Whole-body magnetic resonance neurography in patients with chronic inflammatory demyelinating polyneuropathy

INTRODUCTION/AIMS

Whole-body magnetic resonance neurography (MRN) is an imaging modality that shows peripheral nerve signal change in patients with chronic inflammatory demyelinating polyneuropathy (CIDP). We aimed to explore the diagnostic potential of whole-body MRN and its potential as a monitoring tool after immunotherapy in treatment-naïve CIDP patients.

METHODS

Whole-body MRN using coronal 3-dimensional short tau inversion recovery (STIR) sampling perfection with application-optimized contrasts by using different flip angle evolution (SPACE) techniques was performed in patients being investigated for CIDP and in healthy controls. Baseline clinical neuropathy scales and electrophysiologic parameters were collected, and MRN findings were compared before and after CIDP treatment.

RESULTS

We found highly concordant symmetrical thickening and increased T2 signal intensities in the brachial/lumbosacral plexus, femoral, or sciatic nerves in five of the eight patients with a final diagnosis of CIDP and none of the healthy controls. There were no treatment-related imaging changes in five patients with CIDP who completed a follow-up study. Diffuse, symmetrical thickening, and increased T2 signal in root, plexus, and peripheral nerves were found in two patients ultimately excluded due to a diagnosis of polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, skin changes (POEMS) syndrome in addition to signal changes in the muscles, bony lesions, organomegaly, and lymphadenopathy.

DISCUSSION

Whole-body MRN imaging shows promise in detecting abnormalities in proximal nerve segments in patients with CIDP. Future studies evaluating the role of MRN in assessing treatment response should consider follow-up scans after treatment durations of more than 4 months.

Symptom and Treatment Satisfaction in Members of the US and Canadian GBS/CIDP Foundations with a Diagnosis of Chronic Inflammatory Demyelinating Polyneuropathy

INTRODUCTION

Current guidelines for defining good outcomes in patients with chronic inflammatory demyelinating polyneuropathy (CIDP) are predominately defined by experts. At present, we do not have a patient-anchored definition of what constitutes a "good" outcome. Our study aimed to assess the symptom burden of people living with CIDP, as well as satisfaction with treatments and clinical outcomes.

METHODS

We conducted an online-survey in CIDP patients registered with the US and Canadian GBS/CIDP foundations. Respondents answered general demographic and clinical questions, as well as satisfaction with current symptom burden and treatments, plus validated outcome measures.

RESULTS

A total of 318 individuals with self-reported CIDP completed the online survey, of whom 128 (40%) considered their current disease burden as satisfactory while 190 (60%) did not. Of 305 patients who answered the treatment satisfaction question, 222(74%) were satisfied with their treatments. Patients who were satisfied with their current symptoms had, on average, better scores in quality of life and disease severity scales, although regression modeling showed that only ability to walk, stable symptoms, and health utility scores were associated with symptom satisfaction. Treatment satisfaction was associated with stable symptoms, use of IVIG, and use of one versus no medication.

CONCLUSIONS

A high proportion of members of the US and Canadian GBS/CIDP Foundations reporting a diagnosis of CIDP were unsatisfied with current symptoms, despite a high level of overall satisfaction with treatments. There is an unmet need for improving long-term outcomes in people with a diagnosis of CIDP, and for studying patient-centered long-term treatment goals.

Building the Bridge From Pediatric to Adult Neurological Care

In this brief communication, we discuss the current landscape and unmet needs of pediatric to adult transition care in neurology. Optimizing transition care is a priority for patients, families, and providers with growing discussion in neurology. We also introduce the activities of the University of Toronto Pediatric-Adult Transition Working Group - a collaborative interdivisional and inter-subspeciality group of faculty, advanced-practice providers, trainees, and patient-family advisors pursuing collaboration with patients, families, and universities from across Canada. We envision that these efforts will result in a national neurology transition strategy that will inform designation of health authority attention and funding.

Safety and Tolerability of Intravenous Immunoglobulin in Chronic Inflammatory Demyelinating Polyneuropathy: Results of the ProCID Study

BACKGROUND AND AIMS

The ProCID study evaluated the efficacy and safety of three doses of a 10% liquid intravenous immunoglobulin (IVIg) preparation (panzyga®) in patients with chronic inflammatory demyelinating polyneuropathy (CIDP). This report describes the safety findings.

METHODS

Patients were randomised to receive a 2.0 g/kg induction dose followed by maintenance doses of either 0.5, 1.0 or 2.0 g/kg IVIg every 3 weeks over 24 weeks.

RESULTS

All 142 enrolled patients were included in the safety analyses. In total, 286 treatment-emergent adverse events (TEAEs) were reported in 89 patients, of which 173 (60.5%) were considered treatment-related. Most TEAEs were of mild severity. Eleven serious TEAEs were reported in 6 patients. Two serious TEAEs in one patient (headache and vomiting) were considered related to treatment, which resolved without study discontinuation. No treatment-related thrombotic events, haemolytic transfusion reactions or deaths occurred. One patient discontinued the study due to a TEAE (allergic dermatitis) probably related to IVIg. Headache was the only dose-dependent TEAE, with incidences ranging from 2.9 to 23.7%, the incidence of all other TEAEs was similar across treatment groups. Most TEAEs were associated with the induction dose infusion, and the rate of TEAEs decreased thereafter. The median (IQR) daily IVIg dose was 78 (64-90) g, and 94.4% of patients tolerated the maximal infusion rate of 0.12 ml/kg/min without pre-medication.

INTERPRETATION

Infusions of 10% IVIg at doses up to 2.0 g/kg with high infusion rates were safe and well tolerated in patients with CIDP.

CLINICAL TRIAL NUMBERS

EudraCT 2015-005443-14, NCT02638207.

CSF Findings in Relation to Clinical Characteristics, Subtype, and Disease Course in Patients With Guillain-Barré Syndrome

BACKGROUND AND OBJECTIVES

To investigate CSF findings in relation to clinical and electrodiagnostic subtypes, severity, and outcome of Guillain-Barré syndrome (GBS) based on 1,500 patients in the International GBS Outcome Study.

METHODS

Albuminocytologic dissociation (ACD) was defined as an increased protein level (>0.45 g/L) in the absence of elevated white cell count (<50 cells/μL). We excluded 124 (8%) patients because of other diagnoses, protocol violation, or insufficient data. The CSF was examined in 1,231 patients (89%).

