Chapter 33: Syncope Evaluation & Differential Diagnosis

Syncope Evaluation & Differential Diagnosis meticulously distinguishes true syncope from other states of altered consciousness such as coma, seizures, vertigo, and dizziness, emphasizing that while many etiologies are benign, identifying cardiogenic causes is critical due to the high risk of mortality and sudden cardiac death. The text details the diagnostic reasoning process, prioritizing a focused patient history to identify red flags like exertional syncope, supine events, or a lack of prodromal warning signs, which contrast with the nausea, warmth, and diaphoresis typically associated with neurocardiogenic or vasovagal responses. Considerable attention is given to the various classifications of fainting, including situational syncope triggered by micturition, defecation, or coughing, and orthostatic hypotension resulting from age-related vasomotor instability, dehydration, or pharmaceutical side effects from diuretics and beta-blockers. The chapter outlines the essential components of the physical examination, such as measuring orthostatic blood pressure changes, auscultating for carotid bruits and valvular murmurs, and performing neurological checks to rule out strokes or vertebrobasilar insufficiency. Furthermore, it evaluates the utility of diagnostic testing, advocating for the 12-lead electrocardiogram (ECG) as a primary tool to detect arrhythmias, heart blocks, or conduction intervals, while discussing advanced testing like Holter monitoring, echocardiography, and tilt-table testing for recurrent or unexplained cases. The discussion concludes by reviewing the differential diagnosis, differentiating syncopal episodes from mimics like migraines, metabolic hypoglycemia, and psychogenic factors, ensuring primary care providers can effectively risk-stratify patients for appropriate referral or management.