCI-CTCAE for evaluating chemotherapy-induced neuropathy and guiding treatment decisions in this context. The selection of the nab-paclitaxel regimen should be individualized based on the clinical context and potentially supported by pharmacogenetic analysis. Registry: EudraCT, 2012-002361-36; NCT01763710 IMPLICATIONS FOR PRACTICE: The results of this study call into question the superiority of the Total Neurotoxicity Score over the National Cancer Institute Common Terminology Criteria for Adverse Events for evaluating chemotherapy-induced neuropathy and guiding treatment decisions in this context and suggest that a regimen of 150 mg/m² nab-paclitaxel administered on days 1, 8, and 15 is associated with a greater risk of chemotherapy-induced neuropathy and hematological toxicity compared with other lower-dose nab-paclitaxel regimens or a standard regimen of solvent-based paclitaxel. The selection of the nab-paclitaxel regimen should be individualized based on the clinical context and could benefit from pharmacogenetics analysis.

Sensory Neuropathy Affects Cardiac miRNA Expression Network Targeting IGF-1, SLC2a-12, EIF-4e, and ULK-2 mRNAs

Background: Here we examined myocardial microRNA (miRNA) expression profile in a sensory neuropathy model with cardiac diastolic dysfunction and aimed to identify key mRNA molecular targets of the differentially expressed miRNAs that may contribute to cardiac dysfunction. Methods: Male Wistar rats were treated with vehicle or capsaicin for 3 days to induce systemic sensory neuropathy. Seven days later, diastolic dysfunction was detected by echocardiography, and miRNAs were isolated from the whole ventricles. Results: Out of 711 known miRNAs measured by miRNA microarray, the expression of 257 miRNAs was detected in the heart. As compared to vehicle-treated hearts, miR-344b, miR-466b, miR-98, let-7a, miR-1, miR-206, and miR-34b were downregulated, while miR-181a was upregulated as validated also by quantitative real time polymerase chain reaction (qRT-PCR). By an in silico network analysis, we identified common mRNA targets (insulin-like growth factor 1 (IGF-1), solute carrier family 2 facilitated glucose transporter member 12 (SLC2a-12), eukaryotic translation initiation factor 4e (EIF-4e), and Unc-51 like autophagy activating kinase 2 (ULK-2)) targeted by at least three altered miRNAs. Predicted upregulation of these mRNA targets were validated by qRT-PCR. Conclusion: This is the first demonstration that sensory neuropathy affects cardiac miRNA expression network targeting IGF-1, SLC2a-12, EIF-4e, and ULK-2, which may contribute to cardiac diastolic dysfunction. These results further support the need for unbiased omics approach followed by in silico prediction and validation of molecular targets to reveal novel pathomechanisms.

Clinical Symptoms, Neurological Signs, and Electrophysiological Findings in Surviving Residents with Probable Arsenic Exposure in Toroku, Japan

Chronic arsenic intoxication is known to cause multisystem impairment and is still a major threat to public health in many countries. In Toroku, a small village in Japan, arsenic mines operated from 1920 to 1962, and residents suffered serious sequelae of arsenic intoxication. We have performed annual medical examinations of these residents since 1974, allowing us to characterize participants' long-term health following their last exposure to arsenic. The participants could not be described as having "chronic arsenic intoxication," because their blood arsenic levels were not measured. In this study, we defined them as having "probable arsenic intoxication." Symptoms frequently involved the sensory nervous system, skin, and upper respiratory system (89.1-97.8%). In an analysis of neurological findings, sensory neuropathy was common, and more than half of the participants complained of hearing impairment. Longitudinal assessment with neurological examinations and nerve conduction studies revealed that sensory dysfunction gradually worsened, even after exposure cessation. However, we could not conclude that arsenic caused the long-term decline of sensory function due to a lack of comparisons with age-matched healthy controls. This is the first study to characterize the longitudinal sequelae after probable arsenic exposure. Our study will be helpful to assess the prognosis of patients worldwide who still suffer from chronic arsenic intoxication.

