Prevalence of autonomic dysfunction in hospitalized patients with Guillain-Barré syndrome

Hyponatremia in Guillain-Barre Syndrome: A Review of Its Pathophysiology and Management

Guillain-Barre syndrome (GBS) is the commonest cause of acute polyradiculoneuropathy that requires hospitalization. Many of these patients experience systemic and disease-related complications during its course. Notable among them is hyponatremia. Though recognized for decades, the precise incidence, prevalence, and mechanism of hyponatremia in GBS are not well known. Hyponatremia in GBS patients is associated with more severe in-hospital disease course, prolonged hospitalization, higher mortality, increased costs, and a greater number of other complications in the hospital and worse functional status at 6 months and at 1 year. Though there are several reports of low sodium associated with GBS, many have not included the exact temporal relationship of sodium or its serial values during GBS thereby underestimating the exact incidence, prevalence, and magnitude of the problem. Early detection, close monitoring, and better understanding of the pathophysiology of hyponatremia have therapeutic implications. We review the complexities of the relationship between hyponatremia and GBS with regard to its pathophysiology and treatment.

SARS-CoV-2 and Guillain-Barré Syndrome: Lessons from Viral Infections

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is responsible for the COVID-19 pandemic. COVID-19 has a broad clinical spectrum from asymptomatic patients to multiorgan dysfunction and septic shock. Most of the common symptoms of COVID-19 are classified as respiratory disorders, but some reports show neurological involvements. During the COVID-19 pandemic, a case series of neurological complications, such as Guillain-Barré syndrome (GBS), were reported. GBS is a neuroimmune disorder with acute inflammatory radicular polyneuropathy in different parts of the peripheral nerve. Some studies have reported GBS as an inflammatory neuropathy related to various viral infections, such as cytomegalovirus (CMV), Epstein-Barr Virus (EBV), herpes simplex virus (HSV), human immunodeficiency virus (HIV), influenza, and Zika virus. There are some immunomodulation approaches for the management of GBS. Studies have evaluated the effects of the various therapeutic approaches, including intravenous immunoglobulin (IVIG), plasma exchange (PE), complement inhibitors, and corticosteroids to regulate overactivation of immune responses during GBS in experimental and clinical studies. In this regard, the possible association between GBS and SARS-CoV-2 infection during the outbreak of the current pandemic and also the mentioned therapeutic approaches were reviewed.

Case Report: Abnormal ECG and Pantalgia in a Patient With Guillain-Barré Syndrome

Background: Guillain–Barré syndrome (GBS) is an acute immune-mediated disorder in the peripheral nervous system (PNS) characterized by symmetrical limb weakness, sensory disturbances, and clinically absent or decreased reflexes. Pantalgia and dysautonomia, including cardiovascular abnormalities, are common findings in the spectrum of GBS. It is usually challenging to distinguish GBS-related electrocardiogram (ECG) abnormities and chest pain from acute coronary syndrome (ACS) in patients with GBS due to the similar clinical symptom and ECG characteristics. Here, we present a case of GBS complicating ACS.

Case Summary: A 37-year-old woman with a 2-month history of GBS presented to the emergency department due to pantalgia. The ECG showed a pattern of transitional T-wave inversion in the leads I, aVL, and V2 through V4 and shortly returned to normal, which appeared several times in a short time, but lab testing was unremarkable. Then, a further coronary computed tomography angiography (CTA) revealed the presence of critical stenosis of the left anterior descending artery, leading to the diagnosis of ACS. During the follow-up, she suffered from a non-ST-elevation myocardial infarction and accepted revascularization of the left anterior descending artery in the second week after discharge.

Conclusion: Guillain–Barré syndrome could accompany chest pain and abnormalities on ECG. Meanwhile, it is essential to bear in mind that “GBS-related ECG abnormalities and chest pain” is a diagnosis of exclusion that can only be considered after excluding coronary artery disease, especially when concomitant chest pain, despite being a common presentation of pantalgia, occurs.

A Rare Case of Guillain-Barré Syndrome With Severe Pandysautonomia

Acute pandysautonomia is a rare disorder characterized by autonomic failure affecting sympathetic, parasympathetic, and enteric functions. We present a case of acute inflammatory demyelinating polyneuropathy (AIDP) with severe pandysautonomia in a young, otherwise healthy, female who presented with gastrointestinal symptoms and sensory demyelinating polyneuropathy, which progressively worsened and subsequently developed bladder dysfunction and orthostatic hypotension. We discuss the challenges with diagnostic workup as well as the challenges we encountered as part of the management.

