Incidence and clinical features of acute inflammatory polyradiculoneuropathy in Lombardy, Italy, 1996

Hospital-diagnosed morbidities and recent surgery as risk factors for developing Guillain-Barré syndrome

BACKGROUND AND PURPOSE

This study was undertaken to determine the association of hospital-diagnosed morbidity and recent surgery with risk of subsequent Guillain-Barré syndrome (GBS) development.

METHODS

We conducted a nationwide population-based case-control study of all patients with first-time hospital-diagnosed GBS in Denmark between 2004 and 2016 and 10 age-, sex-, and index date-matched population controls per case. Hospital-diagnosed morbidities included in the Charlson Comorbidity Index were assessed as GBS risk factors up to 10 years prior to the GBS index date. Incident major surgery was assessed within 5 months prior.

RESULTS

In the 13-year study period, there were 1086 incident GBS cases, whom we compared with 10,747 matched controls. Any pre-existing hospital-diagnosed morbidity was observed in 27.5% of GBS cases and 20.0% of matched controls, yielding an overall matched odds ratio (OR) of 1.6 (95% confidence interval [CI] = 1.4-1.9). The strongest associations were found for leukemia, lymphoma, diabetes, liver disease, myocardial infarction, congestive heart failure, and cerebrovascular disease, with 1.6- to 4.6-fold increased risks of subsequent GBS. GBS risk was strongest for morbidities newly diagnosed during the past 5 months (OR = 4.1, 95% CI = 3.0-5.6). Surgical procedures within 5 months prior were observed in 10.6% of cases and 5.1% of controls, resulting in a GBS OR of 2.2 (95% CI = 1.8-2.7). Risk of developing GBS was highest during the first month following surgery (OR = 3.7, 95% CI = 2.6-5.2).

CONCLUSIONS

In this large nationwide study, individuals with hospital-diagnosed morbidity and recent surgery had a considerably increased risk of GBS.

[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.

Nationwide survey of childhood Guillain-Barré syndrome, Fisher syndrome, and Bickerstaff brainstem encephalitis in Japan

OBJECTIVE

Guillain-Barré syndrome (GBS), Fisher syndrome (FS), and Bickerstaff brainstem encephalitis (BBE) are immune-mediated neuropathies presenting with symptoms such as weakness, ophthalmoplegia, ataxia, and consciousness disturbances. Although the epidemiology of GBS and BBE in patients of all ages has been reported, childhood data have not been well-investigated. We aimed to determine the clinical features, therapeutics, and prognoses of childhood GBS, FS, and BBE in Japan.

METHODS

We sent questionnaires to 1068 pediatric neurologists in Japan from 2014 to 2016 to determine the number of children less than 15 years old with GBS, FS, or BBE and their age and sex. We subsequently performed a secondary survey to investigate the clinical features, laboratory data, treatment, and prognosis.

RESULTS

Five-hundred thirty-eight pediatric neurology specialists (50.4%) responded to the first survey. The total number of children with GBS, FS, and BBE in Japan from 2014 to 2016 were 87, 10, and 6, respectively. GBS was classified as acute inflammatory demyelinating neuropathy (35.6%), acute motor axonal neuropathy (20.7%), or acute motor-sensory axonal neuropathy (10.3%), with a male-to-female ratio of 1.29:1.0 and a wide distribution of onset ages. The disease severities of GBS, FS, and BBE were variable, but all children could walk within one year.

CONCLUSION

The prognoses of childhood GBS, FS, and BBE were generally favorable, as long as the patient was promptly treated with either intravenous immunoglobulin or plasma exchange.

Diagnostic Pitfalls in Guillain-Barré Syndrome: Case Report and Literature Review

Guillain-Barré syndrome (GBS) represents a group of acute immune-mediated polyradiculoneuropathies that is usually characterized by symmetrical limb weakness and areflexia. GBS can also lead to atypical clinical findings, which may lead to confusion and errors in the diagnosis. In this report, we describe a case of Guillain-Barré syndrome in a 7-year-old child who presented with neck stiffness, headache and vomiting mimicking acute meningoencephalitis, arthritis and myositis. Symptoms of ascending paralysis developed subsequently. Clearly, the atypical presentation of GBS is a significant dilemma for pediatricians and may lead to delays in diagnosis and treatment.

Guillain-Barré syndrome temporally associated with COVID-19 vaccines in Victoria, Australia

Guillain-Barré syndrome (GBS) is an adverse event of special interest (AESI) for surveillance systems monitoring adverse events following immunisation (AEFI) with COVID-19 vaccines. Emerging data support a temporal association between GBS and adenovirus-vector COVID-19 vaccines. We present a case series of GBS reports submitted between February and November 2021 to our enhanced spontaneous surveillance system (SAEFVIC) in Victoria, Australia, following vaccination with either the adenovirus-vector vaccine Vaxzevria ChadOx1-S (AstraZeneca) or an mRNA vaccine (Comirnaty BNT162b2 [Pfizer-BioNTech] or Spikevax mRNA-1273 [Moderna]). For each report, Brighton Collaboration case definitions were used to describe diagnostic certainty. Severity was graded using the GBS Disability Score. The observed incidence of GBS following immunisation against COVID-19 was compared to expected background ICD10-AM G61.0 coded hospitalisations. There were 41 total cases of GBS reported to SAEFVIC following Vaxzevria (n = 38), Comirnaty (n = 3), or Spikevax (n = 0) vaccines. The observed GBS incidence rate exceeded the expected background rate for Vaxzevria only, with 1.85 reports per 100,000 doses following dose 1, higher than the expected rate of 0.39 hospital admissions per 100,000 adults within 42 days of vaccination. Of 38 GBS reports following Vaxzevria, the median age at vaccination was 66 years and median onset of symptoms was 14 days following immunisation. There was one death. Four cases initially categorised as GBS were later reclassified as acute-onset chronic inflammatory demyelinating polyneuropathy. Fatigue was the predominant persisting symptom reported at follow up. Additional global studies are required to characterise risk factors, clinical variability, and to provide precision and generalizability regarding AEFI risks such as GBS associated with different vaccine platforms, which will help inform communication of the potential benefits and risks of COVID19 vaccination.

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.

