Distribution patterns of demyelination correlate with clinical profiles in chronic inflammatory demyelinating polyneuropathy

CIDP Treatment Outcomes Correlation With First Nerve Conduction Changes: Ascertainment of Initial and Long-Term Responders

BACKGROUND AND AIMS

Nerve conduction studies (NCS) are integral to diagnosing chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), but their role in predicting treatment outcomes remains underexplored. This study evaluates NCS changes at first follow-up (first NCS changes) as predictors of treatment success in CIDP, focusing on their correlation with clinical outcomes over time.

METHODS

Newly diagnosed CIDP patients meeting the 2021 EAN/PNS criteria were retrospectively evaluated. Baseline and first follow-up NCS parameters were compared with clinical outcomes, assessed by the Neuropathy Impairment Score (NIS) and Inflammatory Neuropathy Cause and Treatment (INCAT) disability score. All patients received first-line immunotherapy (intravenous immunoglobulin, corticosteroids, or plasma exchange).

RESULTS

Of 39 treated patients, 26 (66.7%) were responders based on improving NIS trends, while 13 (33.3%) were nonresponders. Responders showed significant improvements at the first follow-up in fibular compound muscle action potential (CMAP) amplitude, ulnar CMAP amplitude, summated CMAP amplitudes, and fibular motor conduction velocity. Changes in fibular CMAP amplitude consistently correlated with NIS (R = -0.8 to -0.6, p ≤ 0.004) and INCAT disability score improvements (R = -0.6 to -0.3, p ≤ 0.032) across all follow-up intervals up to 60 months. Ulnar and summated CMAP amplitude changes also correlated with clinical outcomes, though their associations were less sustained than those of fibular CMAP amplitude.

INTERPRETATION

The first change in fibular CMAP amplitude is a reliable biomarker for predicting CIDP treatment response, with ulnar and summated CMAP amplitudes as alternatives when the fibular response is absent. Our findings highlight the utility of first NCS changes in monitoring and predicting treatment outcomes in CIDP.

Utility of Median Nerve Electrophysiological Parameters in Differentiating Immune-Mediated Demyelination From Compressive Median Neuropathy at the Wrist

INTRODUCTION/AIMS

Prolonged distal median motor latency (DML) may occur in carpal tunnel syndrome (CTS), potentially causing an electrodiagnostic dilemma in acquired demyelinating polyneuropathies. We aimed to demonstrate that parameter values obtained from conventional median nerve conduction studies can distinguish immune-mediated demyelination from compression-induced damage.

METHODS

We retrospectively reviewed the median nerve records of 73 control individuals, 125 patients with pure CTS, 31 with CTS and diabetic distal symmetric polyneuropathy, 36 with acute inflammatory demyelinating polyneuropathy, and 23 with chronic inflammatory demyelinating polyneuropathy. All patients exhibited DML prolonged by ≥ 50%. Optimal cut-off values were calculated with receiver operating characteristic curves.

RESULTS

The sensitivity and specificity of the optimal cut-off values forming the modified electrodiagnostic criteria were as follows: (a) distal compound muscle action potential duration of ≥ 8 ms (55.4% and 99.5%, respectively), (b) reduction of forearm motor conduction velocity by ≥ 30% (30.4% and 99.5%, respectively), (c) prolongation of minimum F-wave latency by ≥ 30% (58.9% and 99%, respectively), or (d) abnormal temporal dispersion of > 30% (14.1% and 100%, respectively). Using the modified electrodiagnostic criteria and the 2021 European Academy of Neurology/Peripheral Nerve Society electrodiagnostic criteria to define immune-mediated demyelination yielded sensitivities of 79.3% and 89.1% and specificities of 98.5% and 92.3%, respectively. Increased proximal conduction time and the presence of a mixed nerve-sparing pattern in the forearm did not offer additional diagnostic accuracy.

DISCUSSION

The proposed electrodiagnostic criteria for the median nerve are reliable for differentiating between immune-mediated demyelination and compression-induced damage, even in patients with extremely prolonged DML.

Correlation between Delayed Relief after Microvascular Decompression and Morphology of the Lateral Spread Response in Patients with Hemifacial Spasm-Temporal versus Mandibular Branch Stimulation

Although microvascular decompression (MVD) is a reliable treatment for hemifacial spasm (HFS), delayed postoperative relief is one of its main issues. We previously evaluated the morphology of the lateral spread response (LSR) and reported the correlation between delayed relief after MVD and polyphasic morphology of the LSR. The purpose of this study was to investigate the correlation between the morphology of the LSR with stimulation of the temporal and mandibular branches of the facial nerve and delayed relief of persistent HFS after MVD. We retrospectively analysed and compared data from 49 of 205 consecutive patients who underwent MVD for HFS at our hospital between January 2015 and March 2022. Based on the pattern of the initial LSR morphology, patients were divided into 4 groups (LSR with temporal branch stimulation/LSR with mandibular branch stimulation; polyphasic/polyphasic group, polyphasic/monophasic group, monophasic/polyphasic group, monophasic/monophasic group). The results of MVD surgery for HFS were evaluated 1 week, 1 month and 1 year postoperatively, by evaluating whether or not the symptoms of HFS persisted at the time of each follow-up. We found significant differences in residual postoperative HFS 1 week postoperatively among the 4 groups (p < 0.05), as assessed using m*n Yates chi-square test. There is a significant correlation between delayed relief after MVD and polyphasic morphology of the initial LSR in patients with HFS. The LSR with temporal rather than mandibular branch stimulation might be useful for predicting delayed relief following MVD in HFS patients.

Correlation between Delayed Relief after Microvascular Decompression and Morphology of the Lateral Spread Response in Patients with Hemifacial Spasm-Further Examination with Compound Motor Action Potentials

Although microvascular decompression (MVD) is a reliable treatment for hemifacial spasm (HFS), postoperative delayed relief is one of its main issues. We previously evaluated the morphology of the lateral spread response (LSR) and reported correlation between delayed relief after MVD and polyphasic morphology of the LSR. This study aimed to investigate the morphology of LSR and the course of recovery of the compound motor action potential (CMAP), to better understand the pathophysiology of delayed healing of HFS. Based on the pattern of the initial LSR morphology on temporal and marginal mandibular branches stimulation, patients were divided into two groups: the monophasic and polyphasic groups. The results of MVD surgery and sequential changes in the CMAP were evaluated 1 week, 1 month, 1 year, and final follow-up after the surgery. Significantly higher rates of persistent postoperative HFS were observed in patients with the polyphasic type of initial LSR at 1 week and 1 month after the surgery (P < 0.05, respectively). In the polyphasic group, the amplitude of the CMAP tended to gradually improve with time, while in the monophasic group, the amplitude of the CMAP decreased on the seventh postoperative day, followed by its gradual improvement. There is a significant correlation between delayed relief after MVD and polyphasic morphology of the initial LSR in patients with HFS. In the polyphasic group, CMAP recovered earlier and showed less reduction in amplitude, suggesting segmental demyelination, with less damage to peripheral nerves.