Sodium Levels Predict Disability at Discharge in Guillain-Barré Syndrome: A Retrospective Cohort Study

Guillain-Barré syndrome (GBS) is an inflammatory polyradiculopathy with potentially severe complications. Clinical tools for risk stratification have been developed, but no definitive prognostic biomarker has been reported. Hyponatremia is frequent in GBS patients, but the impact of serum sodium levels on clinical outcomes is still ill-defined. In this retrospective cohort study, we included all adult patients diagnosed with GBS spectrum disorders at our center from January 2010 to July 2020. Disability at discharge was assessed with the GBS Disability Score (GDS), and all clinical and laboratory data was retrieved from medical charts. Thirty (58.8%) of the 51 subjects included in the study were discharged with severe residual disability (GDS ≥ 3). After accounting for relevant confounders, the odds of experiencing severe disability decreased by 27% (p = 0.027) for each unitary increase in serum sodium concentration. Thirteen (25.5%) patients were diagnosed with mild to moderate hyponatremia; the use of intravenous immune globulin (IVIG) independently increased the odds of developing hyponatremia. In conclusion, we found a significant, independent association between baseline serum sodium levels and severe disability at discharge in GBS patients. In our cohort, hyponatremia was more frequently observed after treatment with IVIG, suggesting dilutional pseudohyponatremia as a probable cause.

Nerve ultrasound evaluation of Guillain-Barré syndrome subtypes in northern China

INTRODUCTION/AIMS

Ultrasound (US) studies have demonstrated patchy enlargement of spinal and peripheral nerves in Guillain-Barré syndrome (GBS). However, whether ultrasound yields useful information for early classification of GBS has not been established. We aimed to evaluate nerve ultrasound in patients with GBS in northern China and compare the sonographic characteristics between demyelinating and axonal subtypes.

METHODS

Between November 2018 and October 2019, 38 hospitalized GBS patients within 3 wk of disease onset and 40 healthy controls were enrolled. Ultrasonographic cross-sectional areas (CSA) of the peripheral nerves, vagus nerve, and cervical nerve roots were prospectively recorded in GBS subtypes and controls.

RESULTS

Ultrasonographic CSA exhibited significant enlargement in most patients' nerves compared with healthy controls, most prominent in cervical nerves. The CSA tended to be larger in acute inflammatory demyelinating polyneuropathy (AIDP) than in acute motor axonal neuropathy (AMAN)/acute motor and sensory axonal neuropathy (AMSAN), especially in cervical nerves (C5: 5.9 ± 1.6 mm² vs. 7.0 ± 1.7 mm² , p = .042; C6: 10.5 ± 1.8 mm² vs. 12.0 ± 2.1 mm² , p = .033). The chi-squared test revealed significant differences in nerve enlargement in C5 (p < .001), C6 (p < .001), the proximal median nerve (p < .001), and the vagus nerve (p = .003) between GBS and controls. The vagus nerve was larger in patients with autonomic dysfunction than in patients without it (2.3 ± 1.0 mm² vs. 1.4 ± 0.5 mm² , p = .003).

DISCUSSION

The demyelinating subtype presented with more significant cervical nerve enlargement in GBS. Vagus nerve enlargement may be a useful marker for autonomic dysfunction.

Guillain-Barre syndrome: demographics, clinical features, and outcome in a single tertiary care hospital, Oman

OBJECTIVE

Guillain-Barre syndrome (GBS) is an acute autoimmune-mediated peripheral nervous system disease. Different studies from various geographical regions have reported considerable variability regarding its epidemiology, clinical features, and outcome. Our study aimed to document demographics, clinical features, and outcomes among GBS patients admitted to a single tertiary care hospital in Muscat, Oman.

METHODS

A retrospective data analysis of 44 GBS patients, who were admitted during a two-year period from January 2016 to December 2018 at Khoula hospital, was carried out. Demographics, antecedent illness, duration of symptoms, muscle power graded by the Medical Research Council scale (MRCs), sensory & autonomic involvements, nerve conduction study results, CSF study, need for ventilation, condition at discharge and subsequent follow-up status were obtained.

