Fainting is a loss of consciousness that happens quickly and sometimes without warning. A fainting episode usually resolves within seconds to minutes. If fainting is caused by another condition, then the condition will need to be treated.
In general, fainting is caused by decreased blood flow to the brain.
Blood Flow to the Brain
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Decreased blood flow to the brain can be caused by:
Most commonly, vasovagal spells. Vasovagal spells can occur:
Fainting can also occur as a side effect to medications. These include:
Symptoms may include:
Call your doctor if you are having episodes of fainting. This is especially important if you:
Call for medical help or go to the emergency room right away if you have:
Your doctor will ask about your symptoms and medical history. A physical exam will be done.
Tests may include:
Treatment will depend on the underlying condition that has caused fainting. This may include medications, lifestyle changes, or surgery.
If you are diagnosed as having fainted, follow your doctor's instructions.
If you are prone to fainting:
There are certain physical maneuvers that rapidly raise blood pressure and blood flow to the brain. They are called physical counterpressure maneuvers. When these are done during warning signs, you may be able to prevent fainting. Examples include:
American Academy of Family Physicians
American Heart Association
Benditt D, Goldstein M. Fainting. American Heart Association, Circulation website. Available at: http://circ.ahajournals.org/content/106/9/1048.full . Published 2002. Accessed April 25, 2013.
Chen LY, Benditt DG, et al. Management of syncope in adults: an update. Mayo Clin Proc . 2008;83(11):1280-1293.
Fainting. American Academy of Family Physicians Family Doctor website. Available at: http://familydocto... . Updated July 2010. Accessed April 25, 2013.
Miller TH, Kruse JE. Evaluation of syncope. Am Fam Physician . 2005;72(8):1492-1500.
Syncope evaluation. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed/what.php . Updated March 5, 2013. Accessed April 25, 2013.
2/6/2007 DynaMed's Systematic Literature Surveillance. Available at: http://dynamed.ebscohost.com/about/about-us : van Dijk N, Quartieri F, Blanc JJ, et al. Effectiveness of physical counterpressure maneuvers in preventing vasovagal syncope: the Physical Counterpressure Manoeuvres Trial (PC-Trial). J Am Coll Cardiol . 2006;48(8):1652-1657.
Last reviewed April 2013
Last Updated: 3/18/2013