Cytokines and chemokines in patients with chronic inflammatory demyelinating polyradiculoneuropathy and multifocal motor neuropathy: A systematic review

Advances in the understanding of cytokines have revolutionized mechanistic treatments for chronic inflammatory and autoimmune diseases, as exemplified by rheumatoid arthritis. We conducted a systematic literature review on the role of cytokines and chemokines in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and multifocal motor neuropathy (MMN). Ovid Medline, EMBASE and Web of Science were searched until August 31, 2022 for human studies investigating cytokines levels in CIDP or MMN. Fifty-five articles on 1061 CIDP patients and 86 MMN patients were included, with a median of 18 patients per study (range 3-71). Studies differed in the inclusion criteria, type of assay, manufacturer, control subjects, and tested biological material. Only a minority of studies reported data on disease activity. Interleukin (IL)-6, IL-17, CXCL10, and tumor necrosis factor alpha (TNF-α), were elevated in CIDP compared to controls in most of the studies. IL-6 and TNF-α levels are also correlated with disability. In MMN patients, IL-1Ra was elevated in the majority of the reports. While acknowledging the challenges in comparing studies and the various limitations of the studies, including small patient numbers, particularly in MMN, our review suggests that IL-6, IL-17, CXCL10, and TNF-α might play a role in CIDP pathogenesis. Larger studies are needed in MMN.

Significant Correlation between Delayed Relief after Microvascular Decompression and Morphology of the Abnormal Muscle Response in Patients with Hemifacial Spasm

Although microvascular decompression (MVD) is a reliable treatment for hemifacial spasm (HFS), postoperative delayed relief of persistent HFS is one of the main issues. In patients with hemifacial spasm, stimulation of a branch of the affected facial nerve elicits an abnormal response in the muscles innervated by another branch. Several specific types of waves were found in the abnormal muscle response (AMR). This study aimed to confirm the relationship between the initial morphology of the AMR wave and delayed relief of persistent HFS after MVD. We retrospectively analyzed and compared the data from 47 of 155 consecutive patients who underwent MVD for HFS at our hospital between January 2015 and March 2020. Based on the pattern of the initial AMR morphology on orbicularis oculi and mentalis muscle stimulation, patients were divided into two groups, namely, the monophasic and polyphasic groups. The results of MVD surgery for HFS were evaluated 1 week, 1 month, and 1 year postoperatively, by evaluating whether or not the symptoms of HFS persisted at the time of each follow-up. There were significantly higher rates of persistent postoperative HFS in patients with the polyphasic type of initial AMR at 1 week and 1 month after the surgery (p < 0.05, respectively), as assessed using Yates chi-squared test and Fisher's exact test. A significant correlation was observed between delayed relief after MVD and polyphasic morphology of the AMR in electromyographic analysis in patients with hemifacial spasm.

Different patterns of sensory nerve involvement in chronic inflammatory demyelinating polyneuropathy subtypes

INTRODUCTION/AIMS

Among subtypes of chronic inflammatory demyelinating polyneuropathy (CIDP), different immune pathophysiologies have been proposed. In this study, sensory nerve conduction studies were compared among clinical subtypes to attempt to better understand the underlying pathophysiology.

METHODS

A total of 138 patients with CIDP was classified into clinical subtypes: typical CIDP (N = 68), multifocal CIDP (N = 27), or other (N = 2). Patients with immunoglobulin M (IgM) neuropathy anti-myelin-associated glycoprotein neuropathy (MAG; N = 19) were also included as disease controls. Sensory nerve action potentials (SNAPs) were recorded in the median, ulnar, and superficial radial and sural nerves.

RESULTS

SNAP amplitudes (P < .05) and conduction velocities (P < .01) in the median nerve and conduction velocities (P < .05) in the ulnar nerve were lower in typical CIDP than in multifocal CIDP, whereas those in the radial and sural nerves were comparable in each group. Low median and normal sural SNAP amplitudes were more common in typical CIDP (P < .005) than in multifocal CIDP, suggesting predominant involvement at terminal portions of the nerves.

DISCUSSION

Terminal portions of sensory nerves are preferentially affected in typical CIDP compared with multifocal CIDP. These findings might be partially explained by the hypothesis of antibody-mediated demyelination in typical CIDP at the regions where the blood-nerve barrier is anatomically deficient, whereas multifocal CIDP predominantly affects the nerve trunks, largely due to cell-mediated demyelination, with disruption of the blood-nerve barrier.

Microstructural Alteration of Lumbosacral Nerve Roots in Chronic Inflammatory Demyelinating Polyradiculoneuropathy: Insights From DTI and Correlations with Electrophysiological Parameters

RATIONALE AND OBJECTIVES

To detect the diffusion characteristics of lumbosacral nerve roots in patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and further to explore their correlations with electrophysiological parameters of lower extremity nerves.

MATERIALS AND METHODS

Eighteen CIDP patients and 18 age and sex-matched healthy volunteers were enrolled in this study from August 2019 to August 2020. Axial diffusion tensor imaging (DTI) of lumbosacral plexus was performed in all subjects and fractional anisotropy (FA), axial diffusivity (AD), radial diffusivity (RD), and mean diffusivity (MD) of lumbosacral nerve roots were measured. Two-sample t test or Mann-Whitney U test was used to compare the difference of DTI parameters between two groups. Receiver operating characteristic curves were plotted to determine the diagnostic accuracy. All patients also underwent nerve conduction studies. Correlations between DTI parameters of lumbosacral nerve roots and electrophysiological parameters were analyzed with Pearson or Spearman coefficients.

RESULTS

CIDP patients showed significantly lower FA as well as higher AD, RD, and MD values of lumbosacral nerve roots (FA:0.24±0.054, 0.32±0.044; AD:2.31±0.256, 2.11±0.230 (×10^-3mm²/s); RD:1.28±0.189, 1.13±0.106 (×10^-3mm²/s); MD:1.68±0.268, 1.45±0.186 (×10^-3mm²/s) in CIDP and control group, respectively, all p < 0.05). Receiver operating characteristic analysis showed among all DTI parameters, FA had the best diagnostic accuracy with an area under the curve of 0.914 and optimal cut-off value of 0.27. FA showed a positive correlation while RD showed a negative correlation with a conduction velocity of tibial and common peroneal nerves. RD also correlated positively with F-wave minimal latency of tibial nerves.