Outcomes of patients presenting with Guillain-Barre Syndrome at a tertiary care center in India

Background

The Guillain-Barre Syndrome (GBS), also known as acute idiopathic polyneuritis, is a critical acquired condition associated with preceding nonspecific infection or triggering factors like trauma, surgery, or vaccination. GBS is currently the most frequent cause of acute flaccid paralysis in India. This study evaluates the short-term and in-hospital outcomes in different subtypes of GBS.

Methods

A prospective observational study was conducted at V.S. Hospital, Ahmedabad, from September 2015 to December 2017. Patients above the age of 12 were included. Patients having other underlying neurological conditions, as well as immunodeficiency disorders, were excluded. The patients were classified into different subtypes of GBS, and functional outcomes were recorded on admission and discharge according to Hughes Scoring System. All statistical analyses were performed by using SPSS software.

Results

Out of 50 patients, 35 (70%) were males. The mean age was of 37.18 +/− 18.35 years. 25 (50%) patients had a preceding infection. 88% of patients presented with cranial nerve (CN) involvement had a Hughes Score of >/= 3 (p = 0.0087). They had less improvement of Hughes Score on discharge (0.13 +/− 0.04) as compared to the patients without cranial nerve involvement (0.38 +/− 0.08) (p = 0.008). Respiratory involvement was associated with a higher Hughes Score (p = 0.005) on admission. 85% of patients diagnosed with an axonal subtype of GBS had a Hughes Score of >/= 3 (p = 0.06) compared to 74% patients with demyelinating subtype. Axonal subtype required double period (11 +/− 2.34) to show improvement as compared to demyelinating subtype (6 +/− 1.2) (p = 0.020). Irrespective of the subtypes, in two different treatment cohorts (PLEX vs IVIG), there was no difference in short term functional outcomes measured by improvement in the Hughes scores (p = 0.89).

Conclusions

Early cranial nerve and respiratory involvement in patients presenting with GBS are associated with poor outcomes warranting immediate critical care involvement. In our study, amongst all the subtypes, axonal had poor clinical outcomes. Further clinical trials on the Indian subpopulation will help us evaluate the impact of different treatment modalities on this disease.

International validation of the Erasmus GBS Respiratory Insufficiency Score

Objective

This study aimed to validate the Erasmus Guillain–Barré Syndrome Respiratory Insufficiency Score in the International Guillain–Barré Syndrome Outcome Study cohort, and to improve its performance and region‐specificity.

Methods

We examined data from the first 1,500 included patients, aged ≥6 years and not ventilated prior to study entry. Patients with a clinical variant or mild symptoms were also included. Outcome was mechanical ventilation within the first week from study entry. Model performance was assessed regarding the discriminative ability (area under the receiver operating characteristic curve) and the calibration (observed vs predicted probability of mechanical ventilation), in the full cohort and in Europe/North America and Asia separately. We recalibrated the model to improve its performance and region‐specificity.

Results

In the group of 1,023 eligible patients (Europe/North America n = 842, Asia n = 104, other n = 77), 104 (10%) required mechanical ventilation within the first week from study entry. Area under the curve values were ≥0.80 for all validation subgroups. Mean observed proportions of mechanical ventilation were lower than predicted risks: full cohort 10% versus 21%, Europe/North America 9% versus 21%, and Asia 17% versus 23%. After recalibration, predicted risks for the full cohort and Europe/North America corresponded to observed proportions.

Interpretation

This prospective, international cohort study validated the Erasmus Guillain–Barré Syndrome Respiratory Insufficiency Score, and showed that the model can be used in the full spectrum of Guillain–Barré syndrome patients. In addition, a more accurate, region‐specific version of the model was developed for patients from Europe/North America. ANN NEUROL 2022;91:521–531

Post-COVID-19 vaccine Guillain-Barré syndrome; first reported case from Qatar

Introduction

Guillain-Barré syndrome (GBS) is an immune-mediated peripheral neuropathy that was reported following meningococcus, polio, influenza and rabies vaccines. However, an association with the COVID-19 vaccine is yet to be established.

Presentation of case

We present the case of an elderly gentleman with no history of SARS-CoV-2 infection or any recent viral or bacterial illnesses who presented with GBS 20 days after the second dose of COVID-19 vaccination. The diagnosis was established based on physical examination, magnetic resonance imaging (MRI) of the spine, cerebrospinal fluid (CSF) analysis and electromyography (EMG).

Discussion

Due to the occurrence of GBS after certain types of infections, molecular mimicry has become widely acceptable as the underlying pathophysiology. The reported cases of GBS following vaccination further supported this theory, however proving a causal relationship between vaccines and GBS on the molecular level remains a challenge.

Conclusions

To the best of our knowledge this is the first reported case in the state of Qatar. It is important to mention that more research is needed to establish an association between COVID-19 vaccine and GBS. In our opinion, the benefits of COIVID-19 vaccine largely outweigh its risks.

•

COVID-19 vaccines and their adverse events are an emerging topic in medicine.

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GBS was reported following influenza, hepatitis A and COVID-19 vaccines.

•

It is an immune-mediated peripheral neuropathy triggered by molecular mimicry.

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More research is needed to confirm an association with COVID-19 vaccine.

Predicting Mechanical Ventilation Using the EGRIS in Guillain-Barré Syndrome in a Latin American Country

BACKGROUND

Up to one fifth of patients with Guillain-Barré syndrome (GBS) require mechanical ventilation (MV). The Erasmus GBS Respiratory Insufficiency Score (EGRIS) is a clinical predictive model developed in Europe to predict MV requirements among patients with GBS. However, there are significant differences between the Latin American and European population, especially in the distribution of GBS subtypes. Therefore, determining if the EGRIS is able to predict MV in a Latin American population is of clinical significance.

METHODS

We retrospectively analyzed clinical and laboratory data of 177 patients with GBS in three Peruvian hospitals. We performed a multivariate logistic regression of the factors making up the EGRIS. Finally, we evaluated the EGRIS discrimination through a receiver operating characteristic curve and determined its calibration through a calibration curve and a Hosmer-Lemeshow test, a test used to determine the goodness of fit.

