Syncope: Difference between revisions
No edit summary |
No edit summary |
||
| Line 1: | Line 1: | ||
__NOTOC__ | __NOTOC__ | ||
'''For patient information click [[{{PAGENAME}} (patient information)|here]]''' | '''For patient information click [[{{PAGENAME}} (patient information)|here]]''' | ||
{{ | {{Syncope}} | ||
{{CMG}} Fainting | |||
{{CMG}} | |||
==Overview== | ==Overview== | ||
Syncope''' ([[International Phonetic Alphabet|IPA]]: {{IPA|[ˈsɪnkəpi]}} and {{IPA|[ˈsɪŋkəpi]}}), is a sudden, and generally momentary, loss of [[consciousness]], or blacking out caused by the [[Central Ischaemic Response]], because of a lack of sufficient blood and oxygen in the brain. The first symptoms a person feels before fainting are [[dizziness]]; a dimming of vision, or [[brownout (medical)|brownout]]; [[tinnitus]]; and feeling hot. Moments later, the person's vision turns black, and he or she drops to the floor (or slumps if seated in a chair). If the person is unable to slump from the position to a near horizontal position, he or she risks dying of the [[Suspension trauma]] effect. More serious causes of fainting include cardiac ([[heart]]-related) causes such as an abnormal heart rhythm (an [[arrhythmia]]), where the heart beats too slowly, too rapidly or too irregularly to pump enough blood to the brain. Some arrhythmias can be life-threatening. Other important cardio-vascular conditions that can be manifested by syncope include [[subclavian steal syndrome]] and [[aortic stenosis]]. | |||
==Common Causes== | ==Common Causes== | ||
*[[Alcohol abuse]] | *[[Alcohol abuse]] | ||
Revision as of 14:18, 5 February 2013
For patient information click here
|
Syncope Microchapters |
|
Diagnosis |
|---|
|
Treatment |
|
Case Studies |
|
Syncope On the Web |
|
American Roentgen Ray Society Images of Syncope |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Fainting
Overview
Syncope (IPA: Template:IPA and Template:IPA), is a sudden, and generally momentary, loss of consciousness, or blacking out caused by the Central Ischaemic Response, because of a lack of sufficient blood and oxygen in the brain. The first symptoms a person feels before fainting are dizziness; a dimming of vision, or brownout; tinnitus; and feeling hot. Moments later, the person's vision turns black, and he or she drops to the floor (or slumps if seated in a chair). If the person is unable to slump from the position to a near horizontal position, he or she risks dying of the Suspension trauma effect. More serious causes of fainting include cardiac (heart-related) causes such as an abnormal heart rhythm (an arrhythmia), where the heart beats too slowly, too rapidly or too irregularly to pump enough blood to the brain. Some arrhythmias can be life-threatening. Other important cardio-vascular conditions that can be manifested by syncope include subclavian steal syndrome and aortic stenosis.
