Fainting or syncope is the sudden loss of consciousness most often caused by a temporary decrease in oxygen and blood flow to the brain.1 Fainting may arise on a neurological, cardiac (structural heart disease) or neurovascular background.2 Most of the time, fainting, particularly in children is not due to a life-threatening or serious cause. It may be provoked by fear, pain, heat stress or low blood sugar (hypoglycemia). Although fainting can be of no medical significance, it must be treated as a medical emergency until the signs and symptoms are relieved and the cause is known.
Heart conditions that can cause fainting include abnormalities of the heart valves, increased blood pressure in the arteries supplying blood to the lungs (pulmonary artery hypertension) and disease of the heart muscle. The noncardiac causes include postural hypotension, stress and emotional upset, dehydration, use of blood pressure medications, diseases of the nerves to the legs or diabetes. Fainting is also seen after situational events such as after urination, defecation or coughing (vasovagal syncope). Most often, fainting may be accompanied by impending syncopal symptoms such as light-headedness, nausea, sweating, weakness and visual disturbances.3
Syncope is more common in older persons than in any other age group. Age-related physiologic changes, a higher prevalence of chronic illness and concomitant intake of multiple medication account for a higher susceptibility of elderly patients to syncope.4 Recovery from fainting is usually followed by almost immediate return of appropriate behavior and orientation. Sometimes the post-recovery period may be marked by fatigue.3
When someone faints:
1.Kapoor WN. Syncope. N Engl J Med. 2000; 343(25): 1856–1862.
2.Mehlsen J, Mehlsen AB. Diagnosis and treatment of syncope. Ugeskr Laeger. 2008; 170(9): 718–723. Danish.
3.Brignole M, Alboni P, Benditt DG, Bergfeldt L, Blanc JJ, Bloch Thomsen PE, et al. Task Force on Syncope, European Society of Cardiology. Guidelines on management (diagnosis and treatment) of syncope--update 2004. Europace. 2004; 6(6): 467–537.
4.Geller JC, Reek S, Klein HU. Syncope in the elderly. Dtsch Med Wochenschr. 2005; 130(12): 717–720 (Article in German).
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