CONCLUSION

DTI can be used to assess the microstructure alterations of lumbosacral nerve roots in CIDP patients. FA and RD may serve as potential markers reflecting the conduction function of tibial and common peroneal nerves.

Prolonged distal motor latency of median nerve does not improve diagnostic accuracy for CIDP

Compression of the median nerve at the carpal tunnel can give demyelinating features and result in distal motor latency (DML) prolongation fulfilling the EFNS/PNS demyelinating criteria for chronic inflammatory demyelinating polyneuropathy (CIDP). Accordingly, being carpal tunnel syndrome (CTS) common in the general population, the EFNS/PNS guidelines recommend excluding the DML of the median nerve when DML prolongation may be consistent with median neuropathy at the wrist from CTS. The main aims of this study were to verify whether the inclusion of DML of the median nerve (when consistent with CTS) could improve electrophysiological diagnostic accuracy for CIDP and if the median nerve at the carpal tunnel was more prone to demyelination. We analyzed electrophysiological data from 499 patients included consecutively into the Italian CIDP Database. According to the EFNS/PNS criteria, 352 patients had a definite, 10 a probable, and 57 a possible diagnosis of CIDP, while 80 were not fulfilling the diagnostic criteria. The inclusion of DML prolongation of median nerve did not improve significantly the diagnostic accuracy for CIDP; overall diagnostic class changed in 6 out of 499 patients (1.2%) and electrodiagnostic class of CIDP changed from not fulfilling to possible in only 2 patients (2.5% of not-fulfilling patients). In conclusion, we can infer that excluding DML prolongation of median nerve does not increase the risk of missing a diagnosis of CIDP thus corroborating the current EFNS/PNS criteria.

Distal Acquired Demyelinating Symmetric Neuropathy Associated with Decreased Electrical Excitability of the Femoral Nerves

Introduction: There are many phenotypic variants of chronic inflammatory demyelinating polyneuropathy. Methods:An Ancient Greek aryvallos painted c. 480-450 BC, now on display at the Louvre museum, was meticulously studied regarding its painted surface, which presents an outpatient clinic in Ancient Greece. Other Ancient Greek works of art presenting medical activities have been also evaluated in order to reach informed conclusions regarding medical practice of that period. Case report: We report a rare case of the distal phenotype of chronic inflammatory demyelinating polyneuropathy with a subacute onset and rapidly progressive course. A 58-year-old male had distal, symmetric, predominantly motor impairment without ataxia and tremor. After a three-month duration of the disease, the patient had already complete paresis of the feet with absence of compound muscle action potentials (CMAPs) over the feet and lower leg muscles, but preserved proprioception and sural sensory nerve action potential. Cerebrospinal fluid protein level was elevated to 3.4 g/L. Demyelinating neuropathy was predominantly in the proximal segment of the nerves. Low amplitude of CMAPs was recorded hardly over the vastus medialis and rectus femoris muscles, while weakness and atrophy in these muscles were not. The patient was refractory to treatment. He died three years after disease onset. Conclusion:We described a new clinical-electrophysiological phenomenon, which was characterized as a decrease in the evoked electrical excitability at the femoral nerve stimulation site (decreased CMAP), while the natural physiological conduction of the impulse from the motor neuron to the muscle was not blocked (preserved muscle strength).

Length-dependent changes of lower limb muscle morphology in Chronic Inflammatory Demyelinating Polyneuropathy assessed with magnetic resonance imaging

The objective of the present study was to assess muscle quantity of the thigh and leg in patients with chronic inflammatory demyelinating polyneuropathy (CIDP) compared to age and sex matched controls in exploring length-dependent changes of innervated muscles. In five people with CIDP and seven controls, magnetic resonance imaging was used to assess muscle morphology of the four parts of the quadriceps and medial hamstring muscles. Findings were compared to the triceps surae from a subset of participants. The CIDP group had less contractile tissue in the quadriceps (11.5%, P<0.05), hamstrings (15.6%, P<0.05) and triceps surae (35.9%, P<0.05) compared to controls. Additionally, CIDP had less contractile tissue (18.7%) in the triceps surae compared to the hamstrings (P<0.05). Muscle quantity in the quadriceps and hamstrings in CIDP was less than controls, but differences were greater for the distal triceps surae. These findings support a length-dependent affect of CIDP on limb musculature composition.

Oligoclonal IgG bands in chronic inflammatory polyradiculoneuropathies

BACKGROUND

Cerebrospinal fluid (CSF) albumincytologic dissociation represents a supportive diagnostic criterion of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP).Few studies have investigated possible systemic or intrathecal humoral immune response activation in CIDP.Aim of our study was to investigate whether the search of oligoclonal IgG bands (OCBs) might provide additional data helpful in CIDP diagnostic work-up.

METHODS

Forty-eight consecutive patients with CIDP (34 men, mean age 59.4, range 16-83) were recruited. CSF analysis included nephelometric measurement of albumin and IgG concentrations, calculation of Q_ALB, QAlb_LIM and intrathecal IgG synthesis, and OCBs detection with isoelectric focusing. Data were compared with those from CSF and serum of 32 patients with Guillain-Barré syndrome (GBS), 18 patients with anti-myelin associated glycoprotein (MAG) antibody neuropathy, 4 patients with multifocal motor neuropathy and 32 patients with non-inflammatory neuropathies (NINPs).

RESULTS

Patients with CIDP and anti-MAG antibody neuropathy had significantly higher CSF albumin concentrations and Q_ALB values than NINPs (p=0.0003 and p=0.0095, respectively). A total of 9 (19%) patients with CIDP presented identical serum and CSF OCBs ('mirror pattern') versus 3 patients (16.6%) with anti-MAG antibody neuropathy, 13 patients (40.6%) with GBS and 12.5% patients with NINPs. Only one patient with CIDP showed unique-to-CSF OCBs. First-line therapy was effective in 80.4% of patients with CIDP, irrespective of CSF findings.

CONCLUSIONS

Compared with NINP, CIDP, GBS and anti-MAG antibody neuropathies had a significantly increased CSF protein and blood-spinal nerve root barrier damage. Intrathecal humoral immune response is rare in our patients with CIDP. Systemic oligoclonal activation is more frequent, but not significantly different from what was detected in the control groups.

Magnetic resonance neurography in diagnosing childhood chronic inflammatory demyelinating polyradiculoneuropathy

BACKGROUND

Peripheral nerve imaging is increasingly recognized as a powerful tool to evaluate nerve hypertrophy in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and Charcot-Marie-Tooth diseases (CMT), whereas data in pediatric patients are limited.

