Very early electrodiagnostic findings in Guillain-Barré syndrome

Efficacy and safety of intravenous immunoglobulin retreatment amongst Guillain-Barré syndrome patients who poorly responded to initial IVIG cycle: a systematic review

INTRODUCTION

Small cross-sectional studies and case reports observed improvement after administration of second IVIG dose (SID) amongst Guillain-Barré Syndrome (GBS) patients not responsive to initial IVIG cycle. Nevertheless, recent clinical trial and larger observational studies did not find any positive effects of SID. Instead, an increased risk of thromboembolism and mortality was noted. The conclusions of these studies however were not robust as confounding and selection bias were present.

METHODOLOGY

Two neurologists conducted the search process (KBA and MBP) using the following terms in Medline: [(" Guillain-Barré Syndrome"[MeSH Terms] or GBS or Acute Motor Axonal Neuropathy or Acute Motor Axonal Neuropathy or Acute Inflammatory Demyelinating Polyneuropathy) AND (Poorly Responsive or Poor Prognosis or Progressive)] AND [("Intravenous Immunoglobulin"[MeSH Terms] or IVIG or IGIV) AND (second dose or retreatment or SID)].

RESULTS

Only 7 articles were included in this review. In terms of primary outcomes, although the cross-sectional study found improvement in GBS DS score at 4 weeks (Median GBS DS: 3 vs 5, p = 0.033) and the 2 case series observed improvement after SID, no significant differences between the control and intervention groups were found in the cohort [Early SIV OR: 0.7 (95% CI 0.16-3.04), Late SIV OR: 0.66 (CI: 0.18-2.5)] and clinical trial studies (Adjusted OR: 1.4 (95% CI:0.6-3.3, p = 0.45). Moreover, 4 patients who died in the clinical trial were from the intervention group.

CONCLUSION

Based on studies with research designs of higher quality, SID is not effective in the management of GBS patients who poorly responded to initial IVIG. Nevertheless, an adequately powered, randomized, double-blinded, placebo-controlled clinical trial, using GBS-DS of 3 and above after first IVIG dose should be done to effectively establish the efficacy and safety of SID as intervention for this cohort of patients.

Guillain-Barré Syndrome Mimicking Lumbar Spinal Stenosis with Segmental Weakness in L5-S1 Myotomes

We herein report two cases of Guillain-Barré syndrome (GBS) mimicking lumbar spinal stenosis (LSS). Both cases were initially diagnosed as LSS based on prominent segmental weakness in the L5 and S1 myotomes and coexisting LSS on magnetic resonance imaging. However, neurological and electrophysiological examinations revealed abnormalities that extended to the upper extremities, although slight, prompting us to suspect GBS. Subsequently, serum antiganglioside antibodies and remarkable responsiveness to intravenous immunoglobulin therapy confirmed GBS. We suspect that the focal blood-nerve barrier disruption due to preexisting LSS might have contributed to the segmental weakness in this atypical GBS case.

Clinical and Electrophysiological Characteristics of Very Early Guillain-Barré Syndrome

PURPOSE

This study compared the clinical and electrodiagnostic (EDX) features and long-term outcomes of patients with very early Guillain-Barré syndrome (VEGBS, duration of illness ≤4 days) and those with early/late (>4 days)-presenting GBS.

METHODS

One hundred patients with GBS were clinically evaluated and categorized into VEGBS and early/late GBS groups. Electrodiagnostic studies were performed on the bilateral median, ulnar, and fibular motor nerves and the bilateral median, ulnar, and sural sensory nerves. Admission and peak disability were assessed using the 0 to 6 Guillain-Barré Syndrome Disability Scale (GBSDS). The primary outcome was disability at 6 months, which was categorized as complete (GBSDS ≤1) or poor (GBSDS ≥2). The secondary outcomes were frequencies of abnormal electrodiagnostic findings, in-hospital progression, and mechanical ventilation (MV).

RESULTS

Patients with VEGBS had higher peak disability (median 5 vs. 4; P = 0.02), frequent in-hospital disease progression (42.9% vs. 19.0%, P < 0.01), needed MV (50% vs. 22.4%; P < 0.01), and less frequent albuminocytologic dissociation (52.4% vs. 74.1%; P = 0.02) than those with early/late GBS. Thirteen patients were lost to follow-up at 6 months (nine patients with VEGBS and four patients with early/late GBS). The proportion of patients with complete recovery at 6 months was comparable (60.6% vs. 77.8%; P = ns ). Reduced d-CMAP was the most common abnormality, noted in 64.7% and 71.6% of patients with VEGBS and early/late GBS, respectively ( P = ns). Prolonged distal motor latency (≥130%) was more common in early/late GBS than in VEGBS (36.2% vs. 25.4%; P = 0.02), whereas absent F-waves were more frequent in VEGBS (37.7% vs. 28.7%; P = 0.03).

CONCLUSIONS

Patients with VEGBS were more disabled at admission than those with early/late GBS. However, 6 month's outcomes were similar between the groups. F-wave abnormalities were frequent in VEGBS, and distal motor latency prolongation was common in early/late GBS.

Atypical Guillain-Barré Syndrome in a Pediatric Patient With a Preceding Non-COVID-19 Coronavirus Infection: A Case Report

This study examines a four-year-and-one-month-old male with no significant past medical, family, or surgical history who initially presented to the pediatric clinic with cough, rhinorrhea, conjunctivitis, emesis, leg and arm pain, and increased difficulty ambulating. The patient was transferred to the emergency department and tested positive for a non-COVID-19 coronavirus infection. The patient was stabilized, given intravenous fluids, and discharged only to return to the clinic the next day with the onset of a headache, right eye ptosis, an inability to bear weight, and bilateral upper and lower extremity weakness resulting in an ataxic gait. In addition to the neurological deficits, the patient was found to have an elevated blood pressure and pulse. The patient was promptly transferred to a tertiary care clinic. Through exclusion of various differentials via testing, the patient was diagnosed and managed for atypical Guillain-Barré syndrome. Targeted therapies were initiated to prevent dysautonomia-associated morbidity. Following management, the patient's condition vastly improved and he was admitted to rehabilitation bringing him back to optimal health. This study underlines the importance of prompt identification of atypical presentations of Guillain-Barré syndrome which may aid in avoiding preventable morbidity and mortality.

Serial Nerve Conduction Studies in Guillain-Barré Syndrome: Its Usefulness and Precise Timing

PURPOSE

Nerve conduction study (NCS) is essential for subclassifying Guillain-Barré syndrome (GBS). It is well known that the GBS subclassification can change through serial NCSs. However, the usefulness of serial NCSs is debatable, especially in patients with early stage GBS.

METHODS

Follow-up NCS data within 3 weeks (early followed NCS, EFN) and within 3 to 10 weeks (late-followed NCS, LFN) were collected from 60 patients with GBS who underwent their first NCS (FN) within 10 days after symptom onset. Each NCS was classified into five subtypes (normal, demyelinating, axonal, inexcitable, and equivocal), according to Hadden's and Rajabally's criteria. We analyzed the frequency of significant changes in classification (SCCs) comprising electrodiagnostic aggravation and subtype shifts between demyelinating and axonal types according to follow-up timing.

