Optimizing the electrodiagnostic accuracy in Guillain-Barré syndrome subtypes: Criteria sets and sparse linear discriminant analysis

Effect of intravenous immunoglobulin and plasmapheresis on nerve conduction parameters compared to the natural course of Guillain-Barré syndrome

BACKGROUND

Intravenous immunoglobulin (IVIg) and plasmapheresis (PLEX) are recommended in moderate to severe Guillain-Barré Syndrome (GBS), but there is paucity of studies evaluating its effect on nerve conduction studies (NCS). We report the effect of IVIg and PLEX on the NCS parameters and clinical outcomes compared to natural course (NC) of GBS patients.

METHOD

Moderate to severe GBS patients were included based on clinical, cerebrospinal fluid, and NCS finding. Six motor and sensory nerves were evaluated at admission, one month and 3 months, and NCS subtyping was done. Axonal and demyelination burden in motor nerves and early reversible conduction block (ERCB) were noted. Patients receiving IVIg, PLEX or on NC were noted. Outcome was defined at 3 months into complete, partial and poor using a 0-6 GBS Disability Scale (GBSDS).

RESULT

Seventy-two patients were included, whose median age was 36 years and 22(30.6 %) were females. 44 patients received IVIg, 9 PLEX and 19 were in NC, and they had comparable peak disability. AIDP was the dominant subtype at admission (58.3 %), which remained so at 3 months (50 %). The shift of subtypes was the highest from the equivocal group followed by AMAN and the least from AIDP. IVIg and PLEX group had more reduction in axonal burden and had ERCB compared to NC. 33(44 %) patients had complete recovery, and 40(55.5 %) patients had concordance in clinical and neurophysiological outcome.

CONCLUSION

Transition of GBS subtype may occur at follow-up from all the subtypes, the highest from the equivocal and the lowest from the AIDP group. IVIg/PLEX treatment may help in reducing conduction block and axonal burden.

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.

Conduction slowing, conduction block and temporal dispersion in demyelinating, dysmyelinating and axonal neuropathies: Electrophysiology meets pathology

Nerve conduction studies are usually the first diagnostic step in peripheral nerve disorders and their results are the basis for planning further investigations. However, there are some commonplaces in the interpretation of electrodiagnostic findings in peripheral neuropathies that, although useful in the everyday practice, may be misleading: (1) conduction block and abnormal temporal dispersion are distinctive features of acquired demyelinating disorders; (2) hereditary neuropathies are characterized by uniform slowing of conduction velocity; (3) axonal neuropathies are simply diagnosed by reduced amplitude of motor and sensory nerve action potentials with normal or slightly slow conduction velocity. In this review, we reappraise the occurrence of uniform and non-uniform conduction velocity slowing, conduction block and temporal dispersion in demyelinating, dysmyelinating and axonal neuropathies attempting, with a translational approach, a correlation between electrophysiological and pathological features as derived from sensory nerve biopsy in patients and animal models. Additionally, we provide some hints to navigate in this complex field.

Guillain-Barré syndrome after surgery: a literature review

Guillain-Barré syndrome (GBS) is a rare postoperative complication that is sometimes characterized by serious motor weakness and prolonged weaning from mechanical ventilation. Although the exact nature of the relationship between GBS and the surgical procedure is still unclear, there is a clear increased incidence of GBS in post-surgical patients compared to non-surgical patients. GBS after surgery is unique in several ways. The course of post-surgical GBS unfolds more rapidly than in other situations where GBS develops, the condition is often more severe, and respiratory muscles are more commonly involved. Prompt diagnosis and appropriate treatment are essential, and the condition can worsen if treated inappropriately. Postoperative sedation, intubation, and restraint use make the diagnosis of GBS difficult, as the onset of symptoms of weakness or numbness in those contexts are not obvious. GBS is often misdiagnosed, being attributed to other postoperative complications, and subsequently mishandled. The lack of relevant information further obscures the clinical picture. We sought to better understand post-surgical GBS by performing an analysis of the relevant literature, focusing on clearly documenting the clinical characteristics, diagnosis, and management of GBS that emerges following surgery. We underscore the importance of physicians being aware of the possibility of GBS after major surgery and of performing a variety of laboratory clinical investigations early on in suspected cases.

The sural-sparing pattern in clinical variants and electrophysiological subtypes of Guillain-Barré syndrome

BACKGROUND

 Guillain-Barré syndrome (GBS) is the most common cause of acute flaccid paralysis worldwide and can be classified into electrophysiological subtypes and clinical variants.

OBJECTIVE

 This study aimed to compare the frequency of the sural-sparing pattern (SSP) in subtypes and variants of GBS.

METHODS

 This retrospective cohort study analyzed clinical and electrophysiological data of 171 patients with GBS hospitalized in public and private hospitals of Natal, Rio Grande do Norte, Brazil, between 1994 and 2018; all cases were followed up by the same neurologist in a reference neurology center. Patients were classified according to electrophysiological subtypes and clinical variants, and the SSP frequency was compared in both categories. The exact Fisher test and Bonferroni correction were used for statistical analysis.

RESULTS

 The SSP was present in 53% (57 of 107) of the patients with acute inflammatory demyelinating polyradiculoneuropathy (AIDP), 8% (4 of 48) of the patients with axonal subtypes, and 31% (5 of 16) of the equivocal cases. The SSP frequency in the AIDP was significantly higher than in the axonal subtypes (p < 0.0001); the value was kept high after serial electrophysiological examinations. Only the paraparetic subtype did not present SSP.

CONCLUSION

 The SSP may be present in AIDP and axonal subtypes, including acute motor axonal neuropathy, but it is significantly more present in AIDP. Moreover, the clinical variants reflect a specific pathological process and are correlated to its typical electrophysiological subtype, affecting the SSP frequency.

Clinical characteristics of Guillain-Barré syndrome in patients with primary Sjögren's syndrome

To investigate the clinical characteristics of Guillain-Barré syndrome (GBS) in patients with primary Sjögren's syndrome (SS). Records of patients with positive anti-SSA antibodies hospitalized in the Beijing Tiantan Hospital between December 2011 and May 2020 were retrieved. Patients who fulfilled the criteria for diagnosis of GBS and primary SS were included, and their clinical data were analyzed. Among the 785 patients with positive anti-SSA, 52 patients were identified in this study. They were 27 males and 25 females with median age of 59 years old. Besides anti-SSA antibodies, multiple autoantibodies were detected in these patients including antinuclear antibody, anti-Ro52, anti-mitochondrial M2, anti-thyroid peroxidase and anti-thyroglobulin autoantibodies. Preceding infection was reported in 42 patients. Hyporeflexia/areflexia and limbs weakness were the most common manifestation and 35 patients presented cranial nerve injuries. GBS disability score of 3, 4 and 5 was scaled in 28 (53.8%), 15 (28.8%) and 3 (5.8%) patients respectively. Forty-six patients received intravenous immunoglobulin (IVIG) monotherapy, 5 patients were treated by IVIG plus glucocorticoids, and 51 patients improved during hospitalization. The frequency of male gender among the patients with both GBS and primary SS suggests an independent onset of GBS and the co-existence of these autoimmune diseases in patients with multiple autoantibodies. Majority of patients with GBS and primary SS experience benign disease course.

Electrodiagnostic methods to verify Guillain-Barré syndrome subtypes in Istanbul: A prospective multicenter study

BACKGROUND AND AIMS

This study aimed to identify the clinical characteristics and electrodiagnostic subtypes of Guillain-Barré syndrome (GBS) in Istanbul.

METHODS

Patients with GBS were prospectively recruited between April 2019 and March 2022 and two electrodiagnostic examinations were performed on each patient. The criteria of Ho et al., Hadden et al., Rajabally et al., and Uncini et al. were compared for the differentiation of demyelinating and axonal subtypes, and their relations with anti-ganglioside antibodies were analyzed.

