Chronic relapsing polyneuritis

Endoneurial immune interplay in peripheral nerve repair: insights and implications for future therapeutic interventions

The mechanisms underlying axonal injury and repair in peripheral nerves, whether due to traumatic damage or autoimmune neuropathies, are complex and not yet fully understood. Recent research indicates that an orchestrated interplay between damaged neurons, Schwann cells, and especially endoneurial immune cells such as macrophages or T cells is crucial to achieve satisfactory nerve recovery. Following axonal injury, degenerating axons and reactive Schwann cells release chemoattractants and cytokines that recruit immune cells into the endoneurium. Among them, macrophages play a pivotal role by clearing axonal and myelin debris and subsequently creating a pro-regenerative microenvironment that supports axonal outgrowth. There is evidence that the timely switch of a pro-inflammatory M1 toward a pro-regenerative M2 macrophage polarization state is crucial for satisfactory nerve recovery, and supportive cellular and humoral factors that influence the endoneurial microenvironment, such as T cells and their cytokines, can substantially impact this fragile recovery process. The latter explains the limited nerve recovery in immune neuropathies, where a pathologic pro-inflammatory shift within the endoneurial immune cell signature hampers axonal outgrowth. This review aims to provide insights into cellular and humoral determinants of the endoneurial microenvironment during nerve damage and repair, which are assumed to hold substantial potential for future therapeutic interventions, especially since current strategies to enhance peripheral nerve recovery are limited to either surgical interventions in traumatic neuropathies or immunomodulatory drugs in immune neuropathies that often fail to achieve satisfactory functional results.

Challenges in the Early Diagnosis and Treatment of Chronic Inflammatory Demyelinating Polyradiculoneuropathy in Adults: Current Perspectives

Diagnosing Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) poses numerous challenges. The heterogeneous presentations of CIDP variants, its mimics, and the complexity of interpreting electrodiagnostic criteria are just a few of the many reasons for misdiagnoses. Early recognition and treatment are important to reduce the risk of irreversible axonal damage, which may lead to permanent disability. The diagnosis of CIDP is based on a combination of clinical symptoms, nerve conduction study findings that indicate demyelination, and other supportive criteria. In 2021, the European Academy of Neurology (EAN) and the Peripheral Nerve Society (PNS) published a revision on the most widely adopted guideline on the diagnosis and treatment of CIDP. This updated guideline now includes clinical and electrodiagnostic criteria for CIDP variants (previously termed atypical CIDP), updated supportive criteria, and sensory criteria as an integral part of the electrodiagnostic criteria. Due to its many rules and exceptions, this guideline is complex and misinterpretation of nerve conduction study findings remain common. CIDP is treatable with intravenous immunoglobulins, corticosteroids, and plasma exchange. The choice of therapy should be tailored to the individual patient's situation, taking into account the severity of symptoms, potential side effects, patient autonomy, and past treatments. Treatment responses should be evaluated as objectively as possible using disability and impairment scales. Applying these outcome measures consistently in clinical practice aids in recognizing the effectiveness (or lack thereof) of a treatment and facilitates timely consideration of alternative diagnoses or treatments. This review provides an overview of the current perspectives on the diagnostic process and first-line treatments for managing the disease.

Autonomic nervous system involvement in chronic inflammatory demyelinating polyradiculoneuropathy: a literature review

BACKGROUND AND AIMS

Although dysautonomia is a well-recognized complication of acute demyelinating polyradiculoneuropathy, it is rarely reported and evaluated in chronic demyelinating neuropathies. The purpose of this review is to search and synthesize the current literature on the prevalence and type of autonomic dysfunction (AD) in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP).

METHODS

PubMed and Web of Science were searched for studies reporting AD in CIDP.

RESULTS

Twelve studies, including 346 patients with CIDP, were found eligible for the review. Seven studies used autonomic tests only as an additional component of the comprehensive clinical evaluation, and found that dysautonomia in CIDP may indicate the presence of a comorbid disease (e.g., diabetes) and facilitate the differentiation of CIDP from other neuropathies (e.g., amyloid neuropathy). Five studies performed quantitative assessment of autonomic function in CIDP as a primary goal. Two studies have used the Composite Autonomic Severity Score (CASS) to assess severity and distribution of dysautonomia. The reported prevalence of dysautonomia in CIDP during quantitative assessment of autonomic function ranged from 25 to 89%, depending on the battery of tests used, with CASS not exceeding 4 points. The abnormalities in autonomic tests indicated both sympathetic and parasympathetic dysfunction and did not correlate with the duration, severity and variant of CIDP.

CONCLUSIONS

Clinical or subclinical involvement of the ANS has been shown to be common and relatively mild in CIDP. The impact of autonomic impairment on disability and of its possible response to therapy in CIDP needs to be further investigated.

The Role of the Complement System in Chronic Inflammatory Demyelinating Polyneuropathy: Implications for Complement-Targeted Therapies

Chronic inflammatory demyelinating polyneuropathy (CIDP) is the most common, heterogeneous, immune-mediated neuropathy, characterized by predominant demyelination of motor and sensory nerves. CIDP follows a relapsing-remitting or a progressive course and causes substantial disability. The pathogenesis of CIDP involves a complex interplay of multiple aberrant immune responses, creating a pro-inflammatory environment, subsequently inflicting damage on the myelin sheath. Though the exact triggers are unclear, diverse immune mechanisms encompassing cellular and humoral pathways are implicated. The complement system appears to play a role in promoting macrophage-mediated demyelination. Complement deposition in sural nerve biopsies, as well as signs of increased complement activation in serum and CSF of patients with CIDP, suggest complement involvement in CIDP pathogenesis. Here, we present a comprehensive overview of the preclinical and clinical evidence supporting the potential role of the complement system in CIDP. This understanding furnishes a strong rationale for targeting the complement system to develop new therapies that could serve the unmet needs of patients affected by CIDP, particularly in those refractory to standard therapies.

European Academy of Neurology/Peripheral Nerve Society guideline on diagnosis and treatment of chronic inflammatory demyelinating polyradiculoneuropathy: Report of a joint Task Force-Second revision

OBJECTIVE

To revise the 2010 consensus guideline on chronic inflammatory demyelinating polyradiculoneuropathy (CIDP).

METHODS

Seventeen disease experts, a patient representative, and two Cochrane methodologists constructed 12 Population/Intervention/Comparison/Outcome (PICO) questions regarding diagnosis and treatment to guide the literature search. Data were extracted and summarized in GRADE summary of findings (for treatment PICOs) or evidence tables (for diagnostic PICOs).