RESULTS

Between FN and EFN, 33.3% of patients with Hadden's criteria and 18.3% with Rajabally's criteria showed SCCs. Between FN and LFN, 23.3% of patients with Hadden's criteria and 21.7% with Rajabally's criteria showed SCCs, of which 71.4% (Hadden's criteria) and 46.2% (Rajabally's criteria) already showed SCCs from the EFN. The conditions of delayed SCCs between EFN and LFN were very early FN, mild symptoms at the FN, or persistent electrophysiological deterioration 3 weeks after symptom onset.

CONCLUSIONS

A substantial proportion of patients with GBS showed significant changes in neurophysiological classification at the early stage. Serial NCS may be helpful for precise neurophysiological classification. This study suggests that follow-up NCSs should be performed within 3 weeks of symptom onset in patients with GBS in whom FN was performed within 10 days of symptom onset.

Current status of Guillain-Barré syndrome (GBS) in China: a 10-year comprehensive overview

Guillain-Barré syndrome (GBS) is an acute inflammatory polyradiculoneuropathy; a disease involving the peripheral nervous system which is the most common cause of acute flaccid paralysis worldwide. So far, it is still lack of a comprehensive overview and understanding of the national epidemiological, clinical characteristics, and the risk factors of GBS in China, as well as differences between China and other countries and regions in these respects. With the global outbreak of the coronavirus disease 2019 (COVID-19), an epidemiological or phenotypic association between severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection and GBS has attracted great attention. In this review, we outlined the current clinical data of GBS in China by retrieving literature, extracting and synthesizing the data of GBS in China from 2010 to 2021. Besides, we compared the characteristics of epidemiology, preceding events and clinical profiles of GBS between China and other countries and regions. Furthermore, in addition to conventional intravenous immunoglobulin (IVIG) and plasma exchange (PE) therapy, the potential therapeutic effects with novel medications in GBS, such as complement inhibitors, etc., have become the research focus in treatments. We found that epidemiological and clinical findings of GBS in China are approximately consistent with those in the International GBS Outcome Study (IGOS) cohort. We provided an overall picture of the present clinical status of GBS in China and summarized the global research progress of GBS, aiming to further understand the characteristics of GBS and improve the future work of GBS worldwide, especially in countries with the middle and low incomes.

European Academy of Neurology/Peripheral Nerve Society Guideline on diagnosis and treatment of Guillain-Barré syndrome

Guillain-Barré syndrome (GBS) is an acute polyradiculoneuropathy. Symptoms may vary greatly in presentation and severity. Besides weakness and sensory disturbances, patients may have cranial nerve involvement, respiratory insufficiency, autonomic dysfunction and pain. To develop an evidence-based guideline for the diagnosis and treatment of GBS, using Grading of Recommendations, Assessment, Development and Evaluation (GRADE) methodology a Task Force (TF) of the European Academy of Neurology (EAN) and the Peripheral Nerve Society (PNS) constructed 14 Population/Intervention/Comparison/Outcome questions (PICOs) covering diagnosis, treatment and prognosis of GBS, which guided the literature search. Data were extracted and summarised in GRADE Summaries of Findings (for treatment PICOs) or Evidence Tables (for diagnostic and prognostic PICOs). Statements were prepared according to GRADE Evidence-to-Decision (EtD) frameworks. For the six intervention PICOs, evidence-based recommendations are made. For other PICOs, good practice points (GPPs) are formulated. For diagnosis, the principal GPPs are: GBS is more likely if there is a history of recent diarrhoea or respiratory infection; CSF examination is valuable, particularly when the diagnosis is less certain; electrodiagnostic testing is advised to support the diagnosis; testing for anti-ganglioside antibodies is of limited clinical value in most patients with typical motor-sensory GBS, but anti-GQ1b antibody testing should be considered when Miller Fisher syndrome (MFS) is suspected; nodal-paranodal antibodies should be tested when autoimmune nodopathy is suspected; MRI or ultrasound imaging should be considered in atypical cases; and changing the diagnosis to acute-onset chronic inflammatory demyelinating polyradiculoneuropathy (A-CIDP) should be considered if progression continues after 8 weeks from onset, which occurs in around 5% of patients initially diagnosed with GBS. For treatment, the TF recommends intravenous immunoglobulin (IVIg) 0.4 g/kg for 5 days, in patients within 2 weeks (GPP also within 2-4 weeks) after onset of weakness if unable to walk unaided, or a course of plasma exchange (PE) 12-15 L in four to five exchanges over 1-2 weeks, in patients within 4 weeks after onset of weakness if unable to walk unaided. The TF recommends against a second IVIg course in GBS patients with a poor prognosis; recommends against using oral corticosteroids, and weakly recommends against using IV corticosteroids; does not recommend PE followed immediately by IVIg; weakly recommends gabapentinoids, tricyclic antidepressants or carbamazepine for treatment of pain; does not recommend a specific treatment for fatigue. To estimate the prognosis of individual patients, the TF advises using the modified Erasmus GBS outcome score (mEGOS) to assess outcome, and the modified Erasmus GBS Respiratory Insufficiency Score (mEGRIS) to assess the risk of requiring artificial ventilation. Based on the PICOs, available literature and additional discussions, we provide flow charts to assist making clinical decisions on diagnosis, treatment and the need for intensive care unit admission.

European Academy of Neurology/Peripheral Nerve Society Guideline on diagnosis and treatment of Guillain-Barré syndrome

Guillain-Barré syndrome (GBS) is an acute polyradiculoneuropathy. Symptoms may vary greatly in presentation and severity. Besides weakness and sensory disturbances, patients may have cranial nerve involvement, respiratory insufficiency, autonomic dysfunction and pain. To develop an evidence-based guideline for the diagnosis and treatment of GBS, using Grading of Recommendations, Assessment, Development and Evaluation (GRADE) methodology, a Task Force (TF) of the European Academy of Neurology (EAN) and the Peripheral Nerve Society (PNS) constructed 14 Population/Intervention/Comparison/Outcome questions (PICOs) covering diagnosis, treatment and prognosis of GBS, which guided the literature search. Data were extracted and summarised in GRADE Summaries of Findings (for treatment PICOs) or Evidence Tables (for diagnostic and prognostic PICOs). Statements were prepared according to GRADE Evidence-to-Decision (EtD) frameworks. For the six intervention PICOs, evidence-based recommendations are made. For other PICOs, good practice points (GPPs) are formulated. For diagnosis, the principal GPPs are: GBS is more likely if there is a history of recent diarrhoea or respiratory infection; CSF examination is valuable, particularly when the diagnosis is less certain; electrodiagnostic testing is advised to support the diagnosis; testing for anti-ganglioside antibodies is of limited clinical value in most patients with typical motor-sensory GBS, but anti-GQ1b antibody testing should be considered when Miller Fisher syndrome (MFS) is suspected; nodal-paranodal antibodies should be tested when autoimmune nodopathy is suspected; MRI or ultrasound imaging should be considered in atypical cases; and changing the diagnosis to acute-onset chronic inflammatory demyelinating polyradiculoneuropathy (A-CIDP) should be considered if progression continues after 8 weeks from onset, which occurs in around 5% of patients initially diagnosed with GBS. For treatment, the TF recommends intravenous immunoglobulin (IVIg) 0.4 g/kg for 5 days, in patients within 2 weeks (GPP also within 2-4 weeks) after onset of weakness if unable to walk unaided, or a course of plasma exchange (PE) 12-15 L in four to five exchanges over 1-2 weeks, in patients within 4 weeks after onset of weakness if unable to walk unaided. The TF recommends against a second IVIg course in GBS patients with a poor prognosis; recommends against using oral corticosteroids, and weakly recommends against using IV corticosteroids; does not recommend PE followed immediately by IVIg; weakly recommends gabapentinoids, tricyclic antidepressants or carbamazepine for treatment of pain; does not recommend a specific treatment for fatigue. To estimate the prognosis of individual patients, the TF advises using the modified Erasmus GBS outcome score (mEGOS) to assess outcome, and the modified Erasmus GBS Respiratory Insufficiency Score (mEGRIS) to assess the risk of requiring artificial ventilation. Based on the PICOs, available literature and additional discussions, we provide flow charts to assist making clinical decisions on diagnosis, treatment and the need for intensive care unit admission.