RESULTS

One hundred seventy-seven patients were included, 69 before the coronavirus disease 2019 pandemic (April 2019-February 2020) and 108 during the pandemic (March 2020-March 2022), without substantial changes in monthly frequencies. As compared with the criteria of Uncini et al., demyelinating GBS subtype diagnosis was more frequent according to the Ho et al. and Hadden et al. criteria (95/162, 58.6% vs. 110/174, 63.2% and 121/174, 69.5%, respectively), and less frequent according to Rajabally et al.'s criteria (76/174, 43.7%). Fourteen patients' diagnoses made using Rajabally et al.'s criteria were shifted to the other subtype with the second electrodiagnostic examination. Of the 106 analyzed patients, 22 had immunoglobulin G anti-ganglioside antibodies (14 with the axonal subtype). They had less frequent sensory symptoms (54.5% vs. 83.1%, p = 0.009), a more frequent history of previous gastroenteritis (54.5% vs. 22.9%, p = 0.007), and a more severe disease as compared with those without antibodies.

INTERPRETATION

Serial electrodiagnostic examinations are more helpful for accurate subtype diagnosis of GBS because of the dynamic pathophysiology of the disease. We observed no significant increase in GBS frequency during the pandemic in this metropolis.

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.

Reversible cerebral vasoconstriction syndrome in Guillain-Barre syndrome: a case report and literature review

BACKGROUND

Reversible cerebral vasoconstriction syndrome (RCVS) is characterized by transient constriction of cerebral arteries, leading to severe headache and potential complications. The association between RCVS and Guillain-Barre syndrome (GBS) is rare and poorly understood and warrants further investigation.

METHODS

A detailed case of RCVS in a patient with GBS was presented, followed by a comprehensive literature review. PubMed, Embase, and Google Scholar were searched for relevant cases and studies.

RESULTS

The case involved a 62-year-old woman with GBS who developed RCVS. The literature review identified three additional reported cases. RCVS in GBS primarily affected middle-aged women and presented with a variety of neurological symptoms. Neuroimaging showed reversible vasoconstriction in the cerebral arteries, along with other complications such as posterior reversible encephalopathy syndrome, subarachnoid hemorrhage, and infarcts. While the treatment for GBS consisted mainly of intravenous immunoglobulin, specific treatments for RCVS remain unclear.

CONCLUSIONS

The coexistence of RCVS and GBS is a rare occurrence. RCVS in GBS may result from the disruption of cerebral vascular tone regulation, possibly influenced by GBS-related dysautonomia and consequent high blood pressure. Recognizing RCVS in GBS patients is critical for appropriate management.

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.

Dose-Effect Relationship of Motor Nerve Inexcitability on Outcome in Guillain-Barré Syndrome: A Prospective Cohort Study

Objective

One or more inexcitable motor (IM) nerves are common during electrodiagnostic (EDx) study in Guillain-Barré syndrome (GBS). This study assessed the dose-effect relationship of IM nerves on outcome in patients with acute inflammatory demyelinating polyneuropathy (AIDP) and acute motor and/or sensory axonal neuropathy (AMAN and AMSAN).

Materials and Methods

Eighty-eight GBS patients admitted during May 2018-June 2023 underwent detailed clinical evaluation and EDx study. Admission and follow-up disability were assessed on a 0-10 Clinical Grading Scale (CGS). Outcome was recovery at 6 months, defined as good (CGS <3) and poor (CGS ≥3). Binary multivariate logistic regression with backward elimination was used to calculate independent predictors of outcome.

Results

Proportion of patients with complete recovery decreased significantly with increasing numbers of IM nerves (P < 0.01). Seventy-six patients were followed for 6 months. Among patients with IM nerves (n = 28), complete recovery was similar between AIDP and axonal GBS (70% vs. 50%, respectively; P = 0.40). However, in patients with recordable compound muscle action potentials (CMAPs) in all the motor nerves (n = 26), axonal GBS had significantly poor recovery compared to AIDP (75% vs. 9.1%; P = 0.01). Among patients receiving intravenous immunoglobulin (IVIg; n = 42), poor recovery was seen in 53.6% with IM nerves compared to 35.7% without (P = 0.28), while it was 37.5% versus 5.6% (P = 0.04), respectively, in those who did not receive IVIg (n = 34). However, only admission disability (odds ratio [OR] 0.88, 95% confidence interval [CI] 0.81-0.97; P = 0.007) was found to be an independent predictor of outcome.

Conclusion

Although increasing numbers of IM nerves were associated with poor outcome on univariate analysis, they did not predict 6 months' outcome independently. Outcome did not differ between axonal GBS and AIDP among those with IM nerves. IVIg improved outcome in patients with IM nerves.

Guillain-Barré Syndrome

OBJECTIVE

This article summarizes the clinical features, diagnostic criteria, differential diagnosis, pathogenesis, and prognosis of Guillain-Barré syndrome (GBS), with insights into the current and future diagnostic and therapeutic interventions for this neuromuscular syndrome.

LATEST DEVELOPMENTS

GBS is an acute, inflammatory, immune-mediated polyradiculoneuropathy that encompasses many clinical variants and divergent pathogenic mechanisms that lead to axonal, demyelinating, or mixed findings on electrodiagnostic studies. The type of antecedent infection, the development of pathogenic cross-reactive antibodies via molecular mimicry, and the location of the target gangliosides affect the subtype and severity of the illness. The data from the International GBS Outcome Study have highlighted regional variances, provided new and internationally validated prognosis tools that are beneficial for counseling, and introduced a platform for discussion of GBS-related open questions. New research has been undertaken, including research on novel diagnostic and therapeutic biomarkers, which may lead to new therapies.

ESSENTIAL POINTS

GBS is among the most frequent life-threatening neuromuscular emergencies in the world. At least 20% of patients with GBS have a poor prognosis and significant residual deficits despite receiving available treatments. Research is ongoing to further understand the pathogenesis of the disorder, find new biomarkers, and develop more effective and specific treatments.

Disability evaluation in patients with Guillain-Barre syndrome and SARS-CoV-2 infection

Objective

Several cases of Guillain-Barre syndrome (GBS) associated with SARS-CoV-2 infection have been described. This study illustrated the demographic, clinical, and neurophysiological characteristics of patients with GBS and COVID-19, as well as associated factors with disability at discharge.

Materials and methods

A retrospective analytical observational study was conducted. It included patients diagnosed with GBS admitted in a national reference center in Peru between 2019 and 2021. Epidemiological, clinical, neurophysiological, and cerebrospinal fluid data were analyzed. A multivariate analysis, using the generalized linear model, was performed, considering the presence of disability at discharge as the dependent variable.

Results

Eight-one subjects diagnosed with GBS were included. The mean age was 46.8 years (SD: 15.2), with a predominance of males (61.73%). The most frequent clinical presentation was the classic sensory-motor form in 74 cases (91.36%) with AIDP (82.35%) as the most frequent neurophysiological pattern in the group with COVID-19, while AMAN pattern predominated (59.26%) in those without COVID-19 (p = <0.000). The disability prevalence ratio at discharge between subjects with COVID-19 and those without COVID-19 was 1.89 (CI 1.06-3.34), p = 0.030, adjusted for age, sex, and neurophysiological subtype.

Conclusion

The neurophysiologic subtype AIDP, and a higher disability were associated with the presence of COVID-19.

Guillain-Barre Syndrome Followed by Covid-19 Infection, Vaccination and Other Precipitating Factors during the Pandemic

Background and Aims

Guillain-Barré syndrome (GBS) is usually triggered by an infection. Vaccination is mentioned as a possible trigger in a small number of GBS cases. The aim of this study was to notice GBS distinctness provoked by various triggers during the COVID-19 pandemic.