Pharmacological and mechanical management of calcium channel blocker toxicity

Cardiovascular instability associated with calcium channel blocker toxicity comprises a small percentage of overdose presentations, yet they are associated with a high mortality rate. We detail the management of a 64-year-old man who took an intentional overdose of 840 mg nimodipine. We include the treatment he received and highlight the scarcity of evidence behind the use of gastric decontamination, calcium, glucagon, intravenous lipid emulsion, high-dose insulin therapy, sodium bicarbonate, vasopressors and methylene blue in calcium channel blocker toxicity. Additionally, the article explores the use of electrical pacing and venoarterial extracorporeal membrane oxygenation (VA-ECMO). Following successful weaning of VA-ECMO, the patient was successfully extubated but remained neurologically impaired due to hypoxic-ischaemic brain injury, critical care polyneuropathy and renal failure requiring dialysis. He has cerebral performance category 3; he has mild cognitive impairment but able to perform some activities of daily living independently and communicate his thoughts and needs. He requires no respiratory or cardiovascular support.

Peripheral Neuropathy Due to Recreational Use of Nitrous Oxide Presenting After an Ankle Sprain With Foot Drop

A 22-year-old man was referred for orthopedic follow-up after an ankle injury. Initial evaluation in urgent care included radiographs with negative findings. After a delayed presentation, a course of functional treatment was recommended. Subsequently, he developed a deep venous thrombosis and pulmonary emboli. He was found to be factor V Leiden deficient and was fully anticoagulated on warfarin. Later reevaluation revealed a steppage gait and foot drop. Electrodiagnostic studies (ie, electromyography and nerve conduction studies) revealed a severe peripheral polyneuropathy. The patient admitted to engaging in high-volume recreational use of nitrous oxide. Neurological evaluation confirmed vitamin B12 deficiency consistent with the toxic effects of nitrous oxide. The patient's condition improved with vitamin B supplementation, bracing, and avoidance of nitrous oxide and similar neurotoxins. He participated in a 3-month physical rehabilitation program, and he displayed partial recovery at most recent follow-up. [Orthopedics. 2018; 41(3):e432-e433.].

[Exposure to organophosphate pesticides and peripheral polyneuropathy in workers from Maule Region, Chile]

OBJECTIVE

Organophosphate pesticides (OP) are used massively for their low cost, low environmental persistence and high effectiveness in insect pest control, however, agricultural workers, when exposed to OP, have negative consequences on their health mainly neurological. For the first time, a research is reported in a Latin American population that studied the association between labor exposure to OP and the presence of peripheral polyneuropathy in agricultural workers. The aim of the study was to estimate the relationship between occupational exposure to organophosphate pesticides (OP) and presence of peripheral polyneuropathy in workers in the Maule Region, Chile.

METHODS

We conducted a cross-sectional study with 55 agricultural workers exposed to OP and 58 non-agricultural workers not exposed. It was applied a test for the detection of peripheral polyneuropathy through pallesthetic threshold assessment by on-off method. To estimate the relationship between exposure to OP pesticides and peripheral polyneuropathy, we used a multiple logistic regression model (95% confidence interval).

RESULTS

26% of the total sample had polyneuropathy, with 38% positive cases for the exposed group and 14% for the non-exposed group. The risk of developing peripheral polyneuropathy was 3.6 times higher in workers exposed to OP than in non-exposed workers.

CONCLUSIONS

There is a positive association between the presence of peripheral polyneuropathy and chronic occupational exposure to OP, adjusting for age and sex.

Acute and sub-acute neurological toxicity in children treated for acute lymphoblastic leukemia

Eighty percent of children with acute lymphoblastic leukemia (ALL) survive with current treatments. Neurotoxicity is an infrequent adverse event. We describe clinical presentations of neurological toxicity, phases of treatment when these adverse events were more frequent and patients ́ outcome. From January-1995 to December-2015, 1379 ALL cases were admitted. Neurotoxicity was diagnosed in 49 patients (3.6%) and classified according to neurological syndromes. Medical records, laboratory-tests and images were reviewed. The diagnosed syndromes were: a) Methotrexate-leukoencephalopathy (MLE) (35.4%); b) Cerebral-venous-sinus thrombosis following L-Asparaginase administration (26.5%); c) Vincristine-induced-vocal-cord paralysis (VVCP) (14.2%); d) Stroke-associated vasospasm (14%), after high-dose methotrexate e) Severe polyneuropathy (6.1%); f) Methotrexate myelopathy (2%); and g) Pseudotumor-cerebri (2%) associated with corticosteroid therapy. Neurotoxicity was diagnosed during induction in 55% of cases. We conclude that MLE was the most frequent syndrome. VVCP was observed in infants and Down patients. Seizure was the most common symptom and toxicity occurred mainly during induction phase.

