Official reprint from UpToDate®
www.uptodate.com ©2017 UpToDate, Inc. and/or its affiliates. All Rights Reserved.

Approach to the adult patient with syncope in the emergency department

Daniel McDermott, MD
James Quinn, MD, MS
Section Editor
Robert S Hockberger, MD, FACEP
Deputy Editor
Jonathan Grayzel, MD, FAAEM


Syncope is a transient loss of consciousness, associated with loss of postural tone, with spontaneous return to baseline neurologic function requiring no resuscitative efforts. The underlying mechanism is global hypoperfusion of both the cerebral cortices or focal hypoperfusion of the reticular activating system. It is not to be confused with loss of consciousness associated with altered mental status or stroke and similarly in vague dizziness and chronic lightheadedness in patients with pre-syncope. To address this issue an international consortium gathered to define syncope and standardize the reporting of outcomes to guide future research [1].

Syncope is a common complaint in the emergency department (ED), accounting for 1 to 3 percent of all ED visits and hospital admissions in the United States [2-6]. Although most potential causes are benign and self-limited, others are associated with significant morbidity and mortality. The differential diagnosis is broad, and management focuses on the underlying cause when this is discernible. However, during the ED evaluation the cause of syncope often remains unclear and management must focus on risk stratification to differentiate among patients safe for discharge and those who require emergent investigation and in-hospital management. Presyncope (ie, near loss of consciousness) and true syncope should be considered a spectrum of the same symptom. Although near syncope is less dramatic and some of the studies and guidelines about its significance less compelling, clinicians should approach them in similar fashion.

When researchers have made a clear effort to distinguish true presyncope from dizziness and vague lightheadedness the outcomes of syncope and near or presyncope parallel on another in terms of significant underlying causes and serious outcomes [7]. In a recent study, researchers in Canada specifically addressed a presyncopal cohort and concluded that patients with pre-syncope can have significant underlying causes [8].

This topic review will discuss how to evaluate and manage patients presenting to the ED with syncope. Detailed discussions of specific types of syncope and the evaluation of syncope in children and adults are found elsewhere. (See "Syncope in adults: Epidemiology, pathogenesis, and etiologies" and "Reflex syncope in adults: Clinical presentation and diagnostic evaluation" and "Emergency evaluation of syncope in children and adolescents".)


Syncope has many causes that are often difficult to determine in the emergency department (ED). After reviewing the history, physical examination, and the electrocardiogram (ECG) physicians in the ED are able to determine a clear underlying diagnosis only about 50 percent of the time [9,10]. Patients often remain undiagnosed despite exhaustive diagnostic testing [4,11]. Tables listing the most dangerous and most common etiologies of syncope are provided (table 1 and table 2 and table 3).

To continue reading this article, you must log in with your personal, hospital, or group practice subscription. For more information on subscription options, click below on the option that best describes you:

Subscribers log in here

Literature review current through: Nov 2017. | This topic last updated: Jun 15, 2017.
The content on the UpToDate website is not intended nor recommended as a substitute for medical advice, diagnosis, or treatment. Always seek the advice of your own physician or other qualified health care professional regarding any medical questions or conditions. The use of this website is governed by the UpToDate Terms of Use ©2017 UpToDate, Inc.
  1. Sun BC, Costantino G, Barbic F, et al. Priorities for emergency department syncope research. Ann Emerg Med 2014; 64:649.
  2. Day SC, Cook EF, Funkenstein H, Goldman L. Evaluation and outcome of emergency room patients with transient loss of consciousness. Am J Med 1982; 73:15.
  3. Kapoor WN, Karpf M, Wieand S, et al. A prospective evaluation and follow-up of patients with syncope. N Engl J Med 1983; 309:197.
  4. Kapoor WN. Evaluation and outcome of patients with syncope. Medicine (Baltimore) 1990; 69:160.
  5. Martin GJ, Adams SL, Martin HG, et al. Prospective evaluation of syncope. Ann Emerg Med 1984; 13:499.
  6. Costantino G, Sun BC, Barbic F, et al. Syncope clinical management in the emergency department: a consensus from the first international workshop on syncope risk stratification in the emergency department. Eur Heart J 2016; 37:1493.
  7. Grossman SA, Babineau M, Burke L, et al. Do outcomes of near syncope parallel syncope? Am J Emerg Med 2012; 30:203.
  8. Thiruganasambandamoorthy V, Stiell IG, Wells GA, et al. Outcomes in presyncope patients: a prospective cohort study. Ann Emerg Med 2015; 65:268.
  9. Linzer M, Yang EH, Estes NA 3rd, et al. Diagnosing syncope. Part 1: Value of history, physical examination, and electrocardiography. Clinical Efficacy Assessment Project of the American College of Physicians. Ann Intern Med 1997; 126:989.
  10. Brignole M, Menozzi C, Bartoletti A, et al. A new management of syncope: prospective systematic guideline-based evaluation of patients referred urgently to general hospitals. Eur Heart J 2006; 27:76.
  11. Farwell DJ, Sulke AN. Does the use of a syncope diagnostic protocol improve the investigation and management of syncope? Heart 2004; 90:52.
  12. Quinn JV, Stiell IG, McDermott DA, et al. Derivation of the San Francisco Syncope Rule to predict patients with short-term serious outcomes. Ann Emerg Med 2004; 43:224.
  13. Middlekauff HR, Stevenson WG, Stevenson LW, Saxon LA. Syncope in advanced heart failure: high risk of sudden death regardless of origin of syncope. J Am Coll Cardiol 1993; 21:110.
  14. Soteriades ES, Evans JC, Larson MG, et al. Incidence and prognosis of syncope. N Engl J Med 2002; 347:878.
  15. Sarasin FP, Louis-Simonet M, Carballo D, et al. Prevalence of orthostatic hypotension among patients presenting with syncope in the ED. Am J Emerg Med 2002; 20:497.
  16. Baraff LJ, Schriger DL. Orthostatic vital signs: variation with age, specificity, and sensitivity in detecting a 450-mL blood loss. Am J Emerg Med 1992; 10:99.
  17. Koziol-McLain J, Lowenstein SR, Fuller B. Orthostatic vital signs in emergency department patients. Ann Emerg Med 1991; 20:606.
  18. Hanlon JT, Linzer M, MacMillan JP, et al. Syncope and presyncope associated with probable adverse drug reactions. Arch Intern Med 1990; 150:2309.
  19. Kapoor WN, Fortunato M, Hanusa BH, Schulberg HC. Psychiatric illnesses in patients with syncope. Am J Med 1995; 99:505.
  20. Narkiewicz K, Cooley RL, Somers VK. Alcohol potentiates orthostatic hypotension : implications for alcohol-related syncope. Circulation 2000; 101:398.
  21. Oh JH, Hanusa BH, Kapoor WN. Do symptoms predict cardiac arrhythmias and mortality in patients with syncope? Arch Intern Med 1999; 159:375.
  22. Martin TP, Hanusa BH, Kapoor WN. Risk stratification of patients with syncope. Ann Emerg Med 1997; 29:459.
