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Continuum (Minneapolis, Minn.) Oct 2023This article reviews the etiologies, presentations, and management of neuropathies related to nutritional deficiencies. (Review)
Review
OBJECTIVE
This article reviews the etiologies, presentations, and management of neuropathies related to nutritional deficiencies.
LATEST DEVELOPMENTS
Peripheral neuropathy can be the predominant or only manifestation of certain nutrient deficiencies. Cognitive difficulties or involvement of other parts of the central nervous system, such as the optic nerve and spinal cord, may accompany nutritional peripheral neuropathies. In most patients, the nutritional deficiency may have a single predominant cause, but in some cases, multiple causes may coexist. Obesity, for unclear reasons, can be associated with nutrient deficiencies. The rising rates of bariatric surgery and the incidence of nutrient deficiencies following bariatric surgery make this a particularly relevant topic for neurologists.
ESSENTIAL POINTS
Neuropathies caused by nutrient deficiencies are preventable with appropriate supplementation in high-risk situations. Early recognition and prompt treatment are essential to ensure an optimal outcome and minimize neurologic morbidity.
Topics: Humans; Peripheral Nervous System Diseases; Obesity; Bariatric Surgery
PubMed: 37851039
DOI: 10.1212/CON.0000000000001292 -
Arteriosclerosis, Thrombosis, and... Aug 2023NT-proBNP (N-terminal pro-B-type natriuretic peptide), high-sensitivity cardiac troponin T (hs-troponin T), and high-sensitivity cardiac troponin I (hs-troponin I) are...
BACKGROUND
NT-proBNP (N-terminal pro-B-type natriuretic peptide), high-sensitivity cardiac troponin T (hs-troponin T), and high-sensitivity cardiac troponin I (hs-troponin I) are increasingly being recommended for risk stratification for a variety of cardiovascular outcomes. The aims of our study were to establish the prevalence and associations of elevated NT-proBNP, hs-troponin T, and hs-troponin I with lower extremity disease, including peripheral artery disease (PAD) and peripheral neuropathy (PN), in the US general adult population without known cardiovascular disease. We also assessed whether the combination of PAD or PN and elevated cardiac biomarkers was associated with an increased risk of all-cause and cardiovascular mortality.
METHODS
We conducted a cross-sectional analysis of the associations of NT-proBNP, hs-troponin T, and hs-troponin I with PAD (based on ankle-brachial index <0.90) and PN (diagnosed by monofilament testing) in adult participants aged ≥40 years of age without prevalent cardiovascular disease in NHANES (National Health and Nutrition Examination Survey) 1999 to 2004. We calculated the prevalence of elevated cardiac biomarkers among adults with PAD and PN and used multivariable logistic regression to assess the associations of each cardiac biomarker, modeled using clinical cut points, with PAD and PN separately. We used multivariable Cox proportional hazards models to assess the adjusted associations of cross categories of clinical categories of each cardiac biomarker and PAD or PN with all-cause and cardiovascular mortality.
RESULTS
In US adults aged ≥40 years, the prevalence (±SE) of PAD was 4.1±0.2% and the prevalence of PN was 12.0±0.5%. The prevalence of elevated NT-proBNP (≥125 ng/L), hs-troponin T (≥6 ng/L), and hs-troponin I (≥6 ng/L for men and ≥4 ng/L for women) was 54.0±3.4%, 73.9±3.5%, and 32.3±3.7%, respectively, among adults with PAD and 32.9±1.9%, 72.8±2.0%, and 22.7±1.9%, respectively, among adults with PN. There was a strong, graded association of higher clinical categories of NT-proBNP with PAD after adjusting for cardiovascular risk factors. Clinical categories of elevated hs-troponin T and hs-troponin I were strongly associated with PN in adjusted models. After a maximum follow-up of 21 years, elevated NT-proBNP, hs-troponin T, and hs-troponin I were each associated with all-cause and cardiovascular mortality, with higher risks of death observed among adults with elevated cardiac biomarkers plus PAD or PN compared with elevated biomarkers alone.
CONCLUSIONS
Our study establishes a high burden of subclinical cardiovascular disease defined by cardiac biomarkers in people with PAD or PN. Cardiac biomarkers provided prognostic information for mortality within and across PAD and PN status, supporting the use of these biomarkers for risk stratification among adults without prevalent cardiovascular disease.