RESULTS

Statements were prepared according to the GRADE Evidence-to-Decision frameworks. Typical CIDP and CIDP variants were distinguished. The previous term "atypical CIDP" was replaced by "CIDP variants" because these are well characterized entities (multifocal, focal, distal, motor, or sensory CIDP). The levels of diagnostic certainty were reduced from three (definite, probable, possible CIDP) to only two (CIDP and possible CIDP), because the diagnostic accuracy of criteria for probable and definite CIDP did not significantly differ. Good Practice Points were formulated for supportive criteria and investigations to be considered to diagnose CIDP. The principal treatment recommendations were: (a) intravenous immunoglobulin (IVIg) or corticosteroids are strongly recommended as initial treatment in typical CIDP and CIDP variants; (b) plasma exchange is strongly recommended if IVIg and corticosteroids are ineffective; (c) IVIg should be considered as first-line treatment in motor CIDP (Good Practice Point); (d) for maintenance treatment, IVIg, subcutaneous immunoglobulin or corticosteroids are recommended; (e) if the maintenance dose of any of these is high, consider either combination treatments or adding an immunosuppressant or immunomodulatory drug (Good Practice Point); and (f) if pain is present, consider drugs against neuropathic pain and multidisciplinary management (Good Practice Point).

European Academy of Neurology/Peripheral Nerve Society guideline on diagnosis and treatment of chronic inflammatory demyelinating polyradiculoneuropathy: Report of a joint Task Force-Second revision

To revise the 2010 consensus guideline on chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). Seventeen disease experts, a patient representative, and two Cochrane methodologists constructed 12 Population/Intervention/Comparison/Outcome (PICO) questions regarding diagnosis and treatment to guide the literature search. Data were extracted and summarized in GRADE summary of findings (for treatment PICOs) or evidence tables (for diagnostic PICOs). Statements were prepared according to the GRADE Evidence-to-Decision frameworks. Typical CIDP and CIDP variants were distinguished. The previous term "atypical CIDP" was replaced by "CIDP variants" because these are well characterized entities (multifocal, focal, distal, motor, or sensory CIDP). The levels of diagnostic certainty were reduced from three (definite, probable, possible CIDP) to only two (CIDP and possible CIDP), because the diagnostic accuracy of criteria for probable and definite CIDP did not significantly differ. Good Practice Points were formulated for supportive criteria and investigations to be considered to diagnose CIDP. The principal treatment recommendations were: (a) intravenous immunoglobulin (IVIg) or corticosteroids are strongly recommended as initial treatment in typical CIDP and CIDP variants; (b) plasma exchange is strongly recommended if IVIg and corticosteroids are ineffective; (c) IVIg should be considered as first-line treatment in motor CIDP (Good Practice Point); (d) for maintenance treatment, IVIg, subcutaneous immunoglobulin or corticosteroids are recommended; (e) if the maintenance dose of any of these is high, consider either combination treatments or adding an immunosuppressant or immunomodulatory drug (Good Practice Point); and (f) if pain is present, consider drugs against neuropathic pain and multidisciplinary management (Good Practice Point).

Macrophages and Autoantibodies in Demyelinating Diseases

Myelin phagocytosis by macrophages has been an essential feature of demyelinating diseases in the central and peripheral nervous systems, including Guillain–Barré syndrome (GBS), chronic inflammatory demyelinating polyneuropathy (CIDP), and multiple sclerosis (MS). The discovery of autoantibodies, including anti-ganglioside GM1 antibodies in the axonal form of GBS, anti-neurofascin 155 and anti-contactin 1 antibodies in typical and distal forms of CIDP, and anti-aquaporin 4 antibodies in neuromyelitis optica, contributed to the understanding of the disease process in a subpopulation of patients conventionally diagnosed with demyelinating diseases. However, patients with these antibodies are now considered to have independent disease entities, including acute motor axonal neuropathy, nodopathy or paranodopathy, and neuromyelitis optica spectrum disorder, because primary lesions in these diseases are distinct from those in conventional demyelinating diseases. Therefore, the mechanisms underlying demyelination caused by macrophages remain unclear. Electron microscopy studies revealed that macrophages destroy myelin as if they are the principal players in the demyelination process. Recent studies suggest that macrophages seem to select specific sites of myelinated fibers, including the nodes of Ranvier, paranodes, and internodes, for the initiation of demyelination in individual cases, indicating that specific components localized to these sites play an important role in the behavior of macrophages that initiate myelin phagocytosis. Along with the search for autoantibodies, the ultrastructural characterization of myelin phagocytosis by macrophages is a crucial step in understanding the pathophysiology of demyelinating diseases and for the future development of targeted therapies.

New evidence for secondary axonal degeneration in demyelinating neuropathies

Development of peripheral nervous system (PNS) myelin involves a coordinated series of events between growing axons and the Schwann cell (SC) progenitors that will eventually ensheath them. Myelin sheaths have evolved out of necessity to maintain rapid impulse propagation while accounting for body space constraints. However, myelinating SCs perform additional critical functions that are required to preserve axonal integrity including mitigating energy consumption by establishing the nodal architecture, regulating axon caliber by organizing axonal cytoskeleton networks, providing trophic and potentially metabolic support, possibly supplying genetic translation materials and protecting axons from toxic insults. The intermediate steps between the loss of these functions and the initiation of axon degeneration are unknown but the importance of these processes provides insightful clues. Prevalent demyelinating diseases of the PNS include the inherited neuropathies Charcot-Marie-Tooth Disease, Type 1 (CMT1) and Hereditary Neuropathy with Liability to Pressure Palsies (HNPP) and the inflammatory diseases Acute Inflammatory Demyelinating Polyneuropathy (AIDP) and Chronic Inflammatory Demyelinating Polyneuropathy (CIDP). Secondary axon degeneration is a common feature of demyelinating neuropathies and this process is often correlated with clinical deficits and long-lasting disability in patients. There is abundant electrophysiological and histological evidence for secondary axon degeneration in patients and rodent models of PNS demyelinating diseases. Fully understanding the involvement of secondary axon degeneration in these diseases is essential for expanding our knowledge of disease pathogenesis and prognosis, which will be essential for developing novel therapeutic strategies.

Diagnostic challenges in chronic inflammatory demyelinating polyradiculoneuropathy

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) consists of a spectrum of autoimmune diseases of the peripheral nerves, causing weakness and sensory symptoms. Diagnosis often is challenging, because of the heterogeneous presentation and both mis- and underdiagnosis are common. Nerve conduction study (NCS) abnormalities suggestive of demyelination are mandatory to fulfil the diagnostic criteria. On the one hand, performance and interpretation of NCS can be difficult and none of these demyelinating findings are specific for CIDP. On the other hand, not all patients will be detected despite the relatively high sensitivity of NCS abnormalities. The electrodiagnostic criteria can be supplemented with additional diagnostic tests such as CSF examination, MRI, nerve biopsy, and somatosensory evoked potentials. However, the evidence for each of these additional diagnostic tests is limited. Studies are often small without the use of a clinically relevant control group. None of the findings are specific for CIDP, meaning that the results of the diagnostic tests should be carefully interpreted. In this update we will discuss the pitfalls in diagnosing CIDP and the value of newly introduced diagnostic tests such as nerve ultrasound and testing for autoantibodies, which are not yet part of the guidelines.