RESULTS

We found that 14.1% of our patients required MV. One predictive factor of a patient's need for early MV was the number of days between the onset of motor symptoms and hospitalization. The Medical Research Council sum score did not alter the likelihood of early MV. Bulbar weakness increased the likelihood without showing statistical significance. In contrast, facial weakness was a protective factor of it. The EGRIS was significantly higher in patients who required early MV than in those who did not (P = 0.018). It showed an area under the curve (AUC) of 0.63, with an insignificant Hosmer-Lemeshow test result.

CONCLUSIONS

Although the EGRIS was higher in patients who required early MV than in those who did not, it only showed a moderate discrimination capacity (AUC = 0.63). Facial weakness, an item of the EGRIS, was not found to be a predictive factor in our population. We suggest assessing whether these findings are due to subtype predominance and whether a modified version of the EGRIS could improve performance.

Neuropathy of the elderly

There is an aging of the peripheral nervous system characterized by a decrease in sensory and motor nerve conduction, amplitudes of motor and above all sensory potentials, an abolition of the ankle jerk reflexes and an alteration of proprioceptive sensitivity in almost two-thirds of individuals over 65 years old. These anomalies tend to increase beyond 80 years. However, these signs of aging do not affect the quality of life of the subjects. The causes of peripheral neuropathies in the elderly differ little from those observed before age 65. Of course, hereditary causes are much less frequent, except cases with a late onset, now easily detectable, such as familial amyloidosis. In our climates and in the most developed countries, diabetes remains the most common cause, the prevalence of neuropathy increasing with age. The so-called idiopathic causes are also frequent and despite extensive investigations, nearly 20% of cases remain without etiological diagnosis, but this type of neuropathy is generally mild and not very progressive. The presence of peripheral neuropathy in the elderly can cause real problems in daily life, including the frequency of falls that can be responsible for deleterious bone damage.

Bickerstaff's brainstem encephalitis associated with anti-GM1 and anti-GD1a antibodies

Bickerstaff's brainstem encephalitis (BBE) is a Guillain-Barré syndrome (GBS) spectrum disorder associated with predominantly central nervous system predilection. Patients exhibit a variable constellation of depressed consciousness, bilateral external ophthalmoplegia, ataxia and long tract signs. Although the pathophysiology is not fully understood, it has been associated with anti-GQ1b antibodies in two-thirds of patients. We present a patient with clinical features consistent with BBE and positive anti-GM1 and anti-GD1a antibodies. A diagnostic approach to the acutely unwell patient with brainstem encephalitis is explored in this clinical context with a literature review of the aforementioned ganglioside antibody significance. Intravenous immunoglobulin therapy is highlighted in BBE using up-to-date evidence-based extrapolation from GBS.

Electrophysiological subtypes and associated prognosis factors of Mexican adults diagnosed with Guillain-Barré syndrome, a single center experience

BACKGROUND

The clinical characteristics of electrophysiological subtypes and prognostic factors of Mexican adults diagnosed with Guillain-Barré Syndrome (GBS) have not been described.

MATERIALS AND METHODS

A single center, ambispective, cohort study was performed (2015-2019). GBS was defined following the Asbury and Cornblath criteria. Electrodiagnosis was made according to Hadden criteria. Clinical, biochemical and electrodiagnostic parameters were described, compared and analyzed using a multivariate model. Only patients who completed a 3-month follow-up were included.

RESULTS

137 GBS patients (92 males; mean age 46.6 ± 16.6).132 (96.3%) underwent an electrodiagnostic assessment.68 (51.5%) were classified as axonal GBS, with further classified into two groups: acute motor axonal neuropathy (AMAN) 45.4%, and acute motor and sensory axonal neuropathy (AMSAN) 8,6%. The following characteristics were lower in the AMAN group: Medical Research Counsel sumscore (MRC) 30.1 ± 16.3 vs 36.4 ± 14.4, unilateral facial palsy 10% vs 25.9% and albuminocytologic dissociation 41.3% vs. 71.7%.Multivariate analysis found AMAN as an independent predictor of an unfavorable outcome OR: 3.34 (p = 0.03) CONCLUSIONS: AMAN subtype is the most frequent presentation of GBS in Mexican adult patients and an independent predictor of inability to walk independently at 3 months after discharge.

Case of Bickerstaff encephalitis with positive glutamic acid decarboxylase antibodies

Bickerstaff brainstem encephalitis (BBE) is a rare inflammatory demyelinating condition, which is similar to Miller-Fisher syndrome (MFS). Ophthalmoplegia and ataxia are common to these syndromes but unlike MFS, BBE is also characterised by central nervous system involvement, most commonly in the form of altered consciousness. BBE usually has a very good prognosis. We present a case of a young female with BBE. Unlike the majority of BBE patients, she (1) was negative for anti-GBQ1b antibodies but positive for glutamic acid decarboxylase (GAD) antibodies and borderline positive for voltage-gated calcium channel antibodies and (2) had a delayed recovery post treatment with intravenous immunoglobulins and plasma exchange. We contemplate a potential role for GAD antibodies as a marker for longer recovery time in patients with BBE.

