The Role of Complement Activation in IgM M-Protein-Associated Neuropathies.

Background And Objectives: Polyneuropathy associated with an immunoglobulin M (IgM) monoclonal gammopathy is characterized by slowly progressive, predominantly distal sensorimotor deficits, sensory ataxia, and electrophysiologic features of demyelination. IgM antibodies against myelin-associated glycoprotein (MAG) are present in serum from most patients. Nerve damage most likely results from the concerted action of binding of anti-MAG antibodies to nerves, followed by complement activation.

Toward a Useful and Cost-Effective Workup in Chronic Polyneuropathy: The EXPRESS Study Protocol.

Background: Knowledge gaps exist about the usefulness and extent of blood tests and nerve conduction studies in the workup of polyneuropathy. We hypothesize that a limited workup improves costs spent on diagnostics without loss of diagnostic reliability or disadvantageous effect on treatment choice in many patients with a clinical diagnosis of chronic polyneuropathy. We aim to determine which investigations are necessary in the workup of patients with suspected chronic polyneuropathy clinically diagnosed by neurologists in an outpatient clinic and will perform an early health technology assessment.

Progressive demyelinating polyneuropathy after hematopoietic cell transplantation in metachromatic leukodystrophy: a case series.

Metachromatic leukodystrophy (MLD) is a neuro-metabolic disorder due to arylsulfatase A deficiency, causing demyelination of the central and peripheral nervous system. Hematopoietic cell transplantation (HCT) can provide a symptomatic and survival benefit for pre-symptomatic and early symptomatic patients by stabilizing CNS disease. This case series, however, illustrates the occurrence of severely progressive polyneuropathy shortly after HCT in two patients with late-infantile, one with late-juvenile, and one with adult MLD, leading to the inability to walk or sit without support.

Red flags and adjusted suspicion index for distinguishing hereditary transthyretin amyloid polyneuropathy from idiopathic axonal polyneuropathy.

Background: Early diagnosis of hereditary ATTR polyneuropathy (ATTRv-PN) is important since treatment options have become available, which are most effective early in the disease course. ATTRv-PN is likely underdiagnosed as patients might be misdiagnosed with idiopathic polyneuropathy. It is uncertain if it is useful to test for TTR gene mutations in patients with a typical presentation for chronic idiopathic axonal polyneuropathy (CIAP) and which are the distinguishing clinical features.

IgM anti-MAG peripheral neuropathy (IMAGiNe) study protocol: An international, observational, prospective registry of patients with IgM M-protein peripheral neuropathies.

Background: International consensus on IgM ± anti-MAG ± PNP (IgM PNP) is lacking. Despite increasing interest in clinical trials, validated disease-specific measures are needed to adequately capture limitations and changes over time. The IMAGiNe (IgM ± anti-myelin associated glycoprotein [MAG] peripheral neuropathy) study surges as an international collaboration to create a standardized registry of patients with IgM ± anti-MAG PNP.

Thoracic outlet syndrome (TROTS) registry: A study protocol for the primary upper extremity deep venous thrombosis section.

Introduction: There is a lack of comprehensive and uniform data on primary upper extremity deep venous thrombosis (pUEDVT). pUEDVT includes venous thoracic outlet syndrome related upper extremity deep venous thrombosis (UEDVT) and idiopathic UEDVT. Research on these conditions has been hampered by their rarity, lack of uniform diagnostic criteria, and heterogeneity in therapeutic strategies.

Enriched enrollment randomized double-blind placebo-controlled cross-over trial with phenytoin cream in painful chronic idiopathic axonal polyneuropathy (EPHENE): a study protocol.

Background: Patients with chronic idiopathic axonal polyneuropathy (CIAP) can have neuropathic pain that significantly impacts quality of life. Oral neuropathic pain medication often has insufficient pain relief and side effects. Topical phenytoin cream could circumvent these limitations.

Evaluation of the cardiac amyloidosis clinical pathway implementation: a real-world experience.

Aims: The aim of this study is to evaluate the implementation of the cardiac amyloidosis (CA) clinical pathway on awareness among referring cardiologists, diagnostic delay, and severity of CA at diagnosis.

Methods And Results: Patients with CA were retrospectively included in this study and divided into two periods: pre-implementation of the CA clinical pathway (2007-18; T1) and post-implementation (2019-20; T2). Patients' and disease characteristics were extracted from electronic health records and compared.