Pathophysiology of Chronic Inflammatory Demyelinating Polyneuropathy: Insights into Classification and Therapeutic Strategy

Chronic inflammatory demyelinating polyneuropathy (CIDP) is classically defined as polyneuropathy with symmetric involvement of the proximal and distal portions of the limbs. In addition to this "typical CIDP", the currently prevailing diagnostic criteria proposed by the European Federation of Neurological Societies and Peripheral Nerve Society (EFNS/PNS) define "atypical CIDP" as encompassing the multifocal acquired demyelinating sensory and motor (MADSAM), distal acquired demyelinating symmetric (DADS), pure sensory, pure motor, and focal subtypes. Although macrophage-induced demyelination is considered pivotal to the pathogenesis of CIDP, recent studies have indicated the presence of distinctive mechanisms initiated by autoantibodies against paranodal junction proteins, such as neurofascin 155 and contactin 1. These findings led to the emergence of the concept of nodopathy or paranodopathy. Patients with these antibodies tend to show clinical features compatible with typical CIDP or DADS, particularly the latter. In contrast, classical macrophage-induced demyelination is commonly found in some patients in each major subtype, including the typical CIDP, DADS, MADSAM, and pure sensory subtypes. Differences in the distribution of lesions and the repair processes underlying demyelination by Schwann cells may determine the differences among subtypes. In particular, the preferential involvement of proximal and distal nerve segments has been suggested to occur in typical CIDP, whereas the involvement of the middle nerve segments is conspicuous in MADSAM. These findings suggest that humoral rather than cellular immunity predominates in the former because nerve roots and neuromuscular junctions lack blood-nerve barriers. Treatment for CIDP consists of intravenous immunoglobulin (IVIg) therapy, steroids, and plasma exchange, either alone or in combination. However, patients with anti-neurofascin 155 and contactin 1 antibodies are refractory to IVIg. It has been suggested that rituximab, a monoclonal antibody to CD20, could have efficacy in these patients. Further studies are needed to validate the CIDP subtypes defined by the EFNS/PNS from the viewpoint of pathogenesis and establish therapeutic strategies based on the pathophysiologies specific to each subtype.

Vagus Nerve Ultrasound in Chronic Inflammatory Demyelinating Polyradiculoneuropathy and Charcot-Marie-Tooth Disease Type 1A

BACKGROUND AND PURPOSE

Both clinical autonomic dysfunction and involvement of autonomic nerves have been reported in a range of peripheral nerve disorders. We employed nerve ultrasound to assess the size of the vagus nerve in a serial study of patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and Charcot-Marie-Tooth type 1B (CMT1B) as compared to healthy controls (HCs). We correlated these findings with involvement of the median and ulnar nerves.

METHODS

Forty-three patients with CIDP, 8 with CMT1A, and 105 HC were prospectively recruited. The cross-sectional areas (CSAs) of the vagus, median, and ulnar nerves were measured bilaterally. The alteration of CSA of those nerves was followed longitudinally in CIDP.

RESULTS

The median (range) CSA of the vagus nerve was 2 (1-28) mm² in CIDP, 3 (2-6) mm² in CMT1A, and 1 (1-2) mm² in HC. The vagus nerve CSA was positively correlated with the maximum CSA of median/ulnar nerve in CIDP and CMT1A. The alteration in vagus nerve CSA was positively correlated with the alteration in mean median/ulnar nerve CSA in CIDP during follow-up.

CONCLUSIONS

The vagus nerve was involved to a similar extent as the median and ulnar nerves in CIDP and CMT1A, although no symptoms or signs of vagus nerve involvement were found. Further study should be performed to explore the clinical relevance of vagus nerve enlargement in these disorders.

Pathological Findings in Chronic Inflammatory Demyelinating Polyradiculoneuropathy: A Single-Center Experience

Objective: Segmental demyelination is the pathological hallmark of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), but other elementary lesions are frequently observed, configuring a series of different pathological pictures. In this article, we review the pathological findings of a large series of sural nerve biopsies from our cohort of CIDP patients. Patients and Methods: Patients with CIDP who underwent nerve biopsy were retrospectively selected from those referred to the Institute of Neurology of the “Università Cattolica del Sacro Cuore” in Rome, Italy, from 1982 to February 2020. Sural nerve biopsy was performed according to standard protocols. Results: Sural nerve biopsy was performed in 43/130 CIDP patients. Demyelinating abnormalities and axonal loss were found in 67.4% and 83.7% of biopsies, respectively. Conversely, onion bulbs and inflammatory infiltrates were rare (18.6% and 4.7%, respectively). In three cases, we observed normal pathological findings. Conclusions: A pathognomonic pathological finding of CIDP cannot be established, but we confirm the utility of nerve biopsy in this setting to confirm the diagnosis (also in atypical phenotypes) and to elucidate pathogenic mechanisms.

Ultrastructural mechanisms of macrophage-induced demyelination in CIDP

Chronic inflammatory demyelinating polyneuropathy (CIDP) is a form of chronic neuropathy that is presumably caused by heterogeneous immune-mediated processes. Recent advances in the search for autoantibodies against components expressed at nodal regions, such as the nodes of Ranvier and paranodes, have substantially contributed to clarifying the pathogenesis of CIDP in a subpopulation of patients. In particular, immunoglobulin G4 (IgG4) antibodies to paranodal junction proteins, including neurofascin-155 and contactin-1, have attracted the attention of researchers. Paranodal dissection resulting from the attachment of IgG4 at paranodal junctions and the absence of macrophage-induced demyelination are characteristic pathologic features in patients who have these antibodies. By contrast, the mechanisms of neuropathy in cases with classical macrophage-induced demyelination remain unclear despite the long-standing recognition of this process in CIDP. In addition to complement-dependent damage provoked by autoantibodies, recent studies have shed light on antibody-dependent phagocytosis by macrophages without participation of complements. However, a direct association between specific autoantibodies and macrophage-induced demyelination has not been reported. Electron microscopic examination of longitudinal sections of sural nerve biopsy specimens suggested that macrophages recognize specific sites of myelinated fibers as the initial target of demyelination. The site that macrophages select to initiate myelin breakdown is located around the nodal regions in some patients and internode in others. Hence, it seems that the components that distinguish between the nodal regions and internode play a pivotal role in the behavior of macrophages that initiate phagocytosis of myelin. Further studies are needed to elucidate the mechanisms underlying macrophage-induced demyelination from this perspective.