Regional variation of Guillain-Barré syndrome

Guillain-Barré syndrome is a heterogeneous disorder regarding the clinical presentation, electrophysiological subtype and outcome. Previous single country reports indicate that Guillain-Barré syndrome may differ among regions, but no systematic comparative studies have been conducted. Comparative studies are required to identify factors determining disease susceptibility, variation and prognosis, and to improve diagnostic criteria. The International Guillain-Barré Syndrome Outcome Study is a prospective, observational cohort study including all patients within the diagnostic spectrum, aiming to describe the heterogeneity of Guillain-Barré syndrome worldwide. The current study was based on the first 1000 inclusions with a follow-up of at least 1 year and confirmed the variation in clinical presentation, course and outcome between patients. The full clinical spectrum of Guillain-Barré syndrome was observed in patients from all countries participating in the International Guillain-Barré Syndrome Outcome Study, but the frequency of variants differed between regions. We compared three regions based on geography, income and previous reports of Guillain-Barré syndrome subtypes: 'Europe/Americas', 'Asia' (without Bangladesh), and 'Bangladesh'. We excluded 75 (8%) patients because of alternative diagnoses, protocol violations, or missing data. The predominant clinical variant was sensorimotor in Europe/Americas (n = 387/562, 69%) and Asia (n = 27/63, 43%), and pure motor in Bangladesh (n = 74/107, 69%). Miller Fisher syndrome and Miller Fisher-Guillain-Barré overlap syndrome were more common in Asia (n = 14/63, 22%) than in the other two regions (Europe/Americas: n = 64/562, 11%; Bangladesh: n = 1/107, 1%) (P < 0.001). The predominant electrophysiological subtype was demyelinating in all regions (Europe/Americas: n = 312/573, 55%; Asia: n = 29/65, 45%; Bangladesh: n = 38/94, 40%). The axonal subtype occurred more often in Bangladesh (n = 34/94, 36%) than in Europe/Americas (n = 33/573, 6%) and other Asian countries (n = 4/65, 6%) (P < 0.001). In all regions, patients with the axonal subtype were younger, had fewer sensory deficits, and showed a trend towards poorer recovery compared to patients with the demyelinating subtype. The proportion of patients able to walk unaided after 1 year varied between Asia (n = 31/34, 91%), Europe/Americas (n = 334/404, 83%) and Bangladesh (n = 67/97, 69%) (P = 0.003). A similar variation was seen for mortality, being higher in Bangladesh (n = 19/114, 17%) than in Europe/Americas (n = 23/486, 5%) and Asia (n = 1/45, 2%) (P < 0.001). This study showed that factors related to geography have a major influence on clinical phenotype, disease severity, electrophysiological subtype, and outcome of Guillain-Barré syndrome.

[Under-diagnosis of neuromuscular diseases in patients of 80 years and older]

Myasthenia gravis (MG), amyotrophic lateral sclerosis and Guillain-Barre syndrome (GBS) have been classically considered as exceptional or unusual diseases in people with a geriatric profile. Over the past 25 years, several population-based studies have been conducted in the Osona area (Barcelona), which, for the first time, has led to describing the high global incidences in the elderly, especially those over 80 years-old. The results suggest the possibility of underdiagnosis of these neuromuscular diseases in the elderly, a fact that could be especially relevant in the case of MG and GBS, since they are 2potentially reversible entities with high mortality in the event of underdiagnosis and absence of treatment.

Increased incidence of axonal Guillain-Barré syndrome in La Spezia area of Italy: A 13-year follow-up study

Guillain-Barré syndrome (GBS) is an acute immune-mediated polyradiculoneuropathy with a worldwide incidence of 0.81-1.89 per 100 000 person-years. In Europe and North America only 5% of patients with GBS have axonal subtypes, which in South America and Asia account for 30%-47% of cases. The aim of our study is to assess the annual incidence and clinical features of GBS in La Spezia area in Italy. A retrospective (from 1 January 2003 to 31 December 2011) followed by a prospective (from 1 January 2012 to 31 December 2015) analysis was carried out on patients admitted to La Spezia hospital who fulfilled the GBS diagnostic criteria. A total of 86 patients (58 men), mean age of 62.7 years (range 21-90), were included. The mean annual incidence rate was 3/100 000 (range: 0.9/100 000-5.37/100 000) significantly higher than the European incidence (P < 0.001). Forty-seven percent were classified as acute inflammatory demyelinating polyradiculoneuropathy (AIDP), 35% as acute motor and motor-sensory axonal neuropathy (AMAN-AMSAN), 13% as variant forms, and 5% were not defined. AIDP was most common in "Golfo dei Poeti" (50%) and "Val di Magra" (63.2%), whereas AMAN/AMSAN prevailed in "Val di Vara" (63.6%) and "Riviera Spezzina" (62.5%) (P = 0.024). In La Spezia area GBS incidence (especially the AMAN subtype) is significantly higher than the incidence reported in Europe. AIDP predominates in the eastern area whereas AMAN/AMSAN in the western, with a significantly different incidence rate (P = 0.003). Prospective studies to assess possible predisposing environmental factors are needed.

Acute bilateral vision deficit as the initial symptom in Guillain-Barre syndrome: A case report

Guillain-Barre syndrome (GBS) is a rare autoimmune-mediated peripheral neuropathy with an acute onset. GBS is associated with posterior cranial nerve injury including the facial, oculomotor, glossopharyngeal and vagus nerves. A 43-year-old female presented with worsening blurred binocular vision accompanied by diplopia, bilateral ptosis, speech difficulties, dysphagia, extremity numbness and weakness of the limbs. A neurological examination was conducted along with magnetic resonance imaging of the brain and spinal cord, electromyography, cerebrospinal fluid analysis and visual evoked potential tests, which led to a diagnosis of GBS. Following immunoglobulin administration, the patient's neurological deficiencies were markedly relieved and they were discharged following a 3-week observation period. To the best of our knowledge, this is the first reported case of GBS associated with cranial nerve damage presenting with bilateral visual deterioration as the initial symptom. It is necessary to emphasize that early diagnosis and commencing the immunological treatment in a timely manner resulted in a favorable prognosis for the patient.

Immunotherapy of Guillain-Barré syndrome

Guillain-Barré syndrome (GBS), the most common cause of acute neuromuscular weakness and paralysis worldwide, encompasses a group of acute immune-mediated disorders restricted to peripheral nerves and roots. Immune-mediated attack of peripheral nervous system myelin, axons or both is presumed to be triggered by molecular mimicry, with both cell- and humoral-dependent mechanisms implicated in disease pathogenesis. Good circumstantial evidence exists for a pathogenic role for molecular mimicry in GBS pathogenesis, especially with its axonal forms, providing insights that could guide future immunotherapy. Intravenous immunoglobulin (IVIg) and plasma exchange (PE) are the most commonly prescribed immunotherapies for GBS with variable efficacy dependent on GBS subtype, severity at initial presentation and other clinical and electrophysiologic prognostic factors. The mechanisms of action of IVIg and PE are not known definitely. Despite recent significant advances in molecular biology that provide insights into GBS pathogenesis, no advances in therapeutics or significant improvements in patient outcomes have occurred over the past three decades. We summarize the clinical aspects of GBS, its current pathogenesis and immunotherapy, and highlight the potential of leukocyte trafficking inhibitors as novel disease-specific immunotherapeutic drugs.