Vegetarians, Pescatarians and Flexitarians with Adequate Vitamin B12 Levels Have No Increased Risk of Polyneuropathy.

Background: In recent years, an increasing number of people adapt to a vegetarian, pescatarian or flexitarian dietary pattern that reduces the consumption of meat and fish. Although these dietary patterns have a risk for developing vitamin B12 deficiency associated polyneuropathy, it is unknown whether this risk is still increased when vitamin B12 levels are adequate.

Objective: To examine whether a vegetarian, pescatarian or flexitarian dietary pattern is associated with an increased risk for idiopathic axonal polyneuropathy.

Study Design Characteristics and Endpoints for Enriched Enrollment Randomized Withdrawal Trials for Chronic Pain Patients: A Systematic Review.

Enriched enrollment randomized withdrawal (EERW) pain trials are designed to include only responders with considerable pain relief without unacceptable side effects into the randomized phase. There are no recommendations for primary endpoints in such trials. Our objective was to propose recommendations based on assessment of trial characteristics, endpoints and effect sizes in EERW pain trials.

No Detectable Phenytoin Plasma Levels After Topical Phenytoin Cream Application in Chronic Pain: Inferences for Mechanisms of Action.

Purpose: Topical phenytoin can act as an analgesic in chronic pain, but it is unclear if topical phenytoin gives rise to systemic side effects. Therefore, the aim of this study is: 1) to evaluate safety in chronic pain patients who used topical phenytoin up to 30% applied daily on intact skin and mucous membrane, through determining phenytoin plasma levels; and 2) to elaborate on the analgesic mechanism of action.

Patients And Methods: In this retrospective study, we collected demographic and clinical data from 33 chronic pain patients who used 10% to 30% phenytoin cream, and in whom blood samples were drawn for phenytoin concentration measurement between January 2017 until September 2020.

Withdrawal of intravenous immunoglobulin in chronic inflammatory demyelinating polyradiculoneuropathy.

Intravenous immunoglobulins are an efficacious treatment for chronic inflammatory demyelinating polyradiculoneuropathy. Biomarkers for disease activity are lacking, making the need for ongoing treatment difficult to assess, leading to potential overtreatment and high health-care costs. Our objective was to determine whether intravenous immunoglobulin withdrawal is non-inferior to continuing intravenous immunoglobulin treatment and to determine how often patients are overtreated.

Clinical relevance of testing for metabolic vitamin B12 deficiency in patients with polyneuropathy.

Objective: Determine vitamin B12 threshold levels below which additional testing of methylmalonic acid (MMA) and/or homocysteine (Hcy) is useful to diagnose metabolic vitamin B12 deficiency in patients with polyneuropathy, and how vitamin B12, MMA and Hcy levels relate to the effect of supplementation therapy.

Methods: In a retrospective cohort study of 331 patients with polyneuropathy, vitamin B12, MMA and Hcy were measured. Linear regression models with vitamin B12 as dependent and Hcy or MMA as covariate were compared, to assess which was best related to vitamin B12.

Usefulness of a Double-Blind Placebo-Controlled Response Test to Demonstrate Rapid Onset Analgesia with Phenytoin 10% Cream in Polyneuropathy.

Purpose: Topical analgesics are an upcoming treatment option for neuropathic pain. In this observational study, we performed a double-blind placebo-controlled response test (DOBRET) in patients with polyneuropathy to determine the personalized analgesic effect of phenytoin 10% cream.

Patients And Methods: In a double-blind fashion, 12 consecutive adult patients with symmetrical painful polyneuropathy and equal pain intensity of ≥4 on the 11-point numerical rating scale (NRS) applied phenytoin10% cream on one painful area and a placebo cream on the corresponding contralateral area.

Neuropathy associated with immunoglobulin M monoclonal gammopathy: A combined sonographic and nerve conduction study.

Introduction: We assessed the specific sonographic pattern of structural nerve abnormalities in immunoglobulin M (IgM) neuropathy and disease controls.

Methods: We enrolled 106 incident patients-32 patients with IgM neuropathy, 42 treatment-naive patients with chronic inflammatory demyelinating polyneuropathy, and 32 patients with axonal neuropathies. All patients underwent standardized ancillary testing in addition to standardized sonography of the brachial plexus and the large arm and leg nerves bilaterally.

