The condition characterized by feeling of being lightheaded and of fainting but does not actually lose consciousness, and is commonly caused by a temporary reduction in the flow of oxygenated blood to the brain
Presyncope is the period prior to the actual syncope or fainting. Individuals who are in a presynscope state feel an impending faint. Common signs include dizziness or lightheadedness, temporary loss of sensation or pain, blurry or narrowed vision (Tunnel vision), temporary tinnitus, feeling sick (nausea), muscular weakness, rapid and heavy heartbeat (heart palpitations), general abdominal discomfort, disorientation, and sweating. Presyncope occurs as a result of diffuse cerebral ischemia, which may be related to cardiac, vascular, or autonomic factors and/or diseases. Presyncope occurs in general due to an abrupt drop in blood pressure (orthostatic hypotension). Possible causes of orthostatic hypotension in individuals leading to presyncope include emotional distress, high stress, or anxieties. 1 Other possible causes of presyncope are migraine and disorders such as postural tachycardia syndrome. Presyncope episode may also be associated with menstrual period, which may be brought on by hormonal changes.
Word origin: pre- (before) + Latin syncope, from Greek synkopḗ (a cutting short)
1 Reeves, Alexander G; Rand S. Swenson. "Chapter 14: Evaluation of the Dizzy Patient" . Disorders of the nervous system: a primer. Dartmouth Medical School.