Immune-Mediated Neuropathies: Pathophysiology and Management

Dysfunction of the immune system can result in damage of the peripheral nervous system. The immunological mechanisms, which include macrophage infiltration, inflammation and proliferation of Schwann cells, result in variable degrees of demyelination and axonal degeneration. Aetiology is diverse and, in some cases, may be precipitated by infection. Various animal models have contributed and helped to elucidate the pathophysiological mechanisms in acute and chronic inflammatory polyradiculoneuropathies (Guillain-Barre Syndrome and chronic inflammatory demyelinating polyradiculoneuropathy, respectively). The presence of specific anti-glycoconjugate antibodies indicates an underlying process of molecular mimicry and sometimes assists in the classification of these disorders, which often merely supports the clinical diagnosis. Now, the electrophysiological presence of conduction blocks is another important factor in characterizing another subgroup of treatable motor neuropathies (multifocal motor neuropathy with conduction block), which is distinct from Lewis-Sumner syndrome (multifocal acquired demyelinating sensory and motor neuropathy) in its response to treatment modalities as well as electrophysiological features. Furthermore, paraneoplastic neuropathies are also immune-mediated and are the result of an immune reaction to tumour cells that express onconeural antigens and mimic molecules expressed on the surface of neurons. The detection of specific paraneoplastic antibodies often assists the clinician in the investigation of an underlying, sometimes specific, malignancy. This review aims to discuss the immunological and pathophysiological mechanisms that are thought to be crucial in the aetiology of dysimmune neuropathies as well as their individual electrophysiological characteristics, their laboratory features and existing treatment options. Here, we aim to present a balance of discussion from these diverse angles that may be helpful in categorizing disease and establishing prognosis.

Sural Sparing Pattern and Sensory Ratio as Electrodiagnostic and Prognostic Markers in Pediatric Guillain-Barré Syndrome

BACKGROUND

We aimed to evaluate the presence of sural sparing pattern (SSP) and sensory ratio in pediatric Guillain-Barré syndrome (GBS), their distribution to subtypes, and their relationship with demographic and clinical features with a focus on the disability and muscle strength.

METHODS

This single-center retrospective study was conducted on pediatric GBS patients of both sexes with 2 years follow-up and two nerve conduction studies in which SSP and sensory ratio were calculated. Three subgroups of SSP were formed by separate calculation of median (SSP-m) and ulnar (SSP-u) and both median and ulnar sensory nerve action potentials (SNAPs; SSP-total). Muscle strength and disability were evaluated with the Medical Research Council (MRC) sum score and Hughes functional grading scale (HFGS), respectively.

RESULTS

SSP total was identified in 70.6% (n: 24) of the patients, while sensory ratio >1 was observed in 20 (66.7%) patients. Patients with SSP-m, SSP-u, SSP-total, or sensory ratio >1 had higher HFGS scores, while patients with SSP-m, SSP-u, or SSP-total had lower MRC sum scores. SSP parameters were significantly associated with muscle strength and disability scores in acute motor axonal neuropathy patients.

CONCLUSION

Both SSP and sensory ratio can be used for diagnostic and prognostic purposes. Disability and muscle strength are associated with SSP and sensory ratio in pediatric GBS.

Axonal pathology in early stages of Guillain-Barré syndrome

INTRODUCTION

Guillain-Barré syndrome (GBS) is an acute-onset, immune-mediated disease of the peripheral nervous system. It may be classified into 2 main subtypes: demyelinating (AIDP) and axonal (AMAN). This study aims to analyse the mechanisms of axonal damage in the early stages of GBS (within 10 days of onset).

DEVELOPMENT

We analysed histological, electrophysiological, and imaging findings from patients with AIDP and AMAN, and compared them to those of an animal model of myelin P2 protein-induced experimental allergic neuritis. Inflammatory oedema of the spinal nerve roots and spinal nerves is the initial lesion in GBS. The spinal nerves of patients with fatal AIDP may show ischaemic lesions in the endoneurium, which suggests that endoneurial inflammation may increase endoneurial fluid pressure, reducing transperineurial blood flow, potentially leading to conduction failure and eventually to axonal degeneration. In patients with AMAN associated with anti-ganglioside antibodies, nerve conduction block secondary to nodal sodium channel dysfunction may affect the proximal, intermediate, and distal nerve trunks. In addition to the mechanisms involved in AIDP, active axonal degeneration in AMAN may be associated with nodal axolemma disruption caused by anti-ganglioside antibodies.

CONCLUSION

Inflammatory oedema of the proximal nerve trunks can be observed in early stages of GBS, and it may cause nerve conduction failure and active axonal degeneration.

Axonal pathology in early stages of Guillain-Barré syndrome

INTRODUCTION

Guillain-Barré syndrome (GBS) is an acute-onset, immune-mediated disease of the peripheral nervous system. It may be classified into 2 main subtypes: demyelinating (AIDP) and axonal (AMAN). This study aims to analyse the mechanisms of axonal damage in the early stages of GBS (within 10days of onset).

DEVELOPMENT

We analysed histological, electrophysiological, and imaging findings from patients with AIDP and AMAN, and compared them to those of an animal model of myelin P2 protein-induced experimental allergic neuritis. Inflammatory oedema of the spinal nerve roots and spinal nerves is the initial lesion in GBS. The spinal nerves of patients with fatal AIDP may show ischaemic lesions in the endoneurium, which suggests that endoneurial inflammation may increase endoneurial fluid pressure, reducing transperineurial blood flow, potentially leading to conduction failure and eventually to axonal degeneration. In patients with AMAN associated with anti-ganglioside antibodies, nerve conduction block secondary to nodal sodium channel dysfunction may affect the proximal, intermediate, and distal nerve trunks. In addition to the mechanisms involved in AIDP, active axonal degeneration in AMAN may be associated with nodal axolemma disruption caused by anti-ganglioside antibodies.

CONCLUSION

Inflammatory oedema of the proximal nerve trunks can be observed in early stages of GBS, and it may cause nerve conduction failure and active axonal degeneration.

Nodopathies in the Early Diagnosis of Axonal Forms of Guillain-Barré Syndrome

Introduction:

Guillain-Barré syndrome (GBS) has been classified into demyelinating and axonal subtypes or forms, such as acute motor axonal neuropathy (AMAN) and regional pharyngeal-cervical-brachial variant (PCBv).