RESULTS

Ninety-one percent of the patients were Omanis, with male predominant 63.6% and the average age was 42.69 years. Quadriparesis was the predominant presenting complaint (61.3%) and AIDP was the commonest variant (52%). All patients received a single cycle of IVIg and (13.6%) patients admitted to the ICU for mechanical ventilation. The study showed good outcome and recovery in 18 months follow up.

CONCLUSION

The clinical presentation of GBS in the majority of patients in Oman is similar to those reported in previous studies, and most patients had favorable prognoses. Our results can be used as baseline data for understanding the characteristics of GBS in Oman and, consequently, for better management.

Dysautonomia in Guillain-Barré Syndrome: Prevalence, Clinical Spectrum, and Outcomes

BACKGROUND

Guillain-Barré syndrome (GBS), when severe, involves the autonomic nervous system; our objective was to assess the spectrum and predictors of dysautonomia, and how it may impact functional outcomes.

METHODS

A retrospective review of patients admitted to the Mayo Clinic in Rochester, MN between January 1, 2000, and December 31, 2017, with GBS and dysautonomia was performed. Demographics, comorbidities, parameters of dysautonomia, clinical course, GBS disability score, and Erasmus GBS Outcome Score (EGOS) at discharge were recorded.

RESULTS

One hundred eighty seven patients were included with 71 (38%) noted to have at least one manifestation of dysautonomia. There are 72% of patients with a demyelinating form of GBS and 36% of patients with demyelination had dysautonomia. Ileus (42%), hypertension (39%), hypotension (37%), fever (29%), tachycardia or bradycardia (27%), and urinary retention (24%) were the most common features. Quadriparesis, bulbar and neck flexor weakness, and mechanical ventilation were associated with autonomic dysfunction. Patients with dysautonomia more commonly had cardiogenic complications, syndrome of inappropriate antidiuretic hormone, posterior reversible encephalopathy syndrome, and higher GBS disability score and EGOS. Mortality was 6% in patients with dysautonomia versus 2% in the entire cohort (P = 0.02).

CONCLUSIONS

Dysautonomia in GBS is a manifestation of more severe involvement of the peripheral nervous system. Accordingly, mortality and functional outcomes are worse. There is a need to investigate if more aggressive treatment is warranted in this category of GBS.

Masquerading Guillain-Barré syndrome: uncommon, in-hospital presentation of Miller-Fisher syndrome shadowed by secondary diseases

Presentation of severe pain syndromes prior to onset of motor weakness is an uncommon but documented finding in patients with Guillain-Barré syndrome (GBS). Sciatica in GBS is a difficult diagnosis when patients present with acute radiculopathy caused by herniated disc or spondylolysis. A middle-aged woman was admitted for severe low back pain, symptomatic hyponatraemia, vomiting and constipation. On further investigation, she was diagnosed with radiculopathy, and appropriate treatment was initiated. Brief symptomatic improvement was followed by new-onset weakness in lower limbs, which progressed to involve upper limbs and right extraocular muscles. With progressive, ascending, new-onset motor and sensory deficits and laboratory evidence of demyelination by Nerve Conduction Study, a diagnosis of variant GBS was made. She was treated with intravenous immunoglobulin 2 g/kg over 5 days. The presentation of severe low back pain that was masking an existing aetiology and possible dysautonomia and the unilateral right extraocular muscles instead of bilateral make our case unique and rare.

Effects of acute neurologic disease on the heart

Patients with acute neurologic disease often also have evidence of cardiac dysfunction. The cardiac dysfunction may result in a number of clinical signs including abnormal EKG changes, variations in blood pressure, development of cardiac arrhythmias, release of cardiac biomarkers, and reduced ventricular function. Although typically reversible, these cardiac complications are important to recognize as they are associated with increased morbidity and mortality. In this chapter, we discuss the suspected pathophysiology, clinical presentation, and management of the cardiac dysfunction that occur as a consequence of different types of acute neurologic illness.