Restoration of a Conduction Block after the Long-term Treatment of CIDP with Anti-neurofascin 155 Antibodies: Follow-up of a Case over 23 Years

We herein report a woman with chronic inflammatory demyelinating polyneuropathy (CIDP) in whom positivity for anti-neurofascin 155 antibodies was revealed 23 years after the onset of neuropathy. The patient initially reported numbness in the face at 50 years of age and subsequently manifested features compatible to typical CIDP. Steroid administration initiated at 54 years of age ameliorated her neuropathic symptoms. Although the nerve conduction indices at 59 years of age deteriorated, those at 68, 72, and 73 years of age showed a gradual recovery. The deterioration and subsequent restoration of compound muscle action potential amplitudes was the most dramatic, suggesting that a conduction block can be reversed earlier than other electrophysiological indices.

Corticosteroids for chronic inflammatory demyelinating polyradiculoneuropathy

BACKGROUND

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is a progressive or relapsing and remitting paralysing illness, probably due to an autoimmune response, which should benefit from corticosteroid treatment. Non-randomised studies suggest that corticosteroids are beneficial. Two commonly used corticosteroids are prednisone and prednisolone. Both are usually given as oral tablets. Prednisone is converted into prednisolone in the liver so that the effect of the two drugs is usually the same. Another corticosteroid, dexamethasone, is more potent and is used in smaller doses. The review was first published in 2001 and last updated in 2015; we undertook this update to identify any new evidence.

OBJECTIVES

To assess the effects of corticosteroid treatment for CIDP compared to placebo or no treatment, and to compare the effects of different corticosteroid regimens.

SEARCH METHODS

On 8 November 2016, we searched the Cochrane Neuromuscular Specialised Register, Cochrane Central Register of Controlled Trials, MEDLINE, and Embase for randomised trials of corticosteroids for CIDP. We searched clinical trials registries for ongoing trials.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) or quasi-RCTs of treatment with any corticosteroid or adrenocorticotrophic hormone for CIDP, diagnosed by an internationally accepted definition.

DATA COLLECTION AND ANALYSIS

Two authors extracted data from included studies and assessed the risk of bias independently. The intended primary outcome was change in disability, with change in impairment after 12 weeks and side effects as secondary outcomes. We assessed strength of evidence using the GRADE approach.

MAIN RESULTS

One non-blinded RCT comparing prednisone with no treatment in 35 eligible participants did not measure the primary outcome for this systematic review. The trial had a high risk of bias. Neuropathy Impairment Scale scores after 12 weeks improved in 12 of 19 participants randomised to prednisone, compared with five of 16 participants randomised to no treatment (risk ratio (RR) for improvement 2.02 (95% confidence interval (CI) 0.90 to 4.52; very low-quality evidence). The trial did not report side effects in detail, but one prednisone-treated participant died.A double-blind RCT comparing daily standard-dose oral prednisolone with monthly high-dose oral dexamethasone in 40 participants reported none of the prespecified outcomes for this review. The trial had a low risk of bias, but the quality of evidence was limited as it came from a single small study. There was little or no difference in number of participants who achieved remission (RR 1.11; 95% CI 0.50 to 2.45 in favour of monthly dexamethasone; moderate-quality evidence), or change in disability or impairment after one year (low-quality evidence). Change of grip strength or Medical Research Council (MRC) scores demonstrated little or no difference between groups (moderate-quality to low-quality evidence). Eight of 16 people in the prednisolone group and seven of 24 people in the dexamethasone group deteriorated. Side effects were similar with each regimen, except that sleeplessness was less common with monthly dexamethasone (low-quality evidence) as was moon facies (moon-shaped appearance of the face) (moderate-quality evidence).Experience from large non-randomised studies suggests that corticosteroids are beneficial, but long-term use causes serious side effects.

AUTHORS' CONCLUSIONS

We are very uncertain about the effects of oral prednisone compared with no treatment, because the quality of evidence from the only RCT that exists is very low. Nevertheless, corticosteroids are commonly used in practice, supported by very low-quality evidence from observational studies. We also know from observational studies that corticosteroids carry the long-term risk of serious side effects. The efficacy of high-dose monthly oral dexamethasone is probably little different from that of daily standard-dose oral prednisolone. Most side effects occurred with similar frequencies in both groups, but with high-dose monthly oral dexamethasone moon facies is probably less common and sleeplessness may be less common than with oral prednisolone. We need further research to identify factors that predict response.

Novel pathomechanisms in inflammatory neuropathies

Inflammatory neuropathies are rare autoimmune-mediated disorders affecting the peripheral nervous system. Considerable progress has recently been made in understanding pathomechanisms of these disorders which will be essential for developing novel diagnostic and therapeutic strategies in the future. Here, we summarize our current understanding of antigenic targets and the relevance of new immunological concepts for inflammatory neuropathies. In addition, we provide an overview of available animal models of acute and chronic variants and how new diagnostic tools such as magnetic resonance imaging and novel therapeutic candidates will benefit patients with inflammatory neuropathies in the future. This review thus illustrates the gap between pre-clinical and clinical findings and aims to outline future directions of development.

Paranodal dissection in chronic inflammatory demyelinating polyneuropathy with anti-neurofascin-155 and anti-contactin-1 antibodies

OBJECTIVE

To investigate the morphological features of chronic inflammatory demyelinating polyneuropathy (CIDP) with autoantibodies directed against paranodal junctional molecules, particularly focusing on the fine structures of the paranodes.

METHODS

We assessed sural nerve biopsy specimens obtained from 9 patients with CIDP with anti-neurofascin-155 antibodies and 1 patient with anti-contactin-1 antibodies. 13 patients with CIDP without these antibodies were also examined to compare pathological findings.

RESULTS

Characteristic light and electron microscopy findings in transverse sections from patients with anti-neurofascin-155 and anti-contactin-1 antibodies indicated a slight reduction in myelinated fibre density, with scattered myelin ovoids, and the absence of macrophage-mediated demyelination or onion bulbs. Teased-fibre preparations revealed that segmental demyelination tended to be found in patients with relatively higher frequencies of axonal degeneration and was tandemly found at consecutive nodes of Ranvier in a single fibre. Assessment of longitudinal sections by electron microscopy revealed that detachment of terminal myelin loops from the axolemma was frequently found at the paranode in patients with anti-neurofascin-155 and anti-contactin-1 antibody-positive CIDP compared with patients with antibody-negative CIDP. Patients with anti-neurofascin-155 antibodies showed a positive correlation between the frequencies of axo-glial detachment at the paranode and axonal degeneration, as assessed by teased-fibre preparations (p<0.05).

CONCLUSIONS

Paranodal dissection without classical macrophage-mediated demyelination is the characteristic feature of patients with CIDP with autoantibodies to paranodal axo-glial junctional molecules.

Immunomodulatory treatment other than corticosteroids, immunoglobulin and plasma exchange for chronic inflammatory demyelinating polyradiculoneuropathy

BACKGROUND

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is a disease that causes progressive or relapsing and remitting weakness and numbness. It is probably caused by an autoimmune process. Immunosuppressive or immunomodulatory drugs would be expected to be beneficial. This review was first published in 2003 and has been updated most recently in 2016.