Objective

To study the relationship between motor nerve conduction blocks (CBs) and prognosis in AMAN and PCBv.

Patients and Methods

We retrospectively analyzed six cases of AMAN and PCBv with serial nerve conduction studies (NCS) and electromyography (EMG).

Results

The serial NCS (1st−2nd and 3rd week) showed, as the most constant data, a decreased amplitude of the compound muscle action potential (CMAP) in 100% of cases. CBs were present in 66.6% of cases. EMG (3rd week) showed signs of severe denervation in 33.3%. All patients were treated from the 1st−2nd week of evolution with intravenous immunoglobulins (IVIGs). Patients with CBs (1st−2nd and 3rd week), showed reversible CBs or reversible conduction failure (RCF) and complete recovery at 1 month. Patients without CBs, with persistent reduced distal CMAP amplitude (dCMAP), showed severe acute denervation due to axonal degeneration (3rd week and 1st−3rd month) and a slow recovery of several months.

Conclusions

Not all axonal forms of GBS have a poor prognosis. This study of AMAN and PCBv shows that patients with CBs can have reversible CBs or RCF, and good prognosis. Patients without CBs, with persistent reduction of dCMAP amplitude decrement, have severe acute denervation, and a worse prognosis. AMAN and PCBv have a continuous spectrum ranging from CBs due to dysfunction/disruption of Nodes of Ranvier, called nodopathies, with reversible CBs or RCF and good prognosis, to axonal degeneration with worse prognosis.

Re-evaluating the accuracy of optimized electrodiagnostic criteria in very early Guillain-Barré syndrome: a sequential study

Using recent optimized electrodiagnostic criteria sets, we aimed at verifying the accuracy of initial nerve conduction studies (NCS) in classic very early Guillain-Barré syndrome (VEGBS), ≤ 4 days after onset, compared with the results of serial NCS. This is a retrospective study based on unreported and consecutive VEGBS patients admitted to two university hospitals between 2015 and 2019. Each patient had serial NCS in at least four nerves. Initial NCS studies were done within 4 days after onset, and serial ones from days 20 to 94. Electrophysiological recordings were blinded evaluated by four of the authors, GBS subtype being established accordingly. Seven adult classic VEGBS patients were identified with a median age of 58 years. At first NCS, GBS subtyping was only possible in 1 case that exhibited an axonal pattern, the remaining patterns being equivocal in 3, and mixed (combining axonal and demyelinating criteria) in the remaining 3. Upon serial NSC there was a rather intricate evolution of electrophysiological GBS patterns, 3 of them being classified as axonal or demyelinating, and the remaining 4 as equivocal or mixed. NCS in VEGBS systematically allows detection of changes suggestive of peripheral neuropathy, though even after serial studies accurate GBS subtyping was only possible in 43% of cases. We provide new pathophysiological insights for better understanding of the observed electrophysiological changes.

Unclassified subtype of Guillain-Barré syndrome is associated with quick recovery

Electrophysiological classification of Guillain-Barré syndrome (GBS) is important for predicting its clinical course; however, few reports discuss GBS patients who do not conform to the acute inflammatory demyelinating polyneuropathy (AIDP) or acute motor axonal neuropathy (AMAN) classifications. Therefore, the present study assessed the features of unclassified types of GBS and compared them to those of AIDP and AMAN. We compared clinical symptoms, nerve conduction, and laboratory data among patients with AIDP, AMAN, and unclassified subtypes of GBS, according to criteria developed by Rajabally, Hadden, and Ho. According to the Rajabally criteria, the F wave frequency in the upper and lower extremities was higher in the unclassified subgroup than in the AIDP and AMAN subgroups; however, according to the Hadden and Ho criteria, the F wave frequency in only the lower extremities was higher in the unclassified subgroup than in the other subgroups. The unclassified subgroup showed better prognosis using the Rajabally criteria. Classification with the Rajabally criteria is useful for predicting prognosis and determining treatment in patients with GBS. Moreover, unclassified patients exhibit the quickest recovery.

Development of Acute Inflammatory Demyelinating Polyneuropathy 11 Days after Spinal Surgery: A Case Report and Literature Review

Guillain–Barré syndrome (GBS) usually has a good prognosis; however, patients may develop sequelae without prompt treatment. We herein describe an 81-year-old woman who developed acute-onset excruciating thigh pain and weakness in her lower extremities after spinal surgery. We diagnosed acute inflammatory demyelinating polyradiculoneuropathy by a nerve conduction study, which showed findings of demyelination without cerebrospinal fluid analysis because of a spinal prosthesis. Although anti-GM1 and anti-GalNAc-GD1a antibodies were positive, the patient was clinically diagnosed with acute inflammatory demyelinating polyradiculoneuropathy (a subtype of GBS), not acute motor axonal neuropathy. She recovered well with immunoglobulin therapy. A literature review of 18 cases revealed that unexplained weakness, areflexia, and numbness of the extremities after spinal surgery, a shorter time from spinal surgery to symptom onset to general GBS, abnormal nerve conduction study results, normal spinal imaging findings, and the development of atypical symptoms such as cranial and autonomic nerve syndrome and respiratory failure are useful for diagnosing GBS when cerebrospinal fluid examination cannot be performed after spinal surgery.

Very early and early neurophysiological abnormalities in Guillain-Barré syndrome: A 4-year retrospective study

Background and purpose

In its initial stages, Guillain–Barré syndrome (GBS) is difficult to identify, because diagnostic criteria may not always be fulfilled. With this retrospective study, we wanted to identify the most common electrophysiological abnormalities seen on neurophysiological examination of GBS patients and its variants in the early phases.

Methods

We reviewed the clinical records of patients admitted to our Neurology Unit with a confirmed diagnosis of GBS. The study sample was divided in two subgroups according to whether the neurophysiological examination was performed: within 7 days (very early group) or within 7–15 days (early group). H reflex, F waves, and motor and sensory conduction parameters were judged abnormal if they were outside the normal range for at least two nerves. We evaluated neurophysiological findings in Miller–Fisher syndrome (MFS) separately.

Results

The study sample comprised 36 patients. In GBS, the most frequent abnormal neurophysiological parameter was the bilateral absence of the H reflex, followed by F wave abnormalities. Motor conduction parameters were altered in less than 50% of patients, and even less common were sensory nerve action potential reduction and the "sural‐sparing" pattern. In MFS, H reflex was absent bilaterally in 100% of patients, followed by a predominant peripheral sensory involvement, whereas motor conduction parameters were frequently normal.

Conclusions

Bilateral absence of the H reflex is the most sensitive parameter in early diagnosis of GBS and its variants.

Nerve conduction studies in Guillain-Barré syndrome: Influence of timing and value of repeated measurements

OBJECTIVE

Nerve conduction studies (NCS) are essential to differentiate between demyelinating and axonal subtypes in Guillain-Barré syndrome (GBS). However, it is debated to which extent the delay of NCS after symptom onset and repeated measurements during the disease course influence the diagnostic accuracy.