Frequency of Autonomic Dysfunction in Patients of Guillain Barre Syndrome in a Tertiary Care Hospital

Introduction

Guillain-Barré syndrome (GBS) is defined as a syndrome manifesting as an acute inflammatory demyelinating polyradiculoneuropathy (AIDP) with coexistent weakness and absent or diminished reflexes clinically.Autonomic dysfunction (AD) or dysautonomia is a common finding in GBS. Autonomic dysfunction usually occurs in the acute phase of the illness but can also be seen in the recovery phase. The rationale of our study is to determine the frequency of autonomic dysfunction in patients of GBS admitted to the Neurology department of Civil Hospital, Karachi.

Methods

A total of 118 admitted patients at a tertiary care hospital in Pakistan who fulfilled the inclusion criteria were enrolled in the study after informed consent. The study was conducted for six months at the department of neurology, Civil Hospital, Karachi. Patients were assessed for autonomic dysfunction by recording blood pressures and pulse rate hourly (both lying and standing positions) by resident doctors. Urinary retention, diarrhea, and constipation were also recorded in a separate chart. All values entered in the pre-approved performa by researchers. The data was collected and analyzed on Statistical Package for Social Sciences (SPSS) version 18.0 (IBM Corp., Armonk, NY, USA). Descriptive statistics included mean, standard deviation (SD) of continuous data, like age, duration of illness, motor weakness assessment by Medical Research Council (MRC) Scale, protein content in cerebrospinal fluid (CSF), pulse, and blood pressure at the time of presentation. Frequencies and percentages were calculated from the categorical data, like gender and patients with autonomic dysfunction (outcome variable). Effect modifiers were controlled by stratification of age, gender, duration of illness. Post-stratification chi-square test was applied with a p-value of ≤ 0.05 taken as significant.

Results

In our study, the average age of the patients was 39.90±9.91 years. Frequency of autonomic dysfunction among patients with GBS was 41.53% (49/118). The most frequent autonomic manifestations were constipation and diarrhea; 22% and 21.2% respectively. Additional manifestations included urinary retention (15.3%) and fluctuation of blood pressure and heart rate at 13.6% each. 

Conclusion

This study showed that the frequency of autonomic dysfunction among patients of Guillain Barre Syndrome was significant, consistent with previous studies. Our study explored the adverse outcomes of autonomic dysfunction in patients with GBS. This will help physicians increase their understanding of dysautonomia so that effective management plans can be formulated for patients with GBS to prevent adverse outcomes and hence provide better patient care.

Self-reported autonomic dysfunction in a recovery phase of Guillain-Barré syndrome

OBJECTIVE

Autonomic dysfunction occurs in approximately two-thirds of Guillain-Barré syndrome (GBS) patients in the acute phase of the disease. Although improving over time, subclinical autonomic involvement may be present for 3-8 years after the GBS episode. The aim of this study was to determine the frequency of self-reported autonomic disorders in GBS patients three and six months after disease onset compared to healthy controls (HCs).

METHODS

Our study included adult patients diagnosed with GBS from May 2017 until May 2018 in seven healthcare centers (67.6 % with demyelinating and 13.6 % with axonal syubtype). Functional disability was assessed by the Guillain-Barré syndrome disability scale (GDS). Each subject filled in the Serbian version of the SCOPA-Aut questionnaire. Using GDS and SCOPA-Aut, patients were tested at month 3 (M3) (n = 71) and month 6 (M6) (n = 70) from symptom onset.

RESULTS

Dysautonomia was more common in patients with GBS compared to HCs at M3 (p < 0.01), while there was no difference at M6 (p > 0.05). Among autonomic disorders, constipation, complications to pass stool, and orthostatic hypotension were the most frequently reported. Patients with axonal variants had worse total SCOPA-Aut scores at M3 in comparison to AIDP patients (11.7 ± 10.1 vs. 6.1 ± 5.1, p < 0.05). GDS score correlated with the total SCOPA-Aut score.

CONCLUSION

Autonomic symptoms are common in GBS patients during the recovery phase. They are more pronounced in patients with axonal forms of GBS and those with a higher degree of functional disability.

Autonomic Hyperactivity

PURPOSE OF REVIEW

Autonomic hyperactivity is a relatively common consequence of severe acute brain injury and can also be seen with spinal cord and peripheral nerve disorders. This article reviews basic pathophysiologic concepts regarding autonomic hyperactivity, its various forms of clinical presentation, and practical management considerations.