Diagnostic value of symptoms in chronic polyneuropathy: The Erasmus Polyneuropathy Symptom Score.

In this study, we evaluated the diagnostic value of symptoms of chronic polyneuropathy and to construct and validate a simple questionnaire that can help diagnose chronic polyneuropathy. In a multi-step procedure, we initially compiled a 12-item questionnaire concerning polyneuropathy symptoms. The questionnaire was completed by 117 polyneuropathy patients and 188 controls (headache, transient ischemic attack, multiple sclerosis).

Statins do not increase risk of polyneuropathy: A case-control study and literature review.

Objective: To investigate whether there is an association between cholesterol-lowering medication use, specifically statins, and chronic polyneuropathy.

Methods: A literature study was carried out to assess the current state of evidence on the association between chronic polyneuropathy and cholesterol-lowering medication use. We also conducted a prospective case-control study to compare exposure to cholesterol-lowering medication between patients with cryptogenic axonal polyneuropathy and controls prior to the index date (defined in patients as date of onset of polyneuropathy symptoms, in controls as date of first study survey).

Protocol of a dose response trial of IV immunoglobulin in chronic inflammatory demyelinating polyradiculoneuropathy (DRIP study).

High peak levels of serum IgG may not be needed for maintenance treatment of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) with intravenous immunoglobulin (IVIg). More frequent dosing of IVIg leads to more stable IgG levels and higher trough levels which may be related with improved clinical efficacy. More frequent lower dosing leads to lower peak levels and may induce less systemic side-effects.

Maintenance IV immunoglobulin treatment in chronic inflammatory demyelinating polyradiculoneuropathy.

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) patients treated with intravenous immunoglobulin (IVIg) usually start with a standard dosage of 2 g/kg bodyweight. Only a minority of patients has a sustained improvement, and most require ongoing maintenance treatment. Preferred IVIg regimens, however, vary considerably between doctors and at present it is unknown which is optimal.

The role of nutrition as risk factor for polyneuropathy: a case-control study.

The aim of this case-control study is to investigate the role of nutrition as risk factor for polyneuropathy. Three hundred eighteen patients with chronic idiopathic axonal polyneuropathy and 636 matched controls completed a validated food frequency questionnaire that covered nutrient intake and alcohol consumption. As risk estimates, we calculated adjusted odds ratios for the intake of energy and nutrients.

Relationships Between Type 2 Diabetes, Neuropathy, and Microvascular Dysfunction: Evidence From Patients With Cryptogenic Axonal Polyneuropathy.

Objective: This study investigated whether the relationship between neuropathy and microvascular dysfunction in patients with type 2 diabetes is independent of diabetes-related factors. For this purpose, we compared skin microvascular function in patients with type 2 diabetes with that of patients with cryptogenic axonal polyneuropathy (CAP), a polyneuropathy of unknown etiology.

Research Design And Methods: Cross-sectional information was collected from 16 healthy controls (HCs), 16 patients with CAP, 15 patients with type 2 diabetes with polyneuropathy (DPN), and 11 patients with type 2 diabetes without polyneuropathy.

Nerve sonography to detect peripheral nerve involvement in vasculitis syndromes.

Background: We sought to determine the usefulness of sonography in the detection of nerve involvement in patients with vasculitic neuropathy.

Methods: We enrolled 16 consecutive patients with vasculitic neuropathy (11 systemic vasculitis and 5 single organ peripheral nerve vasculitis), who met the diagnostic criteria of the Peripheral Nerve Society, and 16 disease controls with noninflammatory axonal polyneuropathy (10 cryptogenic, 4 metabolic, 2 hereditary). Patients underwent standardized nerve conduction studies and assessment of muscle strength (Medical Research Council scale), in addition to sonography of large arm and leg nerves, and brachial plexus.

Incidence of polyneuropathy in Utrecht, the Netherlands.

Objective: Ascertain the incidence of cryptogenic axonal polyneuropathy (CAP) and how this relates to the overall incidence of polyneuropathy.

Methods: Electronic diagnostic registries of all hospital-based neurologic practices in the province of Utrecht (population 1,224,852 = 7.4% of the Dutch population) were consulted in 2010 to identify incident cases with polyneuropathy.