Topics: Male; Humans; Adult; Female; Cardiovascular Diseases; Nutrition Surveys; Troponin T; Cross-Sectional Studies; Troponin I; Peripheral Arterial Disease; Prognosis; Biomarkers; Peripheral Nervous System Diseases; Peptide Fragments; Natriuretic Peptide, Brain; Risk Factors
PubMed: 37317848
DOI: 10.1161/ATVBAHA.122.318774 -
Continuum (Minneapolis, Minn.) Oct 2023The purpose of this article is to provide an overview and update on the most clinically relevant toxic neuropathies.
OBJECTIVE
The purpose of this article is to provide an overview and update on the most clinically relevant toxic neuropathies.
LATEST DEVELOPMENTS
Broadly, toxic neuropathies were previously quite rare with the notable exception of neuropathy from alcohol or older chemotherapeutics. The development of newer therapies, particularly immunotherapy to treat malignancy, has resulted in a substantial increase in the occurrence of toxic neuropathies that require timely recognition and treatment. The understanding of other toxic neuropathies continues to evolve, such as statin-induced neuropathy, which new evidence suggests is much less common than previously suspected.
ESSENTIAL POINTS
Toxic neuropathies can be caused by medications, supplements, and recreational substances that injure peripheral nerves. Medications have evolved in the past 2 decades, as have the types of neuropathies that can be seen as related toxicities. In some areas of medicine, new classes and generations of drugs are associated with a lower incidence of toxic neuropathy.
Topics: Humans; Peripheral Nervous System Diseases; Polyneuropathies
PubMed: 37851038
DOI: 10.1212/CON.0000000000001343 -
Handbook of Clinical Neurology 2024This chapter focuses on neuropathies that present with focal involvement of nerve roots, plexus, and/or peripheral nerves associated with autoimmune and inflammatory... (Review)
Review
This chapter focuses on neuropathies that present with focal involvement of nerve roots, plexus, and/or peripheral nerves associated with autoimmune and inflammatory mechanisms that present with focal involvement of nerve roots, plexus and/or peripheral nerves. The clinical presentation, diagnosis, and treatment of focal autoimmune demyelinating neuropathies, focal nonsystemic vasculitic disorders (diabetic and nondiabetic radiculoplexus neuropathies, postsurgical inflammatory neuropathy, and neuralgic amyotrophy), and focal neuropathies associated with sarcoidosis and bacterial and viral infections are reviewed.
Topics: Humans; Peripheral Nervous System Diseases
PubMed: 38697745
DOI: 10.1016/B978-0-323-90108-6.00009-0 -
Continuum (Minneapolis, Minn.) Oct 2023Coexistence of polyneuropathy and gammopathy is a common but potentially challenging situation in clinical practice. This article reviews the clinical,... (Review)
Review
OBJECTIVE
Coexistence of polyneuropathy and gammopathy is a common but potentially challenging situation in clinical practice. This article reviews the clinical, electrophysiologic, and hematologic phenotypes of the paraproteinemic neuropathies and the diagnostic and treatment strategies for each.
LATEST DEVELOPMENTS
Advances in our understanding of the underlying pathophysiology of various paraproteinemic neuropathies and their corresponding phenotypes have identified potential new therapeutic targets. Therapeutic strategies to diminish anti-myelin-associated glycoprotein (MAG) IgM antibodies have shown partial and inconsistent efficacy; however, antigen-specific immune therapy is being investigated as a novel treatment to remove the presumably pathogenic anti-MAG antibody. Advances in genetic and cell signaling studies have resulted in the approval of Bruton tyrosine kinase inhibitors for Waldenström macroglobulinemia. Monoclonal antibodies are being investigated for the treatment of light chain amyloidosis.
ESSENTIAL POINTS
Early recognition and treatment of underlying plasma cell disorders improves clinical outcomes in patients with paraproteinemic neuropathy. Despite significant progress, our knowledge regarding underlying mechanisms for paraproteinemic neuropathy is still limited. Clinicians' awareness of clinical phenotypes, electrophysiologic hallmarks, and hematologic findings of the different paraproteinemic neuropathies is crucial to promptly identify and treat patients and to avert misdiagnosis. Multidisciplinary collaboration among specialists, including neurologists and hematologists, is paramount for the optimal treatment of these patients with overlapping conditions.
