56-year-old man • increased heart rate • weakness • intense sweating • horseradish consumption • Dx?

The recovery with awareness of time, place, and person may be a feature of VVS, which would differentiate it from seizures and brainstem vascular events. Autonomic prodromal symptoms—including abdominal discomfort, pallor, sweating, and nausea—may precede the loss of consciousness.⁸

An evolutionary response?

VVS may have developed as a trait through evolution, although modern medicine treats it as a disease. Many potential explanations for VVS as a body defense mechanism have been proposed. Examples include fainting at the sight of blood, which developed during the Old Stone Age—a period with extreme human-to-human violence—or acting like a “possum playing dead” as a tactic designed to confuse an attacker.¹⁶

Vasovagal syncope may have developed as a trait through evolution, although modern medicine treats it as a disease.

Another theory involves clot production and suggests that VVS-induced hypotension is a defense against bleeding by improving clot formation.¹⁷

A psychological defense theory maintains that the fainting and memory loss are designed to prevent a painful or overwhelming experience from being remembered. None of these theories, however, explain orthostatic VVS.¹⁸

The brain defense theory could explain all forms of VVS. It postulates that hypotension causes decreased cerebral perfusion, which leads to syncope resulting in the body returning to a more orthostatic position with increased cerebral profusion.¹⁹

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