Patient reports of fainting or "passing out" are common and warrant a meticulous history to guide management and possible hospital admission. Begin by finding out whether the patient has actually lost consciousness. Did the patient hear external noise or voices throughout the episode, feel light-headed or weak, but fail to actually lose consciousness, consistent with near syncope or presyncope? Or did the patient actually experience complete loss of consciousness, a more serious symptom representing true syncope, defined as a sudden but temporary loss of consciousness and postural tone from transient global hypoperfusion of the brain?

Elicit a complete description of the event. What was the patient doing when the episode occurred? Was the patient standing, sitting, or lying down? Were there any triggers or warning symptoms? How long did the episode last? Could voices still be heard? Importantly, were onset and offset slow or fast? Were there any palpitations? Is there a history of heart disease, which has a sensitivity for a cardiac cause of more than 95% (with a specificity of ∼45%)?

Try to interview any witnesses. Consider the possibility of a seizure based on the features described in the following section, especially if the onset was abrupt and without warning.

责任编辑：admin