CASE DESCRIPTION

We describe the case of a 15-year-old Japanese girl with asymmetric demyelinating polyneuropathy, who, at the age of 10 years, was initially diagnosed with a demyelinating form of CMT. Fluorescence in situ hybridization for peripheral myelin 22 was negative, and already-known pathogenic variants were not detected by whole-genome sequencing, and nerve conduction studies revealed multifocal conduction blocks. Over the next 5 years, the patient showed gradual improvement in muscle weakness and sensory disturbance without immunological treatment and was referred to our hospital.

RESULTS

At the age of 15 years, magnetic resonance (MR) neurography showed asymmetric multifocal fusiform enlargement of nerve roots, brachial and lumbosacral plexuses, and intermediated nerve trunks, as well as cranial nerves. Based on the MR neurography findings and multifocal nerve conduction blocks, she was diagnosed as having multifocal CIDP (multifocal demyelinating sensory and motor neuropathy [MADSAM]) according to the European Federation of Neurological Societies/Peripheral Nerve Society diagnostic criteria.

DISCUSSION

Clinical diagnosis of childhood CIDP is challenging because its neurological manifestations and nerve conduction study findings occasionally resemble those of inherited demyelinating neuropathies. MR neurography is helpful for the assessment of patterns of nerve hypertrophy; MADSAM-CIDP is characterized by multiple fusiform nerve enlargement, whereas CMT shows symmetric and diffuse nerve hypertrophy.

CONCLUSION

The MR neurography patterns would help in diagnosing pediatric demyelinating neuropathies.

Finger drop sign as a new variant of acute motor axonal neuropathy

We propose the finger drop sign as a new clinical variant of acute motor axonal neuropathy (AMAN) defined by immunological and radiological evidence. We identified eight consecutive patients who had AMAN. All of them developed prominent involvement of the finger extensors. We performed magnetic resonance imaging (MRI) of the extremity muscles and serological assays for antiganglioside antibodies and Campylobacter jejuni. Patients with AMAN showed characteristic and a markedly sustained weakness of the finger extensors with a distinctive pattern of the finger drop sign. Limb MRI revealed unevenly distributed abnormal signals in the muscles mainly innervated by the posterior interosseous nerve. All tested patients showed positivity for immunoglobulin G antibody against ganglioside complex of GM1 and phosphatidic acid. A pathophysiological understanding of this unique syndrome can provide further insight into antiganglioside-antibody-mediated axonal injury in Guillain-Barré syndrome.

Cranial nerve involvement in typical and atypical chronic inflammatory demyelinating polyneuropathies

BACKGROUND AND PURPOSE

Cranial nerve palsy is occasionally present in patients with chronic inflammatory demyelinating polyneuropathy (CIDP), but its prevalence, characteristics and relations with the CIDP subtypes have rarely been investigated. The aim of this study was to systematically assess cranial nerve involvement in typical and atypical CIDP.

METHODS

Clinical data were reviewed in 132 consecutive patients with CIDP, including typical CIDP (n = 89), multifocal acquired demyelinating sensory and motor neuropathy (MADSAM) (n = 31), distal acquired demyelinating symmetric (DADS) (n = 9) and others (n = 3).

RESULTS

The frequency of cranial nerve palsy was 11% in typical CIDP, 48% in MADSAM and 11% in DADS. Facial and bulbar palsy was most frequently present (9%), followed by ocular motor nerve palsy (5%). Bilateral involvement was seen in all typical CIDP and DADS patients, whereas 80% of MADSAM patients had unilateral palsy. The presence of cranial nerve involvement was associated with more severe limb muscle weakness in typical CIDP, but not in MADSAM. Cranial nerve palsy fully recovered in 90% of typical CIDP and in 67% of MADSAM patients.

CONCLUSION

Amongst the CIDP subtypes, cranial palsy is frequent and unilateral in MADSAM, and less frequent and bilateral in typical CIDP and DADS. In typical CIDP, facial and bulbar palsy reflects more severe and extensive inflammation.

MR neurography of lumbosacral nerve roots: Diagnostic value in chronic inflammatory demyelinating polyradiculoneuropathy and correlation with electrophysiological parameters

PURPOSE

MR neurography(MRN) is an advanced imaging technique to visualize peripheral nerves. Our aim was to determine the value of morphological features of lumbosacral nerve roots on MRN in diagnosing chronic inflammatory demyelinating polyradiculoneuropathy(CIDP) and analyze their correlations with electrophysiological parameters.

METHODS

MRN of lumbosacral plexus was performed in 21 CIDP patients and 21 healthy volunteers. The cross-sectional areas(CSAs) and signal intensities(SI) of L3 to S1 nerve roots were measured and compared between two groups. Receiver operating characteristic(ROC) curves were plotted to assess the diagnostic accuracy. All patients also underwent nerve conduction studies. Correlations between CSAs and SI of lumbosacral nerve roots and electrophysiological parameters were analyzed.

RESULTS

Compared with control group, CIDP patients showed significantly increased CSAs and SI from L3 to S1 nerve root (P < 0.001 and P < 0.05 respectively for all nerve roots). The CSA_mean and SI_mean were 28.04 ± 8.55mm², 1.314 ± 0.199 for patient group and 14.91 ± 2.36mm²,1.155 ± 0.094 for control group. ROC analysis revealed the best diagnostic accuracy for the CSA_mean with an area under the curve of 0.968 and optimal cut-off value of 19.20 mm². CSAs of L5 or S1 nerve root correlated positively with central latency and negatively with conduction velocity of tibial nerve. SI of L5 also had a positive correlation with latency of sural nerve.

CONCLUSIONS

Evaluation of lumbosacral nerve roots on MRN in a quantitative manner may serve as an important tool to support the diagnosis of CIDP.

Hidden Charcot-Marie-Tooth 1A as Revealed by Peripheral Nerve Imaging

Peripheral nerve imaging techniques have recently increasingly revealed their usefulness. We herein describe a man who had a subacute progression of symptom, diffuse and prominent proximal demyelination and conduction block, suggesting a diagnosis of inflammatory demyelinating polyneuropathy. Additional nerve imaging techniques revealed homogeneous and prominent nerve hypertrophy without proximal accentuation and the findings implied inherited polyneuropathies. Intravenous immunoglobulin was administered, and both the symptoms of weakness and findings of nerve conduction studies (NCS) improved. Subsequent genetic testing unveiled Charcot-Marie-Tooth 1A. To diagnose peripheral nerve disorders, a careful history, physical examination and NCS are essential diagnostic tools, but the findings of this case suggest the importance of nerve imaging techniques in clinical situations.