Guillain Barre Syndrome in the elderly: Experience from a tertiary-care hospital in India

Age influences incidence and prognosis of Guillain Barre Syndrome (GBS), common cause of ascending areflexic quadriparesis. Dedicated studies on elderly GBS are infrequent. This study aimed to describe clinical features and outcome at hospital-discharge in patients aged≥60years with GBS. Medical records of 70 elderly GBS over 15years were analysed. Mean symptom-duration was 5.78±4.5days and onset-to-peak 5.14±4.4days. Antecedent events preceded GBS by 8.07±9.9days and included: fever (n=19), respiratory infection (n=6), and gastroenteritis (n=5). Clinical features were weakness of facial (n=34), bulbar (n=13), extraocular (n=4) and respiratory (n=20) muscles and recurrence (n=4). Nine had Hughes disability score (HDS) of three or less. Sensory symptoms and signs included paresthesias (n=40), pain (n=24), and impaired kinaesthetic sensation (n=14). Laboratory abnormalities included albumino-cytological dissociation (n=50), hyponatremia (n=36) and elevated creatine kinase (n=18). Electrophysiological subtypes were: primary demyelinating (n=52), inexcitable (n=3), equivocal (n=2) and axonal (n=1). Fifty-seven patients treated with plasmapheresis (n=48) or intravenous immunoglobulin (n=9) had mean HDS of 3.53±0.7 at discharge. Twenty-one were ambulant (HDS≥3), one had persisting respiratory weakness and one died. Striking differences between the 'elderly' and 100 'adults' seen over 20months were shorter symptom-duration, higher frequency of facial palsy and hyponatremia, lower frequency of pain, lower mean MRC sum score and worse HDS at study-entry and discharge (p<0.05). Requirement for mechanical ventilation and cardiac autonomic dysfunction was higher among elderly (p:0.02). In conclusion, in this cohort of elderly GBS, there was a higher frequency severe GBS and demyelinating electrophysiology.

Guillain-Barré syndrome: causes, immunopathogenic mechanisms and treatment

INTRODUCTION

Guillain-Barré syndrome is a rare disease representing the most frequent cause of acute flaccid symmetrical weakness of the limbs and areflexia usually reaching its peak within a month. The etiology and pathogenesis remain largely enigmatic and the syndrome results in death or severe disability in 9-17% of cases despite immunotherapy. Areas covered: In terms of etiology, Guillain-Barré syndrome is linked to Campylobacter infection but less than 0.1% of infections result in the syndrome. In terms of pathogenesis, activated macrophages and T cells and serum antibodies against gangliosides are observed but their significance is unclear. Expert commentary: Guillain-Barré syndrome is a heterogeneous condition with numerous subtypes and recent data point towards the role of ganglioside epitopes by immunohistochemical methods. Ultimately, the syndrome results from a permissive genetic background on which environmental factors, including infections, vaccination and the influence of aging, lead to disease.

The Importance of Rare Subtypes in Diagnosis and Treatment of Peripheral Neuropathy: A Review

IMPORTANCE

Peripheral neuropathy is a prevalent condition that usually warrants a thorough history and examination but has limited diagnostic evaluation. However, rare localizations of peripheral neuropathy often require more extensive diagnostic testing and different treatments.

OBJECTIVE

To describe rare localizations of peripheral neuropathy, including the appropriate diagnostic evaluation and available treatments.

EVIDENCE REVIEW

References were identified from PubMed searches conducted on May 29, 2015, with an emphasis on systematic reviews and randomized clinical trials. Articles were also identified through the use of the authors' own files. Search terms included common rare neuropathy localizations and their causes, as well as epidemiology, pathophysiology, diagnosis, and treatment.

FINDINGS

Diffuse, nonlength-dependent neuropathies, multiple mononeuropathies, polyradiculopathies, plexopathies, and radiculoplexus neuropathies are rare peripheral neuropathy localizations that often require extensive diagnostic testing. Atypical neuropathy features, such as acute/subacute onset, asymmetry, and/or motor predominant signs, are frequently present. The most common diffuse, nonlength-dependent neuropathies are Guillain-Barré syndrome, chronic inflammatory demyelinating polyneuropathy, multifocal motor neuropathy, and amyotrophic lateral sclerosis. Effective disease-modifying therapies exist for many diffuse, nonlength-dependent neuropathies including Guillain-Barré syndrome, chronic inflammatory demyelinating polyneuropathy, multifocal motor neuropathy, and some paraprotein-associated demyelinating neuropathies. Vasculitic neuropathy (multiple mononeuropathy) also has efficacious treatment options, but definitive evidence of a treatment effect for IgM anti-MAG neuropathy and diabetic amyotrophy (radiculoplexus neuropathy) is lacking.

CONCLUSIONS AND RELEVANCE

Recognition of rare localizations of peripheral neuropathy is essential given the implications for diagnostic testing and treatment. Electrodiagnostic studies are an important early step in the diagnostic evaluation and provide information on the localization and pathophysiology of nerve injury.

Recurrent Guillain-Barré syndrome, Miller Fisher syndrome and Bickerstaff brainstem encephalitis

OBJECTIVE

Guillain-Barré syndrome (GBS), Miller Fisher syndrome (MFS), and Bickerstaff brainstem encephalitis (BBE) are usually monophasic, but some patients experience recurrences after long asymptomatic intervals. We aimed to investigate clinical features of recurrent GBS, MFS, and BBE at a single hospital.

METHODS

Records from 97 consecutive patients with GBS, MFS or BBE who were admitted to a tertiary hospital between 2001 and 2013 were reviewed. Clinical and laboratory features of patients with recurrent GBS, MFS, or BBE were investigated.

RESULTS

Patients included 55 (32 males) with GBS, 34 (22 males) with MFS, and 8 (6 males) with BBE. Recurrent cases occurred in 2 (4%) of the 55 patients with GBS, 4 (12%) of the 34 patients with MFS, and 2 (25%) of the 8 patients with BBE. Patients with recurrent MFS had a tendency to be younger at the first episode than patients with non-recurrent MFS (median, 22 versus 37years old). Symptoms and signs were less severe during relapses than during the initial episode in recurrent patients.

CONCLUSIONS

Recurrences occurred more frequently in patients with MFS or BBE compared with those with GBS. Patients with recurrent MFS might be younger than those with non-recurrent MFS.

