Evaluation of syncope

Syncope is a transient and abrupt loss of consciousness with complete return to preexisting neurologic function. It is classified as neurally mediated (i.e., carotid sinus hypersensitivity, situational, or vasovagal), cardiac, orthostatic, or neurogenic. Older adults are more likely to have orthostatic, carotid sinus hypersensitivity, or cardiac syncope, whereas younger adults are more likely to have vasovagal syncope. Common nonsyncopal syndromes with similar presentations include seizures, metabolic and psychogenic disorders, and acute intoxication. Patients presenting with syncope (other than neurally mediated and orthostatic syncope) are at increased risk of death from any cause. Useful clinical rules to assess the short-term risk of death and the need for immediate hospitalization include the San Francisco Syncope Rule and the Risk Stratification of Syncope in the Emergency Department rule. Guidelines suggest an algorithmic approach to the evaluation of syncope that begins with the history and physical examination. All patients presenting with syncope require electrocardiography, orthostatic vital signs, and QT interval monitoring. Patients with cardiovascular disease, abnormal electrocardiography, or family history of sudden death, and those presenting with unexplained syncope should be hospitalized for further diagnostic evaluation. Patients with neurally mediated or orthostatic syncope usually require no additional testing. In cases of unexplained syncope, further testing such as echocardiography, grade exercise testing, electrocardiographic monitoring, and electrophysiologic studies may be required. Although a subset of patients will have unexplained syncope despite undergoing a comprehensive evaluation, those with multiple episodes compared with an isolated event are more likely to have a serious underlying disorder.     

Syncope. Cost-effective patient workup

Syncope is a common problem in primary care practice that presents a diagnostic challenge. Fortunately, the initial evaluation not only identifies the cause in most patients with an identifiable cause, it also defines the prognosis for these patients. A systematic history, physical examination, and 12-lead ECG are the foundation of this evaluation and provide the most cost-effective diagnostic strategy. When signs and symptoms indicate a neurologic, cardiac, or carotid sinus problem, diagnostic procedures such as angiography, electroencephalography, cardiac catheterization, echocardiography, or carotid sinus massage should be added, but only as necessary to confirm the diagnosis. At the University of Cincinnati, we monitor patients with syncope of unknown origin with 24-hour ambulatory ECG recording and interpret the results as outlined in table 2. If not referred for cardiac or neurologic consultation, these patients are evaluated every three months for a year. This approach can minimize unnecessary testing and improve patient care.     

Sitcom syncope: a case series and literature review of gelastic (laughter-induced) syncope

Syncope is a common complaint that is frequently evaluated without identifying a precipitating cause. Gelastic (laughter-induced) syncope is an uncommon and poorly understood condition. We describe 3 patients who experienced loss of consciousness during vigorous laughter. Each patient had an extensive medical evaluation, including a comprehensive history and physical examination, 12-lead electrocardiography, chest radiograph, routine blood analysis, polysomnography, tilt table testing, 2-dimensional transthoracic echocardiography, nuclear or echocardiographic stress testing, and 24-hour Holter monitoring. All 3 patients had an abnormal response to head-up tilt table testing, with either a significant decrease in systolic blood pressure or inappropriate heart rate response on achieving an upright position. These observations together with our review of the literature suggest that gelastic syncope may be a variant of vasodepressor syncope. Knowledge of this condition, its pathophysiology, and potential treatment options may be of value to clinicians when evaluating patients with unexplained loss of consciousness.     

Cardiovascular causes of syncope. Identifying and controlling trigger mechanisms

Syncope usually has a cardiovascular source, so neurologic evaluation has a low diagnostic yield in these patients. Cardiac arrhythmias in persons with or without structural heart disease can produce syncope. Neurocardiogenic dysfunction that results in diminished venous return and hypercontractility is another frequent cause. Postural hypotension or left ventricular outflow obstruction may also be to blame. Careful history taking and physical examination, head-up tilt testing, echocardiography or radionuclide isotope imaging, and electrophysiologic study are often diagnostic. However, syncope remains undiagnosed in some patients, and they may require periodic reassessment. Treatment options are available for most cardiovascular disorders, among them use of pharmacologic agents; catheter, surgical, or radio-frequency modification of certain tachycardias; and permanent pacing.     

