Normal baseline cardiac autonomic function and increased pupillary parasympathetic tone in patients with vasovagal syncope

It is controversial whether people with vasovagal syncope (VVS) have abnormal autonomic responses at baseline and whether specific diagnostic manoeuvres have a diagnostic value. We investigated whether the pupillary light reflex and cardiac autonomic tests can be used to identify autonomic dysfunction in volunteers with a medical history of VVS. The study groups included 128 healthy volunteers, of whom 31 reported a history of typical VVS. The right pupil was evaluated using an automated, commercial infra-red pupillometer under strict conditions. In addition to miosis and mydriasis kinetics, pupil diameters were measured. Heart rate variability at rest and heart rate changes to standing were quantified with high-resolution electrocardiography and designated software. The demographic and clinical characteristics of both groups were statistically similar. Average constriction velocity (ACV) was significantly higher in VVS patients following a univariate analysis (3.83 ± 0.59 vs. 3.56 ± 0.73 mm/s, p = 0.042) and after correcting for potential confounders (p = 0.049). All other pupillometric and heart rate indices were comparable between groups. Patients with a history of VVS depict pupillary parasympathetic overactivity in response to light stimuli, manifested as increased ACV. The prognostic implications of this finding and the significance of using this simple clinical tool to identify patients who are at risk for developing frequent episodes of VVS or physical injuries following a syncope merits further study.

Recent Advances and Future Directions in Syncope Management: A Comprehensive Narrative Review

Syncope is a highly prevalent clinical condition characterized by a rapid, complete, and brief loss of consciousness, followed by full recovery caused by cerebral hypoperfusion. This symptom carries significance, as its potential underlying causes may involve the heart, blood pressure, or brain, leading to a spectrum of consequences, from sudden death to compromised quality of life. Various factors contribute to syncope, and adhering to a precise diagnostic pathway can enhance diagnostic accuracy and treatment effectiveness. A standardized initial assessment, risk stratification, and appropriate test identification facilitate determining the underlying cause in the majority of cases. New technologies, including artificial intelligence and smart devices, may have the potential to reshape syncope management into a proactive, personalized, and data-centric model, ultimately enhancing patient outcomes and quality of life. This review addresses key aspects of syncope management, including pathogenesis, current diagnostic testing options, treatments, and considerations in the geriatric population.

Triggered episodic vestibular syndrome and transient loss of consciousness due to a retrostyloidal vagal schwannoma: a case report

Background

Various conditions may trigger episodic vertigo or dizziness, with positional changes being the most frequently identified condition. In this study, we describe a rare case of triggered episodic vestibular syndrome (EVS) accompanied by transient loss of consciousness (TLOC) linked to retrostyloidal vagal schwannoma.

Case description

A 27-year woman with known vestibular migraine presented with a 19-month history of nausea, dysphagia, and odynophagia triggered by swallowing food and followed by recurrent TLOC. These symptoms occurred independently of her body position, resulting in a weight loss of 10 kg within 1 year and in an inability to work. An extensive cardiologic diagnostic work-up undertaken before she presented to the neurologic department was normal. On the fiberoptic endoscopic evaluation of swallowing, she showed a decreased sensitivity, a slight bulging of the right lateral pharyngeal wall, and a pathological pharyngeal squeeze maneuver without any further functional deficits. Quantitative vestibular testing revealed an intact peripheral-vestibular function, and electroencephalography was read as normal. On the brain MRI, a 16 x 15 x 12 mm lesion in the right retrostyloidal space suspicious of a vagal schwannoma was detected. Radiosurgery was preferred over surgical resection, as resection of tumors in the retrostyloid space bears the risk of intraoperative complications and may result in significant morbidity. A single radiosurgical procedure (stereotactic CyberKnife radiosurgery, 1 x 13Gy) accompanied by oral steroids was performed. On follow-up, a cessation of (pre)syncopes was noted 6 months after treatment. Only residual infrequent episodes of mild nausea were triggered by swallowing solid food remained. Brain MRI after 6 months demonstrated no progression of the lesion. In contrast, migraine headaches associated with dizziness remained frequent.