Material and Methods

A total of 109 GBS patients were divided into three groups, respectively: COVID-19 infection associated (19 patients), COVID-19 vaccination associated (16 patients) and precipitated by some other factors (74 patients). We compared the clinical, neurophysiological and laboratory characteristics of these three groups.

Results

Neither were differences recorded in the age of the patients of these three groups at the time of illness, nor in the number of days from the precipitating factor to the onset of symptoms. There were no clinical differences between groups related to severity of the disease or patients' recovery. The only clinical difference was observed in relation to facial nerve bilateral affection because it was significantly higher in the post-vaccination group. According to neurophysiological findings, demyelinating form dominated in all three groups.

Conclusion

Clinical characteristics, electrophysiological findings and laboratory characteristics did not differ significantly in Guillain-Barre syndrome followed by COVID-19 infection, vaccination and other precipitating factors during the pandemic. The bilateral involvement of facial nerves was significantly higher in the post-vaccination group. Most of these cases had a mild form of the disorder-distal paresthesias GBS variant.

Nerve Ultrasound Score in Chronic Inflammatory Demyelinating Polyneuropathy

Background and Objectives: Studies have suggested that, by applying certain nerve ultrasound scores, demyelinating and axonal polyneuropathies can be differentiated. In the current study, we investigated the utility of ultrasound pattern sub-score A (UPSA) and intra- and internerve cross-sectional area (CSA) variability in the diagnostic evaluation of demyelinating neuropathies. Materials and Methods: Nerve ultrasound was performed in patients with chronic inflammatory demyelinating polyneuropathy (CIDP) and acute inflammatory demyelinating polyneuropathy (AIDP) and compared to patients with axonal neuropathies. The UPSA, i.e., the sum of ultrasound scores at eight predefined measurement points in the median (forearm, elbow and mid-arm), ulnar (forearm and mid-arm), tibial (popliteal fossa and ankle) and fibular (lateral popliteal fossa) nerves, was applied. Intra- and internerve CSA variability were defined as maximal CSA/minimal CSA for each nerve and each subject, respectively. Results: A total of 34 CIDP, 15 AIDP and 16 axonal neuropathies (including eight axonal Guillain-Barré syndrome (GBS), four hereditary transthyretin amyloidosis, three diabetic polyneuropathy and one vasculitic neuropathy) were included. A total of 30 age- and sex-matched healthy controls were recruited for comparison. Significantly enlarged nerve CSA was observed in CIDP and AIDP with significantly higher UPSA in CIDP compared to the other groups (9.9 ± 2.9 vs. 5.9 ± 2.0 vs. 4.6 ± 1.9 in AIDP vs. axonal neuropathies, p < 0.001). A total of 89.3% of the patients with CIDP had an UPSA score ≥7 compared to the patients with AIDP (33.3%) and axonal neuropathies (25.0%) (p < 0.001). Using this cut-off, the performance of UPSA in differentiating CIDP from other neuropathies including AIDP was excellent (area under the curve of 0.943) with high sensitivity (89.3%), specificity (85.2%) and positive predictive value (73.5%). There were no significant differences in intra- and internerve CSA variability between the three groups. Conclusion: The UPSA ultrasound score was useful in distinguishing CIDP from other neuropathies compared to nerve CSA alone.

Association between hyperCKemia and axonal degeneration in Guillain-Barré syndrome

BACKGROUND

Elevated serum creatine kinase (CK) levels have been reported in patients with Guillain-Barré syndrome (GBS), more frequently in patients with acute motor axonal neuropathy (AMAN) than in those with acute inflammatory demyelinating polyneuropathy (AIDP). However, some patients with AMAN show reversible conduction failure (RCF), characterized by rapid recovery without axonal degeneration. The present study tested the hypothesis that hyperCKemia is associated with axonal degeneration in GBS, regardless of the subtype.

METHODS

We retrospectively enrolled 54 patients with AIDP or AMAN whose serum CK levels were measured within 4 weeks from symptom onset between January 2011 and January 2021. We divided them into hyperCKemia (serum CK ≥ 200 IU/L) and normal CK (serum CK < 200 IU/L) groups. Patients were further classified into axonal degeneration and RCF groups based on more than two nerve conduction studies. The clinical features and frequency of axonal degeneration and RCF were compared between groups.

RESULTS

Clinical characteristics were similar in the hyperCKemia and normal CK groups. Compared with that in the RCF subgroup, the frequency of hyperCKemia was significantly higher in the axonal degeneration group (p = 0.007). Patients with normal serum CK levels showed better clinical prognosis, evaluated by the Hughes score at 6 months from admission (p = 0.037).

CONCLUSION

HyperCKemia is associated with axonal degeneration in GBS, regardless of the electrophysiological subtype. HyperCKemia within 4 weeks from symptom onset might be a marker of axonal degeneration and poor prognosis in GBS. Serial nerve conduction studies and serum CK measurements will help clinicians understand the pathophysiology of GBS.

Identical late motor responses in early Guillain-Barré syndrome: A-waves and repeater F-waves

Electrodiagnostic (EDx) studies play a key role in the investigation of suspected Guillain-Barré syndrome (GBS), providing diagnostic and prognostic information. However, initial EDx findings may not fulfill the neurophysiological criteria for the disease. The aim of this study was to estimate the occurrence and characteristics of A-waves and repeaters F-waves (Freps), both late motor responses identical in latency and configuration, in early stages of GBS. We retrospectively analyzed the initial nerve conduction study (NCS) of 26 GBS patients performed within 10 days from symptom onset. The final subtype diagnosis was acute inflammatory demyelinating polyneuropathy (AIDP) in 16 patients (six met the criteria at the initial EDx study and 10 at follow-up) and acute motor axonal neuropathy (AMAN) in 10 patients (six initially). Identical late responses were commonly found in the majority of nerves (84%). A-waves were present in 59% and an increased frequency of Freps was calculated in 61% of the 105 studied nerves. A-waves morphology (single or complex) could not distinguish between AIDP and AMAN. Nerves with normal NCS had a significantly higher frequency of A-waves, either isolated or in combination with increased index total Freps, as compared to nerves with low compound muscle action potential (CMAP) amplitudes or conduction block. Our findings suggest that both late responses can be useful as early markers of conduction changes of various pathophysiology, being frequently present even prior to abnormalities of CMAP parameters.

Immunological, Clinical, and Epidemiological Features of Guillain-Barré Syndrome Associated with SARS-CoV-2 Infection

Objectives. There is a growing interest in understanding the association between Guillain-Barré syndrome (GBS) and SARS-CoV-2 infection. The aim of this study was to analyse various characteristics of GBS before and after the pandemic outbreak and thus identify possible distinctive features of GBS associated with SARS-CoV-2 (GBS-S). Material and Methods. In our centre, we retrospectively reviewed the records of patients diagnosed with GBS between January 2018 and March 2022. Epidemiological, clinical, and immunological data were analysed and compared between patients with GBS according to the time of diagnosis and antecedent events. Results. Thirty-nine patients with GBS were included: nine (23.1%) were diagnosed with GBS-S. GBS-S was most frequent in 2020 (6/13, 46.1%). Most of these patients developed a postinfectious classic demyelinating variant (4/9, 44.4%) with frequent bilateral facial paralysis (4/9, 44.4%). Serum antiganglioside antibodies (AGAs) were found in 1/9 patients with GBS-S. Serum anti-SSA/Ro60 antibodies were highly prevalent in GBS-S (7/9 (77.8%) vs. 3/11 (27.3%), $p=0.019$ ). Three cases associated with SARS-CoV-2 vaccination (GBS-V) were detected. Of note, two had bilateral facial paralysis and anti-SSA/Ro60 antibodies. Conclusion. Our findings suggest that SARS-CoV-2 has become an important antecedent event associated with GBS in our setting. GBS-S shows a postinfectious demyelinating immune-mediated profile with negative serological testing for AGAs. Serum anti-SSA/Ro60 antibodies were found frequently in these patients. Bilateral facial paralysis stands out as a possible characteristic clinical feature both in GBS-S and GBS-V. Larger, prospective studies are needed for a better understanding of its immunopathogenesis.