Topics: Humans; Peripheral Nervous System Diseases; Paraproteinemias; Polyneuropathies; Myelin-Associated Glycoprotein; Autoantibodies
PubMed: 37851040
DOI: 10.1212/CON.0000000000001294 -
JAMA Network Open Aug 2023Chemotherapy-induced peripheral neuropathy (CIPN), one of the most common and severe adverse effects of chemotherapy, is associated with worse quality of life among... (Randomized Controlled Trial)
Randomized Controlled Trial
IMPORTANCE
Chemotherapy-induced peripheral neuropathy (CIPN), one of the most common and severe adverse effects of chemotherapy, is associated with worse quality of life among survivors of ovarian cancer. Currently, there is no effective treatment for CIPN.
OBJECTIVE
To evaluate the effect of a 6-month aerobic exercise intervention vs attention-control on CIPN among women treated for ovarian cancer in the Women's Activity and Lifestyle Study in Connecticut (WALC) to provide evidence to inform the guidelines and recommendations for prevention or treatment of CIPN.
DESIGN, SETTING, AND PARTICIPANTS
This prespecified secondary analysis evaluated the Women's Activity and Lifestyle Study in Connecticut (WALC), a multicentered, open-label, population-based, phase 3 randomized clinical trial of an aerobic exercise intervention vs attention control for CIPN in patients who were diagnosed with ovarian cancer. Only WALC participants who received chemotherapy were included in this analysis. Participants were randomized 1:1 to either a 6-month aerobic exercise intervention or to attention control. All analyses were conducted between September 2022 and January 2023.
INTERVENTIONS
The exercise intervention consisted of home-based moderate-intensity aerobic exercise facilitated by weekly telephone counseling from an American College of Sports Medicine/American Cancer Society-certified cancer exercise trainer. Attention control involved weekly health education telephone calls from a WALC staff member.
MAIN OUTCOMES AND MEASURE
Change in CIPN was the primary outcome in this secondary analysis. This outcome was represented by CIPN severity, which was self-measured by participants at baseline and 6 months using the Functional Assessment of Cancer Therapy/Gynecologic Oncology Group-Neurotoxicity scale, with a score range of 0 to 44. A mixed-effects model was used to assess the 6-month change in CIPN between the exercise intervention and attention control arms.
RESULTS
Of the 134 participants (all females; mean [SD] age, 57.5 [8.3] years) included in the analysis, 69 were in the exercise intervention arm and 65 were in the attention control arm. The mean (SD) time since diagnosis was 1.7 (1.0) years. The mean (SD) baseline CIPN scores were 8.1 (5.6) in the exercise intervention arm and 8.8 (7.9) in the attention control arm (P = .56). At 6 months, the self-reported CIPN score was reduced by 1.3 (95% CI, -2.3 to -0.2) points in the exercise intervention arm compared with an increase of 0.4 (95% CI, -0.8 to 1.5) points in the attention control arm. The between-group difference was -1.6 (95% CI, -3.1 to -0.2) points. The point estimate was larger among the 127 patients with CIPN symptoms at enrollment (-2.0; 95% CI, -3.6 to -0.5 points).
CONCLUSIONS AND RELEVANCE
Findings of this secondary analysis of the WALC trial indicate that a 6-month aerobic exercise intervention vs attention control significantly improved self-reported CIPN among patients who were treated for ovarian cancer. While replication of the findings in other studies is warranted, incorporating referrals to exercise programs into standard oncology care could reduce CIPN symptoms and increase quality of life in patients with ovarian cancer.
TRIAL REGISTRATION
ClinicalTrials.gov Identifier: NCT02107066.
Topics: United States; Humans; Female; Middle Aged; Quality of Life; Exercise; Ovarian Neoplasms; Peripheral Nervous System Diseases; Antineoplastic Agents
PubMed: 37526937
DOI: 10.1001/jamanetworkopen.2023.26463 -
Brain : a Journal of Neurology Dec 2023Cerebellar ataxia, neuropathy and vestibular areflexia syndrome (CANVAS) is an autosomal recessive neurodegenerative disease, usually caused by biallelic AAGGG repeat...