Demyelinating Guillain-Barré syndrome recurs more frequently than axonal subtypes

Guillain-Barré syndrome (GBS) is considered a monophasic disorder yet recurrences occur in up to 6% of patients. We retrospectively studied an Italian-Japanese population of 236 GBS and 73 Miller Fisher syndrome (MFS) patients and searched for factors which may be associated with recurrence. A recurrent patient was defined as having at least two episodes that fulfilled the diagnostic criteria for GBS and MFS with an identifiable recovery after each episode and a minimum of 2months between episodes. Preceding Campylobacter jejuni (C. jejuni) infection and antiganglioside antibodies were also assessed. Seven (3%) recurrent GBS and one (1.4%) recurrent MFS patients were identified. In the individual patient the clinical features during episodes were usually similar varying in severity whereas the preceding infection differed. None of the patients had GBS in one episode and MFS in the recurrence or vice versa. Recurrent GBS patients, compared with monophasic GBS, did not have preceding diarrhea at the first episode and considering the electrophysiological subtypes, acute inflammatory demyelinating polyneuropathies recurred more frequently than axonal GBS (6.5% vs 0.9%, p=0.04). In conclusion in a GBS population with a balanced number of demyelinating and axonal subtypes less frequent diarrhea and demyelination at electrophysiology were associated with recurrence.

Clinical Features of Miller-Fisher Syndrome in Pregnancy

Miller-Fisher syndrome (MFS) is recognized as a variant of Guillain-Barré syndrome (GBS). MFS is a rare disorder that is characterized by the acute onset of ophthalmoplegia, ataxia, and areflexia/hyporeflexia. MFS has a higher incidence in Asia, where the incidence is estimated to be 18%–26% of GBS compared with 3%–5% in the West. The differential diagnosis of MFS includes Wernicke's encephalopathy (WE) which is characterized by a clinical triad (nystagmus and ophthalmoplegia, mental status changes, and ataxia), myasthenia gravis, and brainstem stroke. The association between MFS and pregnancy has not been reported previously. Here, we describe the clinical features of a pregnant woman in early pregnancy with MFS. This case highlights the fact that it is necessary to establish an accurate diagnosis based on the details from the patient's history on appropriate complementary testing in a pregnant patient with MFS.

Guillain-Barré syndrome: clinical profile and management

INTRODUCTION

Guillain-Barré syndrome (GBS) is a fulminant polyradiculoneuropathy that is acute, frequently severe and autoimmune in nature. Etiology of GBS is incompletely understood, prognosis is usually good with early detection and prompt treatment. This retrospective study was done to evaluate clinical profile, epidemiological, laboratory, and electrodiagnostic features of patients with GBS and mode of management, complications and prognostic factors.

METHODS

Data of 1,166 patients admitted with GBS or presented to outpatient department (previous medical records) with GBS between January 2003 and January 2014 were analyzed.

RESULTS

No difference in genders noted. Around 35% of patients are above 50 years of age. Poor control of diabetes with mean HbA1c of 8.1 ± 2.11 is found on analysis. Seasonal occurrence in GBS is prominent in winter 484 (41.50%) and mechanically ventilated were 449 (38.50%) patients. 48 (4.11%) deaths were attributed to GBS. Neurological analysis revealed cranial nerve involvement in 407 (34.90%) patients, facial palsy in 401 (34.39%) and ataxia in 88 (7.54%) patients. Most patients in plasma exchange group belonged to the lower socio-economic status. Mean cerebrospinal fluid (CSF) protein levels was (n=962) 113.8 ± 11.8 mg/dl. Conduction block determined indirectly by absent H-reflex was noted in 891 (90.64%) patients. No difference in complications and outcome is found in treatment regimens of intravenous immunoglobulin (IVIG) and plasma exchange.

CONCLUSION

Seasonal occurrence predominantly in winter is noted. Peak flow test may be a predictor of assessing requirement of mechanical ventilation and prognosis. Conduction block is the major abnormality noted in electrophysiological studies and proximal nerve segment assessing with Erb's point stimulation has high predictive value. IVIG treatment is more expensive but is associated with less duration of hospital stay.

A Multicentric Prospective Incidence Study of Guillain-Barré Syndrome in Italy. The ITANG Study

Background: To assess Guillain-Barré syndrome (GBS) incidence we relied on the Italian Network for the study of GBS (ITANG) established in 2010 in 7 Italian regions to analyse the association between influenza vaccination and GBS. Methods: All individuals aged ≥18 years, presenting with clinical manifestations that suggested GBS according to the universally accepted Asbury's diagnostic criteria (1990) were prospectively notified to a centralised database by ITANG neurologists over the period October 1, 2010-September 30, 2011. Through a telephone survey, 9 trained interviewers followed up the cases to diagnosis and then for 1 year since hospital discharge. Validation of case reporting was performed with the support of administrative data in 5 regions. Results: We found 365 cases fulfilling the definition for GBS or one of its variants over 19,846,068 population ≥18 years of age, yielding an annual incidence rate of 1.84 per 100,000 (95% CI 1.65-2.03), 2.30 (95% CI 1.99-2.60) in men and 1.41 (95% CI 1.18-1.64) in women. A highly significant peak of incidence was observed in February 2011 as compared to reference month (September 2011, rate ratio 3.3:1, p < 0.01). Conclusions: In Italy, GBS incidence was among the highest reported in Europe and higher than previously observed in Italian studies.

A multicentre prospective study of Guillain-Barré syndrome in Japan: a focus on the incidence of subtypes

OBJECTIVE

Guillain-Barré Syndrome (GBS) is classified into the two major subtypes; acute inflammatory demyelinating polyneuropathy (AIDP) and acute motor axonal neuropathy (AMAN). Previous studies have suggested that AIDP is predominant and AMAN is rare in Western countries, whereas AMAN is not always uncommon in East Asia. We aimed to clarify the incidence of the subtypes of GBS in Japan.

METHODS

We performed a prospective multicentre survey over 3 years (2007-2010). Clinical and electrophysiological findings were collected from 184 patients with GBS in 23 tertiary neurology institutes. Anti-ganglioside antibodies were measured by ELISA. We also surveyed the incidence of Fisher syndrome (FS).