RESULTS

In 846 (70%) patients, CSF examination showed ACD, which increased with time from weakness onset: ≤4 days 57%, >4 days 84%. High CSF protein levels were associated with a demyelinating subtype, proximal or global muscle weakness, and a reduced likelihood of being able to run at week 2 (odds ratio [OR] 0.42, 95% CI 0.25-0.70; p = 0.001) and week 4 (OR 0.44, 95% CI 0.27-0.72; p = 0.001). Patients with the Miller Fisher syndrome, distal predominant weakness, and normal or equivocal nerve conduction studies were more likely to have lower CSF protein levels. CSF cell count was <5 cells/μL in 1,005 patients (83%), 5-49 cells/μL in 200 patients (16%), and ≥50 cells/μL in 13 patients (1%).

DISCUSSION

ACD is a common finding in GBS, but normal protein levels do not exclude this diagnosis. High CSF protein level is associated with an early severe disease course and a demyelinating subtype. Elevated CSF cell count, rarely ≥50 cells/μL, is compatible with GBS after a thorough exclusion of alternative diagnoses.

CLASSIFICATION OF EVIDENCE

This study provides Class IV evidence that CSF ACD (defined by the Brighton Collaboration) is common in patients with GBS.

Phase 2 trial in acetylcholine receptor antibody-positive myasthenia gravis of transition from intravenous to subcutaneous immunoglobulin: The MGSCIg study

BACKGROUND AND PURPOSE

Data on maintenance therapy with subcutaneous immunoglobulin (SCIg) in myasthenia gravis (MG) are limited. We report on transitioning acetylcholine receptor (AChR) antibody-positive (Ab+) MG patients on stable intravenous immunoglobulin (IVIg) regimens as part of routine clinical care to SCIg 1:1.2.

METHODS

This multicenter North American open-label prospective investigator-initiated study had two components: the IVIg Stabilization Period (ISP) enrolling patients already on IVIg as part of routine clinical care (Weeks -10 to -1), followed by transition of stable MG subjects to SCIg in the Experimental Treatment Period (ETP; Weeks 0 to 12). We hypothesized that >65% of patients entering the ETP would have a stable Quantitative Myasthenia Gravis (QMG) score from Week 0 to Week 12. Secondary outcome measures included other efficacy measures, safety, tolerability, IgG levels, and treatment satisfaction.

RESULTS

We recruited 23 patients in the ISP, and 22 entered the ETP. A total of 12 subjects (54.5%) were female, and 18 (81.8%) were White, with mean age 51.4 ± 17 years. We obtained Week 12 ETP QMG data on 19 of 22; one subject withdrew from ETP owing to clinical deterioration, and two subjects withdrew due to dislike of needles. On primary analysis, 19 of 22 participants (86.4%, 95% confidence interval = 0.72-1.00) were treatment successes using last observation carried forward (p = 0.018). Secondary efficacy measures supported MG stability. SCIg was safe and well tolerated, and IgG levels were stable. Treatment satisfaction was comparable between ISP and ETP.

CONCLUSIONS

MG patients on IVIg as part of their routine clinical care remained stable on monthly IVIg dosage, and most maintained similar disease stability on SCIg.

An International Perspective on Preceding Infections in Guillain-Barré Syndrome: The IGOS-1000 Cohort

BACKGROUND AND OBJECTIVES

Infections play a key role in the development of Guillain-Barré syndrome (GBS) and have been associated with specific clinical features and disease severity. The clinical variation of GBS across geographical regions has been suggested to be related to differences in the distribution of preceding infections, but this has not been studied on a large scale.

METHODS

We analyzed the first 1,000 patients included in the International GBS Outcome Study with available biosamples (n = 768) for the presence of a recent infection with Campylobacter jejuni, hepatitis E virus, Mycoplasma pneumoniae, cytomegalovirus, and Epstein-Barr virus.

RESULTS

Serologic evidence of a recent infection with C. jejuni was found in 228 (30%), M. pneumoniae in 77 (10%), hepatitis E virus in 23 (3%), cytomegalovirus in 30 (4%), and Epstein-Barr virus in 7 (1%) patients. Evidence of more than 1 recent infection was found in 49 (6%) of these patients. Symptoms of antecedent infections were reported in 556 patients (72%), and this proportion did not significantly differ between those testing positive or negative for a recent infection. The proportions of infections were similar across continents. The sensorimotor variant and the demyelinating electrophysiologic subtype were most frequent across all infection groups, although proportions were significantly higher in patients with a cytomegalovirus and significantly lower in those with a C. jejuni infection. C. jejuni-positive patients were more severely affected, indicated by a lower Medical Research Council sum score at nadir (p = 0.004) and a longer time to regain the ability to walk independently (p = 0.005). The pure motor variant and axonal electrophysiologic subtype were more frequent in Asian compared with American or European C. jejuni-positive patients (p < 0.001, resp. p = 0.001). Time to nadir was longer in the cytomegalovirus-positive patients (p = 0.004).

DISCUSSION

Across geographical regions, the distribution of infections was similar, but the association between infection and clinical phenotype differed. A mismatch between symptom reporting and serologic results and the high frequency of coinfections demonstrate the importance of broad serologic testing in identifying the most likely infectious trigger. The association between infections and outcome indicates their value for future prognostic models.

Outcomes of Cerebral Venous Thrombosis due to Vaccine-Induced Immune Thrombotic Thrombocytopenia After the Acute Phase

BACKGROUND

Cerebral venous thrombosis (CVT) due to vaccine-induced immune thrombotic thrombocytopenia (VITT) is a severe condition, with high in-hospital mortality rates. Here, we report clinical outcomes of patients with CVT-VITT after SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) vaccination who survived initial hospitalization.

METHODS

We used data from an international registry of patients who developed CVT within 28 days of SARS-CoV-2 vaccination, collected until February 10, 2022. VITT diagnosis was classified based on the Pavord criteria. Outcomes were mortality, functional independence (modified Rankin Scale score 0-2), VITT relapse, new thrombosis, and bleeding events (all after discharge from initial hospitalization).

RESULTS

Of 107 CVT-VITT cases, 43 (40%) died during initial hospitalization. Of the remaining 64 patients, follow-up data were available for 60 (94%) patients (37 definite VITT, 9 probable VITT, and 14 possible VITT). Median age was 40 years and 45/60 (75%) patients were women. Median follow-up time was 150 days (interquartile range, 94-194). Two patients died during follow-up (3% [95% CI, 1%-11%). Functional independence was achieved by 53/60 (88% [95% CI, 78%-94%]) patients. No new venous or arterial thrombotic events were reported. One patient developed a major bleeding during follow-up (fatal intracerebral bleed).

