Acute Motor Conduction Block Neuropathy Research Articles

Reversible Conduction Failure in Guillain-Barré Syndrome

Gangliosides are the primary antigenic target in acute motor axonal neuropathy. When anti-ganglioside antibodies bind to gangliosides near the motor axon node of Ranvier, complement system activation and Wallerian degeneration occur. Nevertheless, debate persists regarding the impact of anti-ganglioside antibodies on Guillain-Barré syndrome (GBS). Certain patients with these antibodies experience a swift recovery or exhibit conduction abnormalities indicative of demyelination in nerve conduction studies. The concept of reversible conduction failure was introduced by Kuwabara et al. in 1998. They proposed that this could result from compromised physiological conduction at the node of Ranvier. Auto-antibodies that bind to GM1 or GD1a gangliosides at this node can activate the complement system and disrupt sodium channel and axo-glial junctions, causing conduction failure. In 2003, Cappaso et al. described two cases of rapidly improving flaccid paralysis following Campylobacter jejuni infection. Initial nerve conduction studies indicated motor conduction block, which resolved quickly within 2 to 5 weeks. The authors termed this phenomenon acute motor conduction block neuropathy and considered it a form of arrested or partial acute motor axonal neuropathy. Since acute motor conduction block neuropathy could be misclassified as acute inflammatory demyelinating polyneuropathy based on existing electrophysiological criteria, several suggestions were made to refine the classification of GBS subtypes.

Antibodies to single glycolipids and glycolipid complexes in Guillain-Barré syndrome subtypes.

To comprehensively investigate the relationship between antibodies to single glycolipids and their complexes and Guillain-Barré syndrome subtypes and clinical features. In acute sera from 199 patients with Guillain-Barré syndrome, immunoglobulin G (IgG) antibodies to glycolipids and ganglioside complexes were tested using ELISA against individual antigens from single glycolipids including gangliosides (LM1, GM1, GM1b, GD1a, GalNAc-GD1a, GD1b, GT1a, GT1b, GQ1b) and a neutral glycolipid, asialo-GM1 (GA1), and antigens from the combination of 2 different glycolipids. Based on serial nerve conduction studies, the electrodiagnoses were as follows: 69 demyelinating subtype, 85 axonal subtypes, and 45 unclassified. Significant associations were detected between acute motor axonal neuropathy subtype and IgG antibodies to GM1, GalNAc-GD1a, GA1, or LM1/GA1 complex. Reversible conduction failure was significantly associated with IgG antibodies to GM1, GalNAc-GD1a, GD1b, or complex of LM1/GA1. No significant association was demonstrated between acute inflammatory demyelinating polyneuropathy and any of the glycolipids or ganglioside complexes. Anti-ganglioside complex antibodies alone were detected in 7 patients (5 axonal subtype). The current study demonstrates that antibodies to single glycolipids and ganglioside complexes are associated with acute motor axonal neuropathy or acute motor conduction block neuropathy but not acute inflammatory demyelinating polyneuropathy. This study provides Class II evidence that antibodies to glycolipids are increased in patients with acute motor axonal neuropathy and acute motor conduction block neuropathy but not acute inflammatory demyelinating polyneuropathy.

P214: Study of sympathetic skin response in diabetic patients with soft tissue rheumatism of the hand

P214: Study of sympathetic skin response in diabetic patients with soft tissue rheumatism of the hand

Association of antibodies to ganglioside complexes and conduction blocks in axonal Guillain-Barré syndrome presenting as acute motor conduction block neuropathy.

A close relationship between acute motor conduction block neuropathy and antibodies against the complex of GM1 and GalNAc-GD1a has been reported. This study investigates the hypothesis that conduction block at the early phase of axonal Guillain-Barré syndrome (GBS) is also associated with such ganglioside complexes. Sera were obtained from seven French patients with initial evidence of isolated conduction blocks that resolved or progressed to acute motor axonal neuropathy. Serum IgG to asialo-GM1 and gangliosides of LM1, GM1, GM1b, GD1a, GalNAc-GD1a, GD1b, GT1a, GT1b, and GQ1b as well as their complexes were measured. Five of seven patients progressed within the first month of disease to AMAN. One patient had IgG antibodies against the complex of asialo-GM1 and each of the other ganglioside antigens. Another patient carried IgG antibodies against GM1 complex with GM1b, GD1a, and GT1a as well as asialo-GM1 complex with GD1a and GT1a. None had IgG antibodies against GM1/GalNAc-GD1a complex. Six patients had IgG against single antigens GM1, GD1a, GalNAc-GD1a, GD1b, and asialo-GM1. In three patients, a reduced reaction against GM1/GalNAc-GD1a complex was observed. The presence of conduction block in axonal GBS is not always associated with anti-GM1/GalNAc-GD1a complex antibodies.

