Joint Task Force of the EFNS and the PNS. European Federation of Neurological Societies/Peripheral Nerve Society Guideline on management of multifocal motor neuropathy. Report of a Joint Task Force of the European Federation of Neurological Societies and the Peripheral Nerve Society - first revis

Subcutaneous IgG in neurologic diseases

Subcutaneous administration of IgG (SCIG) has become widely used in primary immune deficiency diseases but it has only recently been studied for maintenance therapy in autoimmune peripheral neuropathies, such as chronic idiopathic demyelinating polyneuropathy and multifocal motor neuropathy. Weekly self-administration of SCIG is safe and well-tolerated, and results in steady-state serum IgG levels, as contrasted with the peaks and troughs of monthly immune globulin (human) for intravenous use. Freedom from the need for venous access or medical personnel for infusions, flexibility in scheduling, convenience of home therapy, and improved clinical stability due to the steady-state IgG levels, lead many patients to prefer SCIG to immune globulin (human) for intravenous use. Long-term studies are needed to determine if the constant IgG levels and clinical stability translate into better long-term outcomes.

Hemolytic anemia following high dose intravenous immunoglobulin in patients with chronic neurological disorders

BACKGROUND AND PURPOSE

High dose intravenous immunoglobulin (IVIG) is an established treatment for various neuromuscular disorders. Recently, cases of hemolytic anemia following IVIG have been observed. The objective of this study was to determine the extent of anemia and hemolysis after IVIG and its relationship to the AB0 blood type system.

METHODS

In a prospective study 34 de novo treated patients were given 2.0 g/kg bodyweight of Privigen and 50 patients received either Privigen [n = 28; 1.53 ± 0.4 g/kg (mean ± SD)] or Kiovig (n = 22; 1.7 ± 0.4 g/kg) as maintenance therapy. The de novo patients all had a post-polio syndrome, whereas the remaining patients received maintenance therapy for the neuromuscular disorders chronic inflammatory demyelinating polyradiculoneuropathy and multifocal motor neuropathy. Blood sampling was performed before and 2 weeks after infusion of IVIG.

RESULTS

Following IVIG treatment blood hemoglobin declined from 8.6 ± 0.9 to 8.0 ± 1.2 mM, P < 0.001. Reticulocyte counts and levels of bilirubin and lactate dehydrogenase were increased and haptoglobin levels decreased. The decline of hemoglobin was 0.9 ± 1.2 mM after de novo therapy versus 0.4 ± 0.8 mM after maintenance therapy with Privigen (P = 0.05) and 0.2 ± 0.3 mM after maintenance therapy with Kiovig (P = 0.47). In de novo patients compared with patients on maintenance therapy reticulocyte count and lactate dehydrogenase level increased whereas haptoglobin level decreased. Anemia correlated with the AB0 blood type system with a significant difference between type 0 (n = 17; +0.3 ± 0.4 mM) and type A, B and AB (n = 48; -1.0 ± 1.0 mM), anemia being most pronounced in type AB.

CONCLUSION

Moderate hemolytic anemia is a concomitant complication of high dose IVIG in subjects with blood types A, B and AB.

Ultrasound of inherited vs. acquired demyelinating polyneuropathies

We compared features of nerve enlargement in inherited and acquired demyelinating neuropathies using ultrasound. We measured median and ulnar nerve cross-sectional areas in proximal and distal regions in 128 children and adults with inherited [Charcot-Marie-Tooth-1 (CMT-1) (n = 35)] and acquired [chronic inflammatory demyelinating polyneuropathy (CIDP) (n = 55), Guillaine-Barre syndrome (GBS) (n = 21) and multifocal motor neuropathy (MMN) (n = 17)] demyelinating neuropathies. We classified nerve enlargement by degree and number of regions affected. We defined patterns of nerve enlargement as: none, no enlargement; mild, nerves enlarged but never more than twice normal; regional, nerves normal in at least one region and enlarged more than twice normal in at least one region; diffuse, nerves enlarged at all four regions with at least one region more than twice normal size. Nerve enlargement was commonly diffuse (89 %) and generally more than twice normal size in CMT-1, but not (p < 0.001) in acquired disorders which mostly had either no, mild or regional nerve enlargement [CIDP (64 %), GBS (95 %), and MMN (100 %)]. In CIDP, subjects treated within 3 months of disease onset had less nerve enlargement than those treated later. Ultrasound identified patterns of diffuse nerve enlargement can be used to screen patients suspected of having CMT-1. Normal, mildly, or regionally enlarged nerves in demyelinating polyneuropathy suggests an acquired etiology. Early treatment in CIDP may impede nerve enlargement.