OBJECTIVES

To assess the effects of immunomodulatory and immunosuppressive agents other than corticosteroids, immunoglobulin, and plasma exchange in CIDP.

SEARCH METHODS

On 24 May 2016, we searched the Cochrane Neuromuscular Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 4) in the Cochrane Library, MEDLINE, Embase, CINAHL, and LILACS for completed trials, and clinical trial registers for ongoing trials. We contacted the authors of the trials identified and other disease experts seeking other published and unpublished trials.

SELECTION CRITERIA

We sought randomised and quasi-randomised trials of all immunosuppressive agents, such as azathioprine, cyclophosphamide, methotrexate, ciclosporin, mycophenolate mofetil, and rituximab, and all immunomodulatory agents, such as interferon (IFN) alfa and IFN beta, in participants fulfilling standard diagnostic criteria for CIDP. We included all comparisons of these agents with placebo, another treatment, or no treatment.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. We wanted to measure the change in disability after one year as our primary outcome. Our secondary outcomes were change in disability after four or more weeks (from randomisation); change in impairment after at least one year; change in maximum motor nerve conduction velocity and compound muscle action potential amplitude after one year; and for participants who were receiving corticosteroids or intravenous immunoglobulin (IVIg), the amount of this medication given during at least one year after randomisation. Participants with one or more serious adverse events during the first year was also a secondary outcome.

MAIN RESULTS

Four trials fulfilled the selection criteria: one of azathioprine (27 participants), two of IFN beta-1a (77 participants in total) and one of methotrexate (60 participants). The risk of bias was considered low in the trials of IFN beta-1a and methotrexate but high in the trial of azathioprine. None of the trials showed significant benefit in any of the outcomes selected by their authors. The results of the outcomes which approximated most closely to the primary outcome for this review were as follows.In the azathioprine trial there was a median improvement in the Neuropathy Impairment Scale (scale range 0 to 280) after nine months of 29 points (range 49 points worse to 84 points better) in the azathioprine and prednisone treated participants compared with 30 points worse (range 20 points worse to 104 points better) in the prednisone alone group. There were no reports of adverse events.In a cross-over trial of IFN beta-1a with 20 participants, the treatment periods were 12 weeks. The median improvement in the Guy's Neurological Disability Scale (range 1 to 10) was 0.5 grades (interquartile range (IQR) 1.8 grades better to zero grade change) in the IFN beta-1a treatment period and 0.5 grades (IQR 1.8 grades better to 1.0 grade worse) in the placebo treatment period. There were no serious adverse events in either treatment period.In a parallel group trial of IFN beta-1a with 67 participants, none of the outcomes for this review was available. The trial design involved withdrawal from ongoing IVIg treatment. The primary outcome used by the trial authors was total IVIg dose administered from week 16 to week 32 in the placebo group compared with the IFN beta-1a groups. This was slightly but not significantly lower in the combined IFN beta-1a groups (1.20 g/kg) compared with the placebo group (1.34 g/kg, P = 0.75). There were four participants in the IFN beta-1a group and none in the placebo group with one or more serious adverse events, risk ratio (RR) 4.50 (95% confidence interval (CI) 0.25 to 80.05).The methotrexate trial had a similar design involving withdrawal from ongoing corticosteroid or IVIg treatment. At the end of the trial (approximately 40 weeks) there was no significant difference in the change in the Overall Neuropathy Limitations Scale, a disability scale (scale range 0 to 12), the median change being 0 (IQR -1 to 0) in the methotrexate group and 0 (IQR -0.75 to 0) in the placebo group. These changes in disability might have been confounded by the reduction in corticosteroid or IVIg dose required by the protocol. There were three participants in the methotrexate group and one in the placebo with one or more serious adverse events, RR 3.56 (95% CI 0.39 to 32.23).

AUTHORS' CONCLUSIONS

Low-quality evidence from randomised trials does not show significant benefit from azathioprine or interferon beta-1a and moderate-quality evidence from one randomised trial does not show significant benefit from a relatively low dose of methotrexate for the treatment of CIDP. None of the trials was large enough to rule out small or moderate benefit. The evidence from observational studies is insufficient to avoid the need for randomised controlled trials to discover whether these drugs are beneficial. Future trials should have improved designs, more sensitive outcome measures relevant to people with CIDP, and longer treatment durations.

A Functional and Neuropathological Testing Paradigm Reveals New Disability-Based Parameters and Histological Features for P0180-190-Induced Experimental Autoimmune Neuritis in C57BL/6 Mice

We assessed novel disability-based parameters and neuropathological features of the P0180-190 peptide-induced model of experimental autoimmune neuritis (EAN) in C57BL/6 mice. We show that functional assessments such as running capacity provide a more sensitive method for detecting alterations in disease severity than a classical clinical scoring paradigm. We performed detailed ultrastructural analysis and show for the first time that tomaculous neuropathy is a neuropathological feature of this disease model. In addition, we demonstrate that ultrastructural assessments of myelin pathology are sufficiently sensitive to detect significant differences in both mean G-ratio and mean axon diameter between mice with EAN induced with different doses of pertussis toxin. In summary, we have established a comprehensive assessment paradigm for discriminating variations in disease severity and the extent of myelin pathology in this model. Our findings indicate that this model is a powerful tool to study the pathogenesis of human peripheral demyelinating neuropathies and that this assessment paradigm could be used to determine the efficacy of potential therapies that aim to promote myelin repair and protect against nerve damage in autoimmune neuritides.

Novel immunotherapeutic strategies in chronic inflammatory demyelinating polyneuropathy

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is a chronic immune-mediated neuropathy: it is clinically heterogeneous (relapsing-remitting form, chronic progressive form, monophasic form or CIDP having a Guillain-Barré syndrome-like onset), but potentially treatable. Although its pathophysiology remains largely unknown, CIDP is considered an immune-mediated neuropathy. Therefore, many immunotherapies have been proposed in this peripheral nervous system disorder, the most known efficient treatments being intravenous immunoglobulin, corticosteroids and plasma exchange. However, these therapies remain unsatisfactory for many patients, so numerous other immunotherapeutic strategies have been evaluated, based on their immunosuppressant or immunomodulatory potency. We have performed a large review of the literature about treatment in CIDP, with a special emphasis on novel and alternative immunotherapeutic strategies.

Autoimmune-mediated peripheral neuropathies and autoimmune pain

Peripheral neuropathies have diverse acquired and inherited causes. The autoimmune neuropathies represent an important category where treatment is often available. There are overlapping signs and symptoms between autoimmune neuropathies and other forms. Making a diagnosis can be challenging and first assisted by electrophysiologic and sometimes pathologic sampling, with autoimmune biomarkers providing increased assistance. Here we provide a review of the autoimmune and inflammatory neuropathies, their available biomarkers, and approaches to treatment. Also discussed is new evidence to support a mechanism of autoimmune pain.