Understanding syncope. The pathophysiology & assessment of a challenging condition that EMS crews frequently encounter

Syncope is a transient loss of postural tone and consciousness following which, by definition, the patient has a spontaneous recovery without intervention. The differential diagnosis of syncope is broad and spans benign to life-threatening conditions. Identifying and treating serious conditions that may mimic syncope and identifying patients at high risk (cardiac syncope) are challenges that face prehospital providers. A comprehensive history and physical provide the most useful information in making these distinctions. Syncope is a symptom, not a disease; therefore, treatment must be targeted to the underlying disease process.     

Geriatric Syncope and Cardiovascular Risk in the Emergency Department

Background

Syncope is a transient loss of consciousness that is caused by a brief loss in generalized cerebral blood flow.

Stepwise Evaluation of Unexplained Syncope in a Large Ambulatory Population

Background: Up to 60% of syncopal episodes remain unexplained. We report the results of a standardized, stepwise evaluation of patients referred to an ambulatory clinic for unexplained syncope.
Methods and Results: We studied 939 consecutive patients referred for unexplained syncope, who underwent a standardized evaluation, including history, physical examination, electrocardiogram, head-up tilt testing (HUTT), carotid sinus massage (CSM) and hyperventilation testing (HYV). Echocardiogram and stress test were performed when underlying heart disease was initially suspected. Electrophysiological study (EPS) and implantable loop recorder (ILR) were used only in patients with underlying structural heart disease or major unexplained syncope. We identified a cause of syncope in 66% of patients, including 27% vasovagal, 14% psychogenic, 6% arrhythmias, and 6% hypotension. Noninvasive testing identified 92% and invasive testing an additional 8% of the causes. HUTT yielded 38%, CSM 28%, HYV 49%, EPS 22%, and ILR 56% of diagnoses. On average, patients with arrhythmic causes were older, had a lower functional capacity, longer P-wave duration, and presented with fewer prodromes than patients with vasovagal or psychogenic syncope.
Conclusions: A standardized stepwise evaluation emphasizing noninvasive tests yielded 2/3 of causes in patients referred to an ambulatory clinic for unexplained syncope. Neurally mediated and psychogenic mechanisms were behind >50% of episodes, while cardiac arrhythmias were uncommon. Sudden syncope, particularly in older patients with functional limitations or a prolonged P-wave, suggests an arrhythmic cause.     

Diagnostic evaluation and management of patients with syncope

This article focuses on the evaluation of patients with syncope, a symptom not a disease. Syncope is a transient loss of consciousness associated with loss of postural tone with spontaneous recovery. The authors discuss the utility of an indications for different diagnostic tests, the indications for hospital admission, and the management of patients with certain known causes of syncope, including vasovagal and arrhythmic.     

A novel device in evaluating syncope.

Syncope may be a manifestation of many diseases. The etiology is often difficult to determine. Much effort, time, and expense have been required to determine a diagnosis. A thorough history and physical examination are essential (Table 3). Several clinical pearls may be of help in the diagnosis of syncope: (a) the most important elements in the evaluation of syncope are a detailed history and physical examination; (b) syncope is a common problem in young healthy adults and the elderly; (c) a heavy meal is a specific cause of syncopy in the elderly (postprandial), however this etiology often goes unrecognized; (d) syncope is caused by 1 of 3 mechanisms: decreased cardiac output, systemic vascular resistance, or cerebrovascular disease; (e) reflex-mediated syndromes (vasovagal) are common causes of syncope in young adults, and orthostatic hypotension is an important cause of syncope in the elderly; and (f) the 1-year mortality of cardiac syncope (18%-33%) is significantly higher than that from non-cardiac syncope (0%-12%). A proven and useful tool has recently been advanced to aid in the evaluation of syncope. The Reveal Plus insertable loop recorder has auto activation that allows automatic capture and recording of arrhythmic events. Patient activation is an option. The recorder lasts 12 to 14 months and has proven to be a valuable and reliable cost-effective asset in our quest to evaluate syncope.     

