Syncope, defined as transient loss of consciousness, is a common chief complaint in patients presenting to the Emergency Department (ED). Syncope can have many underlying causes— making a differential diagnosis less than straightforward. An ED clinician’s primary aim in treating a patient presenting with syncope is to rule out serious and life-threatening causes for the syncopal episode. Neurally-mediated syncope is common and most often benign, whereas cardiac syncope is associated with increased morbidity and mortality. Obtaining a patient’s history and conducting a thorough physical exam can help stratify patients by risk. (Patel & Quinn, 2015)

One 2009 study conducted in the United States found that half of older patients presenting with syncope were admitted to the hospital for further testing. (Mendu et al) This results in many unnecessary and expensive tests being run. Therefore, the clinician’s secondary aim is to determine the most likely cause for the episode and recommend appropriate treatment and follow-up based on accepted guidelines for evaluating a syncope patient in the ED. 

NICE offers a detailed clinical guideline to follow in cases of transient loss of consciousness (CG109). Emphasis is placed on the initial assessment, as this will set the course for further action. Obtaining the details of the event (both from patient and any available witnesses) will establish whether the event was indeed a syncopal episode or something different (e.g. a fall). Obtaining the patient’s history may point towards an underlying cause (i.e. individual or family history of heart disease). The next recommended step is to record a 12-lead electrocardiogram (ECG) and review for any abnormalities. 

Following the initial assessment, if there is reason to suspect an underlying cause, then appropriate steps should be followed to rule out or confirm the suspicion. Patients should be referred for urgent cardiovascular assessment if an ECG abnormality is present, there is history or physical signs of heart failure, the syncopal episode happened during exertion, there is family history or inherited cardiac condition and if unexplained breathlessness or a heart murmur are present.

Another way to consider possible causes and next steps is by following the San Francisco Syncope Rule, also know as CHESS (history of congestive heart failure; haematocrit < 30%, abnormal findings on 12-lead ECG, history of shortness of breath, and systolic blood pressure < 90 mm Hg at triage). A meta-analysis from 2011 suggests that the CHESS method should only be followed for patients in whom no cause of syncope is evident after initial evaluation in the emergency department. The authors found the probability of a serious outcome given a negative CHESS score was 2% or lower for patients who had already undergone the initial assessment. (Saccilotto et al.)

A diagnosis of uncomplicated vasovagal syncope (uncomplicated faint) can be reached if none of the above factors are present. The clinician should pay attention to features suggesting an uncomplicated faint, such as the three Ps: posture, provoking factors and prodromal symptoms. An alternative diagnosis is situational syncope, if again, no features present an alternative diagnosis in the initial assessment and the episodes appear to be provoked by a specific context (e.g. straining when coughing). If the syncope is determined to be uncomplicated, the patient should be urged to contact their GP for non-emergent follow up at a later date. 

As always, conducting a thorough initial assessment and following recommended guidelines will have the dual benefit of providing the top level of care, while also avoiding unnecessary and expensive testing. ED clinicians would be well advised to familiarise themselves with the possible underlying cause of syncope and the subsequent recommended courses of action.