CONCLUSIONS

In contrast to the high mortality of CVT-VITT in the acute phase, mortality among patients who survived the initial hospitalization was low, new thrombotic events did not occur, and bleeding events were rare. Approximately 9 out of 10 CVT-VITT patients who survived the acute phase were functionally independent at follow-up.

Management of Cerebral Venous Thrombosis Due to Adenoviral COVID-19 Vaccination

Objective

Cerebral venous thrombosis (CVT) caused by vaccine‐induced immune thrombotic thrombocytopenia (VITT) is a rare adverse effect of adenovirus‐based severe acute respiratory syndrome‐coronavirus 2 (SARS‐CoV‐2) vaccines. In March 2021, after autoimmune pathogenesis of VITT was discovered, treatment recommendations were developed. These comprised immunomodulation, non‐heparin anticoagulants, and avoidance of platelet transfusion. The aim of this study was to evaluate adherence to these recommendations and its association with mortality.

Methods

We used data from an international prospective registry of patients with CVT after the adenovirus‐based SARS‐CoV‐2 vaccination. We analyzed possible, probable, or definite VITT‐CVT cases included until January 18, 2022. Immunomodulation entailed administration of intravenous immunoglobulins and/or plasmapheresis.

Results

Ninety‐nine patients with VITT‐CVT from 71 hospitals in 17 countries were analyzed. Five of 38 (13%), 11 of 24 (46%), and 28 of 37 (76%) of the patients diagnosed in March, April, and from May onward, respectively, were treated in‐line with VITT recommendations (p < 0.001). Overall, treatment according to recommendations had no statistically significant influence on mortality (14/44 [32%] vs 29/55 [52%], adjusted odds ratio [OR] = 0.43, 95% confidence interval [CI] = 0.16–1.19). However, patients who received immunomodulation had lower mortality (19/65 [29%] vs 24/34 [70%], adjusted OR = 0.19, 95% CI = 0.06–0.58). Treatment with non‐heparin anticoagulants instead of heparins was not associated with lower mortality (17/51 [33%] vs 13/35 [37%], adjusted OR = 0.70, 95% CI = 0.24–2.04). Mortality was also not significantly influenced by platelet transfusion (17/27 [63%] vs 26/72 [36%], adjusted OR = 2.19, 95% CI = 0.74–6.54).

Conclusions

In patients with VITT‐CVT, adherence to VITT treatment recommendations improved over time. Immunomodulation seems crucial for reducing mortality of VITT‐CVT. ANN NEUROL 2022;92:562–573

Predicting Outcome in Guillain-Barré Syndrome: International Validation of the Modified Erasmus GBS Outcome Score

BACKGROUND AND OBJECTIVES

The clinical course and outcome of the Guillain-Barré syndrome (GBS) are diverse and vary among regions. The modified Erasmus GBS Outcome Score (mEGOS), developed with data from Dutch patients, is a clinical model that predicts the risk of walking inability in patients with GBS. The study objective was to validate the mEGOS in the International GBS Outcome Study (IGOS) cohort and to improve its performance and region specificity.

METHODS

We used prospective data from the first 1,500 patients included in IGOS, aged ≥6 years and unable to walk independently. We evaluated whether the mEGOS at entry and week 1 could predict the inability to walk unaided at 4 and 26 weeks in the full cohort and in regional subgroups, using 2 measures for model performance: (1) discrimination: area under the receiver operating characteristic curve (AUC) and (2) calibration: observed vs predicted probability of being unable to walk independently. To improve the model predictions, we recalibrated the model containing the overall mEGOS score, without changing the individual predictive factors. Finally, we assessed the predictive ability of the individual factors.

RESULTS

For validation of mEGOS at entry, 809 patients were eligible (Europe/North America [n = 677], Asia [n = 76], other [n = 56]), and 671 for validation of mEGOS at week 1 (Europe/North America [n = 563], Asia [n = 65], other [n = 43]). AUC values were >0.7 in all regional subgroups. In the Europe/North America subgroup, observed outcomes were worse than predicted; in Asia, observed outcomes were better than predicted. Recalibration improved model accuracy and enabled the development of a region-specific version for Europe/North America (mEGOS-Eu/NA). Similar to the original mEGOS, severe limb weakness and higher age were the predominant predictors of poor outcome in the IGOS cohort.

DISCUSSION

mEGOS is a validated tool to predict the inability to walk unaided at 4 and 26 weeks in patients with GBS, also in countries outside the Netherlands. We developed a region-specific version of mEGOS for patients from Europe/North America.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that the mEGOS accurately predicts the inability to walk unaided at 4 and 26 weeks in patients with GBS.

TRIAL REGISTRATION INFORMATION

NCT01582763.

Randomized trial of three IVIg doses for treating chronic inflammatory demyelinating polyneuropathy

Intravenous immunoglobulin treatment for chronic inflammatory demyelinating polyneuropathy usually starts with a 2.0 g/kg induction dose followed by 1.0 g/kg maintenance doses every 3 weeks. No dose-ranging studies with intravenous immunoglobulin maintenance therapy have been published.

The Progress in Chronic Inflammatory Demyelinating polyneuropathy (ProCID) study was a prospective, double-blind, randomized, parallel-group, multicentre, phase III study investigating the efficacy and safety of 10% liquid intravenous immunoglobulin (Panzyga^®) in patients with active chronic inflammatory demyelinating polyneuropathy. Patients were randomized 1:2:1 to receive the standard intravenous immunoglobulin induction dose and then either 0.5, 1.0 or 2.0 g/kg maintenance doses every 3 weeks. The primary end point was the response rate in the 1.0 g/kg group, defined as an improvement ≥1 point in adjusted Inflammatory Neuropathy Cause and Treatment score at Week 6 versus baseline and maintained at Week 24. Secondary end points included dose response and safety. This trial was registered with EudraCT (Number 2015–005443-14) and clinicaltrials.gov (NCT02638207).

Between August 2017 and September 2019, the study enrolled 142 patients. All 142 were included in the safety analyses. As no post-infusion data were available for three patients, 139 were included in the efficacy analyses, of whom 121 were previously on corticosteroids. The response rate was 80% (55/69 patients) [95% confidence interval (CI): 69–88%] in the 1.0 g/kg group, 65% (22/34; CI: 48–79%) in the 0.5 g/kg group, and 92% (33/36; CI: 78–97%) in the 2.0 g/kg group. While the proportion of responders was higher with higher maintenance doses, logistic regression analysis showed that the effect on response rate was driven by a significant difference between the 0.5 and 2.0 g/kg groups, whereas the response rates in the 0.5 and 2.0 g/kg groups did not differ significantly from the 1.0 g/kg group. Fifty-six per cent of all patients had an adjusted Inflammatory Neuropathy Cause and Treatment score improvement 3 weeks after the induction dose alone. Treatment-related adverse events were reported in 16 (45.7%), 32 (46.4%) and 20 (52.6%) patients in the 0.5, 1.0 and 2.0 g/kg dose groups, respectively. The most common adverse reaction was headache. There were no treatment-related deaths.