Common Causes
- Alcohol abuse
- Common fainting spell (vasovagal syncope)
- Dehydration due to a wide variety of causes including diarrhea and diuretics
- Drugs including opiates, anxiolytics, sedatives, barbiturates
- Hypoglycemia
- Hypotension
Complete Differential Diagnosis of Syncope
- Addison's Disease
- Adriamycin
- Alpha-blockers
- Alcohol
- Anemia
- Antiarrythmics
- Antihypertensives
- Anxiety
- Aortic Stenosis
- Aortic Dissection
- Arteriosclerosis of the carotid arteries
- Arteriosclerosis of cerebral vessels
- Arrhythmia
- Autonomic insufficiency
- Barbiturates
- Beta blockers
- Bradyarrhythmia
- Cardiac Tamponade
- Cardiomyopathy
- Carotid Sinus Hypersensitivity
- Cerebrovascular Disease
- Cough
- Cerebrovascular accident or stroke
- Defecation
- Dehydration
- Diarrhea
- Digitalis
- Diuretics
- Heart failure
- Hydralazine
- Hypoglycemia
- Hypoxia
- Hypovolemia
- Hyperbradykininemia
- Hypertensive encephalopathy
- Hypertrophic obstructive cardiomyopathy
- Hyperventilation
- Hysteria
- Methamphetamine
- Micturition
- Migrane
- Myocarditis
- Myocardial infarction
- Nitrates
- Opiates
- Orthostatic hypotension
- Pacemaker malfunction
- Phenothiazines
- Pulmonary embolism
- Reduced pulmonary artery flow
- Sedatives
- Seizures
- Sick sinus disease
- Situational syncope
- Somatization disorder
- Stokes-Adams attack
- Subclavian steal syndrome
- Sympathectomy
- Tacharrhythmia
- Takayasu's arteritis
- Transient ischemic attack
- Trauma
- Tricyclic antidepressants
- Vasovagal syncope
- Valsalva maneuver
- Valve thrombus
- Valvular disease
- Ventricular tachycardia
Types
Vasovagal (situational) syncope, one of the most common types, may occur in scary or embarrassing situations or during blood drawing, coughing, or urinating. Other types include postural syncope (caused by a changing in body posture), cardiac syncope (due to heart-related conditions), and neurological syncope (due to neurological conditions). There are many other causes of syncope including low blood sugar levels and lung disease such as emphysema and a pulmonary embolus. The cause of the fainting can be determined by a doctor using a complete history, physical, and various diagnostic tests.
Vasovagal syncope
The vasovagal type can be considered in two forms:
- Isolated episodes of loss of consciousness, unheralded by any warning symptoms for more than a few moments. These tend to occur in the adolescent age group, and may be associated with fasting, exercise, abdominal straining or circumstances promoting vaso-dilatation (eg heat, alcohol). The subject is invariably upright. The tilt-table test, if performed, is generally negative.
- Recurrent syncope with complex associated symptoms. This is so-called Neurally Mediated Syncope (NMS). It is associated with any of the following: preceding or succeeding sleepiness, preceding visual disturbance ("spots before the eyes"), sweating, light-headedness. The subject is usually but not always upright. The tilt-table test, if performed, is generally positive.
A pattern of background factors contributes to the attacks. There is typically an unsuspected relatively low blood volume, for instance, from taking a low salt diet in the absence of any salt-retaining tendency. Heat causes vaso-dilatation and worsens the effect of the relatively insufficient blood volume. That sets the scene, but the next stage is the adrenergic response. If there is underlying fear or anxiety (e.g. social circumstances), or acute fear (e.g. acute threat, needle phobia), the vaso-motor centre demands an increased pumping action by the heart (flight or fight response). This is set in motion via the adrenergic (sympathetic) outflow from the brain but the heart is unable to meet requirement because of the low blood volume, or decreased return. The high (ineffective) sympathetic activity is always modulated by vagal outflow, in these cases leading to excessive slowing of heart rate. The abnormality lies in this excessive vagal response. The tilt-table test typically evokes the attack.
Much of this pathway was discovered in animal experiments by Bezold (Vienna) in the 1860s. In animals, it may represent a defence mechanism when confronted by danger ("playing possum"). This reflex occurs in only some people and may be similar to that described in animals.
The mechanism described here suggests that a practical way to prevent attacks would be, counter-intuitively, to block the adrenergic signal with a Beta Blocker. But simpler plan is to explain the mechanism, discuss causes of fear, and optimise salt as well as water intake.
Pure cardiac syncope
Fainting can also occur if pressure on the carotid artery in the neck triggers a vagal signal to the Vaso-Motor Centre, reflexly causing a vagal response to slow the heart.
A pure cardiac arrhythmia is a serious matter that can appear as syncope but this is unusual. Severe narrowing of the Aortic Valve leading to syncope is included for completeness.
Syncope from vertebro-basilar arterial disease
Arterial disease in the upper spinal cord, or lower brain, causes syncope if there is a reduction in blood supply, which may occur with extending the neck or after drugs to lower blood pressure.