Coexisting myasthenia gravis, myositis, and polyneuropathy induced by ipilimumab and nivolumab in a patient with non-small-cell lung cancer: A case report and literature review

RATIONALE

Immune checkpoint inhibitors have led to the development of new approaches for cancer treatment with positive outcomes. However, checkpoint blockade is associated with a unique spectrum of immune-related adverse events (irAEs), which may cause irreversible neurological deficits and even death.

PATIENT CONCERNS

We presented a case of a 57-year-old man with non-small-cell lung cancer.who developed ptosis, dyspnea, and muscle weakness as initial symptoms with progression after the treatment with ipilimumab and nivolumab.

DIAGNOSES

Myasthenia gravis was confirmed by serum acetylcholine receptor antibody and single fiber electromyography. Myositis was identified by high level of serum creatine phosphokinase and electromyography. Polyneuropathy was identified by nerve conduction study.

INTERVENTIONS

The patient underwent treatment with steroid and pyridostigmine. Respiratory rehabilitation was also performed.

OUTCOMES

Dyspnea and muscle weakness improved gradually. Ipilimumab and nivolumab were permanently discontinued.

LESSONS

This case has increased the clinical awareness by indicating that the checkpoint inhibitors-related neurological irAEs could be complicated and simultaneously involve multiple neurological systems. Early recognition and complete evaluation are critical in clinical practice.

Dorsal root ganglia hypertrophy as in vivo correlate of oxaliplatin-induced polyneuropathy

Purpose

To investigate in vivo morphological and functional correlates of oxaliplatin-induced peripheral neuropathy (OXA-PNP) by magnetic resonance neurography (MRN).

Methods

Twenty patients (7 female, 13 male, 58.9±10.0 years) with mild to moderate OXA-PNP and 20 matched controls (8 female, 12 male, 55.7±15.6 years) were prospectively enrolled. All patients underwent a detailed neurophysiological examination prior to neuroimaging. A standardized imaging protocol at 3.0 Tesla included the lumbosacral plexus and both sciatic nerves and their branches using T2-weighted fat-saturated sequences and diffusion tensor imaging. Quantitative assessment included volumetry of the dorsal root ganglia (DRG), sciatic nerve normalized T2 (nT2) signal and caliber, and fractional anisotropy (FA), mean diffusivity (MD), axial (AD) and radial diffusivity (RD). Additional qualitative evaluation of sciatic, peroneal, and tibial nerves evaluated the presence, degree, and distribution of nerve lesions.

Results

DRG hypertrophy in OXA-PNP patients (207.3±47.7mm³ vs. 153.0±47.1mm³ in controls, p = 0.001) was found as significant morphological correlate of the sensory neuronopathy. In contrast, peripheral nerves only exhibited minor morphological alterations qualitatively. Quantitatively, sciatic nerve caliber (27.3±6.7mm² vs. 27.4±7.4mm², p = 0.80) and nT2 signal were not significantly changed in patients (1.32±0.22 vs. 1.22±0.26, p = 0.16). AD, RD, and MD showed a non-significant decrease in patients, while FA was unchanged.

Conclusion

OXA-PNP manifests with morphological and functional correlates that can be detected in vivo by MRN. We report hypertrophy of the DRG that stands in contrast to experimental and postmortem studies. DRG volume should be further investigated as a biomarker in other sensory peripheral neuropathies and ganglionopathies.

Peripheral nervous system assessment in acromegaly patients under somatostatin analogue therapy

PURPOSE

Acromegaly is known to affect peripheral nervous system (PNS) causing carpal tunnel syndrome (CTS) and polyneuropathy. The frequency of these disorders and the evaluation methods vary among studies. In the present study, we aimed to examine PNS of acromegaly patients under somatostatin analogue (SSA) therapy.

METHODS

Forty-eight acromegaly patients (26 F/22 M, 45.58 ± 11.6 years) under SSA treatment and 44 healthy controls (25 F/19 M, 47.46 ± 8.7 years) were assessed by symptom questionnaires, neurologic examination and electrophysiological studies.