Characteristic cerebrospinal fluid findings in immune checkpoint inhibitor-related peripheral neuropathy: A case report

Although immune checkpoint inhibitors (ICIs) are widely used to treat unresectable malignant tumors, they can cause undesirable side effects called immune-related adverse events, including neurological toxicities. Here, we describe a case of ICI-related peripheral neuropathy (irPN) with characteristic cerebrospinal fluid (CSF) findings. In addition to pleocytosis and increased protein levels, the present case showed increased levels of CSF soluble interleukin-2 receptor (sIL-2R), IL-6, and IL-10, suggesting activated T cell-related autoimmunity. We believe that CSF cytokines and sIL-2R could be novel biomarkers of irPN.

[Guillain-Barre syndrome in children]

Guillain-Barré syndrome (GBS) is an immune-mediated disease of the peripheral nervous system that can occur in both children and adults. The classic presentation of GBS is characterized by progressive symmetrical, ascending muscle weakness. Patients with GBS require meticulous monitoring due to the risk of bulbar syndrome, respiratory failure and autonomic dysfunction, which can be life-threatening. Early diagnosis and timely prescription of pathogenetic therapy for GBS are particularly important, especially in young children. Meanwhile, the spectrum of disorders covered by GBS has expanded significantly; its eponym is now designate any variant of acute dysimmune polyneuropathy, and its atypical forms pose a serious diagnostic problem for clinicians. This review article provides an analysis of the data available in the medical literature on GBS in children and discusses the tactics for diagnosing and managing patients with GBS, taking into account the Russian and European clinical recommendations.

Critical illness-associated weakness and related motor disorders

Weakness of limb and respiratory muscles that occurs in the course of critical illness has become an increasingly common and serious complication of adult and pediatric intensive care unit patients and a cause of prolonged ventilatory support, morbidity, and prolonged hospitalization. Two motor disorders that occur singly or together, namely critical illness polyneuropathy and critical illness myopathy, cause weakness of limb and of breathing muscles, making it difficult to be weaned from ventilatory support, commencing rehabilitation, and extending the length of stay in the intensive care unit, with higher rates of morbidity and mortality. Recovery can take weeks or months and in severe cases, and may be incomplete or absent. Recent findings suggest an improved prognosis of critical illness myopathy compared to polyneuropathy. Prevention and treatment are therefore very important. Its management requires an integrated team approach commencing with neurologic consultation, creatine kinase (CK) measurement, detailed electrodiagnostic, respiratory and neuroimaging studies, and potentially muscle biopsy to elucidate the etiopathogenesis of the weakness in the peripheral and/or central nervous system, for which there may be a variety of causes. These tenets of care are being applied to new cases and survivors of the coronavirus-2 disease pandemic of 2019. This chapter provides an update to the understanding and approach to critical illness motor disorders.

Reversible conduction failure in acute inflammatory demyelinating polyneuropathy

Reversible conduction failure (RCF) has been documented in acute motor axonal neuropathy (AMAN) and is considered a sign of nodopathy. Several reports of RCF in acute inflammatory demyelinating polyneuropathy (AIDP) have suggested that it could be a manifestation of nodopathy. We conducted this study to determine the frequency of RCF in AMAN and AIDP and to compare the clinical features between the two groups with or without RCF. RCF was observed in 38.9% and 18.5% patients in the AMAN and AIDP groups in our study, respectively. AIDP patients with anti-ganglioside antibodies represented 29.4% of the cohort. The clinical features of AIDP with RCF were more similar to those of AMAN with RCF than to those of typical AIDP. However, there were no significant differences in the frequency of anti-ganglioside antibody status between the groups. AIDP with RCF may be a manifestation of nodopathy. The current dichotomous electrodiagnostic criteria, classifying demyelinating and axonal neuropathy, are insufficient to define nodopathy. Further studies are required to revise the electrodiagnostic criteria for Guillain-Barré syndrome.

[Very-early and early neuroelectrophysiological features of childhood Guillain-Barré syndrome]

OBJECTIVES

To study the very-early and early neuroelectrophysiological features of childhood Guillain-Barré syndrome (GBS) and their association with clinical diagnosis.

METHODS

A retrospective analysis was performed on the neuroelectrophysiological data of 43 children with GBS. According to the interval from onset to neuroelectrophysiological examination, the children were divided into a very-early examination group with 18 children (an interval from onset to the examination of ≤7 days) and an early examination group with 25 children (an interval from onset to the examination of 7 to ≤14 days). The children with acute flaccid paralysis, matched for the examination time of GBS children, were enrolled as the control group. The abnormal rates of neuroelectrophysiological parameters were compared between the above groups. According to the results of the H reflex test, the GBS children were divided into an abnormal H reflex group and a normal H reflex group, and related clinical data were compared between the two groups.

RESULTS

Compared with the control group, the very-early and early examination groups had a significantly higher abnormal rate of H reflex (P<0.05), while there was no significant difference in the abnormal rates of F wave, motor nerve conduction, and sensory nerve conduction (P>0.05). Compared with the normal H reflex group, the abnormal H reflex group had a significantly shorter interval from onset to the time of confirmed diagnosis (P<0.05).

CONCLUSIONS

Absence of the H reflex is a valuable parameter of neuroelectrophysiological abnormalities in the early stage of GBS and can help with the diagnosis of GBS.

Sural-sparing pattern: A study against electrodiagnostic subtypes of Guillain–Barre syndrome

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This study investigated sural-sparing in GBS patients who underwent extensive sensory NCS protocol.

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Sural-sparing was less obvious in axonal than demyelinating GBS based on the number of affected upper-limb SNAPs.

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Extended sensory NCS (bilateral or serial) is worth detecting sural-sparing as a supportive EDX feature of GBS.

Objective

To study sural-sparing pattern in Guillain–Barre syndrome (GBS) and compare it among GBS’s electrodiagnostic subtypes, classified by two recent criteria.

Methods

This study retrospectively reviewed clinical data and electrodiagnostic studies (EDXs) of 88 GBS patients diagnosed in a tertiary care hospital (2010–2019).

Results

Overall, 79/88 (89.8%) and 36/45 (80%) patients had bilateral sensory nerve conduction studies (NCS) in the first EDX and follow-up EDX, respectively. Sural-sparing occurred in all subtypes (50% overall occurrence rate), most commonly in demyelination. There was no statistically significant difference in sural-sparing occurrence rates between demyelinating and axonal GBS; however, sural-sparing in axonal GBS tended to show a lower number of abnormal upper-limb sensory nerve action potentials (SNAPs) than demyelinating GBS. Shifting between sural-sparing and no sural-sparing occurred in approximately-one-fourth of patients receiving serial studies. Follow-up EDX additionally discovered 20% of all sural-sparing. Unilateral EDX could have omitted up to 30% of sural-sparing.

Conclusions

Sural-sparing is less obviously manifested in axonal than demyelinating GBS, with respect to the number of affected upper-limb SNAPs. Extended sensory NCS is worth in detecting sural-sparing as a supportive electrodiagnostic GBS feature.

Significance

This report showed one different character of sural-sparing (number of affected upper-limb SNAPs) between demyelinating and axonal GBS.

The outcome of Guillain-Barré syndrome following intravenous immunoglobulin compared to the natural course

BACKGROUND

Intravenous immunoglobulin (IVIg) is recommended in Guillain-Barré syndrome (GBS), but its efficacy may vary in different subtypes. We report the outcomes of patients with GBS following IVIg treatment compared to the natural course (NC). We also compare the effect of IVIg treatment in different subtypes of GBS.