Clinical symptoms
If the patient states, "I felt dizzy with blurry vision, muscle weakness, during the fall I bumped my knee, hit my head and passed out," then it is not syncope, it is termed pre or near-syncope.
If the patient states, "I felt dizzy, shadows came over my eyes, and when I woke up I was lying on the floor," then it is diagnosed as syncope.
Patients who experience a syncoptic episode do not remember falling.
Diagnosis
ECG
EKG below is recorded in an elderly man with syncope
ACC/AHA/ESC 2006 Guidelines (DO NOT EDIT) [1]
Electrophysiological Testing in Patients With Syncope Recommendations
| Class I |
| "1 EP testing is recommended in patients with syncope of unknown cause with impaired LV function or structural heart disease. (Level of Evidence: B) " |
| Class IIa |
| "1 EP testing can be useful in patients with syncope when bradyarrhythmias or tachyarrhythmias are suspected and in whom noninvasive diagnostic studies are not conclusive. (Level of Evidence: B)" |
Treatment
Urgent Treatment
Recommended treatment is to allow the person to lie on the ground with his or her legs slightly elevated. As the dizziness and the momentary blindness passes, the person may experience visual disturbances in the form of small bright dots (phosphene). These will also pass within a few minutes.
After initial stabilization the treatment of syncope depends on the causes.
Cardiac syncope
- Arrthymia: For patient whose syncope is caused by bradycardia or heart block, a pacemaker may be considerd to solve the problems. An implantable cardioverter defibrillator (ICD) may help the patient with repeated ventricular tachycardia. Sometimes, antiarrhythmic drugs may be helpful for some patients. These treatments should be ordered by the cardiologists.
- Abnormal cardiovascular structure: For these kinds of patients, based on the diseases and patients' general stutas, the doctors may consider surgery to correct the abnormities and decrease the possibility of syncope.
Neurologic syncope
Vasovagal syncope
- Educating patients not to wear tight collars, not to cough with difficulty, to try to piss in a seated status.
- Avoiding wounded when falling
Orthostatic hypotension
- Be careful when changing positions from sitting to standing
Sources
Copyleft images obtained courtesy of ECGpedia, http://en.ecgpedia.org/index.php?title=Special:NewFiles&dir=prev&offset=20080806182927&limit=500
Related Chapters
- Orthostatic hypotension blackout after rising
- Shallow water blackout for the special case of fainting arising from hypocapnia
- Deep water blackout for the special case of fainting arising from latent hypoxia
External links
- 2004 European Society of Cardiology Guidelines on Management (Diagnosis and Treatment) of Syncope.
- http://www.syncope.us
- Dysautonomia Information Network
- Dysautonomia Youth Network of America, Inc.
- Dysautonomia Support Network Corp.
- Tilt table test
Template:Skin and subcutaneous tissue symptoms and signs Template:Nervous and musculoskeletal system symptoms and signs Template:Urinary system symptoms and signs Template:Cognition, perception, emotional state and behaviour symptoms and signs Template:Speech and voice symptoms and signs Template:General symptoms and signs
ca:Síncope de:Synkope (Medizin) gl:Síncope it:Sincope (medicina) nl:Syncope (medisch) fi:Pyörtyminen sv:Svimning uk:Синкопе wa:Sdårniyon yi:חלשות
- ↑ Zipes DP, Camm AJ, Borggrefe M, Buxton AE, Chaitman B, Fromer M; et al. (2006). "ACC/AHA/ESC 2006 Guidelines for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death: a report of the American College of Cardiology/American Heart Association Task Force and the European Society of Cardiology Committee for Practice Guidelines (writing committee to develop Guidelines for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death): developed in collaboration with the European Heart Rhythm Association and the Heart Rhythm Society". Circulation. 114 (10): e385–484. doi:10.1161/CIRCULATIONAHA.106.178233. PMID 16935995.