The Bottom Line: Up to 1 in 6 admitted syncope patients may have PE
– Works out to <4% of ED presenters with loss of consciousness (LOC), and likely <<1% of all syncope cases (which includes patients who do not present to an ED)
– Recall: All ED patients with LOC had a structured evaluation (structured history; structured physical exam including orthostatics and complete CV and neuro exam; and EKG)
– Impact on hospital medicine practice: In admitted patients with syncope (without clear etiology)…
∙ Check sWell’s Score and D-dimer è
∙ If either positive, consider imaging for PE (Dressler, 2017)
Reference: Dressler, DD. Effective, Efficient, and Prudent Evaluation of Syncope and Autonomic Syndromes. 2017, April 1. Presented at the annual ACP Internal Medicine Meeting, San Diego, CA.
Prandoni P, Lensing AWA, Prins MH, et al. Prevelance of pulmonary embolism among patients hospitalized with syncope. New England Journal of Medicine. 2016 Oct; 375(16): 1524-1531.
Summary: Syncope is generally expected to occur in patients with pulmonary embolism if they have a sudden obstruction of the most proximal pulmonary arteries that leads to a transient depression in cardiac output (Prandoni et al, 2016). A study of 560 patients by Prandoni et al (2016) found that in at least half of their patients with pulmonary embolism, the extent of thrombosis was large enough to produce an abrupt obstruction of the blood flow that would be likely to result in a sudden loss of consciousness. They found the rate of pulmonary embolism was highest among those who did not have an alternative explanation for syncope.