A 62-year-old woman with syncope

Numerous studies indicate a low diagnostic yield of the use of brain CTs in the evaluation of syncope.(1,2) In addition, a normal CT brain does not completely exclude an early presentation of stroke or a neurological etiology of syncope. The described "defensive medicine" approach is a prevalent but ineffective practice, providing false reassurance through unnecessary testing.(3) The literature indicates that a stronger predictor of patient complaints is poor physician communication skills.(4) Efforts to improve patient-physician communication would be the preferred approach to address any liability concerns.

References

1. Mendu, M. L., McAvay, G., Lampert, R., Stoehr, J. & Tinetti, M. E. Yield of diagnostic tests in evaluating syncopal episodes in older patients. Arch Intern Med 169, 1299-1305 (2009).

2. Disertori, M. et al. Management of patients with syncope referred urgently to general hospitals. Europace 5, 283-291 (2003).

3. Studdert, D. M. et al. Defensive medicine among high-risk specialist physicians in a volatile malpractice environment. JAMA 293, 2609-2617 (2005).

4. Tamblyn, R. et al. Physician scores on a national clinical skills examination as predictors of complaints to medical regulatory authorities. JAMA 298, 993-1001 (2007).

Conflict of Interest:

None declared

We thank Drs. Thiruganasambandamoorthy and Sheldon for clarifying the definition of syncope as a transient loss of consciousness (T-LOC) due to global cerebral hypoperfusion characterized by rapid onset, short duration, and spontaneous complete recovery.(1) However, experts (including Drs. Thiruganasambandamoorthy and Sheldon) acknowledge this approach has pragmatic limitations particularly when applied to undifferentiated patient presentations in the emergency department. In order to guide clinicians in the ED, our approach focuses on all potential causes of patients presenting with transient loss of consciousness, including syncope "mimickers". We agree that stroke, transient loss of consciousness, seizure, and metabolic disturbances do not represent true syncope.

Reference

1. Sun, B. C. et al. Priorities for emergency department syncope research. Annals of emergency medicine 64, 649-55.e2 (2014).

Conflict of Interest:

None declared

We read with great interest the CME Practice article by Soong et al, whose intent is to highlight the overuse of investigations, particularly neuroimaging among patients who have suffered syncope.(1) While the 2009 European Society of Cardiology guideline was cited by Soong et al, the pitfall of not differentiating syncope from other causes of transient loss of consciousness (T-LOC) were not adhered to by the authors.(2) Syncope is due to global cerebral hypoperfusion and none of the listed neurologic diagnoses cause syncope. This confusion has led to great research efforts, consensus conferences, guidelines and statements developed by the European Society of Cardiology, the Gargnano multidisciplinary consensus conference (led by internists), and the Canadian Cardiovascular Society all of which uniformly exclude neurological conditions causing T-LOC from syncope.(2-5) Based on current evidence, syncope is defined as a transient loss of consciousness due to global cerebral hypoperfusion characterized by rapid onset, short duration, and spontaneous complete recovery. Sadly, this article worsens the confusion by clearly stating that neurologic causes of syncope exist which will lead to practicing physicians including neurological causes in the differential diagnosis for true syncope and not differentiating syncope from other causes of T-LOC. This is important as the literature evidence regarding the risk of 'cardiac syncope', and use of neuroimaging apply exist only for true syncope patients and cannot be applied to all patients with T-LOC. The authors could also have cited new evidence for high-risk features for 'cardiac syncope' that have been summarized based on evidence.(6, 7)

Note: The authors listed in reference #7 (Sheldon et al) should be "Sheldon RS, Morillo CA, Krahn AD, et al."

Dr. Venkatesh Thiruganasambandamoorthy Department of Emergency Medicine, University of Ottawa

Dr. Robert Sheldon Division of Cardiology, University of Calgary

References 1. Soong C, Chen BH, Wong BM. A 62-year-old woman with syncope. CMAJ Canadian Medical Association Journal. 2015 Jan 6;187(1):48-9.

2. Moya A., Sutton R., Ammirati F., Blanc JJ, Brignole M., Dahm JB, et al. Guidelines for the diagnosis and management of syncope (version 2009). Eur Heart J. 2009 Nov;30(21):2631-71. Epub 2009 Aug 27. 2009;30(12).

3. Sun BC, Costantino G, Barbic F, Bossi I, Casazza G, Dipaola F, et al. Priorities for emergency department syncope research. Annals of Emergency Medicine. 2014:Submitted.

4. Sun BC, Thiruganasambandamoorthy V, Cruz JD, Consortium to Standardize ED Syncope Risk Stratification,Reporting. Standardized reporting guidelines for emergency department syncope risk-stratification research. Acad Emerg Med. 2012 Jun;19(6):694-702.

5. Sheldon RS, Morillo CA, Krahn AD, O'Neill B, Thiruganasambandamoorthy V, Parkash R, et al. Standardized approaches to the investigation of syncope: Canadian cardiovascular society position paper. Can J Cardiol. 2011 Mar-Apr;27(2):246-53.

6. D'Ascenzo F, Biondi-Zoccai G, Reed MJ, Gabayan GZ, Suzuki M, Costantino G, et al. Incidence, etiology and predictors of adverse outcomes in 43,315 patients presenting to the emergency department with syncope: An international meta-analysis. Int J Cardiol. 2013 Jul 15;167(1):57-62.

7. Berecki-Gisolf J, Sheldon A, Wieling W, van Dijk N, Costantino G, Furlan R, et al. Identifying cardiac syncope based on clinical history: A literature-based model tested in four independent datasets. - PLoS One.2013 Sep 24;8(9):e75255.doi: 10.1371/journal.pone.0075255.eCollection 2013. 2013.

Conflict of Interest:

None declared

We read with great interest the article by Soong et al., on the subject of syncope. The authors and the Canadian Society of Internal Medicine should be commended for their efforts to reduce unnecessary neuroimaging in uncomplicated syncope. We would like to take this opportunity to further re-enforce their message by hi-lighting recent alternate terminology.

Syncope is best defined as transient loss of consciousness (T-LOC) with loss of postural tone and spontaneous recovery, secondary to global cerebral hypoperfusion. Other causes of T-LOC such as transient ischemic attack (TIA), stroke and seizure are therefore, in fact, not syncope. The same applies to anemia, or metabolic disturbances, such as hypoglycemia or hypercapnea. These conditions are best described as "syncope mimics" and can usually be suggested by the history when evaluating a patient with T- LOC (1).

Pathophysiologic causes of syncope can be broadly classified into three categories: Cardiac Syncope, Syncope due to Orthostatic Hypotension and Reflex Syncope (including vasovagal)(1). When approaching a complaint of T -LOC in the ER, the clinician should first establish by history that there was indeed syncope and can then focus their history and physical examination to suggest possible causes. Accompanying neurological symptoms are clues that the event likely does not represent a syncopal episode(2).

Where the message of minimizing neurological investigations for syncope definitely holds true, approaching T-LOC with a pathophysiological framework helps the clinician focus and improves diagnosis and risk stratification

References

1. Moya A, Sutton R, Ammirati F, et al. Guidelines for the diagnosis and management of syncope (version 2009): The Task Force for the Diagnosis and Management of Syncope of the European Society of Cardiology (ESC). Eur Heart J 2009; 30:2631-71.

2. Sheldon RS, Decker WW, Quinn JV, et al. Standardized approaches to the investigation of syncope: Canadian Cardiovascular Society position paper. Can J Cardiol 2011;27:246-53.

Conflict of Interest:

None declared