RECENT FINDINGS

Paroxysmal sympathetic hyperactivity is most common after traumatic brain injury but can also occur after other forms of severe acute diffuse or multifocal brain injury. Formal criteria for the diagnosis and severity grading of paroxysmal sympathetic hyperactivity have now been proposed. A growing body of literature is beginning to elucidate the mechanisms underlying this disorder, but treatment remains based on observational data. Our mechanistic understanding of other distinct forms of autonomic hyperactivity, such as autonomic dysreflexia after traumatic spinal cord injury and dysautonomia after Guillain-Barré syndrome, remains rudimentary, yet clinical experience shows that their appropriate management can minimize the risk of serious complications.

SUMMARY

Syndromes of autonomic hyperactivity can result from injury at all levels of the neuraxis. Much more research is needed to refine our understanding of these disorders and guide optimal management decisions.

Acute urinary retention in children

BACKGROUND

Acute urinary retention is a common emergency in adult patients, foremost in older men. In childhood urinary retention is a rare entity with only sparse literature on the etiology.

OBJECTIVE

To assess the etiology and treatment of acute urinary retention in the pediatric population and assess age and sex distribution.

STUDY DESIGN

A retrospective analysis of all patients admitted to our emergency department with acute urinary retention between 2005 and 2019 was performed. Exclusion criteria were newborns (because of physiologic postnatal oliguria) and postoperative urinary retention during the same hospital stay.

RESULTS

113 children with acute urinary retention (ICD: R33) meeting the above criteria were identified. 16 Patients were excluded because of incomplete medical charts. 97 children were included into the study (age 0.5-18.3 years, mean age 5.3 years). 89 patients had one episode, 8 patients two episodes. A peak around the third year of age was observed. Sex ratio showed a 2:1 male to female distribution. Most common etiology was balanoposthitis (15.5%) and acute constipation/fecal impaction (15.5%). Traumatic urinary retention was found in 11.4% of the cases. Urinary tract infection were found 7.2%. No underlying reason could be found in 12.4% (idiopathic urinary retention). Other causes included febrile non-urinary infection (8.2%), subvesical obstruction (4.1%), vulvovaginitis (3.1%) and urethritis (2.1%). In 50% of the cases of urinary retention under 1 year of age (2 out of 4) an underlying tumor (rhabdomyosarcoma, sacral teratoma) was identified.

DISCUSSION

Age and sex distribution were similar to previously published series; however, this study shows a marked difference concerning the etiology: e. g. we identified a significantly higher proportion of functional disorders as a reason for acute urinary retention in childhood. It is hypothesized that this is partly because previously published studies originate from areas (USA, Israel, Iran) with different socio-demographic and cultural background.

CONCLUSION

AUR in children is a rare condition with very heterogeneous causes. Although the majority of cases exhibit mild underlying conditions, serious reasons, such as malignant diseases especially in the first year of life, must be excluded. AUR relief without catheterization is a child-friendly approach in cases of mild inflammatory or functional disorders and can help to minimize traumatization.

Clinical characteristics of Epstein-Barr virus infection in the pediatric nervous system

BACKGROUND

To investigate the clinical characteristics of Epstein-Barr virus (EBV) infection in the pediatric nervous system (NS).

METHODS

We retrospectively analyzed the clinical data and follow-up results of 89 children with neurological damage caused by EBV who were hospitalized in the children's hospital of Chongqing Medical University from January 2008 to April 2019.

RESULTS

EBV infection of the NS can occur at any time of the year. The highest incidence was seen in the age group of 0-4 years. Fever is the main clinical feature (74/89, 83.1%). The main clinical types were encephalitis/meningoencephalitis (64/89, 71.9%), acute myelitis (2/89, 2.2%), acute disseminated encephalomyelitis (ADEM) (3/89, 3.4%), Guillain-Barré Syndrome (GBS) (15/89, 16.9%), neurological damage caused by EBV-hemophagocytic lymphohistiocytosis (EBV-HLH) (4/89, 4.5%), and NS-post-transplant lymphoproliferative disorder (NS-PTLD) (1/89, 1.1%). Anti-N-methyl-D-aspartate receptor encephalitis was found during the convalescence of EBV encephalitis. EBV encephalitis/meningitis showed no symptoms of tonsillitis, lymph node enlargement, skin rash, hepatosplenomegaly. Acute motor axonal neuropathy is the chief complication in GBS caused by EBV.