Syncope in adults: terminology, classification, and diagnostic strategy

Syncope is a relatively common clinical syndrome that is a subset of a broader range of conditions that cause transient loss of consciousness (TLOC). Other TLOC conditions include seizures, concussions, and intoxications. However, despite frequent confusion in the medical literature, syncope is and should be clearly distinguished from those other causes of TLOC by virtue of its pathophysiology; specifically, syncope is the result of self-terminating inadequacy of global cerebral nutrient perfusion, while the other forms of TLOC have different etiologies. Unfortunately, the diagnostic evaluation of syncope remains for the most part poorly managed and inefficient. Careful history-taking, physical examination, and judicious use of tests can not only increase the diagnostic yield of the evaluation, but also increase patient safety and reduced overall healthcare costs.     

Common emergent pediatric neurologic problems

Although there are a variety of neurologic disease processes that the emergency physician should be aware of the most common of these include seizures, closed head injury, headache, and syncope. When one is evaluating a patient who has had a seizure, differentiating between febrile seizures, afebrile seizures, and SE helps to determine the extent of the work-up. Febrile seizures are typically benign, although a diagnosis of meningitis must not be missed. Educating parents regarding the likelihood of future seizures, and precautions to be taken should a subsequent seizure be witnessed, is important. The etiology of a first-time afebrile seizure varies with the patient's age at presentation, and this age-specific differential drives the diagnostic work-up. A follow-up EEG is often indicated, and imaging studies can appropriate on a nonurgent basis. Appropriate management of SE requires a paradigm of escalating pharmacologic therapy, and early consideration of transport for pediatric intensive care services if the seizure cannot be controlled with conventional three-tiered therapy. Closed head injury frequently is seen in the pediatric emergency care setting. The absence of specific clinical criteria to guide the need for imaging makes management of these children more difficult. A thorough history and physical examination is important to uncover risk factors that prompt emergent imaging. Headaches are best approached by assessing the temporal course, associated symptoms, and the presence of persistent neurologic signs. Most patients ultimately are diagnosed with either a tension or migraine headache; however, in those patients with a chronic progressive headache course, an intracranial process must be addressed and pursued with appropriate imaging. Syncope has multiple causes but can generally be categorized as autonomic, cardiac, or noncardiac. Although vasovagal syncope is the most common cause of syncope, vigilance is required to identify those patients with a potentially fatal arrhythmia or with heart disease that predisposes to hypoperfusion. As such, all patients who present with syncope should have an ECG. Additional work-up studies are guided by the results of individual history and physical examination.     

Management of syncope in adults: an update

Syncope is a clinical syndrome characterized by transient loss of consciousness and postural tone that is most often due to temporary and spontaneously self-terminating global cerebral hypoperfusion. A common presenting problem to health care systems, the management of syncope imposes a considerable socioeconomic burden. Clinical guidelines, such as the European Society of Cardiology Guidelines on Management of Syncope, have helped to streamline its management. In recent years, we have witnessed intensive efforts on many fronts to improve the evaluation process and to explore therapeutic options. For this update, we summarized recent active research in the following areas: the role of the syncope management unit and risk prediction rules in providing high-quality and cost-effective evaluation in the emergency department, the implementation of structured history taking and standardized guideline-based evaluation to improve diagnostic yield, the evolving role of the implantable loop recorder as a diagnostic test for unexplained syncope and for guiding management of neurally mediated syncope, and the shift toward nonpharmacological therapies as mainstay treatment for patients with neurally mediated syncope. Syncope is a multidisciplinary problem; future efforts to address critical issues, including the publication of clinical guidelines, should adopt a multidisciplinary approach.     