Discussion

Distinguishing triggered and spontaneous EVS is important, and identifying specific triggers by structured history-taking is essential. Episodes being elicited by swallowing solid foods and accompanied by (near) TLOC should initiate a thorough search for vagal schwannoma, as symptoms are often disabling, and targeted treatment is available. In the case presented here, cessation of (pre)syncopes and significant reduction of nausea triggered by swallowing was noted with a 6-month delay, illustrating the advantages (no surgical complications) and disadvantages (delayed treatment response) of first-line radiotherapy in vagal schwannoma treatment.

Syncope Diagnosis at Referral to a Tertiary Syncope Unit: An in-Depth Analysis of the FAST II

OBJECTIVE

A substantial number of patients with a transient loss of consciousness (T-LOC) are referred to a tertiary syncope unit without a diagnosis. This study investigates the final diagnoses reached in patients who, on referral, were undiagnosed or inaccurately diagnosed in secondary care.

METHODS

This study is an in-depth analysis of the recently published Fainting Assessment Study II, a prospective cohort study in a tertiary syncope unit. The diagnosis at the tertiary syncope unit was established after history taking (phase 1), following autonomic function tests (phase 2), and confirming after critical follow-up of 1.5-2 years, with the adjudicated diagnosis (phase 3) by a multidisciplinary committee. Diagnoses suggested by the referring physician were considered the phase 0 diagnosis. We determined the accuracy of the phase 0 diagnosis by comparing this with the phase 3 diagnosis.

RESULTS

51% (134/264) of patients had no diagnosis upon referral (phase 0), the remaining 49% (130/264) carried a diagnosis, but 80% (104/130) considered their condition unexplained. Of the patients undiagnosed at referral, three major causes of T-LOC were revealed: reflex syncope (69%), initial orthostatic hypotension (20%) and psychogenic pseudosyncope (13%) (sum > 100% due to cases with multiple causes). Referral diagnoses were either inaccurate or incomplete in 65% of the patients and were mainly altered at tertiary care assessment to reflex syncope, initial orthostatic hypotension or psychogenic pseudosyncope. A diagnosis of cardiac syncope at referral proved wrong in 17/18 patients.

CONCLUSIONS

Syncope patients diagnosed or undiagnosed in primary and secondary care and referred to a syncope unit mostly suffer from reflex syncope, initial orthostatic hypotension or psychogenic pseudosyncope. These causes of T-LOC do not necessarily require ancillary tests, but can be diagnosed by careful history-taking. Besides access to a network of specialized syncope units, simple interventions, such as guideline-based structured evaluation, proper risk-stratification and critical follow-up may reduce diagnostic delay and improve diagnostic accuracy for syncope.

Anxiety and Depression as Risk Factors for Vasovagal Syncope and Potential Treatment Targets: A Systematic Review

Vasovagal syncope (VVS) is a transient, sudden loss of consciousness followed by complete resolution, usually due to a paradoxical autonomic reaction that results in hypotension and/or bradycardia. In this study, we assessed the correlation between VVS and a patient's psychiatric status, as well as if this association could be a target in the treatment of those patients. We conducted a systematic review in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we searched the available literature using the following databases: PubMed, Google Scholar, and ScienceDirect, with last access on July 21, 2022. The search resulted in 1691 articles, and inclusion and exclusion criteria were applied to nine remaining articles, all of which were accepted after using the quality assessment tools, four observational and four randomized controlled trials (RCTs). Four of the included studies assessed the correlation among vasovagal syncope, psychosocial impairment, and quality of life. We found a consistent correlation among VVS, psychosocial impairment, and quality of life (QoL), meaning that VVS patients usually have some degree of psychosocial impairment, especially in the form of anxiety and depression, and a poorer QoL in comparison to their healthy counterparts. The use of psychotherapy and antidepressants was proven to be effective in VVS in RCTs, but further evidence is needed.

Lateral tongue bite in patient with transient loss of consciousness

The finding of a tongue bite is infrequent since it is a physical finding that is often overlooked, but it has a very high diagnostic value. It is important to check for tongue bites when examining any patient with a transient loss of consciousness.

