synkopen

Synkopen are episodes of transient loss of consciousness caused by a temporary reduction in cerebral blood flow. They typically have a rapid onset, short duration, and complete spontaneous recovery. While common across ages, they require careful evaluation to exclude dangerous cardiac conditions. The term describes a symptom, not a disease, and the underlying cause is usually identifiable through history, examination, and selective testing.

Most syncope cases are categorized as reflex (vasovagal or situational), cardiac, orthostatic, or unknown. Reflex syncope results from an inappropriate autonomic reflex causing vasodilation and often bradycardia. Cardiac syncope is due to arrhythmias or structural heart disease that severely reduces cerebral perfusion. Orthostatic syncope occurs on standing and is linked to inadequate autonomic compensation, dehydration, or medications.

Prodromal symptoms such as lightheadedness, nausea, sweating, and visual changes may precede the loss of consciousness, though some cardiac events occur without warning. Differentiating the types is essential because management and prognosis differ.

Evaluation relies on history and physical examination, along with orthostatic vital signs and an electrocardiogram. If indicated, echocardiography, ambulatory rhythm monitoring, tilt-table testing, or imaging may be performed to identify structural heart disease or abnormal heart rhythms and to assess risk.

Management aims to prevent recurrence and protect against serious outcomes. Acute care includes ensuring safety, placing the patient in a supine position, and treating reversible triggers. For reflex syncope, strategies include hydration, salt intake, and physical counter-maneuvers. Orthostatic syncope may respond to volume expansion and compression garments. Cardiac syncope requires treatment of the underlying heart disease and may involve pacing or defibrillator therapy. Prognosis is favorable for most reflex or orthostatic syncope but worse when a cardiac cause is present.