Intravenous immunoglobulin (1.0 g/kg) was efficacious and well tolerated as maintenance treatment for patients with chronic inflammatory demyelinating polyneuropathy. Further studies of different maintenance doses of intravenous immunoglobulin in chronic inflammatory demyelinating polyneuropathy are warranted.

Electrodiagnostic Assessment of Neuromuscular Junction Disorders

Please verify edits, "These techniques", or specify. This article reviews advanced electrodiagnostic techniques used to assess for neuromuscular junction disorders, including repetitive nerve stimulation, conventional or concentric-needle single-fiber electromyography (SFEMG), and stimulated SFEMG. These techniques have high sensitivity but limited specificity. Novel methods currently under investigation are discussed, including vestibular ocular myogenic potential and oculography analysis.

Patient-acceptable symptom states in myasthenia gravis

Objectives

To estimate patient-acceptable symptom state (PASS) cut points for myasthenia gravis (MG) health scales.

Methods

We conducted an electronic survey that included the Myasthenia Gravis Impairment Index (MGII), EuroQol 5-Dimension (EQ5D), and a simple PASS question. PASS-anchored thresholds were estimated for the MGII questionnaire through receiver operating characteristic curves. We used the MGII PASS cut point in a validation cohort of 257 patients to estimate PASS thresholds for other clinically relevant health scales such as the Quantitative Myasthenia Gravis Scale (QMGS), Myasthenia Gravis Activities of Daily Living (MG-ADL), Myasthenia Gravis Composite (MGC), and Myasthenia Quality of Life (MG-QoL15).

Results

One hundred twenty-four of ≈250 invited patients answered the electronic survey (49% response rate), and 80 considered their current symptom state acceptable (PASS-positive). They had lower MGII scores than PASS-negative patients (7.76 ± 9.37 vs 25.0 ± 13.7, p < 0.0001) and better EQ5D scores (0.86 ± 0.17 vs 0.69 ± 0.18, p < 0.0001). The MGII questionnaire threshold for PASS was ≤10 points. With the use of this threshold in an independent dataset of 257 patients, all patients in remission or minimal manifestation status were PASS-positive. In addition, some patients in Classes I, II, and IIIA also achieved PASS status. PASS thresholds for the QMGS, MG-ADL, MGC, and MG-QoL15 were ≤7, 2, 3, and 8 points, respectively.

Conclusions

We have estimated thresholds for commonly used myasthenia health scales reflecting patient-acceptable states in patients with MG. These thresholds indicate a global state of well being, rather than a change in scores, or being better. Therefore, PASS thresholds can be used as secondary endpoints for myasthenia research.

Respiratory Dysfunction and Sleep-Disordered Breathing in Children With Myasthenia Gravis

OBJECTIVES

The purpose of this study was to prospectively evaluate sleep patterns and the presence of sleep-disordered breathing in children with myasthenia gravis. We further aimed to examine the relationship between sleep and daytime respiratory function using spirometry tests including upright and supine forced vital capacity, sniff nasal inspiratory pressure, and maximal inspiratory pressure.

METHODS

Eleven children between 3 and 18 years old with confirmed myasthenia gravis were recruited from The Hospital for Sick Children Neuromuscular Clinic in this prospective observational study. After informed consent was obtained, patients underwent a comprehensive clinical assessment with collection of anthropometric data. Following this, all subjects performed pulmonary function tests, overnight polysomnography and completed the Epworth Sleepiness Scale questionnaire.

RESULTS

Two of eleven children who reported no symptoms of sleep disordered breathing were diagnosed with mild to moderate obstructive sleep apnea. Pulmonary function tests showed abnormal maximal inspiratory pressure in 6 of 11 patients, whereas seated forced vital capacity as well as seated to supine forced vital capacity ratios were normal in the entire group.

CONCLUSIONS

In our small group of pediatric myasthenia gravis subjects, there was an unexpected finding of obstructive sleep apnea in 2 of the 11 patients studied. Maximal inspiratory pressure appears to be a more sensitive method of detecting abnormalities compared to upright or seated forced vital capacity. A larger multicenter study is needed to validate our findings and to determine the impact of obstructive sleep apnea in the pediatric myasthenia gravis population as well as risk factors associated with sleep disordered breathing.

Case Studies in Management of Muscle Cramps

Muscle cramps, defined as a painful contraction of a muscle or muscle group, are a common symptom most people have experienced throughout their lifespan. In some cases cramps can be frequent, severe, and disabling, thus requiring medical assessment and intervention. Physiologic states such as pregnancy and exercise are associated with excessive muscle cramps, as are numerous medical and neurologic conditions, medications such as diuretics and statins, and peripheral nerve hyperexcitability syndromes. Treatment options for muscle cramps are limited, although recent studies have shown that mexiletine could be a safe and efficient alternative for patients with amyotrophic lateral sclerosis.

European Federation of Neurological Societies cutoff values significantly reduce creatine kinase sensitivity for diagnosing neuromuscular disorders

INTRODUCTION

Elevated creatine kinase (CK) level was redefined by the European Federation of Neurological Societies)EFNS(as 1.5 times the upper limit of normal. In the current study we sought to determine the sensitivity and specificity of CK testing for the diagnosis of neuromuscular disorders.

METHODS

Demographics and CK levels were retrospectively extracted from an electronic database for 234 patients with neuromuscular disorders. Sensitivity, specificity, and likelihood ratios and the area under curve were determined for each diagnosis and different cutoff CK values.

RESULTS

Using the EFNS cutoff values significantly reduced CK test sensitivity. Creatine kinase values >1000 IU/L showed a high likelihood (11.04) for myopathies and a low likelihood for polyneuropathies (0).

DISCUSSION

European Federation of Neurological Societies cutoff values significantly reduce CK sensitivity for diagnosing neuromuscular disorders. While low CK values cannot exclude a neuromuscular disease, values >1000 IU/L are associated with a high likelihood of myopathy.

Randomized, controlled crossover study of IVIg for demyelinating polyneuropathy and diabetes

OBJECTIVE

To determine whether IV immunoglobulin (IVIg) is more effective than placebo at reducing disability in patients with diabetes and demyelinating polyneuropathy features.