Syncope Prediction Scores in the Emergency Department

Syncope is a common clinical presentation defined as a transient loss of consciousness (TLOC) due to cerebral hypoperfusion, characterized by a rapid onset, short duration, and spontaneous complete recovery. Different clinical decision rules (CDRs) and risk stratification scores have been developed to predict short- and long-term risks for adverse outcomes after syncope. The central theme of these prediction systems is consistent with the ESC syncope guidelines. Initial assessment according to the ESC guideline is essential until an optimal and well-validated risk score is available. The focus should be accurate risk stratification to allow prevention of adverse outcomes and optimize the use of limited healthcare resources. In this review article, we summarize and critically appraise the evidence regarding the CDRs for patients presenting with syncope.

High-risk features and predictors of unexplained syncope in the young SCD-SOS cohort

INTRODUCTION

The Sudden Cardiac Death-Screening of Risk FactOrS survey included a 12-lead electrocardiogram (ECG) plus a digital-based questionnaire and aimed to screen for warning signs of diseases that may course with sudden cardiac death in children and young adults. We aimed to estimate the prevalence of unexplained syncope (US) and characterize its high-risk features and predictors in this cohort.

METHODS AND RESULTS

We determined the most probable etiology of transient loss of consciousness (TLOC) episodes based on clinical criteria. US was an exclusion diagnosis and we analyzed its potential clinical and ECG predictors. Among 11 878 individuals, with a mean age of 21 ± 6 (range 6-40) years old, the cumulative incidence of TLOC was 26.5%, 76.2% corresponding to females. Reflex syncope was present in 66.4%, orthostatic hypotension in 8.2%, and 14.8% of the individuals had US. Unexplained syncope was independently associated with age < 18 years old (odds ratio [OR] 1.695; 95% confidence interval [CI] 1.26-2.29, p = .001), male gender (OR 1.642; 95% CI 1.22-2.22, p = .001), participation in competitive sports (OR 1.644; 95% CI 1.01-2.66, p = .043), syncope during exertion and/or palpitations preceding syncope (OR 2.556; 95% CI 1.92-3.40, p < .001), syncope after exertion (OR 2.662; 95% CI 1.73-4.10, p < .001), fever context (OR 9.606; 95% CI 4.13-22.34, p < .001), isolated previous syncopal episode (OR 2.780; 95% CI 0.2.06-3.75, p < .001), and history of palpitations requiring medical care (OR 1.945; 95% CI 1.14-3.31, p = .014). We found no ECG predictors of US in this population.

CONCLUSIONS

The cumulative incidence of TLOC in children and young adults is high and remains unexplained in an important proportion of individuals. We identified eight clinical characteristics that may be useful for the risk stratification of individuals evaluated in a nonacute setting.

Three poisonous plants (Oenanthe, Cicuta and Anamirta) that antagonise the effect of γ-aminobutyric acid in human brain

Although we are familiar with common British plants that are poisonous, such as Atropa belladonna (deadly nightshade) and Aconitum napellus (monkshood), the two most poisonous plants in the British Flora are Oenanthe crocata (dead man's fingers) and Cicuta virosa (cowbane). In recent years their poisons have been shown to be polyacetylenes (n-C2H2). The plants closely resemble two of the most common plants in the family Apiaceae (Umbelliferae), celery and parsley. Unwittingly, they are ingested by naive foragers and death occurs very rapidly. The third plant Anamirta derives from South-East Asia and contains a powerful convulsant, picrotoxin, which has been used from time immemorial to catch fish, and more recently to poison Birds of Paradise. All three poisons have been shown to block the γ-aminobutyric acid (GABA) system in the human brain that normally has a powerful inhibitory neuronal action. It has also been established that two groups of sedative drugs, barbiturates and benzodiazepines, exert their inhibitory action by stimulating the GABA system. These drugs are the treatments of choice for poisoning by the three vicious plants.