P215: Anti-ganglioside complex IgM antibodies and immune-mediated neuropathies: a novel case of acute motor conduction block neuropathy (AMCBN)? A case report

P215: Anti-ganglioside complex IgM antibodies and immune-mediated neuropathies: a novel case of acute motor conduction block neuropathy (AMCBN)? A case report

Anti-GD1a Antibody-associated Acute Motor Conduction Block Neuropathy

Anti-GD1a Antibody-associated Acute Motor Conduction Block Neuropathy

Acute-Onset Multifocal Motor Neuropathy (AMMN): How We Meet the Diagnosis

ABSTRACTMultifocal motor neuropathy (MMN) usually progresses insidiously with lower motor neuron-type weakness, minimal or no sensory symptoms. Diagnostic criteria include motor conduction block (CB) at sites not exposed to compression or entrapment. CBs may persist or reverse irrespective of clinical outcome. Acute onset with generalized weakness is uncommon. We report four patients who presented acutely areflexia, pure motor deficits without sensory disturbances, multifocal CBs persisting at the same motor nerves on serial electrophysiological studies. Three patients had preceding infections; two showed IgM reactivity against the ganglioside GM1. Intravenous immuneglobulin (IVIg) improved or stabilized symptoms. Patients 2,3,4 receive maintenance therapy with IVIg for years. Acute-onset MMN (AMMN) should be differentiated from other immune-mediated neuropathies such as acute inflammatory polyneuropathy either demyelinating (AIDP) or axonal (AMAN), acute motor conduction block neuropathy (AMCBN), acute-onset chronic inflammatory demyelinating polyneuropathy (CIDP). The correct diagnosis deserves implications for patient long-term treatment and prognosis. Moreover, the authors address the problem of defining the spectrum of MMN particularly in the acute setting.

A common mechanism and a new categorization for anti-ganglioside antibody-mediated neuropathies

Serum antibodies to different gangliosides have been identified in some Guillain-Barré (GBS) subtypes and variants. In the January issue of Experimental Neurology Susuki and colleagues (2012) showed that in experimental neuropathies associated with antibodies to GM1, GD1a and GD1b the common mechanism is a complement mediated dysfunction and disruption of the nodes of Ranvier which causes a pathophysiological continuum from early reversible conduction failure to axonal degeneration. These observations, correlated and integrated with electrophysiological and pathological findings in humans indicate that the GBS subtypes acute motor conduction block neuropathy, acute motor axonal neuropathy, acute motor and sensory neuropathy and acute sensory neuropathy and possibly also a chronic disorder as multifocal motor neuropathy represent a spectrum of the same immunopathologic process. Being the nodal axolemma and the paranode the focus of the nerve injury, these immune mediated neuropathies could be more properly classified as nodo-paranodopathies.

Axonal conduction block at intermediate nerve segments in pure motor Guillain‐Barré syndrome

The pathophysiology of axonal Guillain-Barré syndrome (GBS) is not simple axonal degeneration, but includes reversible conduction failure. Acute motor axonal neuropathy (AMAN) and acute motor conduction block (CB) neuropathy are the two subtypes of pure motor axonal GBS, but their nosologic boundary is still in debate. We investigated clinical and electrophysiological features of 21 consecutive patients with GBS in Korea. Analysis was focused on the presence of CB at intermediate nerve segments (iCB) in pure motor GBS, and its serial changes during the acute phase of disease. Pure motor GBS was common (81%), and iCB was observed in 12 patients with pure motor GBS. Clinical features of pure motor GBS with iCB were distinct from sensorimotor GBS, but similar to pure motor GBS without iCB, characterized by frequent preceding diarrhea, uncommon cranial nerve palsy, and fast recovery. The iCB was not restricted to common entrapment sites, and the distal segments were also commonly involved in the nerves with iCB. The temporal course of iCB was marked by a rapid and often disproportionate increase of proximal and distal amplitudes without remyelinating slow components. Clinical and electrophysiological features of pure motor GBS in patients with iCB suggest that acute motor CB neuropathy may constitute a spectrum of axonal GBS, sharing a common pathomechanism with AMAN.

Case of acute motor conduction block neuropathy (AMCBN)

We describe a 21 year-old man with an acute development of weakness whose clinical and serial electrophysiological findings were atypical for Guillain-Barré syndrome. Electrophysiological data suggested a diagnosis of "acute motor conduction block neuropathy" (AMCBN). The 6 months of disease duration and the electrophysiological follow-up, which never showed axonal degeneration until complete clinical recovery, raise the issue of the relationship between AMCBN and acute motor axonal neuropathy (AMAN).