RESULTS

By electrodiagnostic criteria of Ho et al, patients were classified as having AIDP (40%), or AMAN (22%), or unclassified (38%). Anti-GM1 IgG antibodies were found for 47% of AMAN patients, and 18% of AIDP patients (p<0.001). There were no specific regional trends of the electrodiagnosis and anti-GM1 positivity. During the same study period, 79 patients with FS were identified; the percentage of FS cases out of all cases (FS/(GBS+FS)) was 26%.

CONCLUSIONS

The frequency of GBS patients with the electrodiagnosis of AMAN by single nerve conduction studies is approximately 20% in Japan, and the AMAN pattern is closely associated with anti-GM1 antibodies. The incidence of FS appears to be much higher in Japan than in Western countries.

Clinical features of patients with Guillain-Barré syndrome at seven hospitals on the East Coast of Australia

To document the clinical features of Guillain-Barré syndrome (GBS) in Australia, we performed a retrospective analysis of all patients admitted to several hospitals along the East Coast of Australia from 2000 to 2012. Using hospital records, we reviewed all patients with a diagnosis of GBS admitted to seven hospitals. From these, we report information of subjects who fulfilled standard diagnostic criteria. We excluded patients where inadequate information was available or who were under the age of 18. We report the features of 335 patients, in 228 of whom neurophysiological data were available. There were 168 cases of acute inflammatory demyelinating polyneuropathy (AIDP), 17 of acute motor axonal neuropathy (AMAN), 4 of acute motor and sensory axonal neuropathy (AMSAN), and 35 of Miller-Fisher syndrome (MFS). The median age at onset was 52.5 years (18-89 years) with a male : female ratio of 1.61 : 1. Upper respiratory tract infections were the most frequently identified trigger (151 subjects, 44.5%). Most patients were severely affected, with 42.7% of subjects bedbound, and an additional 24% requiring ventilatory support. GBS affects adults of all ages and usually follows a severe clinical course. In contrast to other autoimmune diseases, males are more frequently affected. A wide variety of triggering factors leads to a relatively stereotypical clinical syndrome. The most common variant of GBS in Australia is AIDP. This study shows that the clinical features of GBS in Australia are similar to that previously reported and confirms the male predominance, increased incidence with age, and frequent evidence of peripheral nerve demyelination as features of GBS.

Pathophysiology and diagnosis of Guillain-Barré syndrome - challenges and needs

Guillain-Barré syndrome (GBS) is an autoimmune polyneuropathy which presents with acute onset and rapid progression of flaccid, hyporeflexi quadriparesis. Both sensory and autonomic nerve involvement is seen. GBS has various subtypes that vary in their pathophysiology. The pathogenesis involves an immune response triggered by a preceding event which may be an infection, immunisation or surgical procedure. Clinical diagnosis has been largely the primary diagnosing criterion for GBS along with electrodiagnosis, which has several pitfalls and is supported by ancillary testing of cerebrospinal fluid (CSF) analysis and Nerve Conduction Studies. Measurement of anti-ganglioside antibodies is also an effective tool in its diagnosis. Further understanding of pathophysiology and better diagnostic methods are required for better management of GBS.

Cytokines and chemokines at the crossroads of neuroinflammation, neurodegeneration, and neuropathic pain

Cytokines and chemokines are proteins that coordinate the immune response throughout the body. The dysregulation of cytokines and chemokines is a central feature in the development of neuroinflammation, neurodegeneration, and demyelination both in the central and peripheral nervous systems and in conditions of neuropathic pain. Pathological states within the nervous system can lead to activation of microglia. The latter may mediate neuronal and glial cell injury and death through production of proinflammatory factors such as cytokines and chemokines. These then help to mobilize the adaptive immune response. Although inflammation may induce beneficial effects such as pathogen clearance and phagocytosis of apoptotic cells, uncontrolled inflammation can result in detrimental outcomes via the production of neurotoxic factors that exacerbate neurodegenerative pathology. In states of prolonged inflammation, continual activation and recruitment of effector cells can establish a feedback loop that perpetuates inflammation and ultimately results in neuronal injury. A critical balance between repair and proinflammatory factors determines the outcome of a neurodegenerative process. This review will focus on how cytokines and chemokines affect neuroinflammation and disease pathogenesis in bacterial meningitis and brain abscesses, Lyme neuroborreliosis, human immunodeficiency virus encephalitis, and neuropathic pain.

Peripheral neuropathy in the elderly

Peripheral neuropathy is an important factor of disability in the elderly, which is significant now that up to 20% of the population is older than 60 years in industrialized countries. Potentially treatable neuropathies including primary inflammatory polyneuropathies and systemic disorders, especially vasculitic neuropathies, are as common in this age group as in younger patients. Neuropathies associated with diabetes, malignancy, and monoclonal gammopathies are even more common in these patients. It is thus essential to identify the causes of these neuropathies in this group of patients and treat them whenever feasible.

The Guillain-Barré syndrome

The latest estimation for the frequency of Guillain-Barré syndrome (GBS) is 1.1 to 1.8 per 100000 persons per year. Guillain-Barré syndrome is today divided into two major subtypes: acute inflammatory demyelinating polyneuropathy (AIDP) and the axonal subtypes, acute motor axonal neuropathy (AMAN) and acute motor and sensory axonal neuropathy (AMSAN). The axonal forms of GBS are caused by certain autoimmune mechanisms, due to a molecular mimicry between antecedent bacterial infection (particularly Campylobacter jejuni) and human peripheral nerve gangliosides. Improvements in patient management in intensive care units has permitted a dramatic drop in mortality rates. Immunotherapy, including plasma exchange (PE) or intravenous immunoglobulin (IVIg), seems to shorten the time to recovery, but their effect remains limited. Further clinical investigations are needed to assess the effect of PE or IVIg on the GBS patients with mild affection, no response, or relapse.