RESULTS

87.5 % of the acromegaly patients had at least one abnormal finding regarding PNS. With the incorporation of palm-wrist median nerve conduction velocity method, we detected CTS in 50 % of patients. Polyneuropathy was less frequent (29.2 %). Both conditions were independent from the coexisting diabetes mellitus (p = 0.22 for CTS, p = 0.71 for polyneuropathy). Polyneuropathy but not CTS was more common among biochemically uncontrolled acromegaly patients rather than those under control (p = 0.03; p = 0.68, respectively).

CONCLUSION

Our findings emphasize the high prevalence of peripheral nervous system involvement in acromegaly patients under SSA therapy and importance of neurological evaluation of these patients. Early diagnosis and treatment of the disease may reduce the PNS involvement.

[Nitrous oxide-induced polyneuropathy]

Nitrous oxide, laughing gas, is used as a party drug to achieve a euphoric effect. It has been gaining popularity in recent years and is considered a relatively innocent substance. Nitrous oxide is known to cause subacute degeneration of the spinal cord by inactivation of active vitamin B12. Vitamin B12 plays an essential role in the synthesis of myelin. Hence, vitamin B12 deficiency can lead to degeneration of the dorsal and lateral columns of the spinal cord. Polyneuropathy is a less known complication. We present a 17-year-old woman and a 19-year-old man with subacute axonal polyneuropathy caused by laughing gas abuse. Abstinence of laughing gas and treatment with intramuscular and oral vitamin B12 suppletion respectively have led to improvement of their symptoms. Our cases demonstrate a less-known but treatable complication of laughing gas.

Delayed Polyneuropathy Induced by Organophosphate Poisoning

An 89-year-old man attempted suicide by ingesting a pesticide (trichlorfon). After surviving the initial critical period in the intensive care unit, he developed rapidly progressive distal weakness and sensory disturbance. Electrophysiological examinations revealed sensory motor axonal polyneuropathy. Delayed polyneuropathy is a rare manifestation of organophosphate poisoning. Nerve conduction studies play an important role in the diagnosis of this rare clinical condition.

Pyridoxine-induced sensory ataxic neuronopathy and neuropathy: revisited

High dose pyridoxine is neurotoxic. Previous case reports were sparse and little is known about the clinical and electrodiagnostic findings. Three patients with pyridoxine-induced sensory ataxic neuropathy were studied and a review of the involved literature was performed. Three patients, aged 80, 83 and 83 years old, presented with sensory ataxia for 3-8 months. Examination showed signs of polyneuropathy and sensory ataxia. Six hundred milligrams of pyridoxine was consumed each day for 3-10 years, in the form of vitamin B1-6-12 combination tablet. Investigations for other causes of neuropathy were unremarkable. Blood levels of vitamin B6 were markedly elevated at 104.6, 81.4 and 66.9 times of upper normal limits. Electrodiagnostic tests showed symmetric axonal sensory polyneuropathy in two patients. Two years after vitamin discontinuation, all patients showed no significant improvement in the neuropathy and gait. In conclusion, consumption of high dose pyridoxine can cause sensory neuronopathy and axonal sensorimotor polyneuropathy, leading to sensory ataxia which may not be reversible.

Assessment of paclitaxel induced sensory polyneuropathy with "Catwalk" automated gait analysis in mice

Neuropathic pain as a symptom of sensory nerve damage is a frequent side effect of chemotherapy. The most common behavioral observation in animal models of chemotherapy induced polyneuropathy is the development of mechanical allodynia, which is quantified with von Frey filaments. The data from one study, however, cannot be easily compared with other studies owing to influences of environmental factors, inter-rater variability and differences in test paradigms. To overcome these limitations, automated quantitative gait analysis was proposed as an alternative, but its usefulness for assessing animals suffering from polyneuropathy has remained unclear. In the present study, we used a novel mouse model of paclitaxel induced polyneuropathy to compare results from electrophysiology and the von Frey method to gait alterations measured with the Catwalk test. To mimic recently improved clinical treatment strategies of gynecological malignancies, we established a mouse model of dose-dense paclitaxel therapy on the common C57Bl/6 background. In this model paclitaxel treated animals developed mechanical allodynia as well as reduced caudal sensory nerve action potential amplitudes indicative of a sensory polyneuropathy. Gait analysis with the Catwalk method detected distinct alterations of gait parameters in animals suffering from sensory neuropathy, revealing a minimized contact of the hind paws with the floor. Treatment of mechanical allodynia with gabapentin improved altered dynamic gait parameters. This study establishes a novel mouse model for investigating the side effects of dose-dense paclitaxel therapy and underlines the usefulness of automated gait analysis as an additional easy-to-use objective test for evaluating painful sensory polyneuropathy.