METHODS

We evaluated NCS in 93 patients with a classical GBS applying two widely used criteria (Hadden's and Rajabally's). The initial measurements after symptom onset were compared to follow-up studies where available (n = 43). We analyzed the influence of NCS timing after symptom onset and clinical severity on fulfilling the electrophysiological criteria for axonal or demyelinating subtypes and evaluated the impact of repeated measurements. We further evaluated the presence of reversible conduction failure.

RESULTS

A higher GBS disability scale at nadir correlated with a successful subclassification whereas the delay of the first NCS after symptom onset did not influence the diagnostic yield (75% for Hadden's and 68% for Rajabally's criteria for the first assessment). A second measurement allowed the additional successful classification in 19% and 14% of patients, respectively. On the other hand, a repeated measurement in patients with an initial successful classification resulted in a different subtype in 5% and 7%, respectively. Reversible conduction failure was found in 7% of patients.

CONCLUSION

Clinical severity but not timing of NCS influenced the fulfilment of electrophysiological criteria for either the axonal or demyelinating subtype. Repeated electrophysiological measurements led to a further specification or a change in subtype classification in a relevant proportion of patients.

Inflammatory oedema of nerve trunks may be pathogenic in very early Guillain-Barré syndrome

The aim of this paper is to analyse the pathological background of very early Guillain-Barré (VEGBS) (≤ 4 days after onset) comparing it with initial stages of experimental autoimmune neuritis (EAN). The pathological hallmark of VEGBS is inflammatory oedema predominating in proximal nerve trunks. In EAN inflammatory oedema precedes the development of demyelination or axonal degeneration; such oedema may increase endoneurial fluid pressure (EFP) stretching the perineurium and constricting the transperineurial microcirculation. Centrofascicular or wedge-shaped areas of nerve ischemia have been reported in GBS and EAN. Additional support for proximal VEGBS pathology comes from electrophysiology showing alterations in late responses as the most frequent features, and ultrasonography illustrating that main changes rely on ventral rami of spinal nerves. Selective inefficiency of the blood-nerve barrier would explain the topography of changes in VEGBS. Increased serum neurofilament light chain concentration has recently been reported in VEGBS, with no difference between demyelinating and axonal subtypes. This is a marker of axonal damage, which could be correlated with endoneurial ischemia caused by increased EFP. Inflammatory oedema of proximal nerve trunks may be pathogenic in VEGBS, and consequently there is a pressing need for therapeutic strategies to stop its rapid impact on the axons.

Axonal degeneration in Guillain-Barré syndrome: a reappraisal

The aim of this review was to analyse the pathophysiology of axonal degeneration in Guillain-Barré syndrome (GBS) with emphasis on early stages (≤ 10 days after onset). An overview of experimental autoimmune neuritis (EAN) models is provided. Originally GBS and acute inflammatory demyelinating polyneuropathy were equated, presence of axonal degeneration being attributed to a "bystander" effect. Afterwards, primary axonal GBS forms were reported, designated as acute motor axonal neuropathy/acute motor-sensory axonal neuropathy. Revision of the first pathological description of axonal GBS indicates the coexistence of active axonal degeneration and demyelination in spinal roots, and pure Wallerian-like degeneration in peripheral nerve trunks. Nerve conduction studies are essential for syndrome subtyping, though their sensitivity is scanty in early GBS. Serum markers of axonal degeneration include increased levels of neurofilament light chain and presence of anti-ganglioside reactivity. According to nerve ultrasonographic features and autopsy studies, ventral rami of spinal nerves are a hotspot in early GBS. In P₂-induced EAN models, the initial pathogenic change is inflammatory oedema of spinal roots and sciatic nerve, which is followed by demyelination, and Wallerian-like degeneration in nerve trunks possessing epi-perineurium; a critical elevation of endoneurial fluid pressure is a pre-requisite for inducing ischemic axonal degeneration. Similar lesion topography may occur in GBS. The repairing role of adaxonal Schwann cytoplasm in axonal degeneration is analysed. A novel pathophysiological mechanism for nerve trunk pain in GBS, including pure motor forms, is provided. The potential therapeutic role of intravenous boluses of methylprednisolone for early severe GBS and intractable pain is argued.

Diagnosis and treatment of Guillain-Barré Syndrome in childhood and adolescence: An evidence- and consensus-based guideline

This evidence- and consensus-based practical guideline for the diagnosis and treatment of Guillain-Barré Syndrome (GBS) in childhood and adolescence has been developed by a group of delegates from relevant specialist societies and organisations; it is the result of an initiative by the German-Speaking Society of Neuropediatrics (GNP), and is supported by the Association of Scientific Medical Societies (AWMF, Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften). A systematic analysis of the literature revealed that only a few adequately-controlled studies exist for this particular age group, while none carries a low risk of bias. For this reason, the diagnostic and therapeutic recommendations largely rely on findings in adult patients with GBS, for which there are a higher number of suitable studies available. Consensus was established using a written, multi-step Delphi process. A high level of consensus could be reached for the crucial steps in diagnosis and treatment. We recommend basing the diagnostic approach on the clinical criteria of GBS and deriving support from CSF and electrophysiological findings. Repetition of invasive procedures that yield ambiguous results is only recommended if the diagnosis cannot be ascertained from the other criteria. For severe or persistently-progressive GBS treatment with intravenous immunoglobulin (IVIG) is recommended, whereas in cases of IVIG intolerance or inefficacy we recommended treatment with plasmapheresis. Corticosteroids are ineffective for GBS but can be considered when acute onset chronic inflammatory demyelinating polyneuropathy (A-CIDP) is suspected due to a prolonged disease course. The full German version of the Guideline is available on the AWMF website (https://www.awmf.org/leitlinien/detail/ll/022-008.html).

Very early Guillain-Barré syndrome: A clinical-electrophysiological and ultrasonographic study

Objectives

Using recent optimized electrodiagnostic criteria sets, we primarily aimed at verifying the accuracy of the initial electrophysiological test in very early Guillain-Barré syndrome (VEGBS), ≤4 days of onset, compared with the results of serial electrophysiology. Our secondary objective was to correlate early electrophysiological results with sonographic nerve changes.

Methods

This is a retrospective study based on consecutive VEGBS patients admitted to the hospital. Each patient had serial nerve conduction studies (NCS) in at least 4 nerves. Initial NCS were done within 4 days after onset, and serial ones from the second week onwards. Electrophysiological recordings of each case were re-evaluated, GBS subtype being established accordingly. Nerve ultrasonography was almost always performed within 2 weeks after onset.

Results

Fifteen adult VEGBS patients were identified with a mean age of 57.8 years. At first NCS, VEGBS sub-typing was only possible in 3 (20%) cases that showed an axonal pattern, the remaining patterns being mixed (combining axonal and demyelinating features) in 6 (40%), equivocal in 5 (33.3%), and normal in 1 (6.7%). Upon serial NCS, 7 (46.7%) cases were categorized as acute demyelinating polyneuropathy, 7 (46.7%) as axonal GBS, and 1 (6.6%) as unclassified syndrome. Antiganglioside reactivity was detected in 5 out of the 7 axonal cases. Nerve US showed that lesions mainly involved the ventral rami of scanned cervical nerves.

Conclusions

Serial electrophysiological evaluation is necessary for accurate VEGBS subtype classification. Ultrasonography helps delineate the topography of nerve changes.