Membrane property changes in most distal motor axons in chronic inflammatory demyelinating polyneuropathy

INTRODUCTION

Distal nerve terminals, where the blood-nerve barrier is anatomically deficient, are preferentially affected in immune-mediated neuropathies. Excitability alterations near the motor nerve terminals may be more prominent than the nerve trunk in typical chronic inflammatory demyelinating polyneuropathy (CIDP).

METHODS

In 20 patients with typical CIDP, motor nerve excitability testing was performed at the motor point and wrist of the ulnar nerve, and results were compared with those in 20 healthy persons.

RESULTS

Chronic inflammatory demyelinating polyneuropathy patients showed greater threshold changes in hyperpolarizing threshold electrotonus at the motor point (P < .05) but not at the wrist. Strength-duration time constant did not show significant differences between CIDP and controls at both sites.

DISCUSSION

Axonal property changes in CIDP are more prominent in distal portions of axons compared with the nerve trunk, presumably due to salient demyelination near the distal nerve terminals. Motor point excitability measurements could elucidate underlying pathophysiology in immune-mediated neuropathies.

Prospective study of the additional benefit of plexus magnetic resonance imaging in the diagnosis of chronic inflammatory demyelinating polyneuropathy

BACKGROUND AND PURPOSE

Hypertrophy/signal hyperintensity and/or gadolinium enhancement of plexus structures on magnetic resonance imaging (MRI) are observed in two-thirds of cases of typical chronic inflammatory demyelinating polyneuropathy (CIDP). The objective of our study was to determine the additional benefit of plexus MRI in patients referred to tertiary centers with baseline clinical and electrophysiological characteristics suggestive of typical or atypical CIDP.

METHODS

A total of 28 consecutive patients with initial suspicion of CIDP were recruited in nine centers and followed for 2 years. Plexus MRI data from the initial assessment were reviewed centrally. Physicians blinded to the plexus MRI findings established the final diagnosis (CIDP or neuropathy of another cause). The proportion of patients with abnormal MRI was analyzed in each group.

RESULTS

Chronic inflammatory demyelinating polyneuropathy was confirmed in 14 patients (50%), as were sensorimotor CIDP (n = 6), chronic immune sensory polyradiculoneuropathy (n = 2), motor CIDP (n = 1) and multifocal acquired demyelinating sensory and motor neuropathy (n = 5). A total of 37 plexus MRIs were performed (17 brachial, 19 lumbosacral and 8 in both localizations). MRI was abnormal in 5/37 patients (14%), all of whom were subsequently diagnosed with CIDP [5/14(36%)], after an atypical baseline presentation. With plexus MRI results masked, non-invasive procedures confirmed the diagnosis of CIDP in all but one patient [1/14 (7%)]. Knowledge of the abnormal MRI findings in the latter could have prevented nerve biopsy being performed.

CONCLUSION

Systematic plexus MRI in patients with initially suspected CIDP provides little additional benefit in confirming the diagnosis of CIDP.

Electrodiagnostic data-driven clustering identifies a prognostically different subgroup of patients with chronic inflammatory demyelinating polyneuropathy

OBJECTIVE

This study aimed to explore the correlations between electrodiagnostic (EDX) features in patients with chronic inflammatory demyelinating polyneuropathy (CIDP) and to investigate whether EDX data-driven clustering can identify a distinct subgroup regarding clinical phenotype and treatment response.

METHODS

We reviewed clinical and EDX data of 56 patients with definite CIDP fulfilling the 2010 European Federation of Neurological Societies and Peripheral Nerve Society criteria at two teaching hospitals. A hierarchical agglomerative clustering algorithm with complete linkage was used to partition the patients into subgroups with similar EDX features. A stepwise logistic regression analysis was performed to evaluate predictors of the long-term outcome.

RESULTS

EDX data-driven clustering partitioned the patients into two clusters, identifying a distinct subgroup characterised by coexistence of prominent conduction slowing and markedly reduced distally evoked compound muscle action potential (CMAP) amplitudes. This cluster of patients was significantly over-represented by an atypical subtype (distal acquired demyelinating symmetric polyneuropathy) compared with the other cluster (70% vs 26.1%, p=0.042). Furthermore, patients in this cluster invariably showed favourable long-term treatment outcome (100% vs 63%, p=0.023). In logistic regression analyses, the initial disability (OR 6.1, 95% CI 2.4 to 25.4), F-wave latency (OR 0.93, 95% CI 0.86 to 0.98) and distal CMAP duration (OR 0.96, 95% CI 0.91 to 0.99) were significant predictors of the poor long-term outcome.

CONCLUSION

Our results show that EDX data-driven clustering could differentiate a pattern of EDX features with prognostic implication in patients with CIDP. Reduced distally evoked CMAPs may not necessarily predict poor responses to treatment, and active treatment is warranted when prominent slowing of conduction is accompanied in the distal segments.

MRI biomarkers of proximal nerve injury in CIDP

Objective

To evaluate the utility of nerve diffusion tensor imaging (DTI), nerve cross‐sectional area, and muscle magnetic resonance imaging (MRI) multiecho Dixon for assessing proximal nerve injury in chronic inflammatory demyelinating polyneuropathy (CIDP).

Methods

In this prospective observational cohort study, 11 patients with CIDP and 11 healthy controls underwent a multiparametric MRI protocol with DTI of the sciatic nerve and assessment of muscle proton‐density fat fraction of the biceps femoris and the quadriceps femoris muscles by multiecho Dixon MRI. Patients were longitudinally evaluated by MRI, clinical examination, and nerve conduction studies at baseline and after 6 months.

Results

In sciatic nerves of CIDP patients, mean cross‐sectional area was significantly higher and fractional anisotropy value was significantly lower, compared to controls. In contrast, muscle proton‐density fat fraction was significantly higher in thigh muscles of patients with CIDP, compared to controls. MRI parameters showed high reproducibility at baseline and 6 months.

Interpretation

Advanced MRI parameters demonstrate subclinical proximal nerve damage and intramuscular fat accumulation in CIDP. Data suggest DTI and multiecho Dixon MRI might be useful in estimating axonal damage and neurogenic muscle changes in CIDP.

Quantitative muscle ultrasound is useful for evaluating secondary axonal degeneration in chronic inflammatory demyelinating polyneuropathy

INTRODUCTION

In chronic inflammatory demyelinating polyneuropathy (CIDP), exclusion of secondary axonal degeneration is challenging with conventional methods such as nerve conduction study (NCS), needle electromyography, and nerve biopsy. Increased echo intensity (EI) and decreased muscle thickness (MT) identified on muscle ultrasound (MUS) examination represent muscle denervation due to axonal degeneration in neurogenic disorders, suggesting MUS as a new tool to detect secondary axonal degeneration in patients with CIDP.