Lightning can strike twice: an unlucky patient of neurological interest

Poliomyelitis, once a worldwide epidemic, is becoming increasingly rare owing to the introduction of the polio vaccine in the 1950s. It is estimated that the number of cases of polio has reduced by 99% since the Global Polio Eradication Initiative (GPEI) started in 1988. Amyotrophic lateral sclerosis (ALS) is another relatively uncommon condition which also affects anterior horn cells with debilitating neurological, and deadly, consequences. An unusual case of an aggressive form of ALS developing in a 72-year-old patient with paralytic poliomyelitis in childhood is presented. Her initial presentation was puzzling, and our approach to the diagnostic dilemma is discussed.

Polyclonal immunoglobulin G for autoimmune demyelinating nervous system disorders

Demyelinating diseases with presumed autoimmune pathogenesis are characterised by direct or indirect immune-mediated damage to myelin sheaths, which normally surround nerve fibres to ensure proper electrical nerve conduction. Parenteral administration of polyclonal IgG purified from multi-donor human plasma pools may beneficially modulate these misguided immune reactions via several mechanisms that are outlined in this review. Convincing therapeutic evidence from controlled trials now exists for certain disorders of the peripheral nervous system, including Guillain-Barré syndrome, chronic inflammatory demyelinating polyradiculoneuropathy, and multifocal motor neuropathy. In addition, there is evidence for potential therapeutic benefits of IgG in patients with chronic inflammatory demyelinating diseases of the central nervous system, including multiple sclerosis and neuromyelitis optica. This review introduces these disorders, briefly summarises the established treatment options, and discusses therapeutic evidence for the use of polyclonal immunoglobulins with a particular emphasis on recent clinical trials and meta-analyses.

Multifocal motor neuropathy

Multifocal motor neuropathy (MMN) is a chronic immune-mediated neuropathy that is particular for its asymmetric, multifocal, purely motor clinical presentation, often related to the distribution of individual nerves. Upper limbs are usually primarily and more severely affected, but lower limbs may be involved during the course of the disease. The hallmark of the disease is the presence, in electrophysiological studies, of persistent conduction blocks in the affected motor nerves, located outside the usual sites of nerve compression, contrasting with normal sensory nerve conduction velocities. The most typical laboratory finding is the presence of high levels of serum IgM antibodies to the ganglioside GM1, and less frequently to asialo-GM1, GD1a or GM2. These striking features may help distinguishing this neuropathy from both motor neuron disease and other chronic immune-mediated neuropathies. Several randomized controlled trials (RCT) have established the efficacy of high-dose intravenous immunoglobulin (IVIg), as well as subcutaneous immunoglobulin (SCIg). However, this therapy has a short-lasting effect, and need to be maintained with periodic infusions. This disappointing status has led to the search of other immune therapies whose efficacy has not been so far confirmed in RCT. This review intends to summarize current contents in the diagnosis and the treatment of MMN.

Susac syndrome and multifocal motor neuropathy first manifesting in pregnancy

Susac Syndrome (SS) and multifocal motor neuropathy (MMN) are rare autoimmune neurological conditions which can affect women of childbearing years. The effect of pregnancy on these disorders is poorly characterised. We report a case of SS first manifesting in pregnancy with challenges in diagnosis and management and a poor clinical outcome, and a case of MMN manifesting in pregnancy then relapsing in a subsequent pregnancy. A summary of other cases in the literature and the postulated underlying immune mechanisms is presented.

Fatigue in immune-mediated neuropathies

Fatigue, a highly debilitating symptom, is reported in most patients with immune-mediated neuropathies, particularly in Guillain-Barré syndrome, chronic immune-mediated demyelinating polyradiculoneuropathy, monoclonal gammopathy of undetermined significance related polyneuropathy, and multifocal motor neuropathy. Aspects like the degree of known fatigue in these disorders, its impact on daily functioning and quality of life, the suggested underlying mechanisms, and possible therapeutic interventions for fatigue will be addressed in this review.

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.

Multifocal motor neuropathy

Multifocal motor neuropathy (MMN) is a rare disorder in which the symptoms are caused by persistent conduction block lesions. The mononeuropathy multiplex progresses over time with increasing axonal loss. The cause of the conduction blocks and axonal loss are not completely understood but immune mechanisms are involved and response to intravenous immunoglobulin has been established. The importance of MMN goes beyond its clinical incidence as the increasing understanding of the pathogenesis of this disorder has implications for other peripheral nerve diseases and for our knowledge of peripheral nerve biology.