Significance

We provide new VEGBS pathophysiological insights into nerve conduction alterations within the first 4 days of the clinical course.

A unicenter, prospective study of Guillain-Barré syndrome in Spain

OBJECTIVE

We report a prospective study analysing clinical characteristics, subtyping and prognosis in Guillain-Barré syndrome (GBS).

METHOD

The study was based on consecutive GBS patients admitted between 2009 and 2017. Disability was serially assessed using the GBS disability scale.

RESULTS

Fifty-six GBS patients were identified with an average age of 55 years (range, 5-86 years) and a male/female ratio of 2.1. The interval to nadir was <7 days in 59% of cases, and 7 to 28 days in the remainder; at nadir, 35.5% of patients were able to walk unaided, and 64.5% did not. Mechanical ventilation was needed in 20% of cases. There were two fatal cases. Clinical variants included paraparetic GBS seven cases, Miller Fisher syndrome one case, and acute sensory ataxic neuropathy (ASAN) one case. Serial electrophysiology showed a demyelinating pattern in 62.5% of cases, axonal in 28.5%, inexcitable in 1.8%, equivocal in 1.8%, and normal in 5.4%. Very early (1 to 4 days after onset) electrophysiology was done in 18 patients; equivocal or normal features in six of them evolved into an axonal pattern in four. Reversible conduction failure of sensitive nerves occurred in ASAN. Antiganglioside antibodies were only detected in axonal GBS. At 24-month follow-up, functional outcome did not differ between demyelinating and axonal GBS. Clinico-pathological correlation in an early fatal case is reported.

CONCLUSIONS

This GBS study demonstrates comparable clinical features to previous investigations from well-defined populations. There was a relatively high prevalence of axonal GBS. We provide new pathophysiological insights on nerve conduction alterations.

Acute lumbar polyradiculoneuropathy as early sign of methotrexate intrathecal neurotoxicity: Case report and literature review

Acute paraplegia after treatment with intrathecal methotrexate requires a complete spinal cord neuroimaging as well as electrodiagnostic examination. The absence of lumbosacral F waves motor responses without demyelinating findings may indicate early direct root toxicity. Early electromyography (EMG) screening could be a valuable tool for detecting peripheral neurotoxicity.

Indications for neuromuscular ultrasound: Expert opinion and review of the literature

Over the last two decades, dozens of applications have emerged for ultrasonography in neuromuscular disorders. We wanted to measure its impact on practice in laboratories where the technique is in frequent use. After identifying experts in neuromuscular ultrasound and electrodiagnosis, we assessed their use of ultrasonography for different indications and their expectations for its future evolution. We then identified the earliest papers to provide convincing evidence of the utility of ultrasound for particular indications and analyzed the relationship of their date of publication with expert usage. We found that experts use ultrasonography often for inflammatory, hereditary, traumatic, compressive and neoplastic neuropathies, and somewhat less often for neuronopathies and myopathies. Usage significantly correlated with the timing of key publications in the field. We review these findings and the extensive evidence supporting the value of neuromuscular ultrasound. Advancement of the field of clinical neurophysiology depends on widespread translation of these findings.

Serial electromyographic findings in Guillain-Barré syndrome patients

We sought to investigate electromyographic characteristics of Guillain-Barré syndrome (GBS) patients in the recovery phase by using serial electromyography (EMG). We included seven GBS patients and assessed their neurologic function at admission and 2, 3 and 6 months post onset using Hughes Functional Grading Scale scores. All patients underwent serial electromyographic assessment of compound muscle action potentials (CMAPs), mean conduction velocity (MCV), and distal motor latency (DML) of peripheral nerves. F wave was recorded of the median nerve and ulnar nerve. All seven patients had a Hughes Functional Grading Scale score between 3 and 6 at admission, while three patients at 2 months, one patient at 3 months, and no patient at 6 months post GBS onset had a Hughes Functional Grading Scale score between 3 and 6 ( P < 0.05). No F wave was elicited in 41.7% (20/48) of the motor nerves examined at admission, which declined to 25% at 6 months post GBS onset. Decreased amplitude in CMAPs was seen in 50% (24/48) of the motor nerves examined at admission, which decreased to 25% at 6 months ( P < 0.05). Moreover, 60.4% (29/48) of the motor nerves showed abnormal abduction velocity, which declined to 0% at 3 and 6 months post GBS onset ( P < 0.01). In conclusion, GBS patients exhibit a variable course in recovery of electromyographic parameters, and amplitude in CMAPs cannot fully reflect recovery of muscle tone. Conduction block is reversible and in line with rapid muscle tone recovery.

Early electrophysiological findings in Fisher-Bickerstaff syndrome

INTRODUCTION

The term Fisher-Bickerstaff syndrome (FBS) has been proposed to describe the clinical spectrum encompassing Miller-Fisher syndrome (MFS) and Bickerstaff brainstem encephalitis. The pathophysiology of FBS and the nature of the underlying neuropathy (demyelinating or axonal) are still subject to debate. This study describes the main findings of an early neurophysiological study on 12 patients diagnosed with FBS.

PATIENTS AND METHODS

Retrospective evaluation of clinical characteristics and electrophysiological findings of 12 patients with FBS seen in our neurology department within 10 days of disease onset. Follow-up electrophysiological studies were also evaluated, where available.

RESULTS

The most frequent electrophysiological finding, present in 5 (42%) patients, was reduced sensory nerve action potential (SNAP) amplitude in one or more nerves. Abnormalities were rarely found in motor neurography, with no signs of demyelination. The cranial nerve exam revealed abnormalities in 3 patients (facial neurography and/or blink reflex test). Three patients showed resolution of SNAP amplitude reduction in serial neurophysiological studies, suggesting the presence of reversible sensory nerve conduction block. Results from cranial MRI scans were normal in all patients.

CONCLUSION

An electrophysiological pattern of sensory axonal neuropathy, with no associated signs of demyelination, is an early finding of FBS. Early neurophysiological evaluation and follow-up are essential for diagnosing patients with FBS.

Proximal nerve lesions in early Guillain-Barré syndrome: implications for pathogenesis and disease classification

Guillain-Barré syndrome (GBS) is an acute-onset, immune-mediated disorder of the peripheral nervous system. In early GBS, arbitrarily established up to 10 days of disease onset, patients could exhibit selective manifestations due to involvement of the proximal nerves, including nerve roots, spinal nerves and plexuses. Such manifestations are proximal weakness, inaugural nerve trunk pain, and atypical electrophysiological patterns, which may lead to delayed diagnosis. The aim of this paper was to analyze the nosology of early GBS reviewing electrophysiological, autopsy and imaging studies, both in acute inflammatory demyelinating polyneuropathy (AIDP) and acute motor/motor-sensory axonal neuropathy (AMAN/AMSAN). Early electrophysiology showed either well-defined demyelinating or axonal patterns, or a non-diagnostic pattern with abnormal late responses; there may be attenuated M responses upon lumbar root stimulation as the only finding. Pathological changes predominated in proximal nerves, in some studies, most prominent at the sides where the spinal roots unite to form the spinal nerves; on very early GBS endoneurial inflammatory edema was the outstanding feature. In the far majority of cases, spinal magnetic resonance imaging showed contrast enhancement of cauda equina, selectively involving anterior roots in AMAN. Both in AIDP and AMAN/AMSAN, ultrasonography has demonstrated frequent enlargement of ventral rami of C5-C7 nerves with blurred boundaries, whereas sonograms of upper and lower extremity peripheral nerves exhibited variable and less frequent abnormalities. We provide new insights into the pathogenesis and classification of early GBS.