The Longer the Block, the Harder You Fall: Extrinsic Idiopathic Atrioventricular Block Masquerading as Seizures

History and physical examination are the diagnostic cornerstones of transient loss of consciousness (TLOC). However, details can be scarce and examination unrevealing, thus making the diagnosis elusive. In a case of convulsive TLOC, the initial diagnosis was incorrect, but a fortuitously captured event on telemetry yielded the diagnosis: extrinsic idiopathic atrioventricular block. (Level of Difficulty: Beginner.)

If case reports be the food of knowledge, write on: our Cases of the Quarter

The value of publishing case reports has long been debated and the arguments are summarised. Last year, to encourage trainees, the Royal College of Physicians of Edinburgh's Senior Fellows Club inaugurated an annual prize for the best case report or case series published in the Journal of the Royal College of Physicians of Edinburgh by a doctor in training. Some of the highlights of last year's entries are reviewed, commented on and developed. They include cases of myelofibrosis and cherubism due to secondary hyperparathyroidism from renal failure; reversible blindness in diabetic ketoacidosis; the long QT syndrome; ictal asystole; giant cell arteritis; tumour necrosis factor-α inhibition in Lyme borreliosis; and cannabis hyperemesis syndrome.

Timing of Circulatory and Neurological Events in Syncope

Syncope usually lasts less than a minute, in which short time arterial blood pressure temporarily falls enough to decrease brain perfusion so much that loss of consciousness ensues. Blood pressure decreases quickest when the heart suddenly stops pumping, which happens in arrhythmia and in severe cardioinhibitory reflex syncope. Loss of consciousness starts about 8 s after the last heart beat and circulatory standstill occurs after 10-15 s. A much slower blood pressure decrease can occur in syncope due to orthostatic hypotension Standing blood pressure can then stabilize at low values often causing more subtle signs (i.e., inability to act) but often not low enough to cause loss of consciousness. Cerebral autoregulation attempts to keep cerebral blood flow constant when blood pressure decreases. In reflex syncope both the quick blood pressure decrease and its low absolute value mean that cerebral autoregulation cannot prevent syncope. It has more protective value in orthostatic hypotension. Neurological signs are related to the severity and timing of cerebral hypoperfusion. Several unanswered pathophysiological questions with possible clinical implications are identified.

Comparison of clinical and electrophysiological characteristics between ictal and cardiac asystole encountered during video-EEG monitoring

Differentiation between syncope secondary to epileptic seizures and cardiac disease in patients displaying transient loss of consciousness associated with convulsive movements is a diagnostic challenge both for neurologists and cardiologists. In such patients, prolonged video-EEG monitoring not only helps in identifying asystole as the cause of syncope, but also in categorizing asystole as primarily cardiac in origin (cardiac asystole) and secondary to epileptic seizures (ictal asystole). We carried out this study to ascertain the prevalence of asystole in an epilepsy monitoring unit, and to contrast the clinical and electrophysiological characteristics between ictal asystole and cardiac asystole. Through a retrospective search, we identified patients who were shown to have had asystole using a database of patients who underwent prolonged video-EEG monitoring during a 68-month period. We compared the data of 18 consecutive patients; five with ictal asystole and 13 with cardiac asystole, with 121 and 64 events recorded from them, respectively. Of the 10,096 patients who underwent prolonged video-EEG monitoring during the study period, we identified 18 (0.17%) patients with asystole. Cardiac asystole was 2.6 times more frequent than ictal asystole. Older age at onset, heralding symptoms of presyncope, occurrence during wakefulness, and brief duration of the events supported the diagnosis of cardiac asystole. Ictal asystole events were more protracted, and prolonged asystole more frequently occurred in patients with extratemporal seizures compared to temporal lobe seizures. Asystole occurred in only half of the recorded seizures. The accurate categorization of asystole as seizure-related or heart disease-related has huge implications for management strategy and outcome. The necessity of permanent pacemaker implantation is more frequent and urgent in patients with cardiac asystole because of the greater risk of sudden death. Hence, in patients with an ominous diagnosis of cardiac asystole, a thorough cardiac evaluation should surpass neurological evaluation.