CONCLUSION

There were significant differences in neurological complications caused by EBV. The prognosis of EBV infection in the NS is generally good. These illnesses are often self-limiting. A few cases may show residual sequelae.

Flaccid Paralysis with Hyponatremia: Think Guillain-Barre Syndrome

Guillain-Barre syndrome (GBS) is the most common cause of flaccid paralysis in affected patients. Here we present a case of GBS presenting with flaccid paralysis as well as hyponatremia. The association of hyponatremia in GBS is discussed, as well as other potential causes and risk factors.

Guillain-Barré syndrome complicated by takotsubo cardiomyopathy: an under-recognised association

A 41-year-old woman was admitted with progressive paraesthesia and weakness and was diagnosed with Guillain-Barré syndrome. Following an initial period of recovery with intravenous immunoglobulin treatment, she developed acute chest pain associated with electrocardiographic changes. Investigations excluded acute coronary syndrome and instead confirmed a diagnosis of takotsubo cardiomyopathy, which was treated medically. The patient made an excellent neurological and cardiac recovery. Here we discuss the rarely described association between these two conditions and suggest that patients admitted with Guillain-Barré syndrome may benefit from routine screening with echocardiography.

Reversible stress cardiomyopathy in Guillain-Barré syndrome: a case report

Background

Case Presentation

Conclusions

Amiodarone-Induced Syndrome of Inappropriate Antidiuretic Hormone: A Case Report and Review of the Literature

Amiodarone (Cordarone^®, Pfizer Inc) is an antiarrhythmic medication with a well-known toxicity profile, including rare cases of hyponatremia as a result of syndrome of inappropriate antidiuretic hormone (SIADH). We report on such a case in which a patient was found to be hyponatremic after evaluation. An 88-year-old male who presented to the emergency department was found to be hyponatremic secondary to amiodarone-induced SIADH following a fall, with possible seizure and traumatic brain injury. He had a history of hypertension, paroxysmal atrial fibrillation, emphysema, myocardial infarction, benign prostatic hyperplasia, chronic kidney disease, Meniere's disease, anemia, and gastroesophageal reflux. Upon admission, his urine sodium level was elevated, and his serum sodium, urine osmolality, and anion gap were below normal. In the setting of hyponatremia, the patient's amiodarone was held: he had been taking amiodarone 200 mg once daily for nine months prior to admission. He was treated with intravenous (IV) normal saline over four days. He was fluid-restricted and his sodium levels were closely monitored every two hours. Within 19 hours, his serum sodium levels had improved. Amiodarone was restarted approximately three days later. Upon follow-up after discharge, the patient remained on amiodarone for the next two months. His serum sodium level ranged from 126 mEq/L to 131 mEq/L over a two-week period. He was supplemented with sodium chloride tablets and has been otherwise stable. Amiodarone may cause acute or chronic SIADH, with a wide range of symptoms. Seizures have not been reported in the literature but our patient had a witnessed seizure, although his electroencephalogram (EEG) was negative. Syndrome of inappropriate antidiuretic hormone can occur with any formulation of amiodarone in a dose-dependent fashion. Our patient's sodium levels stabilized within two weeks after amiodarone was resumed. The mechanism of amiodarone-induced SIADH remains unclear.

Guillain-Barré syndrome hyponatremia: is it SIADH or pseudohyponatremia?

Approximately 5% of hospitalized patients with Guillain–Barré syndrome (GBS) experience SIADH; but pseudohyponatremia has also been reported in patients treated with IVIG. We present a case of a 51-year-old male with GBS who developed acute hyponatremia the day after initiation of IVIG; his sodium levels began to improve within 24 h of completion of IVIG. Differentiating between pseudohyponatremia caused by the IVIG treatment and SIADH caused by GBS was the key to successfully treating this patient. This case exemplifies the importance of pursuing further studies to determine the exact cause of hyponatremia in GBS in order to prevent further neurologic damage to the patient.