METHODS

From a cohort of 528 GBS, we have extracted 189 patients who received IVIg and compared their outcomes with 199 age and peak disability matched patients who did not receive IVIg, plasmapheresis, or corticosteroid. Disability was assessed using the 0-6 GBS Disability Scale (GBSDS). Clinical and neurophysiological subtypes were recorded. The primary outcome was functional disability at 6-months and was categorized as complete (GBSDS ≤ 1), partial (GBSDS 2-3), and poor (GBSDS > 3). The secondary outcomes were in-hospital death, and duration of hospitalization, and mechanical ventilation (MV).

RESULTS

In-hospital death (2.6% vs 2%; p = 0.74) and 3-months poor recovery (20.7% vs 18%) were similar in the IVIg and NC group. At 6-months, however, a lesser proportion of patients in IVIg group had poor recovery (2.2% vs 8.3%; p = 0.026). The outcomes of IVIg and NC were compared in 72 AMAN and 256 AIDP patients. IVIg therapy did not alter the outcome in AMAN but resulted in a lesser proportion of poor recovery at 6-months in AIDP (0.8% vs. 6.6%; p = 0.03).

CONCLUSION

Intravenous immunoglobulin is beneficial in AIDP variants of GBS but not in the AMAN subtype. A customized treatment may be cost-effective till a randomized controlled trial is conducted in AMAN.

Guillain-Barré Syndrome and COVID-19: a one-year observational multicenter study

Background and purpose

Many single cases and small series of Guillain–Barré syndrome (GBS) associated with severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection were reported during the coronavirus disease 19 (COVID‐19) outbreak worldwide. However, the debate regarding the possible role of infection in causing GBS is still ongoing. This multicenter study aimed to evaluate epidemiological and clinical findings of GBS diagnosed during the COVID‐19 pandemic in northeastern Italy in order to further investigate the possible association between GBS and COVID‐19.

Methods

Guillain–Barré syndrome cases diagnosed in 14 referral hospitals from northern Italy between March 2020 and March 2021 were collected and divided into COVID‐19‐positive and COVID‐19‐negative. As a control population, GBS patients diagnosed in the same hospitals from January 2019 to February 2020 were considered.

Results

The estimated incidence of GBS in 2020 was 1.41 cases per 100,000 persons/year (95% confidence interval 1.18–1.68) versus 0.89 cases per 100,000 persons/year (95% confidence interval 0.71–1.11) in 2019. The cumulative incidence of GBS increased by 59% in the period March 2020–March 2021 and, most importantly, COVID‐19‐positive GBS patients represented about 50% of the total GBS cases with most of them occurring during the two first pandemic waves in spring and autumn 2020. COVID‐19‐negative GBS cases from March 2020 to March 2021 declined by 22% compared to February 2019–February 2020.

Conclusions

Other than showing an increase of GBS in northern Italy in the “COVID‐19 era” compared to the previous year, this study emphasizes how GBS cases related to COVID‐19 represent a significant part of the total, thus suggesting a relation between COVID‐19 and GBS.

Electrodiagnostic subtyping in Guillain-Barré syndrome: Use of criteria in practice based on a survey study in IGOS

Electrodiagnostic (EDx) studies are helpful in diagnosing and subtyping of Guillain‐Barré syndrome (GBS). Published criteria for differentiation into GBS subtypes focus on cutoff values, but other items receive less attention, although they may influence EDx subtyping: (a) extensiveness of EDx testing, (b) nerve‐specific considerations, (c) distal compound muscle action potential (CMAP)‐amplitude requirements, (d) criteria for conduction block and temporal dispersion. The aims of this study were to investigate how these aspects were approached by neuromuscular EDx experts in practice and how this was done in previously published EDx criteria for GBS. A completed questionnaire was returned by 24 (of 49) members of the electrophysiology expertise group from the International GBS Outcome Study. Six published EDx criteria for GBS subtyping were compared regarding these aspects. The indicated minimal number of motor nerves to study varied among respondents and tended to be more extensive in equivocal than normal studies. Respondents varied considerably regarding usage of compression sites for subtyping (median/wrist, ulnar/elbow, peroneal/fibular head): 29% used all variables from all sites, 13% excluded all sites, and 58% used only some sites and/or variables. Thirty‐eight percent of respondents required a minimal distal CMAP amplitude to classify distal motor latency as demyelinating, and 58% did for motor conduction velocity. For proximal/distal CMAP‐amplitude ratio and F‐wave latency, a requisite minimal CMAP amplitude was more often required (79%). Also, the various published criteria sets showed differences on all items. Practical use of EDx criteria for subtyping GBS vary extensively across respondents, potentially lowering the reproducibility of GBS subtyping.

Electrodiagnosis of Guillain-Barre syndrome in the International GBS Outcome Study: Differences in methods and reference values

OBJECTIVE

To describe the heterogeneity of electrodiagnostic (EDx) studies in Guillain-Barré syndrome (GBS) patients collected as part of the International GBS Outcome Study (IGOS).

METHODS

Prospectively collected clinical and EDx data were available in 957 IGOS patients from 115 centers. Only the first EDx study was included in the current analysis.

RESULTS

Median timing of the EDx study was 7 days (interquartile range 4-11) from symptom onset. Methodology varied between centers, countries and regions. Reference values from the responding 103 centers were derived locally in 49%, from publications in 37% and from a combination of these in the remaining 15%. Amplitude measurement in the EDx studies (baseline-to-peak or peak-to-peak) differed from the way this was done in the reference values, in 22% of motor and 39% of sensory conduction. There was marked variability in both motor and sensory reference values, although only a few outliers accounted for this.

CONCLUSIONS

Our study showed extensive variation in the clinical practice of EDx in GBS patients among IGOS centers across the regions.

SIGNIFICANCE

Besides EDx variation in GBS patients participating in IGOS, this diversity is likely to be present in other neuromuscular disorders and centers. This underlines the need for standardization of EDx in future multinational GBS studies.

Chronic inflammatory demyelinating polyneuropathy with an acute onset. Clinical case

Chronic inflammatory demyelinating polyneuropathy (CIDP) is a heterogeneous treatable dysimmune neuropathy. The variety of clinical forms and course of the disease can be challenging for proper diagnosis and early treatment. In a quarter of cases CIDP starts acutely, mimicking GuillainBarr syndrome. The early diagnosis is especially important regarding differences in treatment and prognosis of these conditions. In this article, we present a clinical case of acute onset CIDP with a detailed analysis of the differential diagnosis between acute and chronic immune-mediated neuropathies.

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.

Guillain-Barre Syndrome After Two COVID-19 Vaccinations: Two Case Reports With Follow-up Electrodiagnostic Study

Guillain-Barre syndrome (GBS) is an immune-mediated acute polyradiculoneuropathy and commonly occurs after a preceding infection or immunization sequalae. Following the severe acute respiratory syndrome-coronavirus-2 virus pandemic with co-introduction of massive vaccinations, several GBS cases associated with coronavirus disease 2019 (COVID-19) infection per se or after vaccination for COVID-19 were reported internationally. Herein, we report two cases of Korean GBS presenting with tetraplegia after two different COVID-19 vaccinations (42-year old man by AstraZeneca and 48-year woman by Pfizer vaccines) within four weeks after vaccination. The patients were diagnosed with clinical examination, serial electromyography, and compatible laboratory results and improved after comprehensive rehabilitative treatment and intravenous immunoglobulin therapy. Furthermore, we performed an electrodiagnostic follow-up study of each case to examine their unique characteristics.