  23. Colivicchi F, Ammirati F, Melina D, et al. Development and prospective validation of a risk stratification system for patients with syncope in the emergency department: the OESIL risk score. Eur Heart J 2003; 24:811.
  24. Sarasin FP, Hanusa BH, Perneger T, et al. A risk score to predict arrhythmias in patients with unexplained syncope. Acad Emerg Med 2003; 10:1312.
  25. Calkins H, Shyr Y, Frumin H, et al. The value of the clinical history in the differentiation of syncope due to ventricular tachycardia, atrioventricular block, and neurocardiogenic syncope. Am J Med 1995; 98:365.
  26. Kapoor WN, Hanusa BH. Is syncope a risk factor for poor outcomes? Comparison of patients with and without syncope. Am J Med 1996; 100:646.
  27. Morag RM, Murdock LF, Khan ZA, et al. Do patients with a negative Emergency Department evaluation for syncope require hospital admission? J Emerg Med 2004; 27:339.
  28. American College of Emergency Physicians. Clinical policy: critical issues in the evaluation and management of patients presenting with syncope. Ann Emerg Med 2001; 37:771.
  29. Alboni P, Brignole M, Menozzi C, et al. Diagnostic value of history in patients with syncope with or without heart disease. J Am Coll Cardiol 2001; 37:1921.
  30. Krahn AD, Klein GJ, Yee R, et al. Predictive value of presyncope in patients monitored for assessment of syncope. Am Heart J 2001; 141:817.
  31. Sheldon R, Rose S, Ritchie D, et al. Historical criteria that distinguish syncope from seizures. J Am Coll Cardiol 2002; 40:142.
  32. Benbadis SR, Wolgamuth BR, Goren H, et al. Value of tongue biting in the diagnosis of seizures. Arch Intern Med 1995; 155:2346.
  33. Bergfeldt L. Differential diagnosis of cardiogenic syncope and seizure disorders. Heart 2003; 89:353.
  34. Driscoll DJ, Jacobsen SJ, Porter CJ, Wollan PC. Syncope in children and adolescents. J Am Coll Cardiol 1997; 29:1039.
  35. Huff JS, Decker WW, Quinn JV, et al. Clinical policy: critical issues in the evaluation and management of adult patients presenting to the emergency department with syncope. Ann Emerg Med 2007; 49:431.
  36. Writing Committee Members, Shen WK, Sheldon RS, et al. 2017 ACC/AHA/HRS guideline for the evaluation and management of patients with syncope: Executive summary: A report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. Heart Rhythm 2017; 14:e218.
  37. Quinn J, McDermott D. Electrocardiogram findings in emergency department patients with syncope. Acad Emerg Med 2011; 18:714.
  38. Brignole M, Alboni P, Benditt D, et al. Guidelines on management (diagnosis and treatment) of syncope. Eur Heart J 2001; 22:1256.
  39. Giustetto C, Schimpf R, Mazzanti A, et al. Long-term follow-up of patients with short QT syndrome. J Am Coll Cardiol 2011; 58:587.
  40. Bass EB, Curtiss EI, Arena VC, et al. The duration of Holter monitoring in patients with syncope. Is 24 hours enough? Arch Intern Med 1990; 150:1073.
  41. Brembilla-Perrot B, Beurrier D, de la Chaise AT, et al. Significance and prevalence of inducible atrial tachyarrhythmias in patients undergoing electrophysiologic study for presyncope or syncope. Int J Cardiol 1996; 53:61.
  42. Eagle KA, Black HR. The impact of diagnostic tests in evaluating patients with syncope. Yale J Biol Med 1983; 56:1.
  43. Mendu ML, McAvay G, Lampert R, et al. Yield of diagnostic tests in evaluating syncopal episodes in older patients. Arch Intern Med 2009; 169:1299.
  44. Quinn JV, Stiell IG, McDermott DA, et al. The San Francisco Syncope Rule vs physician judgment and decision making. Am J Emerg Med 2005; 23:782.
  45. Reed MJ, Newby DE, Coull AJ, et al. The ROSE (risk stratification of syncope in the emergency department) study. J Am Coll Cardiol 2010; 55:713.
