Syncope is a brief and sudden loss of consciousness most often associated with a fall of the subject. There is usually a quick and spontaneous return to a normal state of consciousness.
Syncope is secondary to a sharp decline in cerebral blood flow. It is associated with a fall in blood pressure and a weakening or even a disappearance of the pulse.
The causes of syncope are multiple. It is most commonly an abnormality of the autonomic nervous system that controls blood pressure and heart rate. This is called vasovagal syncope. It is most often benign.
But syncope can also be a symptom of a more serious heart condition, such as a rhythm disorder or aortic valve narrowing.
Finally, there are cases of syncope of psychological origin, which can be likened to a hysterical conversion. In this neurosis, the loss of consciousness most often occurs in the presence of other people and is rarely accompanied by a real fall. The clinical examination does not find any physical anomaly that can explain this discomfort.
The syncope is different from the lipothymia in which the loss of consciousness is not total (dizziness, visual blur or black veil in front of the eyes).
Syncope is also not an epileptic seizure because it is not accompanied by convulsion, loss of urine or bite of the tongue.
Syncope should not be confused with hypoglycaemia where loss of consciousness is associated with a drop in glucose in the blood. Neither with a stroke that is accompanied by neurological damage.