The author explains the clinical presentation, pathophysiology, diagnostic work-up, and management of swallow syncope. Swallow syncope is most commonly associated with esophageal disorders that affect the afferent limb of a vagovagal reflex, including such disorders as hiatal hernia, gastroesophageal reflux, diffuse esophageal spasm, esophageal carcinoma, esophageal stricture, esophageal stenosis from ascending aortic aneurysm, distal esophageal Schatzki ring, hypertensive peristaltic waves (nutcracker esophagus), achalasia, and esophageal diverticula.
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• Swallow syncope may occur within 3 to 5 seconds of swallowing. Many bouts result only in presyncope, with associated visual greyout, tunnel vision, etc.
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• Swallow syncope is frequently triggered by liquids, particularly cold, carbonated beverages.
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• Swallow syncope is caused by stimulation, irritation, or dysfunction of the afferent origin of a vagovagal reflex (eg, the distal esophagus), the vagus nerve itself, or the efferent target of the vagovagal reflex (ie, the heart).
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• Swallow syncope may be confused with epilepsy, particularly as the syncopal attacks may be associated with secondary arrhythmic convulsive jerks of the extremities (ie, convulsive syncope).
Historical note and terminology
Swallow syncope is a loss of consciousness during or immediately following a swallow (55). Recognition of the disorder dates from the late 1700s, but most cases have been reported since 1900 (55). Swallow syncope is usually caused by upper gastrointestinal-cardiac vagovagal reflexes initiated by swallowing and rapid gastric distention (70). As such, swallow syncope is often considered 1 of a number of neurally mediated, "situational" syncopes that include those which occur after micturition, defecation, coughing, or, rarely, laughing (27). Cases have also been reported in animals (73).