Neuropathy in Parkinson's disease patients with intestinal levodopa infusion versus oral drugs

Background

Severe polyneuropathy has been observed in a number of patients treated for Parkinson’s disease with Levodopa/Carbidopa intestinal gel infusion. This may reflect a rare individual complication or a systematic side effect.

Objective

To investigate whether peripheral nerve function differed between patients with oral treatment versus Levodopa/Carbidopa intestinal gel infusion.

Methods

In an observational design, data from median, tibial, and peroneal neurography were prospectively assessed and compared between patients with conventional drug treatment (n = 15) and with Levodopa/Carbidopa intestinal gel infusion (n = 15). The groups were matched for age and disease duration. In view of the medical risk profile for polyneuropathy, comorbidity and basic serological parameters were assessed.

Results

Axonal neuropathy was common in both patient groups. However, although group differences in risk factors for polyneuropathy were not evident, neurographic abnormalities were more severe in the patients treated with Levodopa/Carbidopa intestinal gel infusion than in the orally treated patients. In the group with Levodopa/Carbidopa intestinal gel infusion, the degree of neuropathic change correlated with weight lost since therapy initiation and with the drug dose. In contrast to the axonal abnormalities, conduction velocity was found normal in both groups.

Conclusion

The results are compatible with the promotion of axonal neuropathy by Levodopa/Carbidopa intestinal gel infusion. This could be due to the intrinsically high levodopa doses associated with the therapy and/or malnutritional effects from intestinal drug application. The results should be corroborated by a larger longitudinal and controlled trial.

Emerging toxic neuropathies and myopathies

Psychiatrists in practice encounter patients abusing alcohol and street drugs such as cocaine that can lead to toxic myopathies or neuropathies. Psychiatrists also encounter patients with neuropsychiatric systemic lupus erythematosus who are treated with myotoxic medications (e.g., Hydroxychloroquine). Thus a well-rounded knowledge of toxic myopathies and neuropathies is extremely useful. The differential diagnosis of toxic myopathies and neuropathies is expanding rapidly and practical knowledge of these entities is becoming important.

Protective effect of coenzyme Q10 in paclitaxel-induced peripheral neuropathy in rats

OBJECTIVE

To investigate the possible protective effect of coenzyme Q10 (CQ10) on neuropathy in rats.

METHODS

Experiments were conducted in the Department of Pharmacology, Faculty of Medicine, Hacettepe University, Ankara, Turkey between January and March 2012. Forty rats were divided into 4 groups: group 1 (control), group 2 (paclitaxel), group 3 (control + CQ10), and group 4 (paclitaxel + CQ10). Group 2 and 4 rats received paclitaxel (2 mg/kg, intraperitoneally, on days 0, 2, 4, 6). Group 3 and 4 rats were treated with CQ10 (10 mg/kg, intraperitoneally, on days 0, 1, 2, 3, 4, 5, 6, 7, 8, 9). The rats that did not receive paclitaxel or CQ10 received vehicle. Mechanical allodynia tests were performed for each animal on day 0, 2, 6, 8, 10, 14, 16, 19, 39 and 41 for all groups with von Frey filaments.

RESULTS

At day 0, mean mechanical withdrawal thresholds were similar among all groups. Starting from day 2, the threshold of the paclitaxel group decreased. Starting from day 10, paclitaxel+CQ10 treated rats had significantly higher thresholds compared with the paclitaxel group, but these values were still significantly lower than that of the controls. Control and control + CQ10 rats had similar threshold values during the protocol.

CONCLUSION

The CQ10 treatment decreased the degree of paclitaxel-induced peripheral neuropathy in rats.