Evaluation of syncope: focus on diagnosis and treatment of neurally mediated syncope

Syncope, defined as a transient loss of consciousness secondary to global cerebral hypoperfusion, is common in the general population. The single most helpful “test” in the evaluation of patients with syncope is a thoughtful history, with recent evidence that structured histories are remarkably effective in arriving at a diagnosis. In addition to the history, physical examination, and electrocardiogram, arriving at a diagnosis of syncope can involve monitoring and provocative strategies. The majority of patients with syncope have neurally mediated syncope and a favourable prognosis. The management of neurally mediated syncope continues to largely revolve around education, avoidance of triggers, reassurance, and counter-pressure maneuvers. The evidence surrounding medical therapy in vasovagal syncope is not strong to date. Pacemaker therapy is reasonable in older patients with recurrent, unpredictable syncope with pauses, but should be considered as a last resort in younger patients.     

Collapse query cause: the management of adult syncope in the emergency department

Syncope is a commonly encountered problem in the emergency department (ED). Its causes are many and varied, some of which are potentially life threatening. A review was carried out of relevant papers in the available literature, and this article attempts to assimilate current evidence relating to ED management. While the cause of syncope can be identified in many patients, and life threatening conditions subsequently treated, a risk stratification approach should be taken for those in whom a cause is not identified in the ED. Aspects of the history and examination that may help identify high risk patients are explored and the role of investigations to aid this stratification is discussed. Identifying a cardiac cause for syncope is a poor prognostic indicator. Patients with unexplained syncope who have significant cardiac disease should therefore be investigated thoroughly to determine the nature of the underlying heart disease and the cause of syncope, although presently there is little evidence that this improves their dismal prognosis. This risk stratification approach has led to the development of several clinical decision rules, which are discussed along with current international guidelines on syncope management. This review suggests that presently the American College of Emergency Physicians guidelines are the most useful aids specific to the management of syncope in the ED; however, the Osservatorio Epidemiologico sulla Sincope nel Lazio (OESIL) score may also be a useful ED risk stratification tool     

Diagnostic yield and utility of neurovascular ultrasonography in the evaluation of patients with syncope

OBJECTIVE: To determine the diagnostic utility of neurovascular ultrasonography (transcranial Doppler and carotid ultrasonography) in patients with syncope. PATIENTS AND METHODS: We retrospectively identified consecutive patients who underwent neurovascular ultrasonography for the diagnosis of syncope or presyncope at an academic hospital in 1997 and 1998. From medical records we abstracted patient demographic and clinical information, results and consequences of testing, and follow-up data for 3 years. RESULTS: A total of 140 patients participated in the study. The median age of the study patients was 74 years (interquartile range, 66-80 years), and 49% were male. Severe extracranial or Intracranial cerebrovascular disease was found on neurovascular ultrasonography in 20 patients (14%; 95% confidence interval [CI], 9.5%-21%). Focal neurologic signs or symptoms or carotid bruits were found in 19 (95%) of 20 patients with positive test results compared with 46 (38%) of 120 patients without severe disease (P<.001). Ultrasonography identified cerebrovascular lesions that may have contributed to the syncopal process in only 2 (1.4%) of 140 patients (95% CI, 0.39%-5.1%), but the lesions were unlikely to have been the primary cause of syncope in either patient. CONCLUSION: In this predominantly stroke-age population, neurovascular ultrasonography had a low yield for diagnosing vascular lesions that contributed to the pathophysiology of syncope. However, in patients with focal signs or symptoms or carotid bruits, it detected incidental lesions that typically require treatment or follow-up. In patients with syncope, neurovascular ultrasonography should be reserved for this subset. The data suggest enhancements to the American College of Physicians guideline for the use of neurovascular ultrasonography in patients with syncope.     

Clinical Mimics: An Emergency Medicine–Focused Review of Syncope Mimics

Background

Syncope is an event that causes a transient loss of consciousness (LOC) secondary to global cerebral hypoperfusion. The transient nature of the event can make diagnosis in the emergency department (ED) difficult, as symptoms have often resolved by time of initial presentation. The symptoms and presentation of syncope are similar to many other conditions, which can lead to difficulty in establishing a diagnosis in the ED.