Cerebellar ataxia, neuropathy and vestibular areflexia syndrome (CANVAS) is an autosomal recessive neurodegenerative disease, usually caused by biallelic AAGGG repeat expansions in RFC1. In this study, we leveraged whole genome sequencing data from nearly 10 000 individuals recruited within the Genomics England sequencing project to investigate the normal and pathogenic variation of the RFC1 repeat. We identified three novel repeat motifs, AGGGC (n = 6 from five families), AAGGC (n = 2 from one family) and AGAGG (n = 1), associated with CANVAS in the homozygous or compound heterozygous state with the common pathogenic AAGGG expansion. While AAAAG, AAAGGG and AAGAG expansions appear to be benign, we revealed a pathogenic role for large AAAGG repeat configuration expansions (n = 5). Long-read sequencing was used to characterize the entire repeat sequence, and six patients exhibited a pure AGGGC expansion, while the other patients presented complex motifs with AAGGG or AAAGG interruptions. All pathogenic motifs appeared to have arisen from a common haplotype and were predicted to form highly stable G quadruplexes, which have previously been demonstrated to affect gene transcription in other conditions. The assessment of these novel configurations is warranted in CANVAS patients with negative or inconclusive genetic testing. Particular attention should be paid to carriers of compound AAGGG/AAAGG expansions when the AAAGG motif is very large (>500 repeats) or the AAGGG motif is interrupted. Accurate sizing and full sequencing of the satellite repeat with long-read sequencing is recommended in clinically selected cases to enable accurate molecular diagnosis and counsel patients and their families.
Topics: Humans; Bilateral Vestibulopathy; Cerebellar Ataxia; Neurodegenerative Diseases; Peripheral Nervous System Diseases; Syndrome; Vestibular Diseases
PubMed: 37450567
DOI: 10.1093/brain/awad240 -
Diabetes Research and Clinical Practice Dec 2023Diabetic peripheral neuropathy (DPN) is found in around one third of people with diabetes, but remains inadequately diagnosed and treated. Its management includes three... (Review)
Review
Diabetic peripheral neuropathy (DPN) is found in around one third of people with diabetes, but remains inadequately diagnosed and treated. Its management includes three cornerstones: 1) causal treatment with lifestyle modification, intensive diabetes therapy aimed at near-normoglycemia, and multifactorial cardiovascular risk intervention, 2) pathogenesis-oriented pharmacotherapy, and 3) symptomatic pain relief. Since symptomatic analgesic monotherapy only relieves the pain without targeting the underlying neuropathy and both has limited efficacy and is associated with adverse events, there is an unmet need for additional approaches derived from the pathogenetic concepts of DPN. Preclinical studies have suggested that diabetic neuropathy can be prevented or improved through the use of various agents that interfere with the pathophysiology of the underlying condition. Some of these encouraging findings could be translated successfully into the clinical setting. Efficacy and excellent safety were demonstrated in several meta-analyses (α-lipoic acid) and randomized clinical trials (benfotiamine, actovegin, epalrestat) in the treatment of symptomatic DPN. The NATHAN 1 trial demonstrated an improvement of neuropathic signs (deficits, impairments) after four years in asymptomatic DPN. These compounds are currently authorized for treatment of DPN in several countries. Long-term pivotal clinical trials should further establish their value as mono- and combination therapies in DPN.