[The combination of chronic myeloid leukemia and multiple myeloma in one patient]

The article describes the clinical observation of a patient with simultaneous course of lymphoid and myeloid neoplasms. The patient developed two diseases--chronic myeloid leukemia (CML) and multiple myeloma (MM), which were confirmed by corroborated hemogram, myelogram, immunophenotyping of bone marrow cells, biopsy, immunohistochemical, cytogenetic, biochemical and radiological studies. Target therapy of CML with tyrosine kinase inhibitors (imatinib at the standard dose of 400 mg per day) has provided a complete cytogenetic remission at 6 months and major molecular response at 18 months of treatment. Administration of 2 courses of programmed treatment "BD" > (bortezomib + dexamethasone) resulted in a very good partial response, which was maintained through a year and a half. However, against the background of programmed treatment there were developed complications as polyneuropathy of grade 2, which was treated with thioctacide, milgamy, and anemia of grade 2, successfully treated with epoetin beta. Subsequently, the patient was administered continuously with imatinib 400 mg that kept the major molecular response. Relapsed MM was revealed in 20 months and confirmed by a full clinical and hematological examination. The absence of organ dysfunction allowed choosing a supervisory tactics for the patient.

[Clinical characteristics and treatment of polyneuropathy developed after chemotherapy]

Chemotherapy-induced peripheral neuropathy (CIPN) is one of the main problem of modern cytotoxic therapy. Drug dose reduction, delay or even complete stopping of chemotherapy until the regression of CIPN symptoms impair treatment effectiveness and patients' survival. We studied 44 cancer patients with CIPN developed after polychemotherapy. We suggested a treatment regimen that included a complex of allopathic, homeopathic drugs and hydrotherapy. The treatment resulted in a subjective and objective regression of neuropathy symptoms and improving of quality of life in all patients. Patients who had to delay chemotherapy were able to restart it.

Chronic inflammatory demyelinating polyneuropathy due to the administration of pegylated interferon α-2b: a neuropathology case report

We report a 35-year-old man who developed weakness in his extremities five months after pegylated interferon α (IFNα)-2b was administered. The serum tumor necrosis factor-α (TNFα) was elevated and nerve conduction studies revealed demyelination both in the distal and intermediate segments. The sural nerve pathology showed mild demyelinating process. The cessation of IFNα and administration of intravenous immunoglobulin improved both his clinical symptoms and the temporal dispersion in motor nerve conduction study. IFNα-induced CIDP is presumably a transient immunological condition that requires immunomodulatory therapy. The elevated serum TNFα may implicate the degree of downstream autoimmunity induced by IFNα.

Effect of stavudine-based antiretroviral therapy on the severity of polyneuropathy in HIV/AIDS patients: a preliminary report from Zaria, Northern Nigeria

BACKGROUND

Stavudine, a nucleoside reverse transcriptase inhibitor, used as first-line antiretroviral drug in many developing countries is said to exacerbate distal symmetrical polyneuropathy in HIV/AIDS patients.

OBJECTIVE

To evaluate the severity of distal symmetrical polyneuropathy in HIV/AIDS patients on stavudine-based antiretroviral therapy.

METHODS

Two hundred and twenty consecutive HIV-infected antiretroviral-naive adults who were eligible for antiretroviral therapy were studied. Each patient was evaluated using a questionnaire, which contained bio-data and distal neurologic symptoms/signs adapted from the subjective peripheral neuropathy screen and the Leeds assessment of neuropathic symptoms and signs pain score. Patients were then put on stavudine, lamivudine and nevirapine. For three months, after which each patient was re-evaluated using the same protocol. Patients with other risk factors for distal symmetrical polyneuropathy were excluded from the study.

RESULTS

Three months of antiretroviral therapy reduced the mean neuropathic symptoms and signs scores from 0.71 ± 0.76 to 0.26 ± 0.47 (P=0.00) and 0.72 ± 0.57 to 0.58 ± 0.55 (P=0.00) respectively. The number of patients with symptoms and signs also reduced from 97.8% to 24.4% and 65.9% to 55.0% respectively while the mean CD4+ count rose from 194.3 ± 80.4 cells per mL to 416.1±191.2 cells per mL of blood.

CONCLUSION

Three months of stavudine-based antiretroviral therapy reduces the severity of distal symmetrical neuropathy in HIV/AIDS patients, but more studies are needed to evaluate the long-term neuropathic effect of stavudine on Africans.

Pronociceptive pain modulation in patients with painful chemotherapy-induced polyneuropathy

CONTEXT

Several chemotherapy agents induce polyneuropathy that is painful for some patients, but not for others. We assumed that these differences might be attributable to varying patterns of pain modulation.

OBJECTIVES

The aim of the present study was to evaluate pain modulation in such patients.