METHODS

EI and MT of abductor pollicis brevis, abductor digiti minimi, and first dorsal interosseous muscles were measured in 16 CIDP patients. Raw values were converted into z-scores using data from 60 normal controls (NCs).

RESULTS

Six of 45 muscles showed abnormally high EI and low MT, suggesting denervation following secondary axonal degeneration. These six muscles belonged to two patients with long disease history, unresponsiveness to treatment, and long interval from onset to initial therapy. There were no significant differences in EI and MT (p = .23 and .67, respectively) between the CIDP and NC groups, although NCS results revealed obvious demyelinating abnormalities in all CIDP patients, suggesting the fact that muscle structures will be preserved, and EI and MT will not change unless secondary axonal degeneration occurs in CIDP.

CONCLUSION

MUS is a promising tool for evaluating secondary axonal degeneration in patients with CIDP.

Early predictive factors of disability in CIDP

The objective of this study was to identify early clinical, biochemical and electrophysiological prognostic factors of disability in CIDP. We evaluated a dataset from 60 CIDP patients that included sex, age of onset, type of onset, phenotype, disease duration, response to treatment, disability at the time of diagnosis assessed using the modified Rankin Scale (baseline mRS), cerebrospinal fluid protein levels and electrophysiological data. All patients had clinical assessment of disability through the mRS within the last 6 months (last mRS) before enrollment in the study. Stepwise forward logistic regression model was applied to evaluate the impact of clinical, biochemical and electrophysiological parameters on the last mRS, considered as binary outcome (absence or presence of severe disability, i.e., <4/≥4 mRS). Moreover, we used Spearman's rank correlation coefficient to evaluate the relationship between disease duration and last mRS. We observed a significant relationship between last mRS and baseline mRS [p = 0.015, z = 2.44, OR 5.15 (CI 1.38-19.22)] and age of onset [p = 0.017, z = 2.39, OR 1.13 (CI 1.02-1.27) per additional year of age of onset]. There was no correlation between disease duration and last mRS. Our data suggest that a worse clinical status at the beginning of disease and an older age at onset may be negative prognostic factors of long-term disability independent from disease duration.

Improving the management of chronic inflammatory demyelinating polyradiculoneuropathy

This article considers several issues of current interest relating to the management of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), including diagnostic pitfalls, differences between CIDP patients with and without concurrent diabetes mellitus and how to best measure treatment response in daily practice. Despite the availability of diagnostic criteria, many patients diagnosed with CIDP do not meet these criteria; reasons for misdiagnosis are discussed. There are no definitive predictors of treatment response in CIDP; however, certain clinical and electrophysiological characteristics may be helpful. Patients with CIDP and concurrent diabetes present an additional diagnostic challenge; the differences between these groups, including possible differences in response predictors are discussed. Finally, the most appropriate outcome measures for use in daily practice are considered.

Guillain-Barré Syndrome (42 Cases) Occurring During a Zika Virus Outbreak in French Polynesia

Zika virus (transmitted by mosquitoes) reached French Polynesia for the first time in 2013, leading to an epidemic affecting 10% of the total population. So far, it has not been known to induce any neurological complications, but, a few weeks after the outbreak, an unexpectedly high number of 42 patients presented with Guillain-Barré syndrome.We report the clinical and electrophysiological characteristics of this series. Males predominated with a sex ratio of 2.82 (mean age: 46). All patients (except 2) were native Polynesian. At admission, 55% were able to walk unaided against 38% at nadir, 24% had swallowing troubles (nadir: 45%), 74% had motor weakness of the limbs (nadir: 86%) and deep tendon reflexes were diminished or not found in the vast majority of patients. Mean duration of the progressive phase and of the plateau phase was respectively 7 and 9 days. Thirty-eight percent of the patients were admitted in intensive care unit and 10 patients underwent tracheotomy. Nerve electrophysiological studies at admission showed marked distal motor conduction alterations, which had almost completely disappeared at the 4th month; this pattern was more suggestive of acute motor axonal neuropathy (AMAN) than of acute inflammatory demyelinating polyneuropathy (AIDP). Lumbar puncture showed elevated proteins in 90% of the cases, with cell count always inferior to 50/μL.This epidemic raises several questions, such as the potential existence of interactions between Zika virus and Polynesian HLA system and/or the consequences of several recombination events of this virus. This situation should call for increased vigilance, especially in countries where Aedes mosquitoes are present.

Normative NeuroFlexor data for detection of spasticity after stroke: a cross-sectional study

Background and Objective

The NeuroFlexor is a novel instrument for quantification of neural, viscous and elastic components of passive movement resistance. The aim of this study was to provide normative data and cut-off values from healthy subjects and to use these to explore signs of spasticity at the wrist and fingers in patients recovering from stroke.

Methods

107 healthy subjects (age range 28–68 years; 51 % females) and 39 stroke patients (age range 33–69 years; 33 % females), 2–4 weeks after stroke, were assessed with the NeuroFlexor. Cut-off values based on mean + 3SD of the reference data were calculated. In patients, the modified Ashworth scale (MAS) was also applied.

Results

In healthy subjects, neural component was 0.8 ± 0.9 N (mean ± SD), elastic component was 2.7 ± 1.1 N, viscous component was 0.3 ± 0.3 N and resting tension was 5.9 ± 1 N. Age only correlated with elastic component (r = −0.3, p = 0.01). Elasticity and resting tension were higher in males compared to females (p = 0.001) and both correlated positively with height (p = 0.01). Values above healthy population cut-off were observed in 16 patients (41 %) for neural component, in 2 (5 %) for elastic component and in 23 (59 %) for viscous component. Neural component above cut-off did not correspond well to MAS ratings. Ten patients with MAS = 0 had neural component values above cut-off and five patients with MAS ≥ 1 had neural component within normal range.

Conclusion

This study provides NeuroFlexor cut-off values that are useful for detection of spasticity in the early phase after stroke.

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.

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.

Different electrophysiological profiles and treatment response in 'typical' and 'atypical' chronic inflammatory demyelinating polyneuropathy

BACKGROUND

Chronic inflammatory demyelinating polyneuropathy (CIDP) is currently classified into 'typical' CIDP and 'atypical' subtypes such as multifocal acquired demyelinating sensory and motor neuropathy (MADSAM).

OBJECTIVES

To assess the frequency of CIDP subtypes, and to elucidate clinical and electrophysiological features, and treatment response in each subtype.

METHODS

We reviewed data from 100 consecutive patients fulfilling criteria for CIDP proposed by the European Federation of Neurological Societies and the Peripheral Nerve Society. The Kaplan-Meier curve was used to estimate long-term outcome.