  46. Costantino G, Solbiati M, Pisano G, Furlan R. NT-pro-BNP for differential diagnosis in patients with syncope. Int J Cardiol 2009; 137:298.
  47. Reed MJ, Newby DE, Coull AJ, et al. Role of brain natriuretic peptide (BNP) in risk stratification of adult syncope. Emerg Med J 2007; 24:769.
  48. Costantino G, Solbiati M, Casazza G, et al. Usefulness of N-terminal pro-B-type natriuretic Peptide increase as a marker for cardiac arrhythmia in patients with syncope. Am J Cardiol 2014; 113:98.
  49. Thiruganasambandamoorthy V, Ramaekers R, Rahman MO, et al. Prognostic value of cardiac biomarkers in the risk stratification of syncope: a systematic review. Intern Emerg Med 2015; 10:1003.
  50. Pires LA, Ganji JR, Jarandila R, Steele R. Diagnostic patterns and temporal trends in the evaluation of adult patients hospitalized with syncope. Arch Intern Med 2001; 161:1889.
  51. Zaidi A, Clough P, Cooper P, et al. Misdiagnosis of epilepsy: many seizure-like attacks have a cardiovascular cause. J Am Coll Cardiol 2000; 36:181.
  52. Sarasin FP, Junod AF, Carballo D, et al. Role of echocardiography in the evaluation of syncope: a prospective study. Heart 2002; 88:363.
  53. Jiménez D, Díaz G, Valle M, et al. [Prognostic value of syncope in the presentation of pulmonary embolism]. Arch Bronconeumol 2005; 41:385.
  54. Calvo-Romero JM, Pérez-Miranda M, Bureo-Dacal P. Syncope in acute pulmonary embolism. Eur J Emerg Med 2004; 11:208.
  55. Authors' unpublished data.
  56. Turakhia MP, Hoang DD, Zimetbaum P, et al. Diagnostic utility of a novel leadless arrhythmia monitoring device. Am J Cardiol 2013; 112:520.
  57. Schreiber D, Sattar A, Drigalla D, Higgins S. Ambulatory cardiac monitoring for discharged emergency department patients with possible cardiac arrhythmias. West J Emerg Med 2014; 15:194.
  58. Barrett PM, Komatireddy R, Haaser S, et al. Comparison of 24-hour Holter monitoring with 14-day novel adhesive patch electrocardiographic monitoring. Am J Med 2014; 127:95.e11.
  59. Serrano LA, Hess EP, Bellolio MF, et al. Accuracy and quality of clinical decision rules for syncope in the emergency department: a systematic review and meta-analysis. Ann Emerg Med 2010; 56:362.
  60. Costantino G, Casazza G, Reed M, et al. Syncope risk stratification tools vs clinical judgment: an individual patient data meta-analysis. Am J Med 2014; 127:1126.e13.
  61. Quinn J, McDermott D, Stiell I, et al. Prospective validation of the San Francisco Syncope Rule to predict patients with serious outcomes. Ann Emerg Med 2006; 47:448.
  62. Quinn J, McDermott D, Kramer N, et al. Death after emergency department visits for syncope: how common and can it be predicted? Ann Emerg Med 2008; 51:585.
  63. Saccilotto RT, Nickel CH, Bucher HC, et al. San Francisco Syncope Rule to predict short-term serious outcomes: a systematic review. CMAJ 2011; 183:E1116.
  64. Derose SF, Gabayan GZ, Chiu VY, Sun BC. Patterns and preexisting risk factors of 30-day mortality after a primary discharge diagnosis of syncope or near syncope. Acad Emerg Med 2012; 19:488.
  65. Kenny RA, Brignole M, Dan GA, et al. Syncope Unit: rationale and requirement--the European Heart Rhythm Association position statement endorsed by the Heart Rhythm Society. Europace 2015; 17:1325.
  66. Shen WK, Decker WW, Smars PA, et al. Syncope Evaluation in the Emergency Department Study (SEEDS): a multidisciplinary approach to syncope management. Circulation 2004; 110:3636.
  67. Sun BC, McCreath H, Liang LJ, et al. Randomized clinical trial of an emergency department observation syncope protocol versus routine inpatient admission. Ann Emerg Med 2014; 64:167.
  68. van Dijk N, Quartieri F, Blanc JJ, et al. Effectiveness of physical counterpressure maneuvers in preventing vasovagal syncope: the Physical Counterpressure Manoeuvres Trial (PC-Trial). J Am Coll Cardiol 2006; 48:1652.