METHODS

This is a double-blinded, single-center, randomized, controlled crossover trial of IVIg treatment vs placebo. The primary outcome measure was the mean change in Overall Neuropathy Limitation Scale (ONLS) scores during the IVIg phasecompared with the placebo phase. Secondary outcomes include changes in the Rasch-built Overall Disability Scale, Medical Research Council sum scores, grip strength, electrophysiologic measurements, quality of life, and adverse effects.

RESULTS

Twenty-five subjects were recruited between March 2015 and April 2017. The mean change in ONLS scores was -0.2 points during the IVIg phase and 0.0 points during the placebo phase (p = 0.23). Secondary outcomes did not show significant differences between IVIg and placebo.

CONCLUSIONS

IVIg did not reduce disability, improve strength, or quality of life in patients with demyelinating polyneuropathy features and diabetes after 3 months of treatment in comparison with placebo. Therefore, careful consideration of the primary diagnosis is required before immunomodulatory therapy.

CLASSIFICATION OF EVIDENCE

This study provides Class I evidence that for patients with diabetes and demyelinating polyneuropathy features, IVIg did not significantly reduce disability.

A randomised, multi-centre phase III study of 3 different doses of intravenous immunoglobulin 10% in patients with chronic inflammatory demyelinating polyradiculoneuropathy (ProCID trial): Study design and protocol

Patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) show varying degrees of response to intravenous immunoglobulin (IVIg) therapy. This randomised phase III study in patients with CIDP (ProCID trial) will compare the efficacy and safety of 3 different doses (0.5, 1.0, and 2.0 g/kg) of IVIg 10% (panzyga) administered every 3 weeks for 24 weeks. The primary efficacy endpoint is the rate of treatment response, defined as a decrease in adjusted inflammatory neuropathy cause and treatment disability score of ≥1 point, in the IVIg 1.0 g/kg arm at week 24. Patients with definite or probable CIDP according to European Federation of Neurological Sciences/Peripheral Nerve Society criteria with IVIg or corticosteroid dependency and active disease are eligible. All potentially eligible patients will undergo IVIg or corticosteroid dose reduction (washout phase) over ≤12 weeks or until deterioration of CIDP (active disease). Patients with deterioration during the washout phase will be randomised to receive study treatment during a dose‐evaluation phase starting with a loading dose of IVIg 2.0 g/kg followed by maintenance treatment with IVIg 0.5, 1.0, or 2.0 g/kg every 3 weeks. Rescue medication (2 doses of IVIg 2.0 g/kg given 3 weeks apart) will be administered to patients in the IVIg 0.5 and 1.0 g/kg groups who deteriorate after week 3 and before week 18 or who do not improve at week 6. Safety, tolerability and quality of life will be assessed. The ProCID study will provide new information on the best maintenance dose of IVIg for patients with CIDP.

Nerve function varies with hemoglobin A1c in controls and type 2 diabetes

AIMS

To determine the cross-sectional threshold at which hemoglobin A1c (HbA1c) is associated with polyneuropathy in healthy controls, and the values associated with the most pronounced decline in nerve function in patients with diabetes.

METHODS

We used data from a cross-sectional cohort study of healthy controls and type 2 diabetes patients assessed between November 2010 and May 2013. Healthy controls and patients with diabetes were compared at different HbA1c ranges: <5.5%, 5.5-5.9%, and 6-6.4% for controls, and 6.5-7.4% and >7.5% for patients with diabetes.

RESULTS

The total cohort included 53 controls and 164 patients with diabetes. Subclinical small nerve fiber impairments were observed in controls at HbA1c levels of 5.5-6%, compared with HbA1c <5.5%, for example: lower Laser Doppler flare imaging area of 2.8 ± 1.4 versus 3.9 ± 2 mm². The most prominent decline in both small and large nerve fiber function was seen with less impaired glycemic control and shorter duration of diabetes, i.e. at HbA1c levels of 6.5-7.4%, compared with >7.5%.

CONCLUSIONS

These findings underscore the importance of early treatment at the prediabetes and early diabetes stages to prevent nerve fiber decline that is likely irreversible.

Sex differences in neuropathic pain intensity in diabetes

INTRODUCTION

Sex and gender play roles in the pain experience, such that pain is more frequent in women. Explanations for this observation range from factors related to biological sex to those related to psychosocial gender.

OBJECTIVES

To explore neuropathic pain characteristics in females with diabetes with and without established polyneuropathy.

METHODS

We compared the presence and intensity of pain in males and females in 2 separate cohorts of patients with type II diabetes, with and without established diabetic polyneuropathy. Cohort #1 was recruited prospectively, while cohort #2 was studied retrospectively.

RESULTS

Cohort #1 of 223 patients with diabetes with a relatively broad spectrum of nerve injury, showed more frequent pain in females (68% versus 53% in males), a higher frequency of additional neuropathic symptoms, and evidence of milder nerve injury. Cohort #2 of 128 patients with established diabetic polyneuropathy, showed a similar frequency of pain and additional neuropathic symptoms in both sexes. In both cohorts, females reported greater pain intensity (7.9-8.5 versus 6.8-6.9 in males, on visual analog scale).

DISCUSSION

Though nerve injury and polyneuropathy are more common in males, females with diabetes report a higher frequency and intensity of pain despite milder polyneuropathy. Prospective epidemiological studies are required in order to confirm these findings in the community setting.

Muscle biopsy technical safety and quality using a self-contained, vacuum-assisted biopsy technique

Muscle sampling via percutaneous biopsy has been shown to be safe and effective using a Bergström needle; however, the use of a single-operator, self-contained, vacuum-assisted biopsy technique has not been explored. We performed a retrospective chart review of muscle biopsy samples obtained using the Vacora® self-contained vacuum-assisted biopsy system between 2013 and 2016, at the Toronto General Hospital. During this period, 102 single-operator muscle biopsies were performed using the Vacora® system. 54/102 showed normal or non-specific findings, while 39/102 were suggestive or diagnostic of a neuromuscular condition. 8 samples did not provide sufficient muscle tissue for diagnosis, and complications (intramuscular hematoma) occurred in 3/102 cases. Mean sample weight was 0.19 grams, which exceeded reported mean sample weights using the suction-modified Bergström technique (0.125 grams). We therefore conclude that the Vacora® vacuum-assisted biopsy system provides a safe and effective method to obtain diagnostic muscle biopsy samples; although complication rates are slightly higher than reported using the Bergström technique, possibly related to more vigorous suction or a sharp needle tip.