Chronic inflammatory demyelinating polyradiculoneuropathy: from pathology to phenotype

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an inflammatory neuropathy, classically characterised by a slowly progressive onset and symmetrical, sensorimotor involvement. However, there are many phenotypic variants, suggesting that CIDP may not be a discrete disease entity but rather a spectrum of related conditions. While the abiding theory of CIDP pathogenesis is that cell-mediated and humoral mechanisms act together in an aberrant immune response to cause damage to peripheral nerves, the relative contributions of T cell and autoantibody responses remain largely undefined. In animal models of spontaneous inflammatory neuropathy, T cell responses to defined myelin antigens are responsible. In other human inflammatory neuropathies, there is evidence of antibody responses to Schwann cell, compact myelin or nodal antigens. In this review, the roles of the cellular and humoral immune systems in the pathogenesis of CIDP will be discussed. In time, it is anticipated that delineation of clinical phenotypes and the underlying disease mechanisms might help guide diagnostic and individualised treatment strategies for CIDP.

Plasma exchange for chronic inflammatory demyelinating polyradiculoneuropathy

BACKGROUND

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an uncommon progressive or relapsing paralysing disease caused by inflammation of the peripheral nerves. If the hypothesis that it is due to autoimmunity is correct, removal of autoantibodies in the blood by plasma exchange should be beneficial.

OBJECTIVES

To assess the effects of plasma exchange for treating CIDP.

SEARCH METHODS

On 30 June 2015, we searched the Cochrane Neuromuscular Disease Group Specialized Register, the Cochrane Central Register for Controlled Trials (CENTRAL), MEDLINE, EMBASE, CINAHL Plus, and LILACS. We also scrutinised the bibliographies of the trials, contacted the trial authors and other disease experts, and searched trials registries for ongoing studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) or quasi-RCTs in participants of any age comparing plasma exchange with sham treatment or no treatment.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected the trials, extracted the data, and assessed risk of bias. Where possible the review authors combined data according to the methods of the Cochrane Neuromuscular Disease Review Group.

MAIN RESULTS

PRIMARY OUTCOME MEASURE

one cross-over trial including 18 participants showed after four weeks, 2 (95% confidence interval (CI) 0.8 to 3.0) points more improvement on an 11-point disability scale with plasma exchange (10 exchanges over four weeks) than with sham exchange. Rapid deterioration after plasma exchange occurred in eight of 12 who had improved.

SECONDARY OUTCOME MEASURES

when we combined the results of this cross-over trial and a trial with 29 participants treated in a parallel-group design, there were 31 points (95% CI 16 to 45) more improvement on an impairment scale (maximum score 280) after plasma exchange (six exchanges over three weeks) than after sham exchange. There were significant improvements in both trials in an electrophysiological measure, the proximally evoked compound muscle action potential, after three or four weeks. Nonrandomised evidence indicates that plasma exchange induces adverse events in 3% to 17% of procedures. These events are sometimes serious. Both trials had a low risk of bias. A trial that showed no significant difference in the benefit between plasma exchange and intravenous immunoglobulin is included in the Cochrane review of intravenous immunoglobulin for this condition.

AUTHORS' CONCLUSIONS

Moderate- to high-quality evidence from two small trials shows that plasma exchange provides significant short-term improvement in disability, clinical impairment, and motor nerve conduction velocity in CIDP but rapid deterioration may occur afterwards. Adverse events related to difficulty with venous access, use of citrate, and haemodynamic changes are not uncommon. We need more research to identify agents that will prolong the beneficial action of plasma exchange.

Lower urinary tract dysfunction in patients with peripheral nervous system lesions

The prevalence of lower urinary tract (LUT) dysfunction in peripheral nervous system (PNS) disorders is larger than in comparable control populations. This is particularly true for polyneuropathies with autonomic nervous system involvement, and for localized lesions with LUT innervation. LUT symptoms may be the guide to the diagnosis of processes localized in the lumbosacral spinal canal (as in cauda equina syndrome), and in the pelvis. Typical LUT dysfunctions (LUTD) caused by PNS involvement include bladder and sphincter hypoactivity with poor emptying, and incontinence. Paradoxically, bladder overactivity may also occur in pure PNS lesions. The acute cauda equina syndrome is an emergency requiring magnetic resonance imaging and surgery; in chronic neurogenic LUTD due to PNS involvement, the diagnosis of the lesion may be clarified by clinical neurophysiologic testing. Other important causes of neurogenic LUT dysfunction are perineoabdominal and pelvic surgeries. Surgeons are devising nerve-sparing techniques to prevent such major and often persistent complications in patients who are otherwise cured of the underlying disease. LUTD significantly affects the quality of life in patients and may lead to recurring urinary infections and upper urinary tract involvement. Thorough assessment of LUT function by urodynamics may be necessary in patients who are not improved by simple conservative measures.

Corticosteroids for chronic inflammatory demyelinating polyradiculoneuropathy

BACKGROUND

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is a progressive or relapsing and remitting paralysing illness probably due to an autoimmune response which should benefit from corticosteroids. Non-randomised studies suggest that corticosteroids are beneficial. Two commonly used corticosteroids are prednisone and prednisolone. Both are usually given as oral tablets. Prednisone is converted into prednisolone in the liver so that the effect of the two drugs is usually the same. Another corticosteroid, called dexamethasone, is more potent and is used in smaller doses.

OBJECTIVES

To assess the effects of corticosteroid treatment compared to placebo or no treatment for CIDP and to compare the effects of different corticosteroid regimes.

SEARCH METHODS

On 27 October 2014 we searched the Cochrane Neuromuscular Disease Group Specialized Register, CENTRAL, MEDLINE, and EMBASE for randomised trials of corticosteroids for CIDP. We searched three other databases for information to include in the Discussion, and clinical trials registries for ongoing trials.

SELECTION CRITERIA

We included randomised or quasi-randomised trials of treatment with any form of corticosteroids or adrenocorticotrophic hormone for CIDP, diagnosed by an internationally accepted definition.

DATA COLLECTION AND ANALYSIS

Two authors extracted the data and assessed risk of bias independently. The primary outcome was intended to be change in disability, with change in impairment after 12 weeks as a secondary outcome, and adverse events.