RESULTS

Patients were classified as having typical CIDP (60%), MADSAM (34%), demyelinating acquired distal symmetric neuropathy (8%) or pure sensory CIDP (1%). Compared with patients with MADSAM, patients with typical CIDP showed more rapid progression and severe disability, and demyelination predominant in the distal nerve segments. MADSAM was characterised by multifocal demyelination in the nerve trunks. Abnormal median-normal sural sensory responses were more frequently found for typical CIDP (53% vs 13%). Patients with typical CIDP invariably responded to corticosteroids, immunoglobulin or plasmapheresis, whereas patients with MADSAM were more refractory to these treatments. The Kaplan-Meier analyses showed that 64% of patients with typical CIDP and 41% of patients with MADSAM had a clinical remission 5 years later (p=0.02).

CONCLUSIONS

Among the CIDP spectrum, typical CIDP and MADSAM are the major subtypes, and their pathophysiology appears to be distinct. In typical CIDP, the distal nerve terminals and possibly the nerve roots, where the blood-nerve barrier is anatomically deficient, are preferentially affected, raising the possibility of antibody-mediated demyelination, whereas cellular immunity with breakdown of the barrier may be important in MADSAM neuropathy.

Nerve Ultrasound and Electrophysiology for Therapy Monitoring in Chronic Inflammatory Demyelinating Polyneuropathy

BACKGROUND AND PURPOSE

We evaluated prospectively nerve ultrasound and electrophysiology as monitoring methods of intravenous immunoglobulin (IVIG) therapy in chronic inflammatory demyelinating polyneuropathy (CIDP).

METHODS

Overall 15 healthy subjects and 11 CIDP patients undergoing IVIG therapy were recruited in the study. All patients underwent clinical, ultrasound, and electrophysiological evaluation at the time point of first onset of symptoms (<6 weeks of symptoms) and 4, 8, and 12 months after onset.

RESULTS

The intranerve cross-sectional area (CSA) variability of each nerve, but not the CSA alone, correlated with the MRC Scale score during 12-month follow-up. On the other hand, none of the electrophysiological parameters correlated with the MRC Scale Score in each of the peripheral nerves. Interestingly, in ¾ of the CIDP patients, the resolution of the conduction block correlated with the improvement in the MRC Sum score.

CONCLUSIONS

Nerve ultrasound and in particular the intranerve CSA variability seems to be a useful method in monitoring CIDP patients. Although the sample size is small, the intranerve CSA variability seems to be more promising than neurophysiology.

Autoantibodies against vinculin in patients with chronic inflammatory demyelinating polyneuropathy

To identify the target molecules of chronic inflammatory demyelinating polyneuropathy (CIDP), we used proteomic-based approach in the extracted proteins from porcine cauda equina. Two of 31 CIDP patients had markedly elevated serum autoantibodies against vinculin, a cell adhesion protein. Both of the patients with anti-vinculin antibodies had similar clinical manifestation, which are compatible with those of "typical" CIDP. Immunocytochemistry showed that vinculin was stained at the myelin sheath of the sciatic nerves by serum samples. Our results suggest that vinculin is a possible immunological target molecule in a subpopulation of typical CIDP patients.

Treatment responsiveness in CIDP patients with diabetes is associated with unique electrophysiological characteristics, and not with common criteria for CIDP

OBJECTIVES

Characterize treatment responsiveness in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) patients with diabetes mellitus (DM).

METHODS

We performed a retrospective chart review of CIDP subjects assessed between 1997 and 2013 and compared treatment response rates in those with and without DM, using different sets of criteria.

RESULTS

99 CIDP patients were included, 34 CIDP+DM and 65 CIDP-DM patients, both having similar treatment response rates. CIDP patients fulfilling European Federation of Neurological Societies/Peripheral Nerve Society (EFNS/PNS) criteria had higher treatment response rates. Responders fulfilled a higher number of American Academy of Neurology (AAN) and EFNS/PNS criteria and had a higher number of demyelinating features in the total cohort and in CIDP-DM but not in CIDP+DM patients. CIDP+DM responders, however, had unique electrophysiologic characteristics.

CONCLUSION

Fulfilling EFNS/PNS and AAN criteria, and higher number of demyelinating features, are associated with higher treatment response rates in CIDP-DM but not in CIDP+DM patients, implying the need for adjusting current criteria to predict treatment response rates in CIDP-DM patients.

Nerve biopsy findings contribute to diagnosis of multiple mononeuropathy: 78% of findings support clinical diagnosis

Multiple mononeuropathy is an unusual form of peripheral neuropathy involving two or more nerve trunks. It is a syndrome with many different causes. We reviewed the clinical, electrophysiological and nerve biopsy findings of 14 patients who suffered from multiple mononeuropathy in our clinic between January 2009 and June 2013. Patients were diagnosed with vasculitic neuropathy (n = 6), perineuritis (n = 2), chronic inflammatory demyelinating polyradiculoneuropathy (n = 2) or Lewis-Sumner syndrome (n = 1) on the basis of clinical features, laboratory data, electrophysiological investigations and nerve biopsies. Two patients who were clinically diagnosed with vasculitic neuropathy and one patient who was clinically diagnosed with chronic inflammatory demyelinating polyradiculoneuropathy were not confirmed by nerve biopsy. Nerve biopsies confirmed clinical diagnosis in 78.6% of the patients (11/14). Nerve biopsy pathological diagnosis is crucial to the etiological diagnosis of multiple mononeuropathy.

Acquired and genetic channelopathies: in vivo assessment of axonal excitability

Neuronal or axonal ion channel function can be impaired or altered in a number of disorders, such as acquired (autoantibody-mediated, toxic, and metabolic) and genetic channelopathies, and even neurodegenerative (motor neuron disease) or inflammatory diseases (multiple sclerosis, immune-mediated neuropathies). When specific channels are affected, axonal/neuronal excitability primarily alters according to original function of the corresponding channels. Separately, in the 1990s, axonal excitability testing was developed to assess ion channel function, membrane potential, and passive membrane properties non-invasively in human subjects. Using this technique, numerous papers on altered axonal excitability in a variety of disorders have been published since 2000. In a recent issue of Experimental Neurology, Park et al. demonstrated changes in peripheral axonal excitability in limbic encephalitis and acquired neuromyotonia with anti-voltage gated potassium channel antibodies. Unexpectedly, the results were not consistent with those caused by simple potassium channel blockade, suggesting that multiple other factors contribute to altered axonal excitability. In contrast it was reported that patients with episodic ataxia type 1 (genetic channelopathy with mutation of Kv1.1 channel gene) show prominent excitability changes exactly compatible with fast potassium channel blockade. This commentary aims to highlight findings of this study in a broader context, and provides possible explanations for the discrepancy of patterns of axonal excitability changes in acquired and genetic potassium channelopathies.