Updated assessment of the prevalence, spectrum and case definition of autoimmune disease

Autoimmune diseases are heterogeneous with regard to prevalence, manifestations, and pathogenesis. The classification of autoimmune diseases has varied over time. Here, we have compiled a comprehensive up-to-date list of the autoimmune diseases, and have reviewed published literature to estimate their prevalence. We identified 81 autoimmune diseases. The overall estimated prevalence is 4.5%, with 2.7% for males and 6.4% for females. For specific diseases, prevalence ranges from 1% to <1/10(6). Considering all diseases in the class, the most common mean age-of-onset was 40-50 years. This list of autoimmune diseases has also yielded information about autoantigens. Forty-five autoimmune diseases have been associated with well-defined autoantigens. Of the diseases with known autoantigens, 33.3% had highly repetitive sequences, 35.6% had coiled-coil arrangements and 57.8% were associated with cellular membranes, which means that based on these structural motifs alone, autoantigens do not appear to be a random sample of the human proteome. Finally, we identified 19 autoimmune diseases that phenocopy diseases arising from germline mutations in the corresponding autoantigen. Collectively, our findings lead to a tentative proposal for criteria for assigning autoimmune pathogenesis to a particular disease.

Guillain-Barre syndrome, influenzalike illnesses, and influenza vaccination during seasons with and without circulating A/H1N1 viruses

The role of influenzalike illnesses and influenza vaccination in the development of Guillain-Barré syndrome (GBS), particularly the role of A/H1N1 epidemics and A/H1N1 vaccination, is debated. Data on all incident GBS cases meeting the Brighton Collaboration criteria that were diagnosed at 25 neurology centers in France were prospectively collected between March 2007 and June 2010, covering 3 influenzavirus seasons, including the 2009-2010 A/H1N1 outbreak. A total of 457 general practitioners provided a registry of patients from which 1,080 controls were matched by age, gender, index date (calendar month), and region to 145 cases. Causal relations were assessed by multivariate case-control analysis with adjustment for risk factors (personal and family history of autoimmune disorders, among others), while matching on age, gender, and calendar time. Influenza (seasonal or A/H1N1) or influenzalike symptoms in the 2 months preceding the index date was associated with GBS, with a matched odds ratio of 2.3 (95% confidence interval (CI): 0.7, 8.2). The difference in the rates of GBS occurring between influenza virus circulation periods and noncirculation periods was highly statistically significant (P = 0.004). Adjusted odds ratios for GBS occurrence within 6 weeks after seasonal and A/H1N1 vaccination were 1.3 (95% CI: 0.4, 4.1) and 0.9 (95% CI: 0.1, 7.6), respectively. Study results confirm that influenza virus is a likely risk factor for GBS. Conversely, no new concerns have arisen regarding influenza vaccination.

Population incidence of Guillain-Barré syndrome: a systematic review and meta-analysis

Population incidence of Guillain-Barré syndrome (GBS) is required to assess changes in GBS epidemiology, but published estimates of GBS incidence vary greatly depending on case ascertainment, definitions, and sample size. We performed a meta-analysis of articles on GBS incidence by searching Medline (1966-2009), Embase (1988-2009), Cinahl (1981-2009) and CABI (1973-2009) as well as article bibliographies. We included studies from North America and Europe with at least 20 cases, and used population-based data, subject matter experts to confirm GBS diagnosis, and an accepted GBS case definition. With these data, we fitted a random-effects negative binomial regression model to estimate age-specific GBS incidence. Of 1,683 nonduplicate citations, 16 met the inclusion criteria, which produced 1,643 cases and 152.7 million person-years of follow-up. GBS incidence increased by 20% for every 10-year increase in age; the risk of GBS was higher for males than females. The regression equation for calculating the average GBS rate per 100,000 person-years as a function of age in years was exp[-12.0771 + 0.01813(age in years)] × 100,000. Our findings provide a robust estimate of background GBS incidence in Western countries. Our regression model may be used in comparable populations to estimate the background age-specific rate of GBS incidence for future studies.

Clinico-electrophysiological findings and prognosis of Guillain-Barré syndrome--10 years' experience

OBJECTIVE

To assess correlation between the prognosis and epidemiological, clinical, laboratory, electrophysiological findings in patients with Guillain-Barré syndrome (GBS).

METHODS

We reviewed the medical records of 104 GBS patients who were hospitalized and followed up at our outpatient clinic during October 1997-November 2007.

RESULTS

Guillain-Barré syndrome patients were followed up with a median period of 232 days. Full recovery or minor deficits were observed in 41% of patients in the first month, 71% in the third month, 86% in the sixth month and 92% in the first year. We found that there was a correlation between Medical Research Council (MRC) sum scores at admission, clinical subtypes, respiratory distress, interference pattern and prognosis.

CONCLUSIONS

Demographic, clinical and electrophysiological findings of our GBS cases were highly similar to those of the previous reports. Two of our cases were presented with preceding tuberculosis infection, which was not reported before in the literature.

Evaluation of Guillain-Barré Syndrome among recipients of influenza vaccine in 2000 and 2001

BACKGROUND

The 1976-1977 swine influenza vaccine was associated with an elevated risk of Guillain-Barré Syndrome (GBS), especially within 6 weeks after vaccination. A 2004 IOM report concluded that evidence was inadequate to accept or reject a causal relationship between subsequent influenza vaccine formulations and GBS. Studies published after the IOM report have been limited by passively reported data or lack of validation of coded diagnoses.

PURPOSE

To evaluate whether influenza vaccine is associated with GBS.

METHODS

Controlled observational study using national data from the Medicare program, which ensures a predominantly elderly population. People included had a Medicare claim for influenza vaccination during September-December in 2000 or 2001. Medical records were reviewed to classify definite, probable, or possible GBS (or not a case) using a standardized case definition. In a risk interval design, the incidence rate of GBS during Weeks 0-6 after vaccination (exposed period) was compared to Weeks 9-14 after vaccination (comparison period). Data collection occurred during 2003-2007, and analysis was conducted during 2007-2009.

RESULTS

Primary analysis included 22.2 million vaccinees, among whom 164 definite or probable GBS cases with onset during Weeks 0-6 or 9-14 were identified. The incidence rate ratio (IRR [95% CIs]) based on the GBS rate in the vaccine-exposed versus comparison periods, was 1.04 (0.76, 1.43) for combined years; 0.86 (0.52, 1.41) among people vaccinated in 2000; and 1.21 (0.79, 1.86) among people vaccinated in 2001. Secondary analysis additionally included 74 possible GBS cases; results were similar.

CONCLUSIONS

Overall, the results do not support an association between influenza vaccine receipt and GBS among the elderly for the years studied (2000-2001 and 2001-2002 formulations).