MAIN RESULTS

In one non-blinded randomised controlled trial (RCT) with 35 eligible participants, the primary outcome for this review was not available. The trial had a high risk of bias. Twelve of 19 participants treated with prednisone, compared with five of 16 participants randomised to no treatment, had improved neuropathy impairment scores after 12 weeks; the risk ratio (RR) for improvement was 2.02 (95% confidence interval (CI) 0.90 to 4.52). Adverse events were not reported in detail, but one prednisone-treated participant died.In a double-blind RCT comparing daily standard-dose oral prednisolone with monthly high-dose oral dexamethasone in 40 participants, none of the outcomes for this review were available. The trial had a low risk of bias. There were no significant differences in remission (RR 1.11; 95% CI 0.50 to 2.45 in favour of monthly dexamethasone) or change in disability or impairment after one year. Eight of 16 in the prednisolone, and seven of 24 in the dexamethasone group deteriorated. Adverse events were similar with each regimen, except that sleeplessness and moon facies (moon-shaped appearance of the face) were significantly less common with monthly dexamethasone.Experience from large non-randomised studies suggests that corticosteroids are beneficial, but long-term use causes serious side effects.

AUTHORS' CONCLUSIONS

Very low quality evidence from one small, randomised trial did not show a statistically significant benefit from oral prednisone compared with no treatment. Nevertheless, corticosteroids are commonly used in practice. According to moderate quality evidence from one RCT, the efficacy of high-dose monthly oral dexamethasone was not statistically different from that of daily standard-dose oral prednisolone. Most adverse events occurred with similar frequencies in both groups, but sleeplessness and moon facies were significantly less common with monthly dexamethasone. Further research is needed to identify factors which predict response.

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.

Chronic inflammatory demyelinating polyneuropathy: a treatment protocol proposal

Guidelines for diagnostic criteria and treatment of chronic inflammatory demyelinating polyneuropathy (CIDP) have been proposed by a joint task force of the European Federation of Neurological Societies and the Peripheral Nerve Society, based on available evidence and expert consensus. These should prove practical for the clinical management of CIDP. Intravenous immunoglobulin followed by corticosteroids should be considered as the initial treatment, however no clear second drug of choice for patients who do not respond to the initial treatment is given. The author reports the long-term therapeutic efficacy of ciclosporin for patients with CIDP who did not show sustained improvement under steroid therapy. Ciclosporin should be tried for patients with intractable CIDP who require repeated intravenous immunoglobulin. An adequate initial dose of ciclosporin is 3 mg/kg/day, with plasma trough concentrations between 100 and 150 ng/ml. If patients respond to ciclosporin, remission can be maintained for 2 years, after which the dose can be slowly reduced over 1 year. Eventual withdrawal should be considered. This review proposes a treatment strategy that includes long-term maintenance therapy for CIDP based on published clinical trials and the author's clinical experience. Current concepts concerning the clinical spectrum of CIDP and diagnostic approaches are also considered.

In vivo testing of a 3D bifurcating microchannel scaffold inducing separation of regenerating axon bundles in peripheral nerves

Artificial nerve guidance channels enhance the regenerative effectiveness in an injured peripheral nerve but the existing design so far has been limited to basic straight tubes simply guiding the growth to bridge the gap. Hence, one of the goals in development of more effective neuroprostheses is to create bidirectional highly selective neuro-electronic interface between a prosthetic device and the severed nerve. A step towards improving selectivity for both recording and stimulation have been made with some recent in vitro studies which showed that three-dimensional (3D) bifurcating microchannels can separate neurites growing on a planar surface and bring them into contact with individual electrodes. Since the growing axons in vivo have the innate tendency to group in bundles surrounded by connective tissue, one of the big challenges in neuro-prosthetic interface design is how to overcome it. Therefore, we performed experiments with 3D bifurcating guidance scaffolds implanted in the sciatic nerve of rats to test if this new channel architecture could trigger separation pattern of ingrowth also in vivo. Our results showed that this new method enabled the re-growth of neurites into channels with gradually diminished width (80, 40 and 20 µm) and facilitated the separation of the axonal bundles with 91% success. It seems that the 3D bifurcating scaffold might contribute towards conveying detailed neural control and sensory feedback to users of prosthetic devices, and thus could improve the quality of their daily life.

Autonomic involvement in subacute and chronic immune-mediated neuropathies

Autonomic function can be impaired in many disorders in which sympathetic, parasympathetic, and enteric arms of the autonomic nervous system are affected. Signs and symptoms of autonomic involvement are related to impairment of cardiovascular, gastrointestinal, urogenital, thermoregulatory, sudomotor, and pupillomotor autonomic functions. Availability of noninvasive, sensitive, and reproducible tests can help to recognize these disorders and to better understand specific mechanisms of some, potentially treatable, immune-mediated autonomic neuropathies. This paper describes autonomic involvement in immune-mediated neuropathies with a subacute or chronic course.

Immunomodulatory treatment other than corticosteroids, immunoglobulin and plasma exchange for chronic inflammatory demyelinating polyradiculoneuropathy

BACKGROUND

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is a disease causing progressive or relapsing and remitting weakness and numbness. It is probably due to an autoimmune process. Immunosuppressive or immunomodulatory drugs would be expected to be beneficial. This review was first published in 2003 and has been most recently updated in 2013.

OBJECTIVES

We aimed to review systematically the evidence from randomised trials of immunomodulatory and immunosuppressive agents other than corticosteroids, immunoglobulin and plasma exchange for CIDP.

SEARCH METHODS

On 9 July 2012, we searched the Cochrane Neuromuscular Disease Group Specialized Register (July 2012), CENTRAL (2012, Issue 6 in The Cochrane Library), MEDLINE (January 1977 to July 2012), EMBASE (January 1980 to July 2012), CINAHL (January 1982 to July 2012) and LILACS (January 1982 to July 2012). We contacted the authors of the trials identified and other disease experts seeking other published and unpublished trials.

SELECTION CRITERIA

We sought randomised and quasi-randomised trials of all immunosuppressive agents such as azathioprine, cyclophosphamide, methotrexate, ciclosporin, mycophenolate mofetil, and rituximab and all immunomodulatory agents such as interferon alfa and interferon beta, in participants fulfilling standard diagnostic criteria for CIDP.

DATA COLLECTION AND ANALYSIS

Two authors independently selected trials, judged their risk of bias and extracted data. We wanted to measure the change in disability after one year as our primary outcome. Our secondary outcomes were change in disability after four or more weeks (from randomisation), change in impairment after at least one year, change in maximum motor nerve conduction velocity and compound muscle action potential amplitude after one year and for those participants who were receiving corticosteroids or intravenous immunoglobulin, the amount of this medication given during at least one year after randomisation. Participants with one or more serious adverse events during the first year was also a secondary outcome.

MAIN RESULTS

Four trials fulfilled the selection criteria, one of azathioprine (27 participants), two of interferon beta-1a (77 participants in total) and one of methotrexate (60 participants). The risk of bias in the two trials of interferon beta-1a for CIDP and the trial of methotrexate was assessed to be low but bias in the trial of azathioprine was judged high. None of these trials showed significant benefit in the primary outcome (measured only in the methotrexate study) or secondary outcomes selected for this review. Severe adverse events occurred no more frequently than in the placebo groups for methotrexate and interferon beta-1a, but participant numbers were low. There was no adverse event reporting in the azathioprine study.