Fatigue is a relevant outcome in patients with myasthenia gravis

INTRODUCTION

Patients with myasthenia gravis often experience fatigue, but its effect on quality of life (QoL) is underestimated, and fatigue is rarely measured in clinical trials.

METHODS

Two hundred fifty-seven myasthenic patients completed the Neuro-QoL-Fatigue and measures of disease severity and QoL. We studied the relationship between fatigue and clinical and demographic variables. Finally, we studied the responsiveness of the Neuro-QoL-Fatigue in 95 patients receiving treatments for myasthenia and estimated the minimal important difference (MID).

RESULTS

Fatigue correlated with greater disease severity (r = 0.52-0.69, P < 0.0001) and worse QoL (r = 0.65-0.75, P < 0.0001). Patients in remission, with minimal manifestations, and pure ocular symptoms reported minimal fatigue. Regression modeling showed that, in addition to its relationship with disease severity, fatigue was worse in females, patients with generalized disease, and those with anxiety/depression. Fatigue improved after immunomodulation (P < 0.0001), and the MID was 5.3 points.

DISCUSSION

Fatigue in myasthenia correlates with disease severity, affects QoL, and can improve after treatment. Muscle Nerve 58: 197-203, 2018.

Toxic and Endocrine Myopathies

PURPOSE OF REVIEW

This article discusses the clinical features, pathophysiology, and management of toxic and endocrine myopathies.

RECENT FINDINGS

Early detection and expeditious correction of metabolic disturbances in endocrinopathies such as Cushing syndrome, thyroid and parathyroid diseases, and acromegaly can minimize and prevent neurologic complications including myopathy. Recently proposed mechanisms of injury in patients with critical illness myopathy include inhibition of protein synthesis, mitochondrial dysfunction, disruption of the ubiquitin-proteasome system, oxidative stress, and disruption of intramuscular calcium homeostasis, which can cause a myosin-loss myopathy. Mechanisms underlying toxic myopathies include myosin loss; damage to cellular structures, including myofibrils and organelles such as lysosomes and mitochondria; inflammation; and necrosis. Presentations range anywhere from acute, painful, and necrotic myopathies, as can occur in statin myopathy, to more insidious presentations such as steroid myopathy.

SUMMARY

Endocrinopathies known to cause myopathy include thyroid and parathyroid diseases, disorders of the adrenal axis such as Cushing syndrome, and acromegaly. Patients in the intensive care unit are at risk for developing critical illness myopathy, also known as myosin-loss myopathy, which should be considered if intensive care unit acquired weakness develops. The most common toxic agents associated with myopathy include statins and other lipid-lowering medications, corticosteroids, colchicine, amiodarone, hydroxychloroquine, and chloroquine.

High frequency of MGUS in DSP

INTRODUCTION

Monoclonal gammopathy has been reported in several polyneuropathies. In this study, we sought to explore the frequency and characteristics of monoclonal gammopathy in patients with diabetic sensorimotor polyneuropathy (DSP).

METHODS

Patients with type 1 and type 2 diabetes mellitus (DM 1, DM 2) and controls without diabetes were evaluated between November 2008 and December 2013.

RESULTS

Fifty controls, 66 patients with DM 1, and 106 patients with DM 2 were included, with average ages of 43 ± 18, 45 ± 17, and 65 ± 10 years, respectively; the frequency of monoclonal gammopathy was 0%, 8%, and 15%, respectively. In patients with DSP, the frequency of monoclonal gammopathy increased to 14% in DM 1 and 21% in DM 2; the most common monoclonal proteins were immunoglobulin (Ig) M and IgG, respectively.

DISCUSSION

DSP might be associated with a high frequency of monoclonal gammopathy, with different characteristics in DM 1 and in DM 2. Muscle Nerve 57: 1018-1021, 2018.

Toronto Clinical Neuropathy Score is valid for a wide spectrum of polyneuropathies

BACKGROUND AND PURPOSE

The Toronto Clinical Neuropathy Score (TCNS) is a valid and reliable scale for the diagnosis and staging of diabetic sensorimotor polyneuropathy. In this study, we aimed to explore the performance of the TCNS in non-diabetic polyneuropathies.

METHODS

We performed a prospective study from November 2016 to May 2017 of patients with non-diabetic polyneuropathy. Patients had clinical, electrophysiological and functional assessments of their polyneuropathy, and the findings were correlated with the TCNS.

RESULTS

The TCNS correlated with all clinical, electrophysiological and disability measures of polyneuropathy, mostly at a moderate level (e.g. r = -0.58 for sural nerve action potential amplitude). Higher TCNS severity grades were associated with worse polyneuropathy on all measures in the lower limbs, and with worse electrophysiological parameters and vibration perception thresholds in the upper limbs. The scale also showed excellent reliability and accuracy (kappa, 0.92-0.93 for inter- and intra-observer reliability; area under the receiver operating characteristics curve, 0.93).

CONCLUSION

The TCNS is a valid and reliable scale for a wide spectrum of polyneuropathies, and might be useful in clinical practise and research for the diagnosis and staging of polyneuropathy.

Uric acid levels correlate with the severity of diabetic sensorimotor polyneuropathy

INTRODUCTION

Diabetic sensorimotor polyneuropathy (DSP) is the most frequent complication in patients with diabetes mellitus (DM), and is associated with age, DM duration, and HbA1c levels. In addition, higher uric acid (UA) levels are reported in patients with DSP.

OBJECTIVES

To explore whether UA levels correlate with DSP severity.

METHODS

We extracted the demographic data, clinical history, neurological and electrophysiological examinations and laboratory findings of 115 patients diagnosed with DSP from January 2012 to December 2015.

RESULTS

The mean age of the total cohort was 62±13years, with 61% men. A positive correlation was demonstrated between uric acid levels and increasing sensory symptoms, and more abnormal electrophysiological findings and vibration perception thresholds. In addition, correlations with gait abnormality, the presence of paraproteinemia and creatine kinase levels were found.

DISCUSSION

Our study results show that uric acid levels correlate with clinical and electrophysiological severity of DSP, providing additional evidence for the relationship between the two, and a potential therapeutic target for DSP.