Ictal asystole: a diagnostic and management conundrum

We report two cases of adults presenting with transient loss of consciousness (TLoC) followed by a rapid recovery. Careful history taking revealed a stereotyped prodrome of déjà vu, raising the possibility of these events being focal seizures rather than syncope. The patients were commenced on antiepileptic drugs (AEDs) at the same time as having cardiac monitoring organised. This confirmed asystole during the seizure symptoms, resulting in TLoC. It was assumed that the cardiac arrhythmia explained the entire picture, a permanent pacemaker (PPM) was inserted, and the AEDs were withdrawn in one patient and not commenced in the other. However, they both subsequently presented with worsening seizures, including generalised tonic-clonic seizures, despite a functioning pacemaker. The seizures improved on restarting AEDs. The cases illustrate the diagnostic and management difficulties of patients presenting with ictal asystole, a condition that requires input from various medical specialities. There is no strong evidence base for the management of ictal asystole, but we favour a combined approach of AEDs and PPM insertion.

Convexity subarachnoid hemorrhage presented with loss of consciousness

When patients present with transient loss of consciousness without headache and head computed tomography is performed, clinicians should pay attention to cortical high densities as convexity subarachnoid hemorrhage can be a differential diagnosis.

Seizures and epilepsy in the acute medical setting: presentation and management

Epileptic seizures are a common cause for presentation to acute medical services. Whether presenting with an isolated, unprovoked seizure or with status epilepticus, a good understanding of seizures and their mimics ensures appropriate investigation and treatment. This article describes the practical aspects of the management of patients presenting with seizures to the emergency department or the acute medical unit.

Nursing management of reflex anoxic seizures in children

Children who present with transient loss of consciousness (T-LOC) are often first seen in emergency departments (EDs). Reflex anoxic seizure (RAS), vasovagal syncope and prolonged respiratory apnoea are benign, syncopal events that can be generally managed by explanation and reassurance. RAS is a short, paroxysmal, self-reverting episode of asystole that is triggered by pain, fear or anxiety and is caused by increased vagal response. It is an important differential diagnosis in pre-school age children who present with T-LOC, but is often underdiagnosed and can sometimes be misdiagnosed as epilepsy. Nurses working in EDs are among the first healthcare professionals to see children in acute settings and should therefore be aware of RAS, the presenting features and management options. This article discusses the epidemiology, pathophysiology and management of RAS, includes an illustrative case study and discusses the role of ED nurses.

Transient loss of consciousness and syncope

Syncope describes a sudden and brief transient loss of consciousness (TLOC) with postural failure due to cerebral global hypoperfusion. The term TLOC is used when the cause is either unrelated to cerebral hypoperfusion or is unknown. The most common causes of syncopal TLOC include: (1) cardiogenic syncope (cardiac arrhythmias, structural cardiac diseases, others); (2) orthostatic hypotension (due to drugs, hypovolemia, primary or secondary autonomic failure, others); (3) neurally mediated syncope (cardioinhibitory, vasodepressor, and mixed forms). Rarely neurologic disorders (such as epilepsy, transient ischemic attacks, and the subclavian steal syndrome) can lead to cerebal hypoperfusion and syncope. Nonsyncopal TLOC may be due to neurologic (epilepsy, sleep attacks, and other states with fluctuating vigilance), medical (hypoglycemia, drugs), psychiatric, or post-traumatic disorders. Basic diagnostic workup of TLOC includes a thorough history and physical examination, and a 12-lead electrocardiogram (ECG). Blood testing, electroencephalogram (EEG), magnetic resonance imaging (MRI) of the brain, echocardiography, head-up tilt test, carotid sinus massage, Holter monitoring, and loop recorders should be obtained only in specific contexts. Management strategies involve pharmacologic and nonpharmacologic interventions, and cardiac pacing.

A case of mistaken identity: asystole causing convulsions identified using implantable loop recorder

We present herein an interesting tracing of a patient who suffered from recurrent episodes of transient loss of consciousness (TLOC) associated with convulsive activity thought to be due to epilepsy or conversion disorder.