[Focal neuropathy]

The differential diagnosis of focal neuropathy continues to be one of the main tasks in peripheral neurology and clinical neurophysiology. In this respect a detailed medical history a topologically oriented clinical examination based on profound anatomical knowledge and a targeted neurophysiological examination are the cornerstones of successful diagnosis. Refined imaging techniques, such as sonography and magnetic resonance imaging provide - additional and valuable morphological information especially in atypical or unresolved cases. The aim of this overview is therefore to summarize the spectrum of focal neuropathy and diagnostic approaches, particularly in terms of a well-founded differential diagnosis.

Diagnosis, epidemiology and treatment of inflammatory neuropathies

This article reviews the main diagnostic, epidemiological and therapeutic issues relating to the three main inflammatory neuropathies: Guillain-Barré syndrome, chronic inflammatory demyelinating polyradiculoneuropathy and multifocal motor neuropathy. The current knowledge base and recent developments are described.

A comparison between intravenous and subcutmaneous immunogobulin

Multifocal motor neuropathy (MMN) is a rare immune-mediated disease that presents with predominantly distal motor weakness in one or more limbs without sensory loss. Symptoms may give riseto functional impairment and consequently may affect quality of life. High-dose intravenous immunoglobulin's therapy (IVIg) is the current mainstay treatment, however, subcutaneous immunoglobuli(SCIg) is emerging as a viable alternative. The purpose of this study was to explore the patients' experience of SCIg and ascertain if those receiving it had an improved quality of life and treatmentsatisfaction compared to those receiving IVIg. Using a mixed method approach this paper will present its findings and key implications for clinical and research practice are considered. The results from this study suggest that home SCIg therapy may prove a more desirable treatment option than IVIg for a proportion of MMN patients.

Intra- and internerve cross-sectional area variability: new ultrasound measures

INTRODUCTION

Nerve involvement in immune-related neuropathies is non-homogeneous, and therefore characterization of ultrasound (US) abnormalities is difficult. We developed two measures to quantify US abnormalities in immune-related neuropathies.

METHODS

Intranerve cross-sectional area (CSA) variability for each nerve was calculated as: maximal CSA/minimal CSA. Internerve CSA variability for each patient was calculated as: maximal intranerve CSA variability/minimal intranerve CSA variability. Six patients underwent US evaluation of the median, ulnar, and fibular nerves, and the abnormalities were scored with our newly developed measures.

RESULTS

The new measures were applicable to all nerves and patients. The highest degree of intra- and internerve CSA variability was observed in multifocal motor neuropathy, consistent with the asymmetric characteristics of this neuropathy.

CONCLUSIONS

The application of intra- and internerve CSA variability measures allows us to quantify the heterogeneity of nerves and nerve segments and identify different US patterns in diverse immune-related neuropathies.

A case of paraneoplastic demyelinating motor polyneuropathy

Peripheral neuropathy is commonly accompanied by cancer but demyelinating ones are not commonly reported. We report the clinical, neurophysiological, and biological characteristics of an 82-year-old patient who presented with a demyelinating motor neuropathy and high titre of anti-ganglioside antibodies associated with oesophageal cancer. The neurological course worsened rapidly despite immunotherapy, leading to a bedridden status. We propose to suspect a paraneoplastic origin in older patients or when the clinical course progresses rapidly within a few weeks or months.

Activity-dependent conduction failure: molecular insights

Weakness and fatigue are commonly encountered symptoms in neurological disorders and significantly impair quality of life. In the case of motor axons, conduction block contributes to weakness and fatigue and may be associated with aberrant nerve activity including fasciculations and cramp. These symptoms result from dysfunction of the constituent channels and pumps of the axonal membrane. In critically conducting axons, impulse conduction can be impaired by the effects of activity or by other mechanisms that produce a significant shift in membrane potential. Conduction failure may be accentuated or relieved by maneuvers that manipulate the time course of the driving current, including the administration of agents that interfere with Na(+) channel function. In patients with inflammatory neuropathies, normal activity may be sufficient to precipitate conduction failure at sites of impaired function in multifocal motor neuropathy (MMN) and chronic inflammatory demyelinating polyneuropathy (CIDP). From a clinical perspective, these features are not assessed adequately by conventional neurophysiological techniques. As weakness and fatigue may only develop following activity or exertion, it is useful to assess the effects of impulse trains to determine the extent of conduction failure and the resulting symptoms in neurological patients. These techniques and the physiological mechanisms underlying the development of activity-dependent hyperpolarization will be critically appraised in this review, with a focus on demyelinating neuropathies, MMN and the neurodegenerative disease, and amyotrophic lateral sclerosis (ALS).