Diagnostic accuracy of neurophysiological criteria for early diagnosis of AIDP: A prospective study

OBJECTIVE

To assess the diagnostic accuracy of electrodiagnostic (EDX) criteria for the early detection and characterization of Guillain-Barré syndrome (GBS) in clinical practice.

METHODS

We conducted a prospective study in patients referred for an EDX exam with clinical suspicion of GBS. We evaluated four sets of neurophysiological criteria and four neurophysiological tests among those recently proposed for the early diagnosis of GBS.

RESULTS

We recruited 84 patients. Acute inflammatory demyelinating polyneuropathy (AIDP) was the final diagnosis in 23 patients. No axonal forms were found. The best sensitivity was obtained using Rajabally et al.'s criteria (82.1%), whereas the specificity was 90.0% for Ho et al.'s and Hadden et al.'s criteria and 100% for the Dutch GBS study group and Rajabally's criteria. Regarding the neurophysiological tests proposed for early diagnosis, the sensitivity ranged from 16.6 to 100%, whereas specificity ranged from 73.1 to 98.3%.

CONCLUSION

The Dutch GBS study group and Rajabally et al.'s criteria showed an optimal combination of sensitivity and specificity for clinical practice, although with a slightly higher sensitivity for Rajabally et al.'s criteria. None of the neurophysiological parameters recently proposed for early diagnosis have good diagnostic accuracy for clinical application.

SIGNIFICANCE

In a real clinical setting with patients referred by neurologists and emergency doctors, an EDX study performed within a week of symptom onset supports the diagnosis of AIDP in 82% of cases.

Early Electrodiagnostic Features of Upper Extremity Sensory Nerves Can Differentiate Axonal Guillain-Barré Syndrome from Acute Inflammatory Demyelinating Polyneuropathy

BACKGROUND AND PURPOSE

Serial nerve conduction studies (NCSs) are recommended for differentiating axonal and demyelinating Guillain-Barré syndrome (GBS), but this approach is not suitable for early diagnoses. This study was designed to identify possible NCS parameters for differentiating GBS subtypes.

METHODS

We retrospectively reviewed the medical records of 70 patients with GBS who underwent NCS within 10 days of symptom onset. Patients with axonal GBS and acute inflammatory demyelinating polyneuropathy (AIDP) were selected based on clinical characteristics and serial NCSs. An antiganglioside antibody study was used to increase the diagnostic certainty.

RESULTS

The amplitudes of median and ulnar nerve sensory nerve action potentials (SNAPs) were significantly smaller in the AIDP group than in the axonal-GBS group. Classification and regression-tree analysis revealed that the distal ulnar sensory nerve SNAP amplitude was the best predictor of axonal GBS.

CONCLUSIONS

Early upper extremity sensory NCS findings are helpful in differentiating axonal-GBS patients with antiganglioside antibodies from AIDP patients.

Ultrasonography of the peripheral nervous system in the early stage of Guillain-Barré syndrome

Ultrasonography can be used to visualize peripheral nerve abnormalities in immune-mediated neuropathies. The objective of this study was to prove the role of ultrasonography (US) in acute phase of Guillain-Barré syndrome (GBS). Systematic ultrasonic measurements of several peripheral nerves including the vagal nerve as well as the sixth cervical nerve root were performed in 18 patients with GBS at days 1-3 after symptom onset and compared to 21 healthy controls. Nerve conduction studies (NCS) of corresponding nerves were undertaken. Consequently, significant differences between the groups were found in compound muscle action potential amplitudes, F-wave latency, and persistency. Ultrasonic cross-sectional areas (CSAs) showed significant enlargement in all nerves except of the ulnar nerve (upper arm) and the sural nerve compared to healthy controls, most prominent in proximal and middle median nerve (p < 0.01). The vagal nerve also showed enlargement compared to controls (p < 0.05), which was most pronounced in patients with autonomic dysfunction compared to patients without (p < 0.05). C6 root diameter showed a significant correlation to the amount of cerebrospinal fluid (CSF)-protein (Pearson correlation, p < 0.05). US shows nerve enlargement in several peripheral nerves including vagal nerve and C6 root in acute phase of GBS and could be an additional diagnostic tool for example, in GBS of atypical onset and autonomic dysfunction.

Nerve ultrasound in Miller Fisher variant of Guillain-Barré syndrome

INTRODUCTION

Focal enlargement of the peripheral and spinal nerves, visualized using high-resolution ultrasound (HRUS), has been reported in early Guillain-Barré syndrome, but not in the Miller Fisher variant. We report the use of HRUS in 2 patients who presented with acute ataxic neuropathy, areflexia, and ophthalmoparesis.

METHODS

Ultrasound and/or nerve conduction studies (NCS) of peripheral nerves, the vagus, and spinal nerves C5/6 were performed at onset and 2 weeks after immunoglobulin therapy.

RESULTS

Both patients fulfilled criteria for diagnosis of Miller Fisher syndrome (MFS). Laboratory findings revealed elevated ganglioside Q1b antibodies in both and an albuminolocytologic dissociation in 1 patient. In addition, 1 patient had NCS evidence for demyelinating neuropathy. However, ultrasound showed focal enlargement in the vagus, the spinal nerves, and/or in the peripheral nerves in both patients. After therapy, nerve enlargement decreased in parallel with clinical improvement.

CONCLUSION

Spinal and/or peripheral nerve enlargement supports the diagnosis of MFS in early phases of the disease.

Ultrasound and electrophysiologic findings in patients with Guillain-Barré syndrome at disease onset and over a period of six months

OBJECTIVE

To investigate cross-sectional areas (CSAs) of several peripheral nerves including the vagus nerve and the diameter of spinal nerves as measured by nerve ultrasound (NUS) and nerve conduction studies (NCS) in Guillain-Barré syndrome (GBS) patients over at least six months compared to healthy controls.

METHODS

NUS and/or NCS of several nerves, the vagus nerve, and the 5th/6th cervical spinal nerves were performed in patients with GBS at days 2-3 after symptom onset, at days 10-14 after immunoglobulin therapy and after six months compared to healthy controls.

RESULTS

27 GBS-patients and 31 controls were included. Using NUS significant enlargement was found in all measured nerves (P<0.001), except the sural nerve (P=0.086) compared to the controls at onset. The vagus (median 3.0 mm(2) vs. 2.0 mm(2), P<0.0001) and the cervical spinal nerves were significantly enlarged (median 3.5/4.0 mm vs. 2.6/3.2 mm, p<0.0001), the vagus most obviously in patients with autonomic dysregulation (AD, 4.0 mm(2)). Six months later, NCS showed persisting pathology in CMAP-amplitudes with amelioration of F-wave pathology. NUS showed restitution in the spinal nerves (median 2.6/3.2 mm) and the vagus (median 2.0 mm(2)) in all patients excluding the vagus in those with persistent AD (median 4.0 mm(2)). The peripheral nerves did not change significantly (P>0.05).