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A 38-year-old man presented with distal-dominant limb weakness two weeks after an upper respiratory infection. He had no sensory and autonomic signs and no cranial nerve involvement during the course of the disease. Tendon reflexes were preserved except for an absent Achilles' tendon reflex. His disability at nadir was grade 2 on the Hughes functional scale. Cerebrospinal fluid analysis showed albuminocytologic dissociation and he was diagnosed with pure motor Guillain-Barré syndrome (GBS). Thin-layer chromatography immunostaining and an enzyme-linked immunosorbent assay revealed an immunoglobulin G antibody to the ganglioside complex GM1/GalNAc-GD1a in his acute phase serum. A serial nerve conduction study revealed conduction block in the median and ulnar nerve trunks and temporal dispersion in the tibial nerve, without an evident remyelination pattern during the course of the disease. A sensory nerve conduction study was normal. According to Hadden's criteria, the electrodiagnostic findings were judged as a primary demyelinating pattern. Weakness and abnormal motor nerve conduction recovered rapidly after intravenous immunoglobulin therapy. In view of the localization of GM1 and GalNAc-GD1a on the axolemma of the motor nerves, the clinical course and electrophysiological features may have resulted from functional conduction failure at the nodes of Ranvier of the motor nerves, rather than primary demyelination or axonal degeneration. The illness resembled acute motor conduction block neuropathy characterized by preserved sensory function, an early conduction block at intermediate nerve segments, and good recovery. GM1 and GalNAc-GD1a may form a complex in the axolemma at the nodes of Ranvier or paranodes of the motor nerves, and may be a target antigen in pure motor GBS; especially in the form with acute motor conduction block neuropathy. The present case is the first description of a GBS patient with an IgG anti-GM1/GalNAc-GD1a antibody.

GM1/GalNAc-GD1a complex

GM1 and GalNAc-GD1a are located on the axolemma of the motor nerves and are believed to be the antigens associated with pure motor Guillain-Barré syndrome (GBS). Furthermore, GM1 and GalNAc-GD1a may exist nearby and colocalize on the axolemma. Ganglioside complex (GSC) antigens associated with GM1 or GalNAc-GD1a can be target antigens in pure motor GBS. We investigated GBS sera for antibodies to a GSC consisting of GM1 and GalNAc-GD1a (GM1/GalNAc-GD1a) and analyzed the clinical and electrophysiologic findings of patients with antibodies to GM1/GalNAc-GD1a. Sera from 224 patients with GBS were surveyed for antibodies to GSCs consisting of two of nine gangliosides (GM1, GM2, GM3, GD1a, GD3, GT1a, GT1b, GQ1b, and GalNAc-GD1a). We analyzed the clinical and electrophysiologic features of patients with IgG antibodies to the GM1/GalNAc-GD1a complex. Ten patients with GBS had IgG antibodies to the GM1/GalNAc-GD1a complex. The clinical findings of the 10 patients with GBS were characterized by preserved sensory system and infrequent cranial nerve deficits. According to the criteria established by Hadden et al., electrodiagnostic studies showed a demyelinating pattern in four patients and axonal neuropathy pattern in two. Early motor conduction block at intermediate nerve segments was found in five patients. GM1 and GalNAc-GD1a may form a complex in the axolemma at nodes of Ranvier or paranodes of the motor nerves, and may be a target antigen in pure motor Guillain-Barré syndrome, especially in the form of acute motor conduction block neuropathy.

Acute motor conduction block neuropathy pattern occurring in the course of an acute inflammatory demyelinating polyradiculoneuropathy

To describe the case of a young woman with the diagnosis of acute inflammatory demyelinating polyradiculoneuropathy (AIDP), who during the course of the disease developed an electrophysiologic pattern of acute motor conduction block neuropathy (AMCBN). Electrophysiologic techniques including needle EMG, standard motor and sensory nerve conductions studies, and somatosensory evoked potentials were carried out over the four months after symptom onset. The results of four neurophysiological studies, performed on Days 14, 26, 35 and 125 after symptomatic onset are reported. All immunological determinations including antiganglioside antibodies (GM1, GM2, GM3, asialoGM1, GD1a, GD1b, GD3, GQ1b and GT1b) were negative. The patient had a favorable evolution following treatment with intravenous immunoglobulins (IVIg). We conclude that the electrophysiologic hallmark of AMCBN may occur in the course of AIDP. Serial investigation including proximal, intermediate and distal segments of all nerves from upper and lower limbs is essential for its detection.

Acute motor conduction block neuropathy followed by axonal degeneration and poor recovery

Acute motor conduction block neuropathy followed by axonal degeneration and poor recovery

Acute motor conduction block neuropathy followed by axonal degeneration and poor recovery

Acute motor neuropathies with conduction block are rare and often fully recover within weeks without residual axonal involvement.1,2 We report a case occurring after Campylobacter jejuni infection, with anti-GM1 antibody positivity, which presented axonal degeneration. Clinical improvement remained minimal 6 months after onset. This 50-year-old woman presented, 4 weeks after a gastrointestinal illness, with weakness of the lower limbs, which progressed to the arms over 3 days. Her past personal and family medical histories were unremarkable. On examination, she had weakness proximally and distally in all limbs (grade 2 on the Medical Research Council [MRC] scale). Sensory examination showed mild distal hypoesthesia to pinprick and vibration sense up to the ankles. She was areflexic, and plantar reflexes were flexor. Cranial nerve functions were unimpaired. All routine blood investigations were normal. C. jejuni serology for IgM (1:640) and IgG anti-GM1 antibodies were positive. CSF examination done 6 days after onset of the weakness showed no cells and protein level of 0.36 g/L …