The Orthostatic Intolerance (OI) Center
The Basic Faint
AKA Reflex Syncope, Neurally-Mediated Syncope (NMS)
There are a number of medical names to describe the type of faint a person has.
In the overview on Fainting, 3 main causes of fainting (syncope) were identified - heart (cardiac), fainting caused by the communication between the nervous system (neurally-mediated) and the heart-blood vessel system (cardiovascular) and damage to the nervous system, with orthostatic hypotension (low BP)(OH).
We will talk about the neurally-mediated faint - the "common faint".1-4 There are different kinds of neurally-mediated syncope. The most common type is Reflex Syncope.
Reflex Syncope - Fainting
Reflex Syncope is basically fainting after a trigger or event. It is a "reflex" to something that has happened. Reflex syncope is a common type of fainting. It is the diagnosis in 66% of the cases of fainting.3 (If there were 100 people who were fainting, 66 would have reflex syncope). There are 3 major types of Reflex Syncope. (Author's Note: This is not meant to be a complete discussion and list of all causes of fainting. We are only talking about the basic ones.)
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This is the "common faint". It would be the diagnosis if
There are "precipitating" events. A "precipitating" event means that something happens and that triggers the faint. <br/> Precipitating events include
• Fear
• Severe pain, such as pain from injury like a broken bone
• Emotional distress
• Sight of blood, a gory scene
• Medical instrumentation
• Prolonged standing are associated with typical prodromal (warning) symptoms.
It usually happens in younger people.
It occurs in 3 phases:
• First, there is a feeling of light-headedness, nausea and diaphoresis or vision changes
• This is followed by loss of consciousness, and usually a fall to the ground.
• The last phase is recovery. Recovery is rapid, within seconds-few minutes.
No postictal state - there is no long period of mental confusion afterward like there is after a seizure..
It often happens when standing or walking.
Some patients, especially older people, are not aware of any warning symptoms before they faint.
In between fainting episodes, the person doesn’t have orthostatic or autonomic symptoms.
This means there is a "situation" that comes before the faint. These are the types of triggers that would make the faint called a "situational syncope":
• Coughing
• Sneeze
• Laugh
• GI stimulation – swallow, defecation (having a bowel movement),visceral pain
(pain from the internal organs like the stomach and intestines)
• Micturition - or post-micturition (urinating)
• Post-exercise (Syncope is an early sign of Autonomic Nerve Failure before it develops into OH)
• After eating (Post-prandial)
• Others – brass instrument playing, weight-lifting.
This happens when you turn head or put pressure on carotid artery in the neck.
Managing Vasovagal Syncope
If a person continues to have fainting episodes, they might need guidance on how they might improve their situation. Specifically, how they might cut down the number that occur or "head them off" when they feel a faint is coming. Some of the management information provided for POTS and OH has been tried for people with fainting episodes. 4
- Countermeasures - like leg crossing and hand grips/arm tensing have been found to help prevent a faint when the warning signs start.6.7 Go to Tricks to avoid getting dizzy to learn more.
- Tilt-training4, 5. This is a "retraining" approach to decrease how often a person faints. It was first described in 1998, It involves standing up leaning against the wall for 30 minutes each day. It has had limited success. It needs to be continued for at least 6 months to be successful and then continued after that. Most patients do not continue to do it for that long. Sign Up to be notified when we post more on Tilt-training.
- Medications - Medications have not been successful in the long run to reduce how often a person faints when it is reflex syncope4.
Syncope (Fainting) Due to Orthostatic Hypotension (Drop in Blood Pressure)
A faint can also be due to orthostatic hypotension (drop in blood pressure when the person stands up). Fainting will happen when the pulse slows down at the same time that the blood pressure goes down. It can happen early in the course of autonomic failure. To learn more, go to Orthostatic Hypotension (OH).
References
- Wedro, Benjamin, Stoppler, Mellissa. Orthostatic hypotension. Last accessed: June 24, 2012. Article
- Medow MS, Stewart JM, Sanyal S, Mumtaz A, Stca D and Frishman WH. Pathophysiology, Diagnosis, and Treatment of Orthostatic Hypotension and Vasovagal Syncope. Cardiology in Review 2008;16(1):4-20. Abstract
- Moya Guidelines for the diagnosis and management of syncope (version 2009). European Heart Journal (2009); 30: 2631-2671.
- Brignole, M. The syndromes of orthostatic intolerance. E-journal of Cardiology Practice. 2007: 6(5). Access. http://www.escardio.org/communities/councils/ccp/e-journal/volume6/Pages/vol6n5.aspx
- Ector H, Reybrouck T, Heidbuchel H, et al. Tilt training: a new treatment for recurrent neurocardiogenic syncope or severe orthostatic intolerance. Pacing Clin Electrophysiol 1998;21:193–6. as cited in Brignole 2002.
- Brignole M, Croci F, Menozzi C, et al. Isometric arm counter-pressure maneuvers to abort impending vasovagal syncope. J Am Coll Cardiol 2002;40:2054–60.
- Krediet P, van Dijk N, Linzer M, et al. Management of vasovagal syncope:controlling or aborting faints by leg crossing and muscle tensing. Circulation 2002;106:1684–9.
Author: Kay E. Jewell, MD
Page Last Updated: June 24, 2012