The preparticipation athletic evaluation

A comprehensive medical history that includes questions about a personal and family history of cardiovascular disease is the most important initial component of the preparticipation athletic evaluation. Additional questions should focus on any history of neurologic or musculoskeletal problems. A limited physical examination should emphasize cardiac auscultation with provocative maneuvers to screen for hypertrophic cardiomyopathy. This condition is the most common cause of sudden death in young male athletes. Other components of the physical examination include an evaluation of the spine and extremities. Screening tests such as electrocardiography, treadmill stress testing and urinalysis are not indicated in the absence of symptoms or a significant history of risk factors. Specific conditions that would exclude or limit athletic participation include hypertrophic cardiomyopathy, long QT interval syndrome, concussion, significant knee injury, sickle cell disease and uncontrolled seizures. Overall, about 1 percent of athletes who are screened are completely disqualified from sports participation.     

Diagnostic approach to tinnitus

Tinnitus is a common disorder with many possible causes. Most cases of tinnitus are subjective, but occasionally the tinnitus can be heard by an examiner. Otologic problems, especially hearing loss, are the most common causes of subjective tinnitus. Common causes of conductive hearing loss include external ear infection, cerumen impaction, and middle ear effusion. Sensorineural hearing loss may be caused by exposure to excessive loud noise, presbycusis, ototoxic medications, or Meniere's disease. Unilateral hearing loss plus tinnitus should increase suspicion for acoustic neuroma. Subjective tinnitus also may be caused by neurologic, metabolic, or psychogenic disorders. Objective tinnitus usually is caused by vascular abnormalities of the carotid artery or jugular venous systems. Initial evaluation of tinnitus should include a thorough history, head and neck examination, and audiometric testing to identify an underlying etiology. Unilateral or pulsatile tinnitus may be caused by more serious pathology and typically merits specialized audiometric testing and radiologic studies. In patients who are discomforted by tinnitus and have no remediable cause, auditory masking may provide some relief.     

Role of Cardiac Electrophysiologic Studies in Patients with Unexplained Recurrent Syncope

Cardiac electrophysiologic studies (EPS) with programmed electrical stimulation (PES) were performed in 30 patients with recurrent syncope to uncover possible arrhythmic etiology. All patients had undergone thorough medical and neurologic evaluation prior to EPS without finding a definitive cause for syncope. In the majority of patients an arrhythmic etiology for syncope was suspected but could not be documented utilizing the 12-lead surface ECG, extended in-hospital and/or ambulatory monitoring (for ≥ 48 hours) and exercise testing prior to the EPS. The studies provided a clue to the possible underlying rhythm disturbance which could have caused syncope in 16/30 patients. Sustained or nonsustained ventricular tachycardia and/or ventricular fibrillation was induced in 11/30, sinus node dysfunction in 4/30 and intra-His block in the remaining one. Fourteen of the 16 have remained free of symptoms following therapy based on results of EPS during a follow-up period ranging from 6–30 months (mean 16.5 ± 7.8). In 2/16 syncope recurred (one arrhythmic and one non-arrhythmic) despite pacemaker therapy for sinus node dysfunction detected during EPS. In the remaining 14/30 patients, EPS and PES did not induce arrhythmia which could account for patient symptomatology and therefore no specific therapy could be recommended. Eleven of these 14 patients experienced a recurrence of symptoms within a 6–25 month period (mean 16.2 ± 6.8). Of the 16 patients with inducible arrhythmias considered clinically significant, 15 had associated structural heart disease. On the other hand, of the 14 patients without clinically significant arrhythmias, structural heart disease could be detected in only three. It is concluded that cardiac arrhythmias constitute a common cause of unexplained syncope, particularly in patients with structural heart disease, and that EPS with PES can uncover the type of arrhythmic disturbance in a significant number of cases.     

Carotid sinus hypersensitivity and syncope

The patient with a hypersensitive carotid sinus reflex and syncope may pose special challenges in evaluation and treatment. Specifically, although the finding of carotid sinus hypersensitivity may indeed indicate an exaggerated vagal tone that causes syncope, it may also be a chance association in a patient with syncope due to another cause. Careful clinical and electrophysiologic testing may be needed to distinguish these two possibilities. Furthermore, the need for drug therapy or cardiac pacing (or both) must be determined on an individual basis, depending on the relative contributions of cardioinhibitory and vasodepressor components to the patient's symptoms and also on the degree of patient limitation.