Topics: Humans; Combined Modality Therapy; Diabetes Mellitus; Diabetic Neuropathies; Pain; Thioctic Acid
PubMed: 38245327
DOI: 10.1016/j.diabres.2023.110764 -
Muscle & Nerve Nov 2023Myelin-associated glycoprotein (MAG) is a transmembrane glycoprotein concentrated in periaxonal Schwann cell and oligodendroglial membranes of myelin sheaths that serves... (Review)
Review
Myelin-associated glycoprotein (MAG) is a transmembrane glycoprotein concentrated in periaxonal Schwann cell and oligodendroglial membranes of myelin sheaths that serves as an antigen for immunoglobulin M (IgM) monoclonal antibodies. Individuals who harbor anti-MAG antibodies classically develop a progressive autoimmune peripheral neuropathy characterized clinically by ataxia, distal sensory loss, and gait instability, and electrophysiologically by distally accentuated conduction velocity slowing. Although off-label immunotherapy is common, there are currently no proven effective disease-modifying therapeutics, and most patients experience slow accumulation of disability over years and decades. The typically slowly progressive nature of this neuropathy presents unique challenges when trying to find effective anti-MAG therapeutic agents. Drug development has also been hampered by the lack of validated outcome measures that can detect clinically meaningful changes in a reasonable amount of time as well as by the lack of disease activity biomarkers. In this invited review, we provide an update on the state of clinicometric outcome measures and disease activity biomarkers in anti-MAG neuropathy. We highlight the insensitivity of widely used existing clinicometric outcome measures such as the Inflammatory Neuropathy Cause and Treatment (INCAT) disability score as well as the INCAT sensory subscore in anti-MAG neuropathy, referencing the two previous negative randomized controlled clinical trials evaluating rituximab. We then discuss newly emerging candidate therapeutic agents, including tyrosine kinase inhibitors and enhanced B-cell-depleting agents, among others. We conclude with a practical approach to the evaluation and management of anti-MAG neuropathy patients.
Topics: Humans; Myelin-Associated Glycoprotein; Peripheral Nervous System Diseases; Rituximab; Antibodies, Monoclonal; Immunoglobulin M; Autoantibodies; Neuritis; Biomarkers
PubMed: 37602932
DOI: 10.1002/mus.27954 -
Brain : a Journal of Neurology Nov 2023Valid, responsive blood biomarkers specific to peripheral nerve damage would improve management of peripheral nervous system (PNS) diseases. Neurofilament light chain...
Valid, responsive blood biomarkers specific to peripheral nerve damage would improve management of peripheral nervous system (PNS) diseases. Neurofilament light chain (NfL) is sensitive for detecting axonal pathology but is not specific to PNS damage, as it is expressed throughout the PNS and CNS. Peripherin, another intermediate filament protein, is almost exclusively expressed in peripheral nerve axons. We postulated that peripherin would be a promising blood biomarker of PNS axonal damage. We demonstrated that peripherin is distributed in sciatic nerve, and to a lesser extent spinal cord tissue lysates, but not in brain or extra-neural tissues. In the spinal cord, anti-peripherin antibody bound only to the primary cells of the periphery (anterior horn cells, motor axons and primary afferent sensory axons). In vitro models of antibody-mediated axonal and demyelinating nerve injury showed marked elevation of peripherin levels only in axonal damage and only a minimal rise in demyelination. We developed an immunoassay using single molecule array technology for the detection of serum peripherin as a biomarker for PNS axonal damage. We examined longitudinal serum peripherin and NfL concentrations in individuals with Guillain-Barré syndrome (GBS, n = 45, 179 time points), chronic inflammatory demyelinating polyradiculoneuropathy (CIDP, n = 35, 70 time points), multiple sclerosis (n = 30), dementia (as non-inflammatory CNS controls, n = 30) and healthy individuals (n = 24). Peak peripherin levels were higher in GBS than all other groups (median 18.75 pg/ml versus < 6.98 pg/ml, P < 0.0001). Peak NfL was highest in GBS (median 220.8 pg/ml) and lowest in healthy controls (median 5.6 pg/ml), but NfL did not distinguish between CIDP (17.3 pg/ml), multiple sclerosis (21.5 pg/ml) and dementia (29.9 pg/ml). While peak NfL levels were higher with older age (rho = +0.39, P < 0.0001), peak peripherin levels did not vary with age. In GBS, local regression analysis of serial peripherin in the majority of individuals with three or more time points of data (16/25) displayed a rise-and-fall pattern with the highest value within the first week of initial assessment. Similar analysis of serial NfL concentrations showed a later peak at 16 days. Group analysis of serum peripherin and NfL levels in GBS and CIDP patients were not significantly associated with clinical data, but in some individuals with GBS, peripherin levels appeared to better reflect clinical outcome measure improvement. Serum peripherin is a promising new, dynamic and specific biomarker of acute PNS axonal damage.
Topics: Humans; Peripherins; Intermediate Filaments; Polyradiculoneuropathy, Chronic Inflammatory Demyelinating; Guillain-Barre Syndrome; Axons; Biomarkers; Dementia; Multiple Sclerosis
PubMed: 37435933
DOI: 10.1093/brain/awad234