METHODS

Twenty-seven patients with chemotherapy-induced polyneuropathy were tested for detection thresholds (cold, warm, and mechanical) in both the forearm and foot, as well as for heat pain threshold, mechanical temporal summation (TS), and conditioned pain modulation (CPM; also known as the diffuse noxious inhibitory control-like effect), which were tested in the upper limbs.

RESULTS

Positive correlations were found between clinical pain levels and both TS (r=0.52, P=0.005) and CPM (r=0.40, P=0.050) for all patients. In addition, higher TS was associated with less efficient CPM (r=0.56, P=0.004). The group of patients with painful polyneuropathy (n=12) showed a significantly higher warm detection threshold in the foot (P=0.03), higher TS (P<0.01), and less efficient CPM (P=0.03) in comparison to the group with nonpainful polyneuropathy.

CONCLUSION

The painfulness of polyneuropathy is associated with a "pronociceptive" modulation pattern, which may be primary to the development of pain. The higher warm sensory thresholds in the painful polyneuropathy group suggest that the severity of polyneuropathy may be another factor in determining its painfulness.

[Experience of using thalidomide in the treatment of patients with multiple myeloma]

The results of treatment of patients with multiple myeloma with thalidomide and complications of this treatment are presented. Monotherapy with thalidomide and its combinations with corticosteroids and cytostatics is an effective as first line treatment and as a treatment of patients with refractory disease. The most common side effect is toxic neuropathy. Other complications are less common and are easily controlled with medications.

Paclitaxel induces axonal microtubules polar reconfiguration and impaired organelle transport: implications for the pathogenesis of paclitaxel-induced polyneuropathy

In differentiated axons almost all microtubules (MTs) uniformly point their plus ends towards the axonal tip. The uniform polar pattern provides the structural substrate for efficient organelle transport along axons. It is generally believed that the mass and pattern of MTs polar orientation remain unchanged in differentiated neurons. Here we examined long-term effects of the MTs stabilizing reagent paclitaxel (taxol) over MTs polar orientation and organelle transport in cultured Aplysia neurons. Unexpectedly, we found that rather than stabilizing the MTs, paclitaxel leads to their massive polar reconfiguration, accompanied by impaired organelle transport. Washout of paclitaxel does not lead to recovery of the polar orientation indicating that the new pattern is self-maintained. Taken together the data suggest that MTs in differentiated neurons maintain the potential to be reconfigured. Such reconfiguration may serve physiological functions or lead to degeneration. In addition, our observations offer a novel mechanism that could account for the development of peripheral neuropathy in patients receiving paclitaxel as an antitumor drug.

Sex-related differences in cisplatin-induced neuropathy in rats

BACKGROUND

Cisplatin is used as an anti-neoplastic agent against several cancers. Neuropathy is one of its major side effects that contributes to patients' intolerance to the standard regimen. Sex-related differences have been reported in nerve injury and neuropathies. However, there has been no study on cisplatin regarding this issue.

OBJECTIVE

Compare various abnormalities in cisplatin neuropathy between sexes.

MATERIAL AND METHOD

Two mg/kg of cisplatin was administered intraperitoneally twice a week for five consecutive weeks. Body weight, heat latency of hind paw and sciatic motor nerve conduction velocity (MNCV), pathological alterations in the sciatic nerve and dorsal root ganglion (DRG) including the level of NGF in the sciatic nerve were examined. Untreated rats of both sexes were used as controls.

RESULTS

Weight loss, prolonged heat latency, and slow MNCV in the treated rats of both sexes with higher severity in males were showed. Furthermore, reduction in myelinated fiber diameter, myelin thickness, and myelinated fiber density was more severe in females, whereas, atrophy of neuronal cell body, nucleus, and nucleolus was more striking in males. The decreased level of NGF was similar between sexes.

CONCLUSION

These data suggest the differences in various aspects of cisplatin neurotoxicity between sexes. However, future studies are needed to verify this issue in a clinical condition and clarify the underlying mechanisms.