Clinical predictors and electrodiagnostic characteristics in patients with Guillain-Barré syndrome with respiratory failure: a retrospective, matched case-control study

BACKGROUND

Respiratory failure is a common complication of Guillain-Barré syndrome (GBS). This study aimed to determine the clinical predictors and electrodiagnostic (EDx) characteristics in patients with Guillain-Barré syndrome (GBS) with respiratory failure.

METHODS

The retrospective study included 29 confirmed GBS cases with respiratory failure and age- (±5 years) and sex-matched controls (1:1). The dependent t-test and McNemar-Bowker test were used to analyse the continuous and categorical data, respectively. In addition, a multiple logistic regression analysis was used to analyse the predictive factors for respiratory failure.

RESULTS

Among both cases and controls, the majority were male (72.4%), and the average age was 50.9 years. The data showed that patients with respiratory failure had higher GBS disability scores, lower motor power (≤3) of the hip flexors and ankle dorsiflexors, and experienced facial and bulbar palsy. In the multivariate analysis, the significant predictive factors were bulbar palsy (AOR 10.4 [95% CI [2.6-41.4]) and motor power of hip flexors ≤ 3 (AOR 31.4 [95% CI [3.1-314.5]). Patients with respiratory failure had lower compound muscle action potential amplitude of the ulnar and tibial nerves. The median, ulnar, and tibial nerve conduction studies were more likely to reflect inexcitability. The GBS subtypes in GBS patients with and without respiratory failure were not significantly different.

CONCLUSIONS

Bulbar palsy and motor power of the hip flexors ≤ 3 were significant predictors for respiratory failure. The GBS subtypes in patients with and without respiratory failure were not significantly different.

Electrophysiology of Guillain-Barré syndrome in Bangladesh: A prospective study of 312 patients

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Classification of neurophysiologic subtypes of Guillain-Barré syndrome largely depended on the applied criteria.

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Anti-GM1 antibodies were not exclusively associated with axonal Guillain-Barré syndrome.

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Conduction block was not exclusively associated with demyelinating Guillain-Barré syndrome.

Objective

To describe the electrophysiological features in relation to clinical and serological findings of Guillain-Barré syndrome (GBS) in the national neuroscience hospital in Bangladesh. This is one of the few studies that investigated GBS patients using standardized electrophysiology in low-income countries.

Methods

In a prospective and observational study, we investigated 312 GBS patients by standardized clinical, serological and electrophysiological methods. Unilateral motor and sensory nerve conduction studies (NCS) were performed within two weeks of onset of weakness. Follow up NCS were performed in 189 patients and classified according to eight sets of established GBS criteria. Serology included assessment of anti-GM1 antibodies and anti-campylobacter jejuni lipo-oligosaccharide (LOS) antibodies.

Results

Depending on the criteria used, 44–59% patients had axonal GBS with anti-GM1 antibodies being present in 55–58% and 9–42% patients had demyelinating GBS with anti-GM1 antibodies being present in 7–35%. Conduction block (CB) with demyelinative slowing in the same nerve segment was found in 24% (74/312) patients, and CB without demyelinative slowing in the same nerve segment was found in 18% (56/312) patients, of whom anti-GM1 antibodies were found in 27% and 57% patients respectively. Follow-up NCS showed a change in GBS classification in 11–26% of patients, mainly from demyelinating to axonal GBS.

Conclusions

The predominant subtype of GBS in Bangladesh is axonal but demyelinating GBS also occurs with classification being strongly dependent on the applied criteria.

Significance

The present study demonstrates the importance of reaching international agreement on GBS criteria that should be based on the best evidence.

Guillain–Barré Syndrome and Variants Following COVID-19 Vaccination: Report of 13 Cases

Background

Amidst growing concern about an increased risk of Guillain–Barré syndrome (GBS) following COVID-19 vaccination, clinical and electrodiagnostic features have not been fully characterized.

Methods

We retrospectively reviewed medical records of the patients diagnosed with GBS and its variants following COVID-19 vaccination at four referral hospitals during the period of the mass vaccination program in South Korea (February to October 2021).

Results

We identified 13 patients with GBS and variants post COVID-19 vaccination: AstraZeneca vaccine (Vaxzevria) in 8, and Pfizer-BioNTech vaccine (Comirnaty) in 5. The mean time interval from vaccination to symptom onset was 15.6 days (range 4–30 days). Electrodiagnostic classification was demyelinating in 7, axonal in 4 and normal in 2 cases. Clinical manifestations were diverse with varying severity: classical GBS in 8 cases, paraparetic variant in 3, Miller-Fisher syndrome in 1 and acute cervicobrachial weakness in 1. Four patients developed respiratory failure, and 2 of them showed treatment-related fluctuations.

Conclusion

Our observations suggest that COVID-19 vaccines may be associated with GBS of distinctive clinical features characterized by severe quadriplegia, disproportionately frequent bilateral facial palsy or atypical incomplete variants. Continuous surveillance and further studies using robust study designs are warranted to fully assess the significance of the association.

New classification of autoimmune neuropathies based on target antigens and involved domains of myelinated fibres

Autoimmune neuropathies are named by eponyms, by descriptive terminology or because of the presence of specific antibodies and are traditionally classified, on the basis of pathology and electrophysiology, as primary demyelinating or axonal. However, autoimmune disorders targeting specific molecules of the nodal region, although not showing pathological evidence of demyelination, can exhibit all the electrophysiological changes considered characteristic of a demyelinating neuropathy and acute neuropathies with antiganglioside antibodies, classified as axonal and due to nodal dysfunction, can present with reversible conduction failure and prompt recovery that appear contradictory with the common view of an axonal neuropathy. These observations bring into question the concepts of demyelinating and axonal nerve conduction changes and the groundwork of the classical dichotomous classification.We propose a classification of autoimmune neuropathies based on the involved domains of the myelinated fibre and, when known, on the antigen. This classification, in our opinion, helps to better systematise autoimmune neuropathies because points to the site and molecular target of the autoimmune attack, reconciles some contrasting pathological and electrophysiological findings, circumvents the apparent paradox that neuropathies labelled as axonal may be promptly reversible and finally avoids taxonomic confusion and possible misdiagnosis.

Comparison of Five Different Electrophysiological Criteria for Childhood Guillain Barre Syndrome

Background:

Internationally approved electrodiagnostic criteria for Guillain Barre syndrome lack in children. We intended to compare the diagnostic accuracy of the currently available five electrophysiological criteria for childhood Guillain Barre Syndrome (GBS) at the time of sentinel assessment.

Methodology:

In this single-center study, data of children diagnosed with GBS between January 2013 to December 2017 were retrieved. Patient charts were reviewed for clinical features, electrophysiological recordings. The electrodiagnostic results (4 motor nerves and two sensory nerves in upper limbs and lower limbs) were reanalyzed and were classified based on Dutch group; Ho; Hadden; Hughes and Rajabally criteria for GBS.

Results:

During this study period, of the 205 children with clinical features of GBS, 15 children had incomplete electrophysiological data, and four children were excluded due to missing data. The mean age of onset of the 186 children enrolled was 77 months; the median duration from symptom onset to electrodiagnostic evaluation was seven days; pure motor and motor-sensory form of GBS was seen in 71 and 115 children. Based on the Hadden criteria, a demyelinating pattern was noted in 57 children; axonal in 37; Inexcitable in 84 and Equivocal in 8 children. The sensitivity of the various criteria ranged from 71% to 100% for demyelination, 97% to 100% for axonal. The degree of agreement using Hadden and Rajabally criteria for Equivocal subtypes was 0.93.

Conclusions:

The Rajabally criteria showed the best sensitivity, specificity and diagnostic accuracy for electrodiagnosis of GBS in children when compared against Hadden criteria.

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.

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.