Autonomic dysfunction in the neurological intensive care unit

Autonomic dysfunction is common in neuro-critical care patients and may compromise the function of various organs. Among the many diseases causing or being associated with autonomic dysfunction are traumatic brain injury, cerebrovascular diseases, epilepsy, Guillain-Barré syndrome (GBS), alcohol withdrawal syndrome, botulism and tetanus, among many others. Autonomic dysfunction may afflict various organs and may involve hyper- or hypo-activity of the sympathetic or parasympathetic system. In this short overview, we address only a small number of neuro-intensive care diseases with autonomic dysfunction. In GBS, autonomic dysfunction is frequent and may account for increased mortality rates; rapid changes between sympathetic and parasympathetic hypo- or hyper-activity may cause life-threatening cardiovascular complications. Paroxysmal sympathetic hyperactivity occurs after brain injury, hypoxia and cerebrovascular and other events, causes paroxysmal tachycardia, hypertension, tachypnoea and hyperthermia and is associated with a poorer prognosis and prolonged intensive care treatment. Other, at times life-threatening autonomic complications with exaggerated sympathetic activity and compromised baroreflex sensitivity arise during the alcohol withdrawal syndrome triggered by abrupt cessation of alcohol consumption. Botulism and tetanus are examples of life-threatening autonomic dysfunction caused by bacterial neurotoxins. Common neurological diseases, such as epilepsy, stroke or subarachnoid haemorrhage, are also associated with autonomic dysfunction that can on occasion cause critical deterioration of disease severity and prognosis.

Guillain-Barré syndrome, transverse myelitis and infectious diseases

Guillain-Barré syndrome (GBS) and transverse myelitis (TM) both represent immunologically mediated polyneuropathies of major clinical importance. Both are thought to have a genetic predisposition, but as of yet no specific genetic risk loci have been clearly defined. Both are considered autoimmune, but again the etiologies remain enigmatic. Both may be induced via molecular mimicry, particularly from infectious agents and vaccines, but clearly host factor and co-founding host responses will modulate disease susceptibility and natural history. GBS is an acute inflammatory immune-mediated polyradiculoneuropathy characterized by tingling, progressive weakness, autonomic dysfunction, and pain. Immune injury specifically takes place at the myelin sheath and related Schwann-cell components in acute inflammatory demyelinating polyneuropathy, whereas in acute motor axonal neuropathy membranes on the nerve axon (the axolemma) are the primary target for immune-related injury. Outbreaks of GBS have been reported, most frequently related to Campylobacter jejuni infection, however, other agents such as Zika Virus have been strongly associated. Patients with GBS related to infections frequently produce antibodies against human peripheral nerve gangliosides. In contrast, TM is an inflammatory disorder characterized by acute or subacute motor, sensory, and autonomic spinal cord dysfunction. There is interruption of ascending and descending neuroanatomical pathways on the transverse plane of the spinal cord similar to GBS. It has been suggested to be triggered by infectious agents and molecular mimicry. In this review, we will focus on the putative role of infectious agents as triggering factors of GBS and TM.

Heart rate variability and baroreflex sensitivity abnormalities in Guillain-Barré syndrome: a pilot study

OBJECTIVE

The current study aimed to investigate autonomic dysfunction in Guillain-Barré syndrome (GBS) patients and describe the results of computational heart rate variability (HRV)/baroreflex sensitivity (BRS) and autonomic challenge tests.

METHODS

GBS patients were consecutively recruited and the results were compared to age- and gender-matched healthy controls. A series of autonomic function tests including computation-dependent tests (power spectrum analysis of HRV and BRS at rest) and challenge maneuvers (deep breathing, eyeball compression, active standing, the Valsalva maneuver, sustained handgrip, and the cold pressor test) were performed.

RESULTS

Ten GBS patients (six men; mean age = 40.1 ± 13.9 years) and ten gender- and age-matched healthy controls were recruited. The mean GBS functional grading scale at disease plateau was 3.4 ± 1.0. No patients required intensive care unit admission or mechanical ventilation. Low-frequency HRV (p = 0.027), high-frequency HRV (p = 0.008), and the total power spectral density of HRV (p = 0.015) were significantly reduced in patients compared to controls. The mean up slope (p = 0.034), down slope (p = 0.011), and total slope (p = 0.024) BRS were significantly lower in GBS patients. The diastolic rise in blood pressure in the cold pressor test was significantly lower in GBS patients compared to controls (p = 0.008).

INTERPRETATION

Computation-dependent tests (HRV and BRS) were more useful for detecting autonomic dysfunction in GBS patients, whereas the cold pressor test was the only reliable challenge test, making it useful as a bedside measure of autonomic function in GBS patients.