AUTHORS' CONCLUSIONS

The evidence from randomised trials does not show significant benefit from azathioprine, interferon beta-1a or methotrexate but none of the trials was large enough to rule out small or moderate benefit. The evidence from observational studies is insufficient to avoid the need for randomised controlled trials to discover whether these drugs are beneficial. Future trials should have improved designs, more sensitive outcome measures and longer durations.

Multifocal motor neuropathy, multifocal acquired demyelinating sensory and motor neuropathy, and other chronic acquired demyelinating polyneuropathy variants

Chronic acquired demyelinating neuropathies (CADP) constitute an important group of immune neuromuscular disorders affecting myelin. This article discusses CADP with emphasis on multifocal motor neuropathy, multifocal acquired demyelinating sensory and motor neuropathy, distal acquired demyelinating symmetric neuropathy, and less common variants. Although each of these entities has distinctive laboratory and electrodiagnostic features that aid in their diagnosis, clinical characteristics are of paramount importance in diagnosing specific conditions and determining the most appropriate therapies. Knowledge regarding pathogenesis, diagnosis, and management of these disorders continues to expand, resulting in improved opportunities for identification and treatment.

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.

Plasma exchange for chronic inflammatory demyelinating polyradiculoneuropathy

BACKGROUND

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an uncommon progressive or relapsing paralysing disease caused by inflammation of the peripheral nerves. If the hypothesis that it is due to autoimmunity is correct, removal of autoantibodies in the blood by plasma exchange should be beneficial.

OBJECTIVES

To evaluate the efficacy of plasma exchange in CIDP.

SEARCH METHODS

We searched the Cochrane Neuromuscular Disease Group Specialized Register (14 May 2012), CENTRAL (2012, Issue 4), MEDLINE (January 1966 to May 2012), EMBASE (January 1980 to May 2012), CINAHL Plus (January 1937 to May 2012) and LILACS (January 1982 to May 2012). We also scrutinised the bibliographies of the trials, and contacted the trial authors and other disease experts.

SELECTION CRITERIA

Randomised controlled trials (RCTs) or quasi-RCTs in participants of any age comparing plasma exchange with sham treatment or no treatment.

DATA COLLECTION AND ANALYSIS

Two authors selected the trials, extracted the data and assessed risk of bias independently. Where possible data were combined according to the methods of the Cochrane Neuromuscular Disease Review Group.

PRIMARY OUTCOME MEASURE

one cross-over trial including 18 participants showed two (95% confidence interval (CI) 0.8 to 3.0) points more improvement after four weeks on an 11-point disability scale with plasma exchange (10 exchanges over four weeks) than with sham exchange. Rapid deterioration after plasma exchange occurred in eight of 12 who had improved.

SECONDARY OUTCOME MEASURES

when the results of this trial and another with 29 participants treated in a parallel group design trial were combined, there were 31 points (95% CI 16 to 45, maximum score 280) more improvement in an impairment scale after plasma exchange (six exchanges over three weeks) than after sham exchange. There were significant improvements in both trials in an electrophysiological measure, the proximally evoked compound muscle action potential, after three or four weeks. Non-randomised evidence indicates that plasma exchange induces adverse events in 3% to 17% of procedures. These are sometimes serious. A trial showing no significant difference in the benefit between plasma exchange and intravenous immunoglobulin has been included in the Cochrane review of intravenous immunoglobulin for this condition.

AUTHORS' CONCLUSIONS

Moderate to high quality evidence from two small trials showed that plasma exchange provides significant short-term improvement in disability, clinical impairment and motor nerve conduction velocity in CIDP but rapid deterioration may occur afterwards. Adverse events related to difficulty with venous access, use of citrate and haemodynamic changes are not uncommon. More research is needed to identify agents which will prolong the beneficial action of plasma exchange.

Corticosteroids for chronic inflammatory demyelinating polyradiculoneuropathy

BACKGROUND

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is a progressive or relapsing and remitting paralysing illness probably due to an autoimmune response which should benefit from corticosteroids. Non-randomised studies suggest that corticosteroids are beneficial. Two commonly used corticosteroids are prednisone and prednisolone. Both are usually given as oral tablets. Prednisone is converted into prednisolone in the liver so that the effect of the two drugs is usually the same. Another corticosteroid, called dexamethasone, is more potent and is used in smaller doses.

OBJECTIVES

To evaluate the efficacy of corticosteroid treatment compared to placebo or no treatment for CIDP and to compare the efficacy of different corticosteroid regimes.

SEARCH METHODS

We searched the Cochrane Neuromuscular Disease Group Specialized Register (20 February 2012), CENTRAL (2012, Issue 2), MEDLINE (January 1966 to February 2012), and EMBASE (January 1980 to February 2012) for randomised trials of corticosteroids for CIDP.

SELECTION CRITERIA

We included randomised or quasi-randomised trials of treatment with any form of corticosteroids or adrenocorticotrophic hormone for CIDP, diagnosed by an internationally accepted definition.

DATA COLLECTION AND ANALYSIS

Two authors extracted the data and assessed risk of bias independently. The primary outcome was intended to be change in disability, with secondary outcomes of change in impairment, maximum motor nerve conduction velocity, or compound muscle action potential amplitude after 12 weeks, and adverse events.

MAIN RESULTS

In one non-blinded randomised controlled trial (RCT) with 35 eligible participants, the primary outcome for this review was not available. Twelve of 19 participants treated with prednisone, compared with five of 16 participants randomised to no treatment, had improved neuropathy impairment scores after 12 weeks; the risk ratio (RR) for improvement was 2.02 (95% confidence interval (CI) 0.90 to 4.52). Adverse events were not reported in detail, but one prednisone-treated participant died.In a double-blind RCT comparing daily standard-dose oral prednisolone with monthly high-dose oral dexamethasone in 40 participants, none of the outcomes for this review were available. There were no significant differences in remission (RR 1.11; 95% CI 0.50 to 2.45 in favour of monthly dexamethasone) or change in disability or impairment after one year. Eight of 16 in the prednisolone, and seven of 24 in the dexamethasone group deteriorated. Adverse events were similar with each regimen, except that sleeplessness and moon facies (moon-shaped appearance of the face) were significantly less common with monthly dexamethasone.Experience from large non-randomised studies suggests that corticosteroids are beneficial, but long-term use causes serious side effects.

AUTHORS' CONCLUSIONS

Very low quality evidence from one small, randomised trial did not show a statistically significant benefit from oral prednisone compared with no treatment. Nevertheless, corticosteroids are commonly used in practice. According to moderate quality evidence from one RCT, the efficacy of high-dose monthly oral dexamethasone was not statistically different from that of daily standard-dose oral prednisolone. Most adverse events occurred with similar frequencies in both groups, but sleeplessness and moon facies were significantly less common with monthly dexamethasone. Further research is needed to identify factors which predict response.