Transient loss of consciousness or fainting caused by a short-term (seconds to a few minutes) decrease in cerebral blood flow.
The clinical picture is caused by stimulation of the vagus nerve, slowing of the heart rate and dilation of the blood vessels. It can occur with sudden changes of position, standing or sitting for a long time without changing posture, emotional stress, and intense pain. It manifests itself with a loss of body tone and level of consciousness. Anticipatory symptoms such as nausea, pallor, cold skin with sweating often occur before fainting.
Diagnosis is made by a thorough history and physical examination, with further tests required if there is doubt about the cause.
During initial care, the head should be placed below the level of the body to encourage blood return to the brain. The patient should not be given food or drink until full consciousness is regained.
- Brian Olshansky. Reflex syncope. UpToDate. Agosto 2014
- Task Force for the Diagnosis and Management of Syncope, European Society of Cardiology (ESC), European Heart Rhythm Association (EHRA), et al. Guidelines for the diagnosis and management of syncope (version 2009). Eur Heart J 2009; 30:2631.
- Chen-Scarabelli C. Neurocardiogenic syncope. BMJ 2004; 329:336.
- Mosqueda-Garcia R. The elusive pathophysiology of neurally mediated syncope. Circulation 2000; 102:2898.
- Chen MY. Cardiac electrophysiologic and hemodynamic correlates of neurally mediated syncope. Am J Cardiol 1989; 63:66.
- Roy Freeman. Síncope. Harrison. Principios de Medicina Interna, 19e. Capítulo 27
