That Syncope is so common makes it no less worrisome. The proper evaluation of syncope requires a systematic diagnostic approach by a physician-diagnostician, usually a specialist in Internal Medicine. Such an evaluation takes time, usually a 30-40 minute first visit and, for that reason is generally not within the scope of a busy primary care physician or an emergency room physician. Fortunately there are well established protocols for determining the cause of syncope that will usually require a variety of tests
The following is from Cecil’s Textbook of Medicine and as you can see, there are many potential etiologies including neurogenic (far and away the most common), cardiac (with or without arrhythmias) . With a good physical exam and a careful history the likely causes can be narrowed-down to a couple categories.
I suggest that you seek consultation with a specialist in Internal Medicine because of the broad spectrum of disease to be considered. The IM specialist may, in turn, refer you to another specialist, such as a Neurologist but it would be a mistake to first seek assistance with a Neurologist or any other sub-specialist. The cause of syncope can be determined and treated in most instances.
TABLE 62-1 -- Causes of Syncope and Their Prevalence
Vasovagal (8–41% of patients)
Situational (1–8% of patients)
Carotid sinus syncope (0.4% of patients)
ORTHOSTATIC HYPOTENSION (4–10% OF PATIENTS)
DECREASED CARDIAC OUTPUT
Obstruction to flow (1–8% of patients)
Obstruction to left ventricular outflow or inflow: aortic stenosis, hypertrophic obstructive cardiomyopathy, mitral stenosis, myxoma
Obstruction to right ventricular outflow or inflow: pulmonic stenosis, pulmonary embolism, pulmonary hypertension, myxoma
Other heart disease
Pump failure, myocardial infarction, coronary artery disease, coronary spasm, tamponade, aortic dissection
ARRHYTHMIAS (4–38% OF PATIENTS)
Bradyarrhythmias: sinus node disease, second- and third-degree atrioventricular block, pacemaker malfunction, drug-induced bradyarrhythmias
Tachyarrhythmias: ventricular tachycardia, torsades de pointes (e.g., associated with congenital long QT syndrome or acquired QT prolongation), supraventricular tachycardia
NEUROLOGIC AND PSYCHIATRIC DISEASES (3–32% OF PATIENTS)
Transient ischemic attacks
UNKNOWN (13–41% OF PATIENTS)
Adapted from Kapoor W. Approach to the patient with syncope. In: Braunwald E, Goldman L, eds. Primary Cardiology, 2nd ed. Philadelphia: Saunders; 2003.
Because most spells of episodic loss of consciousness occur outside medical observation, the history is the most critical part of the evaluation (Table 62-2). Each syncopal episode should be reviewed in detail, with special attention to symptoms preceding the episode, events during unconsciousness, and the symptoms and time course of regaining orientation after consciousness is restored. Information from a witness can be essential to the evaluation.