Measuring disease activity and clinical response during maintenance therapy in CIDP: from ICE trial outcome measures to future clinical biomarkers

Some patients with chronic inflammatory demyelinating polyradiculoneuropathy who respond to initial intravenous immunoglobulin require repeated courses over prolonged periods of time; however, evidence to guide dosage and interval of intravenous immunoglobulin during maintenance therapy is limited. Optimizing treatment requires assessment of underlying disease activity and clinical outcome. Electrophysiological measures of demyelination, and clinical measures using handgrip strength and walking velocity promise to be particularly informative. Major advances in resolution and image processing have expanded clinical applications for ultrasound to include the study of peripheral nerves. Ultrasonography shows promise in diagnosing chronic inflammatory demyelinating polyradiculoneuropathy and distinguishing it from other conditions, providing first ever insight into gross pathology of peripheral nerves. Ultrasonography may also have a role in monitoring disease activity and treatment response.

Electrophysiological testing is correlated with myasthenia gravis severity

INTRODUCTION

Electrophysiological studies play an important role in the diagnosis of myasthenia gravis (MG). The objectives of this study was to explore the correlation of jitter and decrement with various clinical symptoms and signs and disease severity.

METHODS

We performed a retrospective chart review of 75 MG patients who attended the neuromuscular clinic from April 2013 to May 2014. We compared clinical characteristics between patients with high jitter (>100 µs) and decrement (>10%), and patients with lower values to explore the correlations and optimal thresholds of jitter and decrement for different clinical features.

RESULTS

High jitter and decrement values were associated with more severe disease, manifested by more frequent symptomatic bulbar and limb muscle weakness, more frequent ocular and limb muscle weakness on examination, higher quantitative MG score, and generalized disease.

CONCLUSIONS

The yield of the electrophysiological assessment in MG extends beyond disease diagnosis and correlates with disease severity and the presence of generalized disease. Muscle Nerve 56: 445-448, 2017.

The sensitivity and specificity of the neurological examination in polyneuropathy patients with clinical and electrophysiological correlations

Introduction

Polyneuropathy is one of the most prevalent neurologic disorders. Although several studies explored the role of the neurological examination in polyneuropathy, they were mostly restricted to specific subgroups of patients and have not correlated examination findings with symptoms and electrophysiological results.

Objectives

To explore the sensitivity and specificity of different neurological examination components in patients with diverse etiologies for polyneuropathy, find the most sensitive combination of examination components for polyneuropathy detection, and correlate examination findings with symptoms and electrophysiological results.

Methods

Patients with polyneuropathy attending the neuromuscular clinic from 01/2013 to 09/2015 were evaluated. Inclusion criteria included symptomatic polyneuropathy, which was confirmed by electrophysiological studies. 47 subjects with no symptoms or electrophysiological findings suggestive for polyneuropathy, served as controls.

Results

The total cohort included 312 polyneuropathy patients, with a mean age of 60±14 years. Abnormal examination was found in 95%, most commonly sensory findings (86%). The most common abnormal examination components were impaired ankle reflexes (74%), vibration (73%), and pinprick (72%) sensation. Combining ankle reflex examination with vibration or pinprick perception had the highest sensitivity, of 88%. The specificities of individual examination component were generally high, excluding ankle reflexes (62%), and vibration perception (77%). Abnormal examination findings were correlated with symptomatic weakness and worse electrophysiological parameters.

Conclusion

The neurological examination is a valid, sensitive and specific tool for diagnosing polyneuropathy, and findings correlate with polyneuropathy severity. Ankle reflex examination combined with either vibration or pinprick sensory testing is the most sensitive combination for diagnosing polyneuropathy, and should be considered minimal essential components of the physical examination in patients with suspected polyneuropathy.

Clinical characteristics, and impairment and disability scale scores for different CIDP Disease Activity Status classes

INTRODUCTION

Selecting proper outcome measures is important for clinical practice and clinical studies assessing treatable neuropathies, such as chronic inflammatory demyelinating polyneuropathy (CIDP).

OBJECTIVES

To explore clinical characteristics and impairment and disability scores in CIDP patients, and assess their relationship to different CIDP Disease Activity Status (CDAS) classes.

METHODS

We performed a retrospective chart review of CIDP patients attending the neuromuscular clinic between January 2014 and December 2015, and explored clinical characteristics, and various impairment and disability scores for different CDAS classes.

RESULTS

The total cohort included 69 CIDP patients. A higher CDAS class was correlated with more frequent motor and sensory deficits, worse sensory sum score, worse scores on the disability scales, including the Rasch-built overall disability scale (RODS) and Overall Neuropathy Limitation Scale (ONLS), and lower treatment responsiveness. ONLS and RODS scales were significantly correlated (r=-0.86, p<0.0001). A change of one point or more in the ONLS score, was associated with a corresponding change of 4.1-4.5 points in the RODS score.

DISCUSSION

The study results show that a higher CDAS class is correlated with a more severe neuropathy. This was reflected by the sensory sum score, RODS and ONLS. These results might help profile CIDP patients at different CDAS classes for clinical practice and future clinical studies.

Laser Doppler Flare Imaging and Quantitative Thermal Thresholds Testing Performance in Small and Mixed Fiber Neuropathies

Introduction

Small fiber neuropathy might be a part of typical mixed small and large fiber neuropathy, or a distinct entity, affecting exclusively small nerve fibers.

Objectives

Explore the utility of small nerve fiber testing in patients with clinical presentation suggesting small fiber neuropathy, with and without evidence for concomitant large fiber neuropathy.

Methods

Patients attending the neuromuscular clinic from 2012 to 2015 with a clinical presentation suggesting small nerve fiber impairment, who had Laser Doppler flare imaging (LDI_Flare) and quantitative thermal testing (QTT) were evaluated for this study. Patients with clinical or electrophysiological evidence for concomitant large fiber neuropathy were not excluded.

Results

The sensitivities of LDI_Flare, cooling and heat threshold testing were 64%, 36%, and 0% respectively for clinically highly suggestive small fiber neuropathy, 64%, 56%, and 19% respectively for mixed fiber neuropathy, and 86%, 79%, and 29% respectively for diabetic mixed fiber neuropathy.

Discussion

LDI_Flare and cooling thresholds testing are non-invasive small nerve fiber testing modalities, with moderate performance in patients with small and mixed fiber neuropathy, and excellent performance in diabetic mixed fiber neuropathy.

Frequent laboratory abnormalities in CIDP patients

INTRODUCTION

The role of screening laboratory tests in chronic inflammatory demyelinating polyneuropathy (CIDP) is currently unknown. The objectives of this study are to explore common laboratory test abnormalities in CIDP patients.

METHODS

CIDP subjects attending the Neuromuscular Clinic between 01/2013 and 12/2014 were evaluated. Demographic data, clinical history, physical examination, and laboratory test results were extracted from their charts.