Different antinociceptive effects of botulinum toxin type A in inflammatory and peripheral polyneuropathic rat models

In addition to inhibition of acetylcholine release in the neuromuscular junction botulinum toxin type A (BoNT-A) also inhibits the release of mediators involved in pain perception. We have investigated the effect of two types of BoNT-A on mechanical hyperalgesia in the rat models of carrageenan-induced hyperalgesia and of paclitaxel-induced peripheral neuropathy. A subplantar (s.p.) injection of BoNT-A in the ipsilateral hindpaw 3 days before carrageenan administration reduced hypersensitivity. Dysport and Botox elicited comparable antihyperalgesic effects. Dysport up to 30 U/kg and Botox up to 20 U/kg did not impair the rat withdrawal nociceptive reflex or the locomotor performance as assessed by the rotarod test. Intraperitoneal administration of the skeletal muscle relaxant dantrolene produced, in contrast to BoNT-A, more motor impairment than analgesia. Paclitaxel treatment resulted in a peripheral neuropathy that affected the two hindpaws. Injection of 20 U/kg (s.p.) Dysport produced a significant antihyperalgesic effect in the injected paw of neuropathic animals 3 days after administration. Unexpectedly, a similar analgesic effect was observed in the contralateral paw. The same results were also observed when Botox was used instead of Dysport. In contrast, a contralateral administration of Dysport in the carrageenan test was ineffective. We conclude that BoNT-A elicits antinociceptive effects independent of the effects on muscular relaxation. Our results suggest that different mechanisms of action are responsible for the effect of BoNT-A in inflammatory and peripheral polyneuropathic rat models.

Multifocal leukoencephalopathy and polyneuropathy after 18 years on interferon a

Multifocal leukoencephalopathy and sensory-motor polyneuropathy have not been reported as side-effects of long-lasting interferon alpha therapy in a single patient. In a 77-year-old man interferon alpha2b and interferon alpha2a were administered subsequently but continuously since 1984 for hairy cell leukemia. Since early 2000, left-sided hemi-hypesthesia occurred and the patient developed gait disturbance, proximal weakness of the lower limbs, bilateral stocking-type sensory disturbances, and restless leg syndrome. Repeated cerebral magnetic resonance images showed multifocal T2-hyperintense white matter lesions supratentorially. The nerve conduction velocity of the peroneal and sural nerve was reduced. After exclusion of various differential diagnoses of leukoencephalopathy and application of a screening program for polyneuropathy, central and peripheral nervous system abnormalities were attributed to the long-lasting interferon alpha therapy. In single patients abnormally long-lasting interferon alpha therapy may cause multifocal white matter lesions supratentorially and sensory-motor polyneuropathy.

Chronic inflammatory demyelinating polyneuropathy after treatment with interferon-alpha

Interferon-alpha (IFN-alpha), though widely used for the treatment of chronic viral hepatitis, may be associated with the occurrence of autoimmune disorders. In this case report, a patient with chronic hepatitis C virus infection had chronic inflammatory demyelinating polyneuropathy (CIDP) after the initiation of IFN-alpha therapy. The neurological symptoms of this patient continued to progress even though the treatment with IFN-alpha had been withdrawn; the symptoms improved dramatically following treatment with intravenous immunoglobulin. This case may therefore provide an important clue to understand the immune mechanism of CIDP and IFN-alpha.

Intensive care unit-acquired neuromyopathy and corticosteroids in survivors of persistent ARDS

OBJECTIVES

To determine the incidence and outcomes of intensive care unit-acquired neuromyopathy and to investigate the role of methylprednisolone in survivors of persistent acute lung injury.

DESIGN

Secondary analysis of completed randomized placebo-controlled trial.

SETTING

Twenty-five hospitals in the NHLBI ARDS Network.

PATIENTS AND PARTICIPANTS

Patients enrolled in the ARDS Network study of methylprednisolone versus placebo for persistent ARDS who survived 60 days or to hospital discharge.

MEASUREMENTS AND RESULTS

One hundred and twenty-eight study patients survived 60 days. Forty-three (34%) of these patients had evidence by chart review of ICU-acquired neuromyopathy, which was associated with prolonged mechanical ventilation, return to mechanical ventilation, and delayed return to home after critical illness. Treatment with methylprednisolone was not significantly associated with an increase in risk of neuromyopathy (OR 1.5; 95% CI 0.7-3.2).

CONCLUSIONS

ICU-acquired-neuromyopathy is common among survivors of persistent ARDS and is associated with poorer clinical outcomes. We did not find a significant association between methylprednisolone treatment and neuromyopathy. Limitations of this study preclude definitive conclusions about the causal relationship between corticosteroids and ICU-acquired neuromuscular dysfunction.