Severity and patterns of blood-nerve barrier breakdown in patients with chronic inflammatory demyelinating polyradiculoneuropathy: correlations with clinical subtypes

Objective

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is currently classified into clinical subtypes, including typical and atypical forms (multifocal acquired demyelinating sensory and motor neuropathy (MADSAM) and distal acquired demyelinating symmetric neuropathy (DADS)). The aim of this study was to elucidate the patterns and severity of breakdown of the blood-nerve barrier (BNB) in each CIDP subtype.

Methods

We evaluated the effects of sera obtained from patients with typical CIDP, MADSAM and DADS and control subjects on the expression levels of tight junction proteins and transendothelial electrical resistance (TEER) value in human peripheral nerve microvascular endothelial cells (PnMECs).

Results

The sera obtained from the patients with the three clinical phenotypes of CIDP decreased the amount of claudin-5 protein levels and TEER values in the PnMECs. In addition, the sera obtained from typical CIDP patients more prominently reduced claudin-5 protein levels and TEER values in the PnMECs than did that obtained from the MADSAM and DADS patients. Furthermore, the severity of BNB disruption after exposure to the sera was associated with higher Hughes grade, lower MRC score, more pronounced slowing of motor nerve conduction in the median nerve and higher frequency of abnormal temporal dispersion.

Conclusions

Sera derived from typical CIDP patients destroy the BNB more severely than those from MADSAM or DADS patients. The extent of BNB disruption in the setting of CIDP is associated with clinical disability and demyelination in the nerve trunk. These observations may explain the phenotypical differences between CIDP subtypes.

Diagnosis and treatment of chronic acquired demyelinating polyneuropathies

Chronic neuropathies are operationally classified as primarily demyelinating or axonal, on the basis of electrodiagnostic or pathological criteria. Demyelinating neuropathies are further classified as hereditary or acquired-this distinction is important, because the acquired neuropathies are immune-mediated and, thus, amenable to treatment. The acquired chronic demyelinating neuropathies include chronic inflammatory demyelinating polyneuropathy (CIDP), neuropathy associated with monoclonal IgM antibodies to myelin-associated glycoprotein (MAG; anti-MAG neuropathy), multifocal motor neuropathy (MMN), and POEMS syndrome. They have characteristic--though overlapping--clinical presentations, are mediated by distinct immune mechanisms, and respond to different therapies. CIDP is the default diagnosis if the neuropathy is demyelinating and no other cause is found. Anti-MAG neuropathy is diagnosed on the basis of the presence of anti-MAG antibodies, MMN is characterized by multifocal weakness and motor conduction blocks, and POEMS syndrome is associated with IgG or IgA λ-type monoclonal gammopathy and osteosclerotic myeloma. The correct diagnosis, however, can be difficult to make in patients with atypical or overlapping presentations, or nondefinitive laboratory studies. First-line treatments include intravenous immunoglobulin (IVIg), corticosteroids or plasmapheresis for CIDP; IVIg for MMN; rituximab for anti-MAG neuropathy; and irradiation or chemotherapy for POEMS syndrome. A correct diagnosis is required for choosing the appropriate treatment, with the aim of preventing progressive neuropathy.

Treatment of chronic inflammatory demyelinating polyneuropathy: from molecular bases to practical considerations

Chronic inflammatory demyelinating polyneuropathy (CIDP) is an autoimmune disease of the peripheral nervous system, in which both cellular and humoral immune responses are involved. The disease is clinically heterogeneous with some patients displaying pure motor form and others also showing a variable degree of sensory dysfunction; disease evolution may also differ from patient to patient, since monophasic, progressive, and relapsing forms are reported. Underlying such clinical variability there is probably a broad spectrum of molecular dysfunctions that are and will be the target of therapeutic strategies. In this review we first explore the biological bases of current treatments and subsequently we focus on the practical management that must also take into account pharmacoeconomic issues.

Pathophysiology of immune-mediated demyelinating neuropathies--Part II: Neurology

In the second part of this review we deal with the clinical aspects of immune-mediated demyelinating neuropathies. We describe the relationship between pathophysiology and symptoms and discuss the pathophysiology of specific disease entities, including Guillain-Barré syndrome, chronic inflammatory demyelinating polyneuropathy, multifocal motor neuropathy, anti-myelin-associated glycoprotein neuropathy, and POEMS syndrome.

Chronic inflammatory demyelinative polyneuropathy

Chronic inflammatory demyelinative polyneuropathy (CIDP) is an acquired polyneuropathy presumably of immunological origin. It is characterized by a progressive or a relapsing course with predominant motor deficit. The diagnosis rests on the association of non-length-dependent predominantly motor deficit following a progressive or a relapsing course associated with increased CSF protein content. The demonstration of asymmetrical demyelinating features on nerve conduction studies is needed for diagnosis. The outcome depends on the amplitude of axon loss associated with demyelination. CIDP must be differentiated from acquired demyelinative neuropathies associated with monoclonal gammopathies. CIDP responds well to treatment with corticosteroids, intravenous immunoglobulins, and plasma exchanges, at least initially.

An unusual case of POEMS syndrome

We report a 48-year-old man, a farmer, presenting with chronic sensori-motor polyneuropathy. Electrophysiology revealed demyelinating type of neuropathy. Immunoelectrophoresis for monoclonal protein was negative; however, plasmacytoma was discovered on spine imaging. After receiving radiotherapy and chemotherapy over past 9 months there has been a considerable improvement in patient's disability. This case highlights the role of skeletal survey in evaluation of chronic demyelinating neuropathy.

The role of T cell apoptosis in nervous system autoimmunity

Fas is a transmembrane receptor involved in the death program of several cell lines, including T lymphocytes. Deleterious mutations hitting genes involved in the Fas pathway cause the autoimmune lymphoprolipherative syndrome (ALPS). Moreover, defective Fas function is involved in the development of common autoimmune diseases, including autoimmune syndromes hitting the nervous system, such as multiple sclerosis (MS) and chronic inflammatory demyelinating polyneuropathy (CIDP). In this review, we first explore some peculiar aspects of Fas mediated apoptosis in the central versus peripheral nervous system (CNS, PNS); thereafter, we analyze what is currently known on the role of T cell apoptosis in both MS and CIDP, which, in this regard, may be seen as two faces of the same coin. In fact, we show that, in both diseases, defective Fas mediated apoptosis plays a crucial role favoring disease development and its chronic evolution.