RESULTS

Seventy-nine charts were reviewed. Mean age was 61 ± 11 years. Most (84%) CIDP patients had laboratory test abnormalities; the most frequent were paraproteinemia (29%) and elevated HbA1C (28%) and creatine kinase (27%). Additional abnormalities included anemia in 19%, and elevated anti-neutrophil cytoplasmic antibody, erythrocyte sedimentation rate, and urate in 17%, elevated antinuclear antibodies, rheumatoid factor, and thyroid-stimulating hormone in 11%, and abnormal C3 in 10%.

CONCLUSIONS

Laboratory test abnormalities were found in most CIDP patients. The most common were paraproteinemia, higher than expected frequency of diabetes, and unexpected CK elevation. Additional abnormalities included anemia, high urate levels, and common biomarkers for vasculitic neuropathies. Muscle Nerve 53: 862-865, 2016.

Elevated Vibration Perception Thresholds in CIDP Patients Indicate More Severe Neuropathy and Lower Treatment Response Rates

INTRODUCTION

Vibration perception threshold (VPT) examination using a neurothesiometer provides objective, sensitive and specific information, and has been utilized mainly in patients with diabetic polyneropathy.

OBJECTIVES

Explore the utility of VPT examination in CIDP patients.

METHODS

CIDP subjects attending the Neuromuscular clinic between 01/2013 and 12/2014 were evaluated. Demographic data, clinical history, physical examination, VPT values, and electrophysiologic data from their charts were extracted.

RESULTS

70 charts were reviewed. 55 CIDP patients had elevated VPT, associated with higher frequency of abnormal sensory testing for various modalities (92.7% vs. 46.7%, p<0.0001), lower sensory and motor amplitudes and reduced conduction velocities on nerve conduction studies, and lower treatment response rates (54% vs. 93%, p = 0.01).

CONCLUSION

VPT examination is a simple tool, which is a reliable and sensitive measure not only for diabetic neuropathy, but also for CIDP. Moreover, in CIDP, elevated VPT values are also associated with lower treatment response rates.

Epidemiology of myasthenia gravis in Ontario, Canada

Incidence and prevalence estimates in myasthenia gravis have varied widely. Recent studies based on administrative health data have large sample sizes but lack rigorous validation of MG cases, and have not examined the North American population. Our aim was to explore trends in MG incidence and prevalence for the years 1996-2013 in the province of Ontario, Canada (population 13.5 million). We employed a previously validated algorithm to identify MG cases. Linking with census data allowed for the calculation of crude- and age/sex-standardized incidence and prevalence rates for the years 1996-2013. The regional distribution of MG cases throughout the province was examined. Mean age at the first myasthenia gravis encounter was 60.2 ± 17.1 years. In 2013, there were 3611 prevalent cases in Ontario, and the crude prevalence rate was 32.0/100,000 population. Age- and sex-standardized prevalence rates rose consistently over time from 16.3/100,000 (15.4-17.1) in 1996 to 26.3/100,000 (25.4-27.3) in 2013. Standardized incidence rates remained stable between 1996 (2.7/100,000; 95% CL 2.3-3.0) and 2013 (2.3/100,000; 2.1-2.6). Incidence was highest in younger women and older men, and geographic variation was evident throughout the province. In conclusion, this large epidemiological study shows rising myasthenia gravis prevalence with stable incidence over time, which is likely reflective of patients living longer, possibly due to improved disease treatment. Our findings provide accurate information on the Canadian epidemiology of myasthenia gravis and burden for health care resources planning for the province, respectively.

Treatment Responsiveness in CIDP Patients with Diabetes Is Associated with Higher Degrees of Demyelination

Introduction

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is one of several chronic treatable acquired demyelinating neuropathies.

Objectives

To explore the association between the degree of demyelination in CIDP, and treatment responsiveness.

Methods

A retrospective chart review of CIDP subjects assessed between 1997 and 2013 was performed to compare treatment responsiveness using different sets of criteria.

Results

99 CIDP patients were included, 34 with diabetes mellitus (DM). Treatment responsiveness was higher in CIDP-DM fulfilling 1 or more EFNS/PNS criteria, (63% vs. 31%, p = 0.03), and in CIDP+DM fulfilling 2 or more criteria (89% vs. 36%, p = 0.01). Nonetheless, treatment responsiveness in CIDP+DM had the highest odds ratio (3.73, p = 0.01). Similar results were also shown in simplified uniform study criteria, with 10% cut off values for CIDP-DM, compared to 30% for CIDP+DM.

Conclusion

In CIDP+DM, higher degrees of demyelination are associated with treatment responsiveness, implying the need to adjust current criteria in these patients.

New insights into the management of chronic inflammatory demyelinating polyradiculoneuropathy

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and its variants can be challenging to diagnose and treat. A combination of clinical, electrophysiological and laboratory features is often required to reach a diagnosis. New data are emerging about potential biomarkers and factors that may indicate treatment needs in individual patients. High-quality evidence exists for the efficacy of intravenous immunoglobulin (IVIG) in the treatment of CIDP, including quality of life (QoL) benefits. Besides pharmacological treatment, psychological factors must also be addressed to improve patients' QoL. Home-based IVIG infusion therapy is currently a well-established approach in some countries. A 6-month pilot study conducted in Ontario, Canada, provided proof of safety and patient acceptance of home-based IVIG therapy, although some logistical issues emerged.

Acquired immune axonal neuropathies

PURPOSE OF REVIEW

This article discusses the clinical features, pathophysiology, and management of primary and secondary acquired immune axonal neuropathies.

RECENT FINDINGS

Although there are many collagen vascular disorders associated with vasculitic neuropathy, a quarter of cases have been described to be due to nonsystemic vasculitis of the peripheral nervous system. Enhanced surveillance and aggressive treatment of conditions such as cryoglobulin-related vasculitic neuropathy with cyclophosphamide, rituximab, and alfa interferons has led to improved morbidity and mortality, however, many cases of immune axonal acquired neuropathy are still associated with poor outcomes. Acute motor axonal neuropathy (AMAN) and acute motor sensory axonal neuropathy (AMSAN) are well-characterized variants of Guillain-Barré syndrome.

SUMMARY

Characterizing the clinical and electrophysiologic phenotype can help diagnose conditions such as nonsystemic vasculitic neuropathy, AMAN, AMSAN, and immune small fiber neuropathy, while careful evaluation of systemic features is key to identifying secondary immune axonal neuropathies such as vasculitic neuropathy related to collagen vascular disease. Additional research is needed to determine the exact immune pathogenesis and optimized treatment regimens for all acquired immune axonal neuropathies.