Guillain-Barré syndrome and COVID-19: an observational multicentre study from two Italian hotspot regions

OBJECTIVE

Single cases and small series of Guillain-Barré syndrome (GBS) have been reported during the SARS-CoV-2 outbreak worldwide. We evaluated incidence and clinical features of GBS in a cohort of patients from two regions of northern Italy with the highest number of patients with COVID-19.

METHODS

GBS cases diagnosed in 12 referral hospitals from Lombardy and Veneto in March and April 2020 were retrospectively collected. As a control population, GBS diagnosed in March and April 2019 in the same hospitals were considered.

RESULTS

Incidence of GBS in March and April 2020 was 0.202/100 000/month (estimated rate 2.43/100 000/year) vs 0.077/100 000/month (estimated rate 0.93/100 000/year) in the same months of 2019 with a 2.6-fold increase. Estimated incidence of GBS in COVID-19-positive patients was 47.9/100 000 and in the COVID-19-positive hospitalised patients was 236/100 000. COVID-19-positive patients with GBS, when compared with COVID-19-negative subjects, showed lower MRC sum score (26.3±18.3 vs 41.4±14.8, p=0.006), higher frequency of demyelinating subtype (76.6% vs 35.3%, p=0.011), more frequent low blood pressure (50% vs 11.8%, p=0.017) and higher rate of admission to intensive care unit (66.6% vs 17.6%, p=0.002).

CONCLUSIONS

This study shows an increased incidence of GBS during the COVID-19 outbreak in northern Italy, supporting a pathogenic link. COVID-19-associated GBS is predominantly demyelinating and seems to be more severe than non-COVID-19 GBS, although it is likely that in some patients the systemic impairment due to COVID-19 might have contributed to the severity of the whole clinical picture.

Electrophysiological characteristics of patients with nitrous oxide abuse

Objective: In the young generations with nitrous oxide abuse (N₂O), featured electrophysiological response of the peripheral neuropathy caused by nitrous oxide remains to be defined.Methods: Patients with nitrous oxide abuse (20 cases), two variants of Guillain-Barré syndrome (GBS), that is, acute inflammatory demyelinating polyradiculoneuropathy (GBS-AIDP, 19 cases) and acute motor axonal neuropathy (GBS-AMAN, 18 cases), as well as diabetic peripheral neuropathy (DPN, 20 cases) were enrolled into this study. Electrophysiological parameters including distal motor latency (DML), motor nerve conduction velocity (MNCV), sensory nerve conduction velocity (SNCV), amplitudes of compound muscle action potential (CMAP), and sensory nerve action potential (SNAP) were measured and analyzed by comparing the parameters between the aforementioned patients groups as well as normal control group (20 subjects).Results: Compared to normal control subjects, patients with nitrous oxide abuse showed prolonged DML, slower MNCV and SNCV in the limbs, lower amplitudes of CMAP in the median, tibial and peroneal nerves, and lower SNAP in median and ulnar nerves. Abnormalities of MNCV and amplitudes of CMAP in the lower limbs were significantly higher than that in the upper limbs . Abnormal electrophysiological features of patients with nitrous oxide abuse were dramatically different from those in GBS-AIDP or DPN patients, but similar to those in GBS-AMAN patients.Conclusions: Nitrous oxide abuse could cause abnormal electrophysiological response in the limbs. Some of the parameters (DML, MNCV, SNCV, CMAP and SNAP) appeared significantly different between the patients with nitrous oxide abuse, GBS with AIDP or AMAN, and DPN patients.Significance: Electrophysiological examination could be considered as an important supporting factor in differential diagnosis for nitrous oxide abuse, GBS with AIDP or AMAN, and DPN.

Characteristics of Guillain-Barré syndrome in a Lebanese tertiary care center

Guillain-Barré Syndrome (GBS) is a group of acute inflammatory disorders that share a clinical presentation of progressive polyradiculo-neuropathy. Data on GBS in the Middle East and Lebanon are scarce; hence, we explored the characteristics of patients presenting with GBS to a tertiary care center in Beirut, Lebanon. This was a single-centered retrospective study over a 12-year period. We reviewed the charts of patients presenting with GBS to the American University of Beirut medical center and examined their presentation, management and outcome. 61 patients were included, with the majority being males. 59% of the patients reported an infection prior to admission. 77% had sensory and motor symptoms and 69% were diagnosed with acute inflammatory demyelinating polyneuropathy (AIDP). 57% of patients had initial symptoms in the lower extremities, 25% experienced cranial neuropathies, and 26% complained of pain. 77% were managed by intravenous immunoglobulin with a median hospital stay of 6.5 days. AIDP was noted to be the most prevalent GBS variant in Lebanon. More than 50% had an unfavorable outcome at discharge, which raises the need for better treatment and management approaches.

Elektrodiagnostik im frühen Stadium des Guillain-Barré-Syndroms

Das Guillain-Barré-Syndrom (GBS) ist eine entzündliche Erkrankung des Nervensystems mit fortschreitenden Lähmungen und Sensibilitätsstörungen. Es ist umstritten, ob GBS-Subtypen bereits durch einzelne elektrophysiologische Untersuchungen sicher klassifizierbar sind. In dieser Studie verglichen die Autoren elektrophysiologische Tests in frühen und späten Stadien des GBS und bewerteten im Ultraschall sichtbare Nervenveränderungen.

Determining the Utility of the Guillain-Barré Syndrome Classification Criteria

Background and Purpose

Several variants of Guillain-Barré syndrome (GBS) and Miller Fisher syndrome (MFS) exist, but their frequencies vary in different populations and do not always meet the inclusion criteria of the existing diagnostic criteria. However, the GBS classification criteria by Wakerley and colleagues recognize and define the clinical characteristics of each variant. We applied these criteria to a GBS and MFS cohort with the aim of determining their utility.

Methods

Consecutive GBS and MFS patients presenting to our center between 2010 and 2020 were analyzed. The clinical characteristics, electrophysiological data, and antiganglioside antibody profiles of the patients were utilized in determining the clinical classification.

Results

This study classified 132 patients with GBS and its related disorders according to the new classification criteria as follows: 64 (48.5%) as classic GBS, 2 (1.5%) as pharyngeal-cervical-brachial (PCB) variant, 7 (5.3%) as paraparetic GBS, 29 (22%) as classic MFS, 3 (2.3%) as acute ophthalmoparesis, 2 (1.5%) as acute ataxic neuropathy, 2 (1.5%) as Bickerstaff brainstem encephalitis (BBE), 17 (12.9%) as GBS/MFS overlap, 4 (3%) as GBS/BBE overlap, 1 (0.8%) as MFS/PCB overlap, and 1 (0.8%) as polyneuritis cranialis. The electrodiagnosis was demyelinating in 55% of classic GBS patients but unclassified in 79% of classic MFS patients. Anti-GM1, anti-GD1a, anti-GalNAc-GD1a, and anti-GD1b IgG ganglioside antibodies were more commonly detected in the axonal GBS subtype, whereas the anti-GQ1b and anti-GT1a IgG ganglioside antibodies were more common in classic MFS and its subtypes.

Conclusions

Most of the patients in the present cohort met the criteria of either classic GBS or MFS, but variants were seen in one-third of patients. These findings support the need to recognize variants of both syndromes in order to achieve a more-complete case ascertainment in GBS.

The value of sensory nerve conduction studies in the diagnosis of Guillain-Barré syndrome

Electrophysiology plays a determinant role in Guillain-Barré syndrome (GBS) diagnosis, classification, and prognostication. However, traditional electrodiagnostic (EDX) criteria for GBS rely on motor nerve conduction studies (NCS) and are suboptimal early in the course of the disease or in the setting of GBS variants. Sensory nerve conduction studies, including the sural-sparing pattern and the sensory ratio are not yet included in EDX criteria despite their well-established role in GBS diagnosis. The aim of this review is to discuss the diagnostic value of sensory NCS in GBS, their role in establishing the diagnosis and predicting the outcome according to the various subtypes of the disease.