CONCLUSION

Ultrasonographic detection of cervical spinal nerve enlargement supports the diagnosis of GBS in the early phase. Its regression may be a good parameter for the clinical restitution over time. Vagus enlargement may be a risk marker for development of AD.

SIGNIFICANCE

Ultrasound is a reliable diagnostic follow-up tool in early GBS.

Sural sparing pattern discriminates Guillain-Barré syndrome from its mimics

INTRODUCTION

Electrodiagnostic features of demyelination are essential for establishing the diagnosis in demyelinating subtypes of Guillain-Barré syndrome (GBS), but they may also occur in disorders that mimic GBS clinically. Information about their frequency in GBS mimics is sparse.

METHODS

Evaluation of electrodiagnostic features from 38 patients with suspected GBS in whom the diagnosis was later refuted (GBS mimics). Their diagnostic accuracy was analyzed by comparison with nerve conduction studies (NCS) from 73 confirmed GBS patients.

RESULTS

Disorders that mimicked GBS clinically at the time of hospital admission included other inflammatory, metabolic, toxic, or infectious neuropathies and spinal cord disorders. The sural sparing pattern was the most specific electrodiagnostic feature for demyelinating GBS.

CONCLUSIONS

Common electrodiagnostic abnormalities in early demyelinating GBS do not usually exclude other rare differential diagnoses. An exception to this is the sural sparing pattern described here, which strongly supports the diagnosis of demyelinating GBS.

Spinal nerve involvement in early Guillain-Barré syndrome: a clinico-electrophysiological, ultrasonographic and pathological study

OBJECTIVE

Although prevailing spinal nerve involvement has been recognized in a few detailed Guillain-Barré syndrome (GBS) autopsy reports, imaging studies addressing this question in cervical nerves are lacking.

METHODS

We describe clinical, electrophysiological, ultrasonographic (US) and pathological findings in six consecutive early GBS patients, evaluated within 10 days of onset.

RESULTS

Patients' ages ranged from 37 to 80 years. Five patients required mechanical ventilation, two of them having died 9 and 28 days after onset. Upper- and lower-limb nerve US showed abnormal findings in just 8.8% of scanned peripheral nerves. In comparison with 46 aged-matched control subjects, US of the fifth to seventh cervical nerves showed changes in four cases, which consisted of significant nerve enlargement, blurred boundaries of the corresponding ventral rami, or both. Autopsy study in one case demonstrated that pathology, consisting of demyelination and endoneurial inflammatory oedema, mainly involved cervical and lumbar nerves.

CONCLUSIONS

In early GBS inflammatory oedema of spinal nerves is a pathogenically relevant feature to understanding the mechanism of ascending paralysis, particularly when conventional electrophysiological studies are normal or not diagnostic.

SIGNIFICANCE

Findings advocate the use of cervical nerve US in early GBS.

Electrophysiological measurement at Erb's point during the early stage of Guillain-Barré syndrome

This study aimed to find the electrophysiological significance of proximal nerve stimulation at Erb's point during the early stage of Guillain-Barré syndrome (GBS). Twenty-one healthy volunteers and 13 patients within the first week of GBS were studied. Latency and amplitude at wrist, elbow and Erb's point, and F waves were calculated after compound muscle action potentials (CMAP) were obtained at the median and ulnar nerve. There were statistically significant differences between groups for CMAP latency and amplitude at Erb's point for the median (p=0.005 and 0.001, respectively) and ulnar nerves (p=0.007 and 0.007, respectively). Latency or amplitude of CMAP after Erb's point stimulation was abnormal in 77% of patients while F wave latency was abnormal in only 46% of patients. Conduction block was observed in 62% of patients. Abnormal parameters at Erb's point were the only abnormality in four patients at the first electrophysiological examination. We conclude that electrophysiological examination at Erb's point is a simple and non-invasive method that can be used in the early stage of GBS, especially for patients who exhibit normal F waves and nerve conduction studies at distal nerves.

Evaluation of the child with acute ataxia: a systematic review

Evaluation of acute ataxia in a child poses a dilemma for the clinician in determining the extent and timing of initial screening tests. This article reviews the evidence concerning the diagnostic yield of commonly ordered tests in evaluating the child with acute ataxia. The literature revealed the following frequencies of laboratory screening abnormalities in children with acute ataxia: CT (∼2.5%), MRI (∼5%), lumbar puncture (43%), EEG (42%), and toxicology (49%). In most studies, abnormalities detected by these screening tests were nondiagnostic. There are insufficient data to assess yields of testing for autoimmune disorders or inborn errors of metabolism. A toxicology screen should be considered in all children presenting with acute ataxia. Neuroimaging should be considered in all children with new onset ataxia. Cerebrospinal fluid analysis has limited diagnostic specificity unless clinically indicated. Studies to examine neurophysiology testing did have sufficient evidence to support their use. There is insufficient evidence to establish a role for autoantibody testing or for routine screening for inborn error of metabolism in children presenting with acute ataxia. Finally, in a child presenting with ataxia and opsoclonus myoclonus, urine catecholamine testing for occult neuroblastoma is recommended. Nuclear scan may be considered, however, there is insufficient evidence for additional body imaging.

Muscle MRI in severe Guillain-Barré syndrome with motor nerve inexcitability

We report on the clinical, electrophysiological, and lower-limb musculature MRI findings in a severe demyelinating Guillain-Barré syndrome (GBS) patient with follow-up over 6 months. After 3 weeks of tetraplegia and mechanical ventilation, there was progressive improvement until almost complete recovery. On day 4 after onset, electrophysiological study revealed absent F waves and widespread conduction block. On four further electrophysiological studies on days 12, 19, 45, and 150, there was marked and reversible slow down of motor conduction velocities in upper-limb nerves, and persistent inexcitability of lower-limb nerves. Mild signs of active denervation were recorded in calf and foot muscles as of day 45. On day 39, MRI T2-weighted fat-suppressed images showed patchy hypersignal of variable intensity involving pelvic, thigh, and calf muscles, which disappeared in a second imaging study on day 190; in this study T1-weighted images did not disclose muscle fatty atrophy. We conclude that in severe demyelinating GBS prolonged motor nerve inexcitability should not necessarily be taken as a predictor of poor prognosis, and that MRI is useful in assessing the topography and evolution of muscle denervation.

[Electromyography (EMG) and neurography in patients with severe neuromuscular diseases]

BACKGROUND

Many neuromuscular diseases are potentially severe, and EMG and neurography are methods used in the assessment of these conditions.

METHOD

The article is based on the authors' knowledge and experience, with special emphasis on the use of these methods in the assessment of severe diseases affecting striated muscle and peripheral nerves. A PubMed search was performed with the cut-off fifteen years back in time, and in addition a discretionary selection was made of articles known to the authors.

RESULTS

EMG is the most valuable method for assessing myopathy, and neurography provides most information about neuropathy, but the methods are complementary. These examinations are the most sensitive for diagnosing some conditions (for example myasthaenia) A high level of expertise is necessary for diagnosing these conditions.

INTERPRETATION

EMG and neurography are important and often necessary means of assessing patients with severe neuromuscular disease.