Guillain-Barré syndrome

Guillain-Barré syndrome is the most common cause of acute flaccid paralysis worldwide. Most patients present with an antecedent illness, most commonly upper respiratory tract infection, before the onset of progressive motor weakness. Several microorganisms have been associated with Guillain-Barré syndrome, most notably Campylobacter jejuni, Zika virus, and in 2020, the severe acute respiratory syndrome coronavirus 2. In C jejuni-related Guillain-Barré syndrome, there is good evidence to support an autoantibody-mediated immune process that is triggered by molecular mimicry between structural components of peripheral nerves and the microorganism. Making a diagnosis of so-called classical Guillain-Barré syndrome is straightforward; however, the existing diagnostic criteria have limitations and can result in some variants of the syndrome being missed. Most patients with Guillain-Barré syndrome do well with immunotherapy, but a substantial proportion are left with disability, and death can occur. Results from the International Guillain-Barré Syndrome Outcome Study suggest that geographical variations exist in Guillain-Barré syndrome, including insufficient access to immunotherapy in low-income countries. There is a need to provide improved access to treatment for all patients with Guillain-Barré syndrome, and to develop effective disease-modifying therapies that can limit the extent of nerve injury. Clinical trials are currently underway to investigate some of the potential therapeutic candidates, including complement inhibitors, which, together with emerging data from large international collaborative studies on the syndrome, will contribute substantially to understanding the many facets of this disease.

Acute non-traumatic tetraparesis - Differential diagnosis

INTRODUCTION

Potentially life-threatening disorders may present in the emergency department with acute tetraparesis, and their recognition is crucial for an appropriate management and timely treatment. Our review aims to systematize the differential diagnosis of acute non-traumatic tetraparesis.

RESULTS

Causes of tetraparesis can be classified based on the site of defect: upper motor neuron (UMN), peripheral nerve, neuromuscular junction or muscle. History of present illness should include the distribution of weakness (symmetric/asymmetric or distal/proximal/diffuse) and associated clinical features (pain, sensory findings, dysautonomia, and cranial nerve abnormalities such as diplopia and dysphagia). Neurological examination, particularly tendon reflexes, helps further in the localization of nerve lesions and distinction between UMN and lower motor neuron. Ancillary studies include blood and cerebral spinal fluid analysis, neuroaxis imaging, electromyography, muscle magnetic resonance and muscle biopsy.

CONCLUSIONS

Acute tetraparesis is still a debilitating and potentially serious neurological condition. Despite all the supplementary ancillary tests, the neurological examination is the key to achieve a correct diagnosis. The identification of life-threatening neurologic disorders is pivotal, since failing to identify patients at risk of complications, such as acute respiratory failure, may have catastrophic results.

Clinical and Electrophysiological Outcome Measures of Patients With Post-Infectious Neurological Syndromes Related to COVID-19 Treated With Intensive Neurorehabilitation

Background: The clinical spectrum of coronavirus disease 2019 (COVID-19), due to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, may be quite wide, including neurological symptoms. Among them, para-infectious or post-infectious neurological syndromes (PINS), caused by an inflammatory response against the central and/or peripheral nervous system, have been reported. The aim of this paper is to illustrate the functional and neurophysiological recovery in a series of subjects with COVID-19-related PINS who underwent intensive neurorehabilitation.

Materials and Methods: Five patients with PINS associated with COVID-19 were evaluated at baseline and followed up for 6 months. Three of them had polyradiculoneuropathy and two patients had myelitis. The onset of the neurological syndromes was temporally associated with the SARS-CoV-2 infection. After completing the acute neurological treatments in the intensive care unit, patients underwent a personalized multidisciplinary rehabilitation program. An in-depth clinical, functional, and electrophysiological assessment was carried out at baseline and at 3- and 6-month follow-ups.

Results: Among patients with polyradiculoneuropathy, the electrophysiological evaluation at baseline disclosed an acute inflammatory demyelinating polyradiculoneuropathy (AIDP) in two patients and an acute motor and sensory axonal neuropathy (AMSAN) in the third patient. At follow-up, the electrophysiological features improved in one subject with AIDP and were stable in the remaining two cases. The functional assessment after neurorehabilitation showed global recovery and full independence in walking and in activities of daily life in one patient and mild improvement in the other two cases. Of the two subjects with myelitis, the baseline electrophysiological examination showed a prolonged central motor conduction time, which returned to normal in one patient, whereas it improved but remained pathological in the other patient at follow-up. The neurorehabilitation led to a substantial functional improvement in both subjects.

Discussion and Conclusions: This is the first study to describe clinical and electrophysiological aspects along with medium-term outcome in patients with COVID-19-related neurological manifestations who underwent an intensive rehabilitation program. The functional outcome following neurorehabilitation in patients with PINS related to SARS-CoV-2 infection is variable. In our small case series, subjects with polyradiculoneuropathy had a poorer recovery compared to patients with myelitis. The clinical course largely paralleled the follow-up electrophysiological findings.

Acute Axonal Motor Neuropathy With Completely Reversible Conduction Failure-Is It Really Axonal?

ABSTRACT

We present the case of a 24-year-old man with a 3-day history of limb weakness and flaccid tetraparesis, hyporreflexia, and gait difficulties (Hughes grade 3) in the examination. Electromyography at presentation revealed severe amplitude reduction in distal compound muscle action potentials of several nerves without features of demyelination, fulfilling electrodiagnostic criteria for acute axonal motor neuropathy. The patient was treated with immunoglobulin and recovered completely 21 days after symptom onset. Electromyography at this timepoint showed normalization of compound muscle action potentials without increased temporal dispersion. The electroclinical recovery profile in this patient is consistent with reversible conduction failure in distal nerve segments in detriment of axonal degeneration. Thus, it is an "axonal motor neuropathy" where axonopathy is unlikely, giving strength to the concept of "nodopathies/paranodopathies."

Guillain-Barré Syndrome Outbreak in Peru 2019 Associated With Campylobacter jejuni Infection

OBJECTIVE

To identify the clinical phenotypes and infectious triggers in the 2019 Peruvian Guillain-Barré syndrome (GBS) outbreak.

METHODS

We prospectively collected clinical and neurophysiologic data of patients with GBS admitted to a tertiary hospital in Lima, Peru, between May and August 2019. Molecular, immunologic, and microbiological methods were used to identify causative infectious agents. Sera from 41 controls were compared with cases for antibodies to Campylobacter jejuni and gangliosides. Genomic analysis was performed on 4 C jejuni isolates.

RESULTS

The 49 included patients had a median age of 44 years (interquartile range [IQR] 30-54 years), and 28 (57%) were male. Thirty-two (65%) had symptoms of a preceding infection: 24 (49%) diarrhea and 13 (27%) upper respiratory tract infection. The median time between infectious to neurologic symptoms was 3 days (IQR 2-9 days). Eighty percent had a pure motor form of GBS, 21 (43%) had the axonal electrophysiologic subtype, and 18% the demyelinating subtype. Evidence of recent C jejuni infection was found in 28/43 (65%). No evidence of recent arbovirus infection was found. Twenty-three cases vs 11 controls (OR 3.3, confidence interval [CI] 95% 1.2-9.2, p < 0.01) had IgM and/or IgA antibodies against C jejuni. Anti-GM1:phosphatidylserine and/or anti-GT1a:GM1 heteromeric complex antibodies were strongly positive in cases (92.9% sensitivity and 68.3% specificity). Genomic analysis showed that the C jejuni strains were closely related and had the Asn51 polymorphism at cstII gene.

CONCLUSIONS

Our study indicates that the 2019 Peruvian GBS outbreak was associated with C jejuni infection and that the C jejuni